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4158 lines
106 KiB
4158 lines
106 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Shared application/kernel submission and completion ring pairs, for |
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* supporting fast/efficient IO. |
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* |
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* A note on the read/write ordering memory barriers that are matched between |
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* the application and kernel side. |
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* |
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* After the application reads the CQ ring tail, it must use an |
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* appropriate smp_rmb() to pair with the smp_wmb() the kernel uses |
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* before writing the tail (using smp_load_acquire to read the tail will |
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* do). It also needs a smp_mb() before updating CQ head (ordering the |
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* entry load(s) with the head store), pairing with an implicit barrier |
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* through a control-dependency in io_get_cqe (smp_store_release to |
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* store head will do). Failure to do so could lead to reading invalid |
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* CQ entries. |
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* |
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* Likewise, the application must use an appropriate smp_wmb() before |
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* writing the SQ tail (ordering SQ entry stores with the tail store), |
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* which pairs with smp_load_acquire in io_get_sqring (smp_store_release |
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* to store the tail will do). And it needs a barrier ordering the SQ |
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* head load before writing new SQ entries (smp_load_acquire to read |
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* head will do). |
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* |
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* When using the SQ poll thread (IORING_SETUP_SQPOLL), the application |
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* needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after* |
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* updating the SQ tail; a full memory barrier smp_mb() is needed |
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* between. |
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* |
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* Also see the examples in the liburing library: |
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* |
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* git://git.kernel.dk/liburing |
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* |
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* io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens |
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* from data shared between the kernel and application. This is done both |
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* for ordering purposes, but also to ensure that once a value is loaded from |
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* data that the application could potentially modify, it remains stable. |
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* |
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* Copyright (C) 2018-2019 Jens Axboe |
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* Copyright (c) 2018-2019 Christoph Hellwig |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/init.h> |
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#include <linux/errno.h> |
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#include <linux/syscalls.h> |
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#include <net/compat.h> |
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#include <linux/refcount.h> |
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#include <linux/uio.h> |
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#include <linux/bits.h> |
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|
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#include <linux/sched/signal.h> |
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#include <linux/fs.h> |
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#include <linux/file.h> |
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#include <linux/fdtable.h> |
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#include <linux/mm.h> |
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#include <linux/mman.h> |
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#include <linux/percpu.h> |
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#include <linux/slab.h> |
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#include <linux/bvec.h> |
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#include <linux/net.h> |
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#include <net/sock.h> |
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#include <net/af_unix.h> |
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#include <net/scm.h> |
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#include <linux/anon_inodes.h> |
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#include <linux/sched/mm.h> |
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#include <linux/uaccess.h> |
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#include <linux/nospec.h> |
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#include <linux/highmem.h> |
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#include <linux/fsnotify.h> |
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#include <linux/fadvise.h> |
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#include <linux/task_work.h> |
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#include <linux/io_uring.h> |
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#include <linux/audit.h> |
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#include <linux/security.h> |
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|
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#define CREATE_TRACE_POINTS |
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#include <trace/events/io_uring.h> |
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|
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#include <uapi/linux/io_uring.h> |
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|
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#include "io-wq.h" |
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|
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#include "io_uring.h" |
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#include "opdef.h" |
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#include "refs.h" |
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#include "tctx.h" |
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#include "sqpoll.h" |
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#include "fdinfo.h" |
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#include "kbuf.h" |
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#include "rsrc.h" |
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#include "cancel.h" |
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#include "net.h" |
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#include "notif.h" |
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|
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#include "timeout.h" |
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#include "poll.h" |
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#include "alloc_cache.h" |
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|
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#define IORING_MAX_ENTRIES 32768 |
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#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES) |
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|
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#define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \ |
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IORING_REGISTER_LAST + IORING_OP_LAST) |
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|
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#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \ |
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IOSQE_IO_HARDLINK | IOSQE_ASYNC) |
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|
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#define SQE_VALID_FLAGS (SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \ |
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IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS) |
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|
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#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \ |
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REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \ |
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REQ_F_ASYNC_DATA) |
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|
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#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\ |
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IO_REQ_CLEAN_FLAGS) |
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|
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#define IO_TCTX_REFS_CACHE_NR (1U << 10) |
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|
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#define IO_COMPL_BATCH 32 |
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#define IO_REQ_ALLOC_BATCH 8 |
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|
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enum { |
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IO_CHECK_CQ_OVERFLOW_BIT, |
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IO_CHECK_CQ_DROPPED_BIT, |
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}; |
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|
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enum { |
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IO_EVENTFD_OP_SIGNAL_BIT, |
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IO_EVENTFD_OP_FREE_BIT, |
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}; |
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|
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struct io_defer_entry { |
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struct list_head list; |
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struct io_kiocb *req; |
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u32 seq; |
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}; |
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|
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/* requests with any of those set should undergo io_disarm_next() */ |
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#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL) |
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#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK) |
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|
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static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx, |
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struct task_struct *task, |
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bool cancel_all); |
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|
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static void io_dismantle_req(struct io_kiocb *req); |
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static void io_clean_op(struct io_kiocb *req); |
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static void io_queue_sqe(struct io_kiocb *req); |
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static void io_move_task_work_from_local(struct io_ring_ctx *ctx); |
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static void __io_submit_flush_completions(struct io_ring_ctx *ctx); |
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|
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static struct kmem_cache *req_cachep; |
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|
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struct sock *io_uring_get_socket(struct file *file) |
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{ |
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#if defined(CONFIG_UNIX) |
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if (io_is_uring_fops(file)) { |
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struct io_ring_ctx *ctx = file->private_data; |
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|
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return ctx->ring_sock->sk; |
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} |
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#endif |
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return NULL; |
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} |
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EXPORT_SYMBOL(io_uring_get_socket); |
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|
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static inline void io_submit_flush_completions(struct io_ring_ctx *ctx) |
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{ |
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if (!wq_list_empty(&ctx->submit_state.compl_reqs)) |
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__io_submit_flush_completions(ctx); |
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} |
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|
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static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx) |
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{ |
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return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head); |
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} |
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|
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static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx) |
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{ |
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return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head); |
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} |
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|
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static bool io_match_linked(struct io_kiocb *head) |
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{ |
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struct io_kiocb *req; |
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|
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io_for_each_link(req, head) { |
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if (req->flags & REQ_F_INFLIGHT) |
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return true; |
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} |
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return false; |
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} |
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|
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/* |
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* As io_match_task() but protected against racing with linked timeouts. |
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* User must not hold timeout_lock. |
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*/ |
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bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task, |
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bool cancel_all) |
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{ |
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bool matched; |
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|
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if (task && head->task != task) |
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return false; |
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if (cancel_all) |
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return true; |
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|
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if (head->flags & REQ_F_LINK_TIMEOUT) { |
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struct io_ring_ctx *ctx = head->ctx; |
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|
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/* protect against races with linked timeouts */ |
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spin_lock_irq(&ctx->timeout_lock); |
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matched = io_match_linked(head); |
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spin_unlock_irq(&ctx->timeout_lock); |
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} else { |
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matched = io_match_linked(head); |
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} |
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return matched; |
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} |
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|
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static inline void req_fail_link_node(struct io_kiocb *req, int res) |
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{ |
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req_set_fail(req); |
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io_req_set_res(req, res, 0); |
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} |
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|
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static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx) |
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{ |
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wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list); |
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} |
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|
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static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref) |
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{ |
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struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs); |
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|
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complete(&ctx->ref_comp); |
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} |
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|
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static __cold void io_fallback_req_func(struct work_struct *work) |
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{ |
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struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, |
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fallback_work.work); |
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struct llist_node *node = llist_del_all(&ctx->fallback_llist); |
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struct io_kiocb *req, *tmp; |
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bool locked = false; |
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percpu_ref_get(&ctx->refs); |
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llist_for_each_entry_safe(req, tmp, node, io_task_work.node) |
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req->io_task_work.func(req, &locked); |
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|
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if (locked) { |
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io_submit_flush_completions(ctx); |
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mutex_unlock(&ctx->uring_lock); |
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} |
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percpu_ref_put(&ctx->refs); |
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} |
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|
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static int io_alloc_hash_table(struct io_hash_table *table, unsigned bits) |
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{ |
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unsigned hash_buckets = 1U << bits; |
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size_t hash_size = hash_buckets * sizeof(table->hbs[0]); |
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|
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table->hbs = kmalloc(hash_size, GFP_KERNEL); |
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if (!table->hbs) |
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return -ENOMEM; |
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table->hash_bits = bits; |
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init_hash_table(table, hash_buckets); |
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return 0; |
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} |
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static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) |
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{ |
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struct io_ring_ctx *ctx; |
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int hash_bits; |
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|
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ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); |
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if (!ctx) |
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return NULL; |
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xa_init(&ctx->io_bl_xa); |
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/* |
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* Use 5 bits less than the max cq entries, that should give us around |
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* 32 entries per hash list if totally full and uniformly spread, but |
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* don't keep too many buckets to not overconsume memory. |
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*/ |
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hash_bits = ilog2(p->cq_entries) - 5; |
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hash_bits = clamp(hash_bits, 1, 8); |
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if (io_alloc_hash_table(&ctx->cancel_table, hash_bits)) |
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goto err; |
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if (io_alloc_hash_table(&ctx->cancel_table_locked, hash_bits)) |
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goto err; |
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ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL); |
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if (!ctx->dummy_ubuf) |
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goto err; |
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/* set invalid range, so io_import_fixed() fails meeting it */ |
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ctx->dummy_ubuf->ubuf = -1UL; |
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|
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if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, |
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0, GFP_KERNEL)) |
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goto err; |
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ctx->flags = p->flags; |
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init_waitqueue_head(&ctx->sqo_sq_wait); |
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INIT_LIST_HEAD(&ctx->sqd_list); |
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INIT_LIST_HEAD(&ctx->cq_overflow_list); |
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INIT_LIST_HEAD(&ctx->io_buffers_cache); |
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io_alloc_cache_init(&ctx->apoll_cache); |
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io_alloc_cache_init(&ctx->netmsg_cache); |
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init_completion(&ctx->ref_comp); |
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xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1); |
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mutex_init(&ctx->uring_lock); |
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init_waitqueue_head(&ctx->cq_wait); |
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spin_lock_init(&ctx->completion_lock); |
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spin_lock_init(&ctx->timeout_lock); |
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INIT_WQ_LIST(&ctx->iopoll_list); |
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INIT_LIST_HEAD(&ctx->io_buffers_pages); |
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INIT_LIST_HEAD(&ctx->io_buffers_comp); |
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INIT_LIST_HEAD(&ctx->defer_list); |
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INIT_LIST_HEAD(&ctx->timeout_list); |
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INIT_LIST_HEAD(&ctx->ltimeout_list); |
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spin_lock_init(&ctx->rsrc_ref_lock); |
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INIT_LIST_HEAD(&ctx->rsrc_ref_list); |
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INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work); |
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init_llist_head(&ctx->rsrc_put_llist); |
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init_llist_head(&ctx->work_llist); |
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INIT_LIST_HEAD(&ctx->tctx_list); |
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ctx->submit_state.free_list.next = NULL; |
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INIT_WQ_LIST(&ctx->locked_free_list); |
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INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func); |
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INIT_WQ_LIST(&ctx->submit_state.compl_reqs); |
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return ctx; |
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err: |
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kfree(ctx->dummy_ubuf); |
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kfree(ctx->cancel_table.hbs); |
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kfree(ctx->cancel_table_locked.hbs); |
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kfree(ctx->io_bl); |
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xa_destroy(&ctx->io_bl_xa); |
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kfree(ctx); |
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return NULL; |
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} |
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|
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static void io_account_cq_overflow(struct io_ring_ctx *ctx) |
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{ |
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struct io_rings *r = ctx->rings; |
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|
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WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1); |
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ctx->cq_extra--; |
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} |
|
|
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static bool req_need_defer(struct io_kiocb *req, u32 seq) |
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{ |
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if (unlikely(req->flags & REQ_F_IO_DRAIN)) { |
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struct io_ring_ctx *ctx = req->ctx; |
|
|
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return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail; |
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} |
|
|
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return false; |
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} |
|
|
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static inline void io_req_track_inflight(struct io_kiocb *req) |
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{ |
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if (!(req->flags & REQ_F_INFLIGHT)) { |
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req->flags |= REQ_F_INFLIGHT; |
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atomic_inc(&req->task->io_uring->inflight_tracked); |
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} |
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} |
|
|
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static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req) |
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{ |
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if (WARN_ON_ONCE(!req->link)) |
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return NULL; |
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|
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req->flags &= ~REQ_F_ARM_LTIMEOUT; |
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req->flags |= REQ_F_LINK_TIMEOUT; |
|
|
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/* linked timeouts should have two refs once prep'ed */ |
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io_req_set_refcount(req); |
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__io_req_set_refcount(req->link, 2); |
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return req->link; |
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} |
|
|
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static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req) |
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{ |
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if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT))) |
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return NULL; |
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return __io_prep_linked_timeout(req); |
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} |
|
|
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static noinline void __io_arm_ltimeout(struct io_kiocb *req) |
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{ |
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io_queue_linked_timeout(__io_prep_linked_timeout(req)); |
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} |
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|
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static inline void io_arm_ltimeout(struct io_kiocb *req) |
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{ |
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if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT)) |
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__io_arm_ltimeout(req); |
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} |
|
|
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static void io_prep_async_work(struct io_kiocb *req) |
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{ |
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const struct io_op_def *def = &io_op_defs[req->opcode]; |
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struct io_ring_ctx *ctx = req->ctx; |
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|
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if (!(req->flags & REQ_F_CREDS)) { |
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req->flags |= REQ_F_CREDS; |
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req->creds = get_current_cred(); |
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} |
|
|
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req->work.list.next = NULL; |
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req->work.flags = 0; |
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req->work.cancel_seq = atomic_read(&ctx->cancel_seq); |
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if (req->flags & REQ_F_FORCE_ASYNC) |
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req->work.flags |= IO_WQ_WORK_CONCURRENT; |
|
|
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if (req->file && !io_req_ffs_set(req)) |
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req->flags |= io_file_get_flags(req->file) << REQ_F_SUPPORT_NOWAIT_BIT; |
|
|
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if (req->flags & REQ_F_ISREG) { |
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if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL)) |
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io_wq_hash_work(&req->work, file_inode(req->file)); |
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} else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) { |
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if (def->unbound_nonreg_file) |
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req->work.flags |= IO_WQ_WORK_UNBOUND; |
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} |
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} |
|
|
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static void io_prep_async_link(struct io_kiocb *req) |
|
{ |
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struct io_kiocb *cur; |
|
|
|
if (req->flags & REQ_F_LINK_TIMEOUT) { |
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struct io_ring_ctx *ctx = req->ctx; |
|
|
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spin_lock_irq(&ctx->timeout_lock); |
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io_for_each_link(cur, req) |
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io_prep_async_work(cur); |
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spin_unlock_irq(&ctx->timeout_lock); |
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} else { |
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io_for_each_link(cur, req) |
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io_prep_async_work(cur); |
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} |
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} |
|
|
|
void io_queue_iowq(struct io_kiocb *req, bool *dont_use) |
|
{ |
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struct io_kiocb *link = io_prep_linked_timeout(req); |
|
struct io_uring_task *tctx = req->task->io_uring; |
|
|
|
BUG_ON(!tctx); |
|
BUG_ON(!tctx->io_wq); |
|
|
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/* init ->work of the whole link before punting */ |
|
io_prep_async_link(req); |
|
|
|
/* |
|
* Not expected to happen, but if we do have a bug where this _can_ |
|
* happen, catch it here and ensure the request is marked as |
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* canceled. That will make io-wq go through the usual work cancel |
|
* procedure rather than attempt to run this request (or create a new |
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* worker for it). |
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*/ |
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if (WARN_ON_ONCE(!same_thread_group(req->task, current))) |
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req->work.flags |= IO_WQ_WORK_CANCEL; |
|
|
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trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work)); |
|
io_wq_enqueue(tctx->io_wq, &req->work); |
|
if (link) |
|
io_queue_linked_timeout(link); |
|
} |
|
|
|
static __cold void io_queue_deferred(struct io_ring_ctx *ctx) |
|
{ |
|
while (!list_empty(&ctx->defer_list)) { |
|
struct io_defer_entry *de = list_first_entry(&ctx->defer_list, |
|
struct io_defer_entry, list); |
|
|
|
if (req_need_defer(de->req, de->seq)) |
|
break; |
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list_del_init(&de->list); |
|
io_req_task_queue(de->req); |
|
kfree(de); |
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} |
|
} |
|
|
|
|
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static void io_eventfd_ops(struct rcu_head *rcu) |
|
{ |
|
struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu); |
|
int ops = atomic_xchg(&ev_fd->ops, 0); |
|
|
|
if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT)) |
|
eventfd_signal(ev_fd->cq_ev_fd, 1); |
|
|
|
/* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback |
|
* ordering in a race but if references are 0 we know we have to free |
|
* it regardless. |
|
*/ |
|
if (atomic_dec_and_test(&ev_fd->refs)) { |
|
eventfd_ctx_put(ev_fd->cq_ev_fd); |
|
kfree(ev_fd); |
|
} |
|
} |
|
|
|
static void io_eventfd_signal(struct io_ring_ctx *ctx) |
|
{ |
|
struct io_ev_fd *ev_fd = NULL; |
|
|
|
rcu_read_lock(); |
|
/* |
|
* rcu_dereference ctx->io_ev_fd once and use it for both for checking |
|
* and eventfd_signal |
|
*/ |
|
ev_fd = rcu_dereference(ctx->io_ev_fd); |
|
|
|
/* |
|
* Check again if ev_fd exists incase an io_eventfd_unregister call |
|
* completed between the NULL check of ctx->io_ev_fd at the start of |
|
* the function and rcu_read_lock. |
|
*/ |
|
if (unlikely(!ev_fd)) |
|
goto out; |
|
if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED) |
|
goto out; |
|
if (ev_fd->eventfd_async && !io_wq_current_is_worker()) |
|
goto out; |
|
|
|
if (likely(eventfd_signal_allowed())) { |
|
eventfd_signal(ev_fd->cq_ev_fd, 1); |
|
} else { |
|
atomic_inc(&ev_fd->refs); |
|
if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops)) |
|
call_rcu(&ev_fd->rcu, io_eventfd_ops); |
|
else |
|
atomic_dec(&ev_fd->refs); |
|
} |
|
|
|
out: |
|
rcu_read_unlock(); |
|
} |
|
|
|
static void io_eventfd_flush_signal(struct io_ring_ctx *ctx) |
|
{ |
|
bool skip; |
|
|
|
spin_lock(&ctx->completion_lock); |
|
|
|
/* |
|
* Eventfd should only get triggered when at least one event has been |
|
* posted. Some applications rely on the eventfd notification count |
|
* only changing IFF a new CQE has been added to the CQ ring. There's |
|
* no depedency on 1:1 relationship between how many times this |
|
* function is called (and hence the eventfd count) and number of CQEs |
|
* posted to the CQ ring. |
|
*/ |
|
skip = ctx->cached_cq_tail == ctx->evfd_last_cq_tail; |
|
ctx->evfd_last_cq_tail = ctx->cached_cq_tail; |
|
spin_unlock(&ctx->completion_lock); |
|
if (skip) |
|
return; |
|
|
|
io_eventfd_signal(ctx); |
|
} |
|
|
|
void __io_commit_cqring_flush(struct io_ring_ctx *ctx) |
|
{ |
|
if (ctx->off_timeout_used || ctx->drain_active) { |
|
spin_lock(&ctx->completion_lock); |
|
if (ctx->off_timeout_used) |
|
io_flush_timeouts(ctx); |
|
if (ctx->drain_active) |
|
io_queue_deferred(ctx); |
|
spin_unlock(&ctx->completion_lock); |
|
} |
|
if (ctx->has_evfd) |
|
io_eventfd_flush_signal(ctx); |
|
} |
|
|
|
static inline void io_cqring_ev_posted(struct io_ring_ctx *ctx) |
|
{ |
|
io_commit_cqring_flush(ctx); |
|
io_cqring_wake(ctx); |
|
} |
|
|
|
static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx) |
|
__releases(ctx->completion_lock) |
|
{ |
|
io_commit_cqring(ctx); |
|
spin_unlock(&ctx->completion_lock); |
|
io_cqring_ev_posted(ctx); |
|
} |
|
|
|
void io_cq_unlock_post(struct io_ring_ctx *ctx) |
|
{ |
|
__io_cq_unlock_post(ctx); |
|
} |
|
|
|
/* Returns true if there are no backlogged entries after the flush */ |
|
static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force) |
|
{ |
|
bool all_flushed; |
|
size_t cqe_size = sizeof(struct io_uring_cqe); |
|
|
|
if (!force && __io_cqring_events(ctx) == ctx->cq_entries) |
|
return false; |
|
|
|
if (ctx->flags & IORING_SETUP_CQE32) |
|
cqe_size <<= 1; |
|
|
|
io_cq_lock(ctx); |
|
while (!list_empty(&ctx->cq_overflow_list)) { |
|
struct io_uring_cqe *cqe = io_get_cqe_overflow(ctx, true); |
|
struct io_overflow_cqe *ocqe; |
|
|
|
if (!cqe && !force) |
|
break; |
|
ocqe = list_first_entry(&ctx->cq_overflow_list, |
|
struct io_overflow_cqe, list); |
|
if (cqe) |
|
memcpy(cqe, &ocqe->cqe, cqe_size); |
|
else |
|
io_account_cq_overflow(ctx); |
|
|
|
list_del(&ocqe->list); |
|
kfree(ocqe); |
|
} |
|
|
|
all_flushed = list_empty(&ctx->cq_overflow_list); |
|
if (all_flushed) { |
|
clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq); |
|
atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags); |
|
} |
|
|
|
io_cq_unlock_post(ctx); |
|
return all_flushed; |
|
} |
|
|
|
static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx) |
|
{ |
|
bool ret = true; |
|
|
|
if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) { |
|
/* iopoll syncs against uring_lock, not completion_lock */ |
|
if (ctx->flags & IORING_SETUP_IOPOLL) |
|
mutex_lock(&ctx->uring_lock); |
|
ret = __io_cqring_overflow_flush(ctx, false); |
|
if (ctx->flags & IORING_SETUP_IOPOLL) |
|
mutex_unlock(&ctx->uring_lock); |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
void __io_put_task(struct task_struct *task, int nr) |
|
{ |
|
struct io_uring_task *tctx = task->io_uring; |
|
|
|
percpu_counter_sub(&tctx->inflight, nr); |
|
if (unlikely(atomic_read(&tctx->in_idle))) |
|
wake_up(&tctx->wait); |
|
put_task_struct_many(task, nr); |
|
} |
|
|
|
void io_task_refs_refill(struct io_uring_task *tctx) |
|
{ |
|
unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR; |
|
|
|
percpu_counter_add(&tctx->inflight, refill); |
|
refcount_add(refill, ¤t->usage); |
|
tctx->cached_refs += refill; |
|
} |
|
|
|
static __cold void io_uring_drop_tctx_refs(struct task_struct *task) |
|
{ |
|
struct io_uring_task *tctx = task->io_uring; |
|
unsigned int refs = tctx->cached_refs; |
|
|
|
if (refs) { |
|
tctx->cached_refs = 0; |
|
percpu_counter_sub(&tctx->inflight, refs); |
|
put_task_struct_many(task, refs); |
|
} |
|
} |
|
|
|
static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data, |
|
s32 res, u32 cflags, u64 extra1, u64 extra2) |
|
{ |
|
struct io_overflow_cqe *ocqe; |
|
size_t ocq_size = sizeof(struct io_overflow_cqe); |
|
bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32); |
|
|
|
if (is_cqe32) |
|
ocq_size += sizeof(struct io_uring_cqe); |
|
|
|
ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT); |
|
trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe); |
|
if (!ocqe) { |
|
/* |
|
* If we're in ring overflow flush mode, or in task cancel mode, |
|
* or cannot allocate an overflow entry, then we need to drop it |
|
* on the floor. |
|
*/ |
|
io_account_cq_overflow(ctx); |
|
set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq); |
|
return false; |
|
} |
|
if (list_empty(&ctx->cq_overflow_list)) { |
|
set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq); |
|
atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags); |
|
|
|
} |
|
ocqe->cqe.user_data = user_data; |
|
ocqe->cqe.res = res; |
|
ocqe->cqe.flags = cflags; |
|
if (is_cqe32) { |
|
ocqe->cqe.big_cqe[0] = extra1; |
|
ocqe->cqe.big_cqe[1] = extra2; |
|
} |
|
list_add_tail(&ocqe->list, &ctx->cq_overflow_list); |
|
return true; |
|
} |
|
|
|
bool io_req_cqe_overflow(struct io_kiocb *req) |
|
{ |
|
if (!(req->flags & REQ_F_CQE32_INIT)) { |
|
req->extra1 = 0; |
|
req->extra2 = 0; |
|
} |
|
return io_cqring_event_overflow(req->ctx, req->cqe.user_data, |
|
req->cqe.res, req->cqe.flags, |
|
req->extra1, req->extra2); |
|
} |
|
|
|
/* |
|
* writes to the cq entry need to come after reading head; the |
|
* control dependency is enough as we're using WRITE_ONCE to |
|
* fill the cq entry |
|
*/ |
|
struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx, bool overflow) |
|
{ |
|
struct io_rings *rings = ctx->rings; |
|
unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1); |
|
unsigned int free, queued, len; |
|
|
|
/* |
|
* Posting into the CQ when there are pending overflowed CQEs may break |
|
* ordering guarantees, which will affect links, F_MORE users and more. |
|
* Force overflow the completion. |
|
*/ |
|
if (!overflow && (ctx->check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))) |
|
return NULL; |
|
|
|
/* userspace may cheat modifying the tail, be safe and do min */ |
|
queued = min(__io_cqring_events(ctx), ctx->cq_entries); |
|
free = ctx->cq_entries - queued; |
|
/* we need a contiguous range, limit based on the current array offset */ |
|
len = min(free, ctx->cq_entries - off); |
|
if (!len) |
|
return NULL; |
|
|
|
if (ctx->flags & IORING_SETUP_CQE32) { |
|
off <<= 1; |
|
len <<= 1; |
|
} |
|
|
|
ctx->cqe_cached = &rings->cqes[off]; |
|
ctx->cqe_sentinel = ctx->cqe_cached + len; |
|
|
|
ctx->cached_cq_tail++; |
|
ctx->cqe_cached++; |
|
if (ctx->flags & IORING_SETUP_CQE32) |
|
ctx->cqe_cached++; |
|
return &rings->cqes[off]; |
|
} |
|
|
|
bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags, |
|
bool allow_overflow) |
|
{ |
|
struct io_uring_cqe *cqe; |
|
|
|
ctx->cq_extra++; |
|
|
|
/* |
|
* If we can't get a cq entry, userspace overflowed the |
|
* submission (by quite a lot). Increment the overflow count in |
|
* the ring. |
|
*/ |
|
cqe = io_get_cqe(ctx); |
|
if (likely(cqe)) { |
|
trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0); |
|
|
|
WRITE_ONCE(cqe->user_data, user_data); |
|
WRITE_ONCE(cqe->res, res); |
|
WRITE_ONCE(cqe->flags, cflags); |
|
|
|
if (ctx->flags & IORING_SETUP_CQE32) { |
|
WRITE_ONCE(cqe->big_cqe[0], 0); |
|
WRITE_ONCE(cqe->big_cqe[1], 0); |
|
} |
|
return true; |
|
} |
|
|
|
if (allow_overflow) |
|
return io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0); |
|
|
|
return false; |
|
} |
|
|
|
bool io_post_aux_cqe(struct io_ring_ctx *ctx, |
|
u64 user_data, s32 res, u32 cflags, |
|
bool allow_overflow) |
|
{ |
|
bool filled; |
|
|
|
io_cq_lock(ctx); |
|
filled = io_fill_cqe_aux(ctx, user_data, res, cflags, allow_overflow); |
|
io_cq_unlock_post(ctx); |
|
return filled; |
|
} |
|
|
|
static void __io_req_complete_put(struct io_kiocb *req) |
|
{ |
|
/* |
|
* If we're the last reference to this request, add to our locked |
|
* free_list cache. |
|
*/ |
|
if (req_ref_put_and_test(req)) { |
|
struct io_ring_ctx *ctx = req->ctx; |
|
|
|
if (req->flags & IO_REQ_LINK_FLAGS) { |
|
if (req->flags & IO_DISARM_MASK) |
|
io_disarm_next(req); |
|
if (req->link) { |
|
io_req_task_queue(req->link); |
|
req->link = NULL; |
|
} |
|
} |
|
io_req_put_rsrc(req); |
|
/* |
|
* Selected buffer deallocation in io_clean_op() assumes that |
|
* we don't hold ->completion_lock. Clean them here to avoid |
|
* deadlocks. |
|
*/ |
|
io_put_kbuf_comp(req); |
|
io_dismantle_req(req); |
|
io_put_task(req->task, 1); |
|
wq_list_add_head(&req->comp_list, &ctx->locked_free_list); |
|
ctx->locked_free_nr++; |
|
} |
|
} |
|
|
|
void __io_req_complete_post(struct io_kiocb *req) |
|
{ |
|
if (!(req->flags & REQ_F_CQE_SKIP)) |
|
__io_fill_cqe_req(req->ctx, req); |
|
__io_req_complete_put(req); |
|
} |
|
|
|
void io_req_complete_post(struct io_kiocb *req) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
|
|
io_cq_lock(ctx); |
|
__io_req_complete_post(req); |
|
io_cq_unlock_post(ctx); |
|
} |
|
|
|
inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags) |
|
{ |
|
io_req_complete_post(req); |
|
} |
|
|
|
void io_req_complete_failed(struct io_kiocb *req, s32 res) |
|
{ |
|
const struct io_op_def *def = &io_op_defs[req->opcode]; |
|
|
|
req_set_fail(req); |
|
io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED)); |
|
if (def->fail) |
|
def->fail(req); |
|
io_req_complete_post(req); |
|
} |
|
|
|
/* |
|
* Don't initialise the fields below on every allocation, but do that in |
|
* advance and keep them valid across allocations. |
|
*/ |
|
static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx) |
|
{ |
|
req->ctx = ctx; |
|
req->link = NULL; |
|
req->async_data = NULL; |
|
/* not necessary, but safer to zero */ |
|
req->cqe.res = 0; |
|
} |
|
|
|
static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx, |
|
struct io_submit_state *state) |
|
{ |
|
spin_lock(&ctx->completion_lock); |
|
wq_list_splice(&ctx->locked_free_list, &state->free_list); |
|
ctx->locked_free_nr = 0; |
|
spin_unlock(&ctx->completion_lock); |
|
} |
|
|
|
/* |
|
* A request might get retired back into the request caches even before opcode |
|
* handlers and io_issue_sqe() are done with it, e.g. inline completion path. |
|
* Because of that, io_alloc_req() should be called only under ->uring_lock |
|
* and with extra caution to not get a request that is still worked on. |
|
*/ |
|
__cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx) |
|
__must_hold(&ctx->uring_lock) |
|
{ |
|
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; |
|
void *reqs[IO_REQ_ALLOC_BATCH]; |
|
int ret, i; |
|
|
|
/* |
|
* If we have more than a batch's worth of requests in our IRQ side |
|
* locked cache, grab the lock and move them over to our submission |
|
* side cache. |
|
*/ |
|
if (data_race(ctx->locked_free_nr) > IO_COMPL_BATCH) { |
|
io_flush_cached_locked_reqs(ctx, &ctx->submit_state); |
|
if (!io_req_cache_empty(ctx)) |
|
return true; |
|
} |
|
|
|
ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs); |
|
|
|
/* |
|
* Bulk alloc is all-or-nothing. If we fail to get a batch, |
|
* retry single alloc to be on the safe side. |
|
*/ |
|
if (unlikely(ret <= 0)) { |
|
reqs[0] = kmem_cache_alloc(req_cachep, gfp); |
|
if (!reqs[0]) |
|
return false; |
|
ret = 1; |
|
} |
|
|
|
percpu_ref_get_many(&ctx->refs, ret); |
|
for (i = 0; i < ret; i++) { |
|
struct io_kiocb *req = reqs[i]; |
|
|
|
io_preinit_req(req, ctx); |
|
io_req_add_to_cache(req, ctx); |
|
} |
|
return true; |
|
} |
|
|
|
static inline void io_dismantle_req(struct io_kiocb *req) |
|
{ |
|
unsigned int flags = req->flags; |
|
|
|
if (unlikely(flags & IO_REQ_CLEAN_FLAGS)) |
|
io_clean_op(req); |
|
if (!(flags & REQ_F_FIXED_FILE)) |
|
io_put_file(req->file); |
|
} |
|
|
|
__cold void io_free_req(struct io_kiocb *req) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
|
|
io_req_put_rsrc(req); |
|
io_dismantle_req(req); |
|
io_put_task(req->task, 1); |
|
|
|
spin_lock(&ctx->completion_lock); |
|
wq_list_add_head(&req->comp_list, &ctx->locked_free_list); |
|
ctx->locked_free_nr++; |
|
spin_unlock(&ctx->completion_lock); |
|
} |
|
|
|
static void __io_req_find_next_prep(struct io_kiocb *req) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
|
|
io_cq_lock(ctx); |
|
io_disarm_next(req); |
|
io_cq_unlock_post(ctx); |
|
} |
|
|
|
static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req) |
|
{ |
|
struct io_kiocb *nxt; |
|
|
|
/* |
|
* If LINK is set, we have dependent requests in this chain. If we |
|
* didn't fail this request, queue the first one up, moving any other |
|
* dependencies to the next request. In case of failure, fail the rest |
|
* of the chain. |
|
*/ |
|
if (unlikely(req->flags & IO_DISARM_MASK)) |
|
__io_req_find_next_prep(req); |
|
nxt = req->link; |
|
req->link = NULL; |
|
return nxt; |
|
} |
|
|
|
static void ctx_flush_and_put(struct io_ring_ctx *ctx, bool *locked) |
|
{ |
|
if (!ctx) |
|
return; |
|
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG) |
|
atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags); |
|
if (*locked) { |
|
io_submit_flush_completions(ctx); |
|
mutex_unlock(&ctx->uring_lock); |
|
*locked = false; |
|
} |
|
percpu_ref_put(&ctx->refs); |
|
} |
|
|
|
static unsigned int handle_tw_list(struct llist_node *node, |
|
struct io_ring_ctx **ctx, bool *locked, |
|
struct llist_node *last) |
|
{ |
|
unsigned int count = 0; |
|
|
|
while (node != last) { |
|
struct llist_node *next = node->next; |
|
struct io_kiocb *req = container_of(node, struct io_kiocb, |
|
io_task_work.node); |
|
|
|
prefetch(container_of(next, struct io_kiocb, io_task_work.node)); |
|
|
|
if (req->ctx != *ctx) { |
|
ctx_flush_and_put(*ctx, locked); |
|
*ctx = req->ctx; |
|
/* if not contended, grab and improve batching */ |
|
*locked = mutex_trylock(&(*ctx)->uring_lock); |
|
percpu_ref_get(&(*ctx)->refs); |
|
} |
|
req->io_task_work.func(req, locked); |
|
node = next; |
|
count++; |
|
} |
|
|
|
return count; |
|
} |
|
|
|
/** |
|
* io_llist_xchg - swap all entries in a lock-less list |
|
* @head: the head of lock-less list to delete all entries |
|
* @new: new entry as the head of the list |
|
* |
|
* If list is empty, return NULL, otherwise, return the pointer to the first entry. |
|
* The order of entries returned is from the newest to the oldest added one. |
|
*/ |
|
static inline struct llist_node *io_llist_xchg(struct llist_head *head, |
|
struct llist_node *new) |
|
{ |
|
return xchg(&head->first, new); |
|
} |
|
|
|
/** |
|
* io_llist_cmpxchg - possibly swap all entries in a lock-less list |
|
* @head: the head of lock-less list to delete all entries |
|
* @old: expected old value of the first entry of the list |
|
* @new: new entry as the head of the list |
|
* |
|
* perform a cmpxchg on the first entry of the list. |
|
*/ |
|
|
|
static inline struct llist_node *io_llist_cmpxchg(struct llist_head *head, |
|
struct llist_node *old, |
|
struct llist_node *new) |
|
{ |
|
return cmpxchg(&head->first, old, new); |
|
} |
|
|
|
void tctx_task_work(struct callback_head *cb) |
|
{ |
|
bool uring_locked = false; |
|
struct io_ring_ctx *ctx = NULL; |
|
struct io_uring_task *tctx = container_of(cb, struct io_uring_task, |
|
task_work); |
|
struct llist_node fake = {}; |
|
struct llist_node *node = io_llist_xchg(&tctx->task_list, &fake); |
|
unsigned int loops = 1; |
|
unsigned int count = handle_tw_list(node, &ctx, &uring_locked, NULL); |
|
|
|
node = io_llist_cmpxchg(&tctx->task_list, &fake, NULL); |
|
while (node != &fake) { |
|
loops++; |
|
node = io_llist_xchg(&tctx->task_list, &fake); |
|
count += handle_tw_list(node, &ctx, &uring_locked, &fake); |
|
node = io_llist_cmpxchg(&tctx->task_list, &fake, NULL); |
|
} |
|
|
|
ctx_flush_and_put(ctx, &uring_locked); |
|
|
|
/* relaxed read is enough as only the task itself sets ->in_idle */ |
|
if (unlikely(atomic_read(&tctx->in_idle))) |
|
io_uring_drop_tctx_refs(current); |
|
|
|
trace_io_uring_task_work_run(tctx, count, loops); |
|
} |
|
|
|
static void io_req_local_work_add(struct io_kiocb *req) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
|
|
if (!llist_add(&req->io_task_work.node, &ctx->work_llist)) |
|
return; |
|
/* need it for the following io_cqring_wake() */ |
|
smp_mb__after_atomic(); |
|
|
|
if (unlikely(atomic_read(&req->task->io_uring->in_idle))) { |
|
io_move_task_work_from_local(ctx); |
|
return; |
|
} |
|
|
|
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG) |
|
atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags); |
|
|
|
if (ctx->has_evfd) |
|
io_eventfd_signal(ctx); |
|
__io_cqring_wake(ctx); |
|
} |
|
|
|
static inline void __io_req_task_work_add(struct io_kiocb *req, bool allow_local) |
|
{ |
|
struct io_uring_task *tctx = req->task->io_uring; |
|
struct io_ring_ctx *ctx = req->ctx; |
|
struct llist_node *node; |
|
|
|
if (allow_local && ctx->flags & IORING_SETUP_DEFER_TASKRUN) { |
|
io_req_local_work_add(req); |
|
return; |
|
} |
|
|
|
/* task_work already pending, we're done */ |
|
if (!llist_add(&req->io_task_work.node, &tctx->task_list)) |
|
return; |
|
|
|
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG) |
|
atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags); |
|
|
|
if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method))) |
|
return; |
|
|
|
node = llist_del_all(&tctx->task_list); |
|
|
|
while (node) { |
|
req = container_of(node, struct io_kiocb, io_task_work.node); |
|
node = node->next; |
|
if (llist_add(&req->io_task_work.node, |
|
&req->ctx->fallback_llist)) |
|
schedule_delayed_work(&req->ctx->fallback_work, 1); |
|
} |
|
} |
|
|
|
void io_req_task_work_add(struct io_kiocb *req) |
|
{ |
|
__io_req_task_work_add(req, true); |
|
} |
|
|
|
static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx) |
|
{ |
|
struct llist_node *node; |
|
|
|
node = llist_del_all(&ctx->work_llist); |
|
while (node) { |
|
struct io_kiocb *req = container_of(node, struct io_kiocb, |
|
io_task_work.node); |
|
|
|
node = node->next; |
|
__io_req_task_work_add(req, false); |
|
} |
|
} |
|
|
|
int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked) |
|
{ |
|
struct llist_node *node; |
|
struct llist_node fake; |
|
struct llist_node *current_final = NULL; |
|
int ret; |
|
unsigned int loops = 1; |
|
|
|
if (unlikely(ctx->submitter_task != current)) |
|
return -EEXIST; |
|
|
|
node = io_llist_xchg(&ctx->work_llist, &fake); |
|
ret = 0; |
|
again: |
|
while (node != current_final) { |
|
struct llist_node *next = node->next; |
|
struct io_kiocb *req = container_of(node, struct io_kiocb, |
|
io_task_work.node); |
|
prefetch(container_of(next, struct io_kiocb, io_task_work.node)); |
|
req->io_task_work.func(req, locked); |
|
ret++; |
|
node = next; |
|
} |
|
|
|
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG) |
|
atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags); |
|
|
|
node = io_llist_cmpxchg(&ctx->work_llist, &fake, NULL); |
|
if (node != &fake) { |
|
loops++; |
|
current_final = &fake; |
|
node = io_llist_xchg(&ctx->work_llist, &fake); |
|
goto again; |
|
} |
|
|
|
if (*locked) |
|
io_submit_flush_completions(ctx); |
|
trace_io_uring_local_work_run(ctx, ret, loops); |
|
return ret; |
|
|
|
} |
|
|
|
int io_run_local_work(struct io_ring_ctx *ctx) |
|
{ |
|
bool locked; |
|
int ret; |
|
|
|
if (llist_empty(&ctx->work_llist)) |
|
return 0; |
|
|
|
__set_current_state(TASK_RUNNING); |
|
locked = mutex_trylock(&ctx->uring_lock); |
|
ret = __io_run_local_work(ctx, &locked); |
|
if (locked) |
|
mutex_unlock(&ctx->uring_lock); |
|
|
|
return ret; |
|
} |
|
|
|
static void io_req_tw_post(struct io_kiocb *req, bool *locked) |
|
{ |
|
io_req_complete_post(req); |
|
} |
|
|
|
void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags) |
|
{ |
|
io_req_set_res(req, res, cflags); |
|
req->io_task_work.func = io_req_tw_post; |
|
io_req_task_work_add(req); |
|
} |
|
|
|
static void io_req_task_cancel(struct io_kiocb *req, bool *locked) |
|
{ |
|
/* not needed for normal modes, but SQPOLL depends on it */ |
|
io_tw_lock(req->ctx, locked); |
|
io_req_complete_failed(req, req->cqe.res); |
|
} |
|
|
|
void io_req_task_submit(struct io_kiocb *req, bool *locked) |
|
{ |
|
io_tw_lock(req->ctx, locked); |
|
/* req->task == current here, checking PF_EXITING is safe */ |
|
if (likely(!(req->task->flags & PF_EXITING))) |
|
io_queue_sqe(req); |
|
else |
|
io_req_complete_failed(req, -EFAULT); |
|
} |
|
|
|
void io_req_task_queue_fail(struct io_kiocb *req, int ret) |
|
{ |
|
io_req_set_res(req, ret, 0); |
|
req->io_task_work.func = io_req_task_cancel; |
|
io_req_task_work_add(req); |
|
} |
|
|
|
void io_req_task_queue(struct io_kiocb *req) |
|
{ |
|
req->io_task_work.func = io_req_task_submit; |
|
io_req_task_work_add(req); |
|
} |
|
|
|
void io_queue_next(struct io_kiocb *req) |
|
{ |
|
struct io_kiocb *nxt = io_req_find_next(req); |
|
|
|
if (nxt) |
|
io_req_task_queue(nxt); |
|
} |
|
|
|
void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node) |
|
__must_hold(&ctx->uring_lock) |
|
{ |
|
struct task_struct *task = NULL; |
|
int task_refs = 0; |
|
|
|
do { |
|
struct io_kiocb *req = container_of(node, struct io_kiocb, |
|
comp_list); |
|
|
|
if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) { |
|
if (req->flags & REQ_F_REFCOUNT) { |
|
node = req->comp_list.next; |
|
if (!req_ref_put_and_test(req)) |
|
continue; |
|
} |
|
if ((req->flags & REQ_F_POLLED) && req->apoll) { |
|
struct async_poll *apoll = req->apoll; |
|
|
|
if (apoll->double_poll) |
|
kfree(apoll->double_poll); |
|
if (!io_alloc_cache_put(&ctx->apoll_cache, &apoll->cache)) |
|
kfree(apoll); |
|
req->flags &= ~REQ_F_POLLED; |
|
} |
|
if (req->flags & IO_REQ_LINK_FLAGS) |
|
io_queue_next(req); |
|
if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS)) |
|
io_clean_op(req); |
|
} |
|
if (!(req->flags & REQ_F_FIXED_FILE)) |
|
io_put_file(req->file); |
|
|
|
io_req_put_rsrc_locked(req, ctx); |
|
|
|
if (req->task != task) { |
|
if (task) |
|
io_put_task(task, task_refs); |
|
task = req->task; |
|
task_refs = 0; |
|
} |
|
task_refs++; |
|
node = req->comp_list.next; |
|
io_req_add_to_cache(req, ctx); |
|
} while (node); |
|
|
|
if (task) |
|
io_put_task(task, task_refs); |
|
} |
|
|
|
static void __io_submit_flush_completions(struct io_ring_ctx *ctx) |
|
__must_hold(&ctx->uring_lock) |
|
{ |
|
struct io_wq_work_node *node, *prev; |
|
struct io_submit_state *state = &ctx->submit_state; |
|
|
|
io_cq_lock(ctx); |
|
wq_list_for_each(node, prev, &state->compl_reqs) { |
|
struct io_kiocb *req = container_of(node, struct io_kiocb, |
|
comp_list); |
|
|
|
if (!(req->flags & REQ_F_CQE_SKIP)) |
|
__io_fill_cqe_req(ctx, req); |
|
} |
|
__io_cq_unlock_post(ctx); |
|
|
|
io_free_batch_list(ctx, state->compl_reqs.first); |
|
INIT_WQ_LIST(&state->compl_reqs); |
|
} |
|
|
|
/* |
|
* Drop reference to request, return next in chain (if there is one) if this |
|
* was the last reference to this request. |
|
*/ |
|
static inline struct io_kiocb *io_put_req_find_next(struct io_kiocb *req) |
|
{ |
|
struct io_kiocb *nxt = NULL; |
|
|
|
if (req_ref_put_and_test(req)) { |
|
if (unlikely(req->flags & IO_REQ_LINK_FLAGS)) |
|
nxt = io_req_find_next(req); |
|
io_free_req(req); |
|
} |
|
return nxt; |
|
} |
|
|
|
static unsigned io_cqring_events(struct io_ring_ctx *ctx) |
|
{ |
|
/* See comment at the top of this file */ |
|
smp_rmb(); |
|
return __io_cqring_events(ctx); |
|
} |
|
|
|
/* |
|
* We can't just wait for polled events to come to us, we have to actively |
|
* find and complete them. |
|
*/ |
|
static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx) |
|
{ |
|
if (!(ctx->flags & IORING_SETUP_IOPOLL)) |
|
return; |
|
|
|
mutex_lock(&ctx->uring_lock); |
|
while (!wq_list_empty(&ctx->iopoll_list)) { |
|
/* let it sleep and repeat later if can't complete a request */ |
|
if (io_do_iopoll(ctx, true) == 0) |
|
break; |
|
/* |
|
* Ensure we allow local-to-the-cpu processing to take place, |
|
* in this case we need to ensure that we reap all events. |
|
* Also let task_work, etc. to progress by releasing the mutex |
|
*/ |
|
if (need_resched()) { |
|
mutex_unlock(&ctx->uring_lock); |
|
cond_resched(); |
|
mutex_lock(&ctx->uring_lock); |
|
} |
|
} |
|
mutex_unlock(&ctx->uring_lock); |
|
} |
|
|
|
static int io_iopoll_check(struct io_ring_ctx *ctx, long min) |
|
{ |
|
unsigned int nr_events = 0; |
|
int ret = 0; |
|
unsigned long check_cq; |
|
|
|
if (!io_allowed_run_tw(ctx)) |
|
return -EEXIST; |
|
|
|
check_cq = READ_ONCE(ctx->check_cq); |
|
if (unlikely(check_cq)) { |
|
if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)) |
|
__io_cqring_overflow_flush(ctx, false); |
|
/* |
|
* Similarly do not spin if we have not informed the user of any |
|
* dropped CQE. |
|
*/ |
|
if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) |
|
return -EBADR; |
|
} |
|
/* |
|
* Don't enter poll loop if we already have events pending. |
|
* If we do, we can potentially be spinning for commands that |
|
* already triggered a CQE (eg in error). |
|
*/ |
|
if (io_cqring_events(ctx)) |
|
return 0; |
|
|
|
do { |
|
/* |
|
* If a submit got punted to a workqueue, we can have the |
|
* application entering polling for a command before it gets |
|
* issued. That app will hold the uring_lock for the duration |
|
* of the poll right here, so we need to take a breather every |
|
* now and then to ensure that the issue has a chance to add |
|
* the poll to the issued list. Otherwise we can spin here |
|
* forever, while the workqueue is stuck trying to acquire the |
|
* very same mutex. |
|
*/ |
|
if (wq_list_empty(&ctx->iopoll_list) || |
|
io_task_work_pending(ctx)) { |
|
u32 tail = ctx->cached_cq_tail; |
|
|
|
(void) io_run_local_work_locked(ctx); |
|
|
|
if (task_work_pending(current) || |
|
wq_list_empty(&ctx->iopoll_list)) { |
|
mutex_unlock(&ctx->uring_lock); |
|
io_run_task_work(); |
|
mutex_lock(&ctx->uring_lock); |
|
} |
|
/* some requests don't go through iopoll_list */ |
|
if (tail != ctx->cached_cq_tail || |
|
wq_list_empty(&ctx->iopoll_list)) |
|
break; |
|
} |
|
ret = io_do_iopoll(ctx, !min); |
|
if (ret < 0) |
|
break; |
|
nr_events += ret; |
|
ret = 0; |
|
} while (nr_events < min && !need_resched()); |
|
|
|
return ret; |
|
} |
|
|
|
void io_req_task_complete(struct io_kiocb *req, bool *locked) |
|
{ |
|
if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) { |
|
unsigned issue_flags = *locked ? 0 : IO_URING_F_UNLOCKED; |
|
|
|
req->cqe.flags |= io_put_kbuf(req, issue_flags); |
|
} |
|
|
|
if (*locked) |
|
io_req_complete_defer(req); |
|
else |
|
io_req_complete_post(req); |
|
} |
|
|
|
/* |
|
* After the iocb has been issued, it's safe to be found on the poll list. |
|
* Adding the kiocb to the list AFTER submission ensures that we don't |
|
* find it from a io_do_iopoll() thread before the issuer is done |
|
* accessing the kiocb cookie. |
|
*/ |
|
static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; |
|
|
|
/* workqueue context doesn't hold uring_lock, grab it now */ |
|
if (unlikely(needs_lock)) |
|
mutex_lock(&ctx->uring_lock); |
|
|
|
/* |
|
* Track whether we have multiple files in our lists. This will impact |
|
* how we do polling eventually, not spinning if we're on potentially |
|
* different devices. |
|
*/ |
|
if (wq_list_empty(&ctx->iopoll_list)) { |
|
ctx->poll_multi_queue = false; |
|
} else if (!ctx->poll_multi_queue) { |
|
struct io_kiocb *list_req; |
|
|
|
list_req = container_of(ctx->iopoll_list.first, struct io_kiocb, |
|
comp_list); |
|
if (list_req->file != req->file) |
|
ctx->poll_multi_queue = true; |
|
} |
|
|
|
/* |
|
* For fast devices, IO may have already completed. If it has, add |
|
* it to the front so we find it first. |
|
*/ |
|
if (READ_ONCE(req->iopoll_completed)) |
|
wq_list_add_head(&req->comp_list, &ctx->iopoll_list); |
|
else |
|
wq_list_add_tail(&req->comp_list, &ctx->iopoll_list); |
|
|
|
if (unlikely(needs_lock)) { |
|
/* |
|
* If IORING_SETUP_SQPOLL is enabled, sqes are either handle |
|
* in sq thread task context or in io worker task context. If |
|
* current task context is sq thread, we don't need to check |
|
* whether should wake up sq thread. |
|
*/ |
|
if ((ctx->flags & IORING_SETUP_SQPOLL) && |
|
wq_has_sleeper(&ctx->sq_data->wait)) |
|
wake_up(&ctx->sq_data->wait); |
|
|
|
mutex_unlock(&ctx->uring_lock); |
|
} |
|
} |
|
|
|
static bool io_bdev_nowait(struct block_device *bdev) |
|
{ |
|
return !bdev || bdev_nowait(bdev); |
|
} |
|
|
|
/* |
|
* If we tracked the file through the SCM inflight mechanism, we could support |
|
* any file. For now, just ensure that anything potentially problematic is done |
|
* inline. |
|
*/ |
|
static bool __io_file_supports_nowait(struct file *file, umode_t mode) |
|
{ |
|
if (S_ISBLK(mode)) { |
|
if (IS_ENABLED(CONFIG_BLOCK) && |
|
io_bdev_nowait(I_BDEV(file->f_mapping->host))) |
|
return true; |
|
return false; |
|
} |
|
if (S_ISSOCK(mode)) |
|
return true; |
|
if (S_ISREG(mode)) { |
|
if (IS_ENABLED(CONFIG_BLOCK) && |
|
io_bdev_nowait(file->f_inode->i_sb->s_bdev) && |
|
!io_is_uring_fops(file)) |
|
return true; |
|
return false; |
|
} |
|
|
|
/* any ->read/write should understand O_NONBLOCK */ |
|
if (file->f_flags & O_NONBLOCK) |
|
return true; |
|
return file->f_mode & FMODE_NOWAIT; |
|
} |
|
|
|
/* |
|
* If we tracked the file through the SCM inflight mechanism, we could support |
|
* any file. For now, just ensure that anything potentially problematic is done |
|
* inline. |
|
*/ |
|
unsigned int io_file_get_flags(struct file *file) |
|
{ |
|
umode_t mode = file_inode(file)->i_mode; |
|
unsigned int res = 0; |
|
|
|
if (S_ISREG(mode)) |
|
res |= FFS_ISREG; |
|
if (__io_file_supports_nowait(file, mode)) |
|
res |= FFS_NOWAIT; |
|
return res; |
|
} |
|
|
|
bool io_alloc_async_data(struct io_kiocb *req) |
|
{ |
|
WARN_ON_ONCE(!io_op_defs[req->opcode].async_size); |
|
req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL); |
|
if (req->async_data) { |
|
req->flags |= REQ_F_ASYNC_DATA; |
|
return false; |
|
} |
|
return true; |
|
} |
|
|
|
int io_req_prep_async(struct io_kiocb *req) |
|
{ |
|
const struct io_op_def *def = &io_op_defs[req->opcode]; |
|
|
|
/* assign early for deferred execution for non-fixed file */ |
|
if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE)) |
|
req->file = io_file_get_normal(req, req->cqe.fd); |
|
if (!def->prep_async) |
|
return 0; |
|
if (WARN_ON_ONCE(req_has_async_data(req))) |
|
return -EFAULT; |
|
if (!io_op_defs[req->opcode].manual_alloc) { |
|
if (io_alloc_async_data(req)) |
|
return -EAGAIN; |
|
} |
|
return def->prep_async(req); |
|
} |
|
|
|
static u32 io_get_sequence(struct io_kiocb *req) |
|
{ |
|
u32 seq = req->ctx->cached_sq_head; |
|
struct io_kiocb *cur; |
|
|
|
/* need original cached_sq_head, but it was increased for each req */ |
|
io_for_each_link(cur, req) |
|
seq--; |
|
return seq; |
|
} |
|
|
|
static __cold void io_drain_req(struct io_kiocb *req) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
struct io_defer_entry *de; |
|
int ret; |
|
u32 seq = io_get_sequence(req); |
|
|
|
/* Still need defer if there is pending req in defer list. */ |
|
spin_lock(&ctx->completion_lock); |
|
if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) { |
|
spin_unlock(&ctx->completion_lock); |
|
queue: |
|
ctx->drain_active = false; |
|
io_req_task_queue(req); |
|
return; |
|
} |
|
spin_unlock(&ctx->completion_lock); |
|
|
|
ret = io_req_prep_async(req); |
|
if (ret) { |
|
fail: |
|
io_req_complete_failed(req, ret); |
|
return; |
|
} |
|
io_prep_async_link(req); |
|
de = kmalloc(sizeof(*de), GFP_KERNEL); |
|
if (!de) { |
|
ret = -ENOMEM; |
|
goto fail; |
|
} |
|
|
|
spin_lock(&ctx->completion_lock); |
|
if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) { |
|
spin_unlock(&ctx->completion_lock); |
|
kfree(de); |
|
goto queue; |
|
} |
|
|
|
trace_io_uring_defer(req); |
|
de->req = req; |
|
de->seq = seq; |
|
list_add_tail(&de->list, &ctx->defer_list); |
|
spin_unlock(&ctx->completion_lock); |
|
} |
|
|
|
static void io_clean_op(struct io_kiocb *req) |
|
{ |
|
if (req->flags & REQ_F_BUFFER_SELECTED) { |
|
spin_lock(&req->ctx->completion_lock); |
|
io_put_kbuf_comp(req); |
|
spin_unlock(&req->ctx->completion_lock); |
|
} |
|
|
|
if (req->flags & REQ_F_NEED_CLEANUP) { |
|
const struct io_op_def *def = &io_op_defs[req->opcode]; |
|
|
|
if (def->cleanup) |
|
def->cleanup(req); |
|
} |
|
if ((req->flags & REQ_F_POLLED) && req->apoll) { |
|
kfree(req->apoll->double_poll); |
|
kfree(req->apoll); |
|
req->apoll = NULL; |
|
} |
|
if (req->flags & REQ_F_INFLIGHT) { |
|
struct io_uring_task *tctx = req->task->io_uring; |
|
|
|
atomic_dec(&tctx->inflight_tracked); |
|
} |
|
if (req->flags & REQ_F_CREDS) |
|
put_cred(req->creds); |
|
if (req->flags & REQ_F_ASYNC_DATA) { |
|
kfree(req->async_data); |
|
req->async_data = NULL; |
|
} |
|
req->flags &= ~IO_REQ_CLEAN_FLAGS; |
|
} |
|
|
|
static bool io_assign_file(struct io_kiocb *req, unsigned int issue_flags) |
|
{ |
|
if (req->file || !io_op_defs[req->opcode].needs_file) |
|
return true; |
|
|
|
if (req->flags & REQ_F_FIXED_FILE) |
|
req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags); |
|
else |
|
req->file = io_file_get_normal(req, req->cqe.fd); |
|
|
|
return !!req->file; |
|
} |
|
|
|
static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags) |
|
{ |
|
const struct io_op_def *def = &io_op_defs[req->opcode]; |
|
const struct cred *creds = NULL; |
|
int ret; |
|
|
|
if (unlikely(!io_assign_file(req, issue_flags))) |
|
return -EBADF; |
|
|
|
if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred())) |
|
creds = override_creds(req->creds); |
|
|
|
if (!def->audit_skip) |
|
audit_uring_entry(req->opcode); |
|
|
|
ret = def->issue(req, issue_flags); |
|
|
|
if (!def->audit_skip) |
|
audit_uring_exit(!ret, ret); |
|
|
|
if (creds) |
|
revert_creds(creds); |
|
|
|
if (ret == IOU_OK) { |
|
if (issue_flags & IO_URING_F_COMPLETE_DEFER) |
|
io_req_complete_defer(req); |
|
else |
|
io_req_complete_post(req); |
|
} else if (ret != IOU_ISSUE_SKIP_COMPLETE) |
|
return ret; |
|
|
|
/* If the op doesn't have a file, we're not polling for it */ |
|
if ((req->ctx->flags & IORING_SETUP_IOPOLL) && req->file) |
|
io_iopoll_req_issued(req, issue_flags); |
|
|
|
return 0; |
|
} |
|
|
|
int io_poll_issue(struct io_kiocb *req, bool *locked) |
|
{ |
|
io_tw_lock(req->ctx, locked); |
|
if (unlikely(req->task->flags & PF_EXITING)) |
|
return -EFAULT; |
|
return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT); |
|
} |
|
|
|
struct io_wq_work *io_wq_free_work(struct io_wq_work *work) |
|
{ |
|
struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
|
|
|
req = io_put_req_find_next(req); |
|
return req ? &req->work : NULL; |
|
} |
|
|
|
void io_wq_submit_work(struct io_wq_work *work) |
|
{ |
|
struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
|
const struct io_op_def *def = &io_op_defs[req->opcode]; |
|
unsigned int issue_flags = IO_URING_F_UNLOCKED; |
|
bool needs_poll = false; |
|
int ret = 0, err = -ECANCELED; |
|
|
|
/* one will be dropped by ->io_free_work() after returning to io-wq */ |
|
if (!(req->flags & REQ_F_REFCOUNT)) |
|
__io_req_set_refcount(req, 2); |
|
else |
|
req_ref_get(req); |
|
|
|
io_arm_ltimeout(req); |
|
|
|
/* either cancelled or io-wq is dying, so don't touch tctx->iowq */ |
|
if (work->flags & IO_WQ_WORK_CANCEL) { |
|
fail: |
|
io_req_task_queue_fail(req, err); |
|
return; |
|
} |
|
if (!io_assign_file(req, issue_flags)) { |
|
err = -EBADF; |
|
work->flags |= IO_WQ_WORK_CANCEL; |
|
goto fail; |
|
} |
|
|
|
if (req->flags & REQ_F_FORCE_ASYNC) { |
|
bool opcode_poll = def->pollin || def->pollout; |
|
|
|
if (opcode_poll && file_can_poll(req->file)) { |
|
needs_poll = true; |
|
issue_flags |= IO_URING_F_NONBLOCK; |
|
} |
|
} |
|
|
|
do { |
|
ret = io_issue_sqe(req, issue_flags); |
|
if (ret != -EAGAIN) |
|
break; |
|
/* |
|
* We can get EAGAIN for iopolled IO even though we're |
|
* forcing a sync submission from here, since we can't |
|
* wait for request slots on the block side. |
|
*/ |
|
if (!needs_poll) { |
|
if (!(req->ctx->flags & IORING_SETUP_IOPOLL)) |
|
break; |
|
cond_resched(); |
|
continue; |
|
} |
|
|
|
if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK) |
|
return; |
|
/* aborted or ready, in either case retry blocking */ |
|
needs_poll = false; |
|
issue_flags &= ~IO_URING_F_NONBLOCK; |
|
} while (1); |
|
|
|
/* avoid locking problems by failing it from a clean context */ |
|
if (ret < 0) |
|
io_req_task_queue_fail(req, ret); |
|
} |
|
|
|
inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd, |
|
unsigned int issue_flags) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
struct file *file = NULL; |
|
unsigned long file_ptr; |
|
|
|
io_ring_submit_lock(ctx, issue_flags); |
|
|
|
if (unlikely((unsigned int)fd >= ctx->nr_user_files)) |
|
goto out; |
|
fd = array_index_nospec(fd, ctx->nr_user_files); |
|
file_ptr = io_fixed_file_slot(&ctx->file_table, fd)->file_ptr; |
|
file = (struct file *) (file_ptr & FFS_MASK); |
|
file_ptr &= ~FFS_MASK; |
|
/* mask in overlapping REQ_F and FFS bits */ |
|
req->flags |= (file_ptr << REQ_F_SUPPORT_NOWAIT_BIT); |
|
io_req_set_rsrc_node(req, ctx, 0); |
|
out: |
|
io_ring_submit_unlock(ctx, issue_flags); |
|
return file; |
|
} |
|
|
|
struct file *io_file_get_normal(struct io_kiocb *req, int fd) |
|
{ |
|
struct file *file = fget(fd); |
|
|
|
trace_io_uring_file_get(req, fd); |
|
|
|
/* we don't allow fixed io_uring files */ |
|
if (file && io_is_uring_fops(file)) |
|
io_req_track_inflight(req); |
|
return file; |
|
} |
|
|
|
static void io_queue_async(struct io_kiocb *req, int ret) |
|
__must_hold(&req->ctx->uring_lock) |
|
{ |
|
struct io_kiocb *linked_timeout; |
|
|
|
if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) { |
|
io_req_complete_failed(req, ret); |
|
return; |
|
} |
|
|
|
linked_timeout = io_prep_linked_timeout(req); |
|
|
|
switch (io_arm_poll_handler(req, 0)) { |
|
case IO_APOLL_READY: |
|
io_kbuf_recycle(req, 0); |
|
io_req_task_queue(req); |
|
break; |
|
case IO_APOLL_ABORTED: |
|
io_kbuf_recycle(req, 0); |
|
io_queue_iowq(req, NULL); |
|
break; |
|
case IO_APOLL_OK: |
|
break; |
|
} |
|
|
|
if (linked_timeout) |
|
io_queue_linked_timeout(linked_timeout); |
|
} |
|
|
|
static inline void io_queue_sqe(struct io_kiocb *req) |
|
__must_hold(&req->ctx->uring_lock) |
|
{ |
|
int ret; |
|
|
|
ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER); |
|
|
|
/* |
|
* We async punt it if the file wasn't marked NOWAIT, or if the file |
|
* doesn't support non-blocking read/write attempts |
|
*/ |
|
if (likely(!ret)) |
|
io_arm_ltimeout(req); |
|
else |
|
io_queue_async(req, ret); |
|
} |
|
|
|
static void io_queue_sqe_fallback(struct io_kiocb *req) |
|
__must_hold(&req->ctx->uring_lock) |
|
{ |
|
if (unlikely(req->flags & REQ_F_FAIL)) { |
|
/* |
|
* We don't submit, fail them all, for that replace hardlinks |
|
* with normal links. Extra REQ_F_LINK is tolerated. |
|
*/ |
|
req->flags &= ~REQ_F_HARDLINK; |
|
req->flags |= REQ_F_LINK; |
|
io_req_complete_failed(req, req->cqe.res); |
|
} else if (unlikely(req->ctx->drain_active)) { |
|
io_drain_req(req); |
|
} else { |
|
int ret = io_req_prep_async(req); |
|
|
|
if (unlikely(ret)) |
|
io_req_complete_failed(req, ret); |
|
else |
|
io_queue_iowq(req, NULL); |
|
} |
|
} |
|
|
|
/* |
|
* Check SQE restrictions (opcode and flags). |
|
* |
|
* Returns 'true' if SQE is allowed, 'false' otherwise. |
|
*/ |
|
static inline bool io_check_restriction(struct io_ring_ctx *ctx, |
|
struct io_kiocb *req, |
|
unsigned int sqe_flags) |
|
{ |
|
if (!test_bit(req->opcode, ctx->restrictions.sqe_op)) |
|
return false; |
|
|
|
if ((sqe_flags & ctx->restrictions.sqe_flags_required) != |
|
ctx->restrictions.sqe_flags_required) |
|
return false; |
|
|
|
if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed | |
|
ctx->restrictions.sqe_flags_required)) |
|
return false; |
|
|
|
return true; |
|
} |
|
|
|
static void io_init_req_drain(struct io_kiocb *req) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
struct io_kiocb *head = ctx->submit_state.link.head; |
|
|
|
ctx->drain_active = true; |
|
if (head) { |
|
/* |
|
* If we need to drain a request in the middle of a link, drain |
|
* the head request and the next request/link after the current |
|
* link. Considering sequential execution of links, |
|
* REQ_F_IO_DRAIN will be maintained for every request of our |
|
* link. |
|
*/ |
|
head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC; |
|
ctx->drain_next = true; |
|
} |
|
} |
|
|
|
static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, |
|
const struct io_uring_sqe *sqe) |
|
__must_hold(&ctx->uring_lock) |
|
{ |
|
const struct io_op_def *def; |
|
unsigned int sqe_flags; |
|
int personality; |
|
u8 opcode; |
|
|
|
/* req is partially pre-initialised, see io_preinit_req() */ |
|
req->opcode = opcode = READ_ONCE(sqe->opcode); |
|
/* same numerical values with corresponding REQ_F_*, safe to copy */ |
|
req->flags = sqe_flags = READ_ONCE(sqe->flags); |
|
req->cqe.user_data = READ_ONCE(sqe->user_data); |
|
req->file = NULL; |
|
req->rsrc_node = NULL; |
|
req->task = current; |
|
|
|
if (unlikely(opcode >= IORING_OP_LAST)) { |
|
req->opcode = 0; |
|
return -EINVAL; |
|
} |
|
def = &io_op_defs[opcode]; |
|
if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) { |
|
/* enforce forwards compatibility on users */ |
|
if (sqe_flags & ~SQE_VALID_FLAGS) |
|
return -EINVAL; |
|
if (sqe_flags & IOSQE_BUFFER_SELECT) { |
|
if (!def->buffer_select) |
|
return -EOPNOTSUPP; |
|
req->buf_index = READ_ONCE(sqe->buf_group); |
|
} |
|
if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS) |
|
ctx->drain_disabled = true; |
|
if (sqe_flags & IOSQE_IO_DRAIN) { |
|
if (ctx->drain_disabled) |
|
return -EOPNOTSUPP; |
|
io_init_req_drain(req); |
|
} |
|
} |
|
if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) { |
|
if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags)) |
|
return -EACCES; |
|
/* knock it to the slow queue path, will be drained there */ |
|
if (ctx->drain_active) |
|
req->flags |= REQ_F_FORCE_ASYNC; |
|
/* if there is no link, we're at "next" request and need to drain */ |
|
if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) { |
|
ctx->drain_next = false; |
|
ctx->drain_active = true; |
|
req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC; |
|
} |
|
} |
|
|
|
if (!def->ioprio && sqe->ioprio) |
|
return -EINVAL; |
|
if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL)) |
|
return -EINVAL; |
|
|
|
if (def->needs_file) { |
|
struct io_submit_state *state = &ctx->submit_state; |
|
|
|
req->cqe.fd = READ_ONCE(sqe->fd); |
|
|
|
/* |
|
* Plug now if we have more than 2 IO left after this, and the |
|
* target is potentially a read/write to block based storage. |
|
*/ |
|
if (state->need_plug && def->plug) { |
|
state->plug_started = true; |
|
state->need_plug = false; |
|
blk_start_plug_nr_ios(&state->plug, state->submit_nr); |
|
} |
|
} |
|
|
|
personality = READ_ONCE(sqe->personality); |
|
if (personality) { |
|
int ret; |
|
|
|
req->creds = xa_load(&ctx->personalities, personality); |
|
if (!req->creds) |
|
return -EINVAL; |
|
get_cred(req->creds); |
|
ret = security_uring_override_creds(req->creds); |
|
if (ret) { |
|
put_cred(req->creds); |
|
return ret; |
|
} |
|
req->flags |= REQ_F_CREDS; |
|
} |
|
|
|
return def->prep(req, sqe); |
|
} |
|
|
|
static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe, |
|
struct io_kiocb *req, int ret) |
|
{ |
|
struct io_ring_ctx *ctx = req->ctx; |
|
struct io_submit_link *link = &ctx->submit_state.link; |
|
struct io_kiocb *head = link->head; |
|
|
|
trace_io_uring_req_failed(sqe, req, ret); |
|
|
|
/* |
|
* Avoid breaking links in the middle as it renders links with SQPOLL |
|
* unusable. Instead of failing eagerly, continue assembling the link if |
|
* applicable and mark the head with REQ_F_FAIL. The link flushing code |
|
* should find the flag and handle the rest. |
|
*/ |
|
req_fail_link_node(req, ret); |
|
if (head && !(head->flags & REQ_F_FAIL)) |
|
req_fail_link_node(head, -ECANCELED); |
|
|
|
if (!(req->flags & IO_REQ_LINK_FLAGS)) { |
|
if (head) { |
|
link->last->link = req; |
|
link->head = NULL; |
|
req = head; |
|
} |
|
io_queue_sqe_fallback(req); |
|
return ret; |
|
} |
|
|
|
if (head) |
|
link->last->link = req; |
|
else |
|
link->head = req; |
|
link->last = req; |
|
return 0; |
|
} |
|
|
|
static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, |
|
const struct io_uring_sqe *sqe) |
|
__must_hold(&ctx->uring_lock) |
|
{ |
|
struct io_submit_link *link = &ctx->submit_state.link; |
|
int ret; |
|
|
|
ret = io_init_req(ctx, req, sqe); |
|
if (unlikely(ret)) |
|
return io_submit_fail_init(sqe, req, ret); |
|
|
|
/* don't need @sqe from now on */ |
|
trace_io_uring_submit_sqe(req, true); |
|
|
|
/* |
|
* If we already have a head request, queue this one for async |
|
* submittal once the head completes. If we don't have a head but |
|
* IOSQE_IO_LINK is set in the sqe, start a new head. This one will be |
|
* submitted sync once the chain is complete. If none of those |
|
* conditions are true (normal request), then just queue it. |
|
*/ |
|
if (unlikely(link->head)) { |
|
ret = io_req_prep_async(req); |
|
if (unlikely(ret)) |
|
return io_submit_fail_init(sqe, req, ret); |
|
|
|
trace_io_uring_link(req, link->head); |
|
link->last->link = req; |
|
link->last = req; |
|
|
|
if (req->flags & IO_REQ_LINK_FLAGS) |
|
return 0; |
|
/* last request of the link, flush it */ |
|
req = link->head; |
|
link->head = NULL; |
|
if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL)) |
|
goto fallback; |
|
|
|
} else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS | |
|
REQ_F_FORCE_ASYNC | REQ_F_FAIL))) { |
|
if (req->flags & IO_REQ_LINK_FLAGS) { |
|
link->head = req; |
|
link->last = req; |
|
} else { |
|
fallback: |
|
io_queue_sqe_fallback(req); |
|
} |
|
return 0; |
|
} |
|
|
|
io_queue_sqe(req); |
|
return 0; |
|
} |
|
|
|
/* |
|
* Batched submission is done, ensure local IO is flushed out. |
|
*/ |
|
static void io_submit_state_end(struct io_ring_ctx *ctx) |
|
{ |
|
struct io_submit_state *state = &ctx->submit_state; |
|
|
|
if (unlikely(state->link.head)) |
|
io_queue_sqe_fallback(state->link.head); |
|
/* flush only after queuing links as they can generate completions */ |
|
io_submit_flush_completions(ctx); |
|
if (state->plug_started) |
|
blk_finish_plug(&state->plug); |
|
} |
|
|
|
/* |
|
* Start submission side cache. |
|
*/ |
|
static void io_submit_state_start(struct io_submit_state *state, |
|
unsigned int max_ios) |
|
{ |
|
state->plug_started = false; |
|
state->need_plug = max_ios > 2; |
|
state->submit_nr = max_ios; |
|
/* set only head, no need to init link_last in advance */ |
|
state->link.head = NULL; |
|
} |
|
|
|
static void io_commit_sqring(struct io_ring_ctx *ctx) |
|
{ |
|
struct io_rings *rings = ctx->rings; |
|
|
|
/* |
|
* Ensure any loads from the SQEs are done at this point, |
|
* since once we write the new head, the application could |
|
* write new data to them. |
|
*/ |
|
smp_store_release(&rings->sq.head, ctx->cached_sq_head); |
|
} |
|
|
|
/* |
|
* Fetch an sqe, if one is available. Note this returns a pointer to memory |
|
* that is mapped by userspace. This means that care needs to be taken to |
|
* ensure that reads are stable, as we cannot rely on userspace always |
|
* being a good citizen. If members of the sqe are validated and then later |
|
* used, it's important that those reads are done through READ_ONCE() to |
|
* prevent a re-load down the line. |
|
*/ |
|
static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) |
|
{ |
|
unsigned head, mask = ctx->sq_entries - 1; |
|
unsigned sq_idx = ctx->cached_sq_head++ & mask; |
|
|
|
/* |
|
* The cached sq head (or cq tail) serves two purposes: |
|
* |
|
* 1) allows us to batch the cost of updating the user visible |
|
* head updates. |
|
* 2) allows the kernel side to track the head on its own, even |
|
* though the application is the one updating it. |
|
*/ |
|
head = READ_ONCE(ctx->sq_array[sq_idx]); |
|
if (likely(head < ctx->sq_entries)) { |
|
/* double index for 128-byte SQEs, twice as long */ |
|
if (ctx->flags & IORING_SETUP_SQE128) |
|
head <<= 1; |
|
return &ctx->sq_sqes[head]; |
|
} |
|
|
|
/* drop invalid entries */ |
|
ctx->cq_extra--; |
|
WRITE_ONCE(ctx->rings->sq_dropped, |
|
READ_ONCE(ctx->rings->sq_dropped) + 1); |
|
return NULL; |
|
} |
|
|
|
int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr) |
|
__must_hold(&ctx->uring_lock) |
|
{ |
|
unsigned int entries = io_sqring_entries(ctx); |
|
unsigned int left; |
|
int ret; |
|
|
|
if (unlikely(!entries)) |
|
return 0; |
|
/* make sure SQ entry isn't read before tail */ |
|
ret = left = min3(nr, ctx->sq_entries, entries); |
|
io_get_task_refs(left); |
|
io_submit_state_start(&ctx->submit_state, left); |
|
|
|
do { |
|
const struct io_uring_sqe *sqe; |
|
struct io_kiocb *req; |
|
|
|
if (unlikely(!io_alloc_req_refill(ctx))) |
|
break; |
|
req = io_alloc_req(ctx); |
|
sqe = io_get_sqe(ctx); |
|
if (unlikely(!sqe)) { |
|
io_req_add_to_cache(req, ctx); |
|
break; |
|
} |
|
|
|
/* |
|
* Continue submitting even for sqe failure if the |
|
* ring was setup with IORING_SETUP_SUBMIT_ALL |
|
*/ |
|
if (unlikely(io_submit_sqe(ctx, req, sqe)) && |
|
!(ctx->flags & IORING_SETUP_SUBMIT_ALL)) { |
|
left--; |
|
break; |
|
} |
|
} while (--left); |
|
|
|
if (unlikely(left)) { |
|
ret -= left; |
|
/* try again if it submitted nothing and can't allocate a req */ |
|
if (!ret && io_req_cache_empty(ctx)) |
|
ret = -EAGAIN; |
|
current->io_uring->cached_refs += left; |
|
} |
|
|
|
io_submit_state_end(ctx); |
|
/* Commit SQ ring head once we've consumed and submitted all SQEs */ |
|
io_commit_sqring(ctx); |
|
return ret; |
|
} |
|
|
|
struct io_wait_queue { |
|
struct wait_queue_entry wq; |
|
struct io_ring_ctx *ctx; |
|
unsigned cq_tail; |
|
unsigned nr_timeouts; |
|
}; |
|
|
|
static inline bool io_has_work(struct io_ring_ctx *ctx) |
|
{ |
|
return test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq) || |
|
((ctx->flags & IORING_SETUP_DEFER_TASKRUN) && |
|
!llist_empty(&ctx->work_llist)); |
|
} |
|
|
|
static inline bool io_should_wake(struct io_wait_queue *iowq) |
|
{ |
|
struct io_ring_ctx *ctx = iowq->ctx; |
|
int dist = READ_ONCE(ctx->rings->cq.tail) - (int) iowq->cq_tail; |
|
|
|
/* |
|
* Wake up if we have enough events, or if a timeout occurred since we |
|
* started waiting. For timeouts, we always want to return to userspace, |
|
* regardless of event count. |
|
*/ |
|
return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts; |
|
} |
|
|
|
static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode, |
|
int wake_flags, void *key) |
|
{ |
|
struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, |
|
wq); |
|
struct io_ring_ctx *ctx = iowq->ctx; |
|
|
|
/* |
|
* Cannot safely flush overflowed CQEs from here, ensure we wake up |
|
* the task, and the next invocation will do it. |
|
*/ |
|
if (io_should_wake(iowq) || io_has_work(ctx)) |
|
return autoremove_wake_function(curr, mode, wake_flags, key); |
|
return -1; |
|
} |
|
|
|
int io_run_task_work_sig(struct io_ring_ctx *ctx) |
|
{ |
|
if (io_run_task_work_ctx(ctx) > 0) |
|
return 1; |
|
if (task_sigpending(current)) |
|
return -EINTR; |
|
return 0; |
|
} |
|
|
|
/* when returns >0, the caller should retry */ |
|
static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx, |
|
struct io_wait_queue *iowq, |
|
ktime_t timeout) |
|
{ |
|
int ret; |
|
unsigned long check_cq; |
|
|
|
/* make sure we run task_work before checking for signals */ |
|
ret = io_run_task_work_sig(ctx); |
|
if (ret || io_should_wake(iowq)) |
|
return ret; |
|
|
|
check_cq = READ_ONCE(ctx->check_cq); |
|
if (unlikely(check_cq)) { |
|
/* let the caller flush overflows, retry */ |
|
if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)) |
|
return 1; |
|
if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) |
|
return -EBADR; |
|
} |
|
if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS)) |
|
return -ETIME; |
|
return 1; |
|
} |
|
|
|
/* |
|
* Wait until events become available, if we don't already have some. The |
|
* application must reap them itself, as they reside on the shared cq ring. |
|
*/ |
|
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, |
|
const sigset_t __user *sig, size_t sigsz, |
|
struct __kernel_timespec __user *uts) |
|
{ |
|
struct io_wait_queue iowq; |
|
struct io_rings *rings = ctx->rings; |
|
ktime_t timeout = KTIME_MAX; |
|
int ret; |
|
|
|
if (!io_allowed_run_tw(ctx)) |
|
return -EEXIST; |
|
|
|
do { |
|
/* always run at least 1 task work to process local work */ |
|
ret = io_run_task_work_ctx(ctx); |
|
if (ret < 0) |
|
return ret; |
|
io_cqring_overflow_flush(ctx); |
|
|
|
/* if user messes with these they will just get an early return */ |
|
if (__io_cqring_events_user(ctx) >= min_events) |
|
return 0; |
|
} while (ret > 0); |
|
|
|
if (sig) { |
|
#ifdef CONFIG_COMPAT |
|
if (in_compat_syscall()) |
|
ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig, |
|
sigsz); |
|
else |
|
#endif |
|
ret = set_user_sigmask(sig, sigsz); |
|
|
|
if (ret) |
|
return ret; |
|
} |
|
|
|
if (uts) { |
|
struct timespec64 ts; |
|
|
|
if (get_timespec64(&ts, uts)) |
|
return -EFAULT; |
|
timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns()); |
|
} |
|
|
|
init_waitqueue_func_entry(&iowq.wq, io_wake_function); |
|
iowq.wq.private = current; |
|
INIT_LIST_HEAD(&iowq.wq.entry); |
|
iowq.ctx = ctx; |
|
iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); |
|
iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events; |
|
|
|
trace_io_uring_cqring_wait(ctx, min_events); |
|
do { |
|
/* if we can't even flush overflow, don't wait for more */ |
|
if (!io_cqring_overflow_flush(ctx)) { |
|
ret = -EBUSY; |
|
break; |
|
} |
|
prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq, |
|
TASK_INTERRUPTIBLE); |
|
ret = io_cqring_wait_schedule(ctx, &iowq, timeout); |
|
cond_resched(); |
|
} while (ret > 0); |
|
|
|
finish_wait(&ctx->cq_wait, &iowq.wq); |
|
restore_saved_sigmask_unless(ret == -EINTR); |
|
|
|
return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0; |
|
} |
|
|
|
static void io_mem_free(void *ptr) |
|
{ |
|
struct page *page; |
|
|
|
if (!ptr) |
|
return; |
|
|
|
page = virt_to_head_page(ptr); |
|
if (put_page_testzero(page)) |
|
free_compound_page(page); |
|
} |
|
|
|
static void *io_mem_alloc(size_t size) |
|
{ |
|
gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP; |
|
|
|
return (void *) __get_free_pages(gfp, get_order(size)); |
|
} |
|
|
|
static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries, |
|
unsigned int cq_entries, size_t *sq_offset) |
|
{ |
|
struct io_rings *rings; |
|
size_t off, sq_array_size; |
|
|
|
off = struct_size(rings, cqes, cq_entries); |
|
if (off == SIZE_MAX) |
|
return SIZE_MAX; |
|
if (ctx->flags & IORING_SETUP_CQE32) { |
|
if (check_shl_overflow(off, 1, &off)) |
|
return SIZE_MAX; |
|
} |
|
|
|
#ifdef CONFIG_SMP |
|
off = ALIGN(off, SMP_CACHE_BYTES); |
|
if (off == 0) |
|
return SIZE_MAX; |
|
#endif |
|
|
|
if (sq_offset) |
|
*sq_offset = off; |
|
|
|
sq_array_size = array_size(sizeof(u32), sq_entries); |
|
if (sq_array_size == SIZE_MAX) |
|
return SIZE_MAX; |
|
|
|
if (check_add_overflow(off, sq_array_size, &off)) |
|
return SIZE_MAX; |
|
|
|
return off; |
|
} |
|
|
|
static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg, |
|
unsigned int eventfd_async) |
|
{ |
|
struct io_ev_fd *ev_fd; |
|
__s32 __user *fds = arg; |
|
int fd; |
|
|
|
ev_fd = rcu_dereference_protected(ctx->io_ev_fd, |
|
lockdep_is_held(&ctx->uring_lock)); |
|
if (ev_fd) |
|
return -EBUSY; |
|
|
|
if (copy_from_user(&fd, fds, sizeof(*fds))) |
|
return -EFAULT; |
|
|
|
ev_fd = kmalloc(sizeof(*ev_fd), GFP_KERNEL); |
|
if (!ev_fd) |
|
return -ENOMEM; |
|
|
|
ev_fd->cq_ev_fd = eventfd_ctx_fdget(fd); |
|
if (IS_ERR(ev_fd->cq_ev_fd)) { |
|
int ret = PTR_ERR(ev_fd->cq_ev_fd); |
|
kfree(ev_fd); |
|
return ret; |
|
} |
|
|
|
spin_lock(&ctx->completion_lock); |
|
ctx->evfd_last_cq_tail = ctx->cached_cq_tail; |
|
spin_unlock(&ctx->completion_lock); |
|
|
|
ev_fd->eventfd_async = eventfd_async; |
|
ctx->has_evfd = true; |
|
rcu_assign_pointer(ctx->io_ev_fd, ev_fd); |
|
atomic_set(&ev_fd->refs, 1); |
|
atomic_set(&ev_fd->ops, 0); |
|
return 0; |
|
} |
|
|
|
static int io_eventfd_unregister(struct io_ring_ctx *ctx) |
|
{ |
|
struct io_ev_fd *ev_fd; |
|
|
|
ev_fd = rcu_dereference_protected(ctx->io_ev_fd, |
|
lockdep_is_held(&ctx->uring_lock)); |
|
if (ev_fd) { |
|
ctx->has_evfd = false; |
|
rcu_assign_pointer(ctx->io_ev_fd, NULL); |
|
if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_FREE_BIT), &ev_fd->ops)) |
|
call_rcu(&ev_fd->rcu, io_eventfd_ops); |
|
return 0; |
|
} |
|
|
|
return -ENXIO; |
|
} |
|
|
|
static void io_req_caches_free(struct io_ring_ctx *ctx) |
|
{ |
|
int nr = 0; |
|
|
|
mutex_lock(&ctx->uring_lock); |
|
io_flush_cached_locked_reqs(ctx, &ctx->submit_state); |
|
|
|
while (!io_req_cache_empty(ctx)) { |
|
struct io_kiocb *req = io_alloc_req(ctx); |
|
|
|
kmem_cache_free(req_cachep, req); |
|
nr++; |
|
} |
|
if (nr) |
|
percpu_ref_put_many(&ctx->refs, nr); |
|
mutex_unlock(&ctx->uring_lock); |
|
} |
|
|
|
static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx) |
|
{ |
|
io_sq_thread_finish(ctx); |
|
io_rsrc_refs_drop(ctx); |
|
/* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */ |
|
io_wait_rsrc_data(ctx->buf_data); |
|
io_wait_rsrc_data(ctx->file_data); |
|
|
|
mutex_lock(&ctx->uring_lock); |
|
if (ctx->buf_data) |
|
__io_sqe_buffers_unregister(ctx); |
|
if (ctx->file_data) |
|
__io_sqe_files_unregister(ctx); |
|
if (ctx->rings) |
|
__io_cqring_overflow_flush(ctx, true); |
|
io_eventfd_unregister(ctx); |
|
io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free); |
|
io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free); |
|
mutex_unlock(&ctx->uring_lock); |
|
io_destroy_buffers(ctx); |
|
if (ctx->sq_creds) |
|
put_cred(ctx->sq_creds); |
|
if (ctx->submitter_task) |
|
put_task_struct(ctx->submitter_task); |
|
|
|
/* there are no registered resources left, nobody uses it */ |
|
if (ctx->rsrc_node) |
|
io_rsrc_node_destroy(ctx->rsrc_node); |
|
if (ctx->rsrc_backup_node) |
|
io_rsrc_node_destroy(ctx->rsrc_backup_node); |
|
flush_delayed_work(&ctx->rsrc_put_work); |
|
flush_delayed_work(&ctx->fallback_work); |
|
|
|
WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list)); |
|
WARN_ON_ONCE(!llist_empty(&ctx->rsrc_put_llist)); |
|
|
|
#if defined(CONFIG_UNIX) |
|
if (ctx->ring_sock) { |
|
ctx->ring_sock->file = NULL; /* so that iput() is called */ |
|
sock_release(ctx->ring_sock); |
|
} |
|
#endif |
|
WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list)); |
|
|
|
if (ctx->mm_account) { |
|
mmdrop(ctx->mm_account); |
|
ctx->mm_account = NULL; |
|
} |
|
io_mem_free(ctx->rings); |
|
io_mem_free(ctx->sq_sqes); |
|
|
|
percpu_ref_exit(&ctx->refs); |
|
free_uid(ctx->user); |
|
io_req_caches_free(ctx); |
|
if (ctx->hash_map) |
|
io_wq_put_hash(ctx->hash_map); |
|
kfree(ctx->cancel_table.hbs); |
|
kfree(ctx->cancel_table_locked.hbs); |
|
kfree(ctx->dummy_ubuf); |
|
kfree(ctx->io_bl); |
|
xa_destroy(&ctx->io_bl_xa); |
|
kfree(ctx); |
|
} |
|
|
|
static __poll_t io_uring_poll(struct file *file, poll_table *wait) |
|
{ |
|
struct io_ring_ctx *ctx = file->private_data; |
|
__poll_t mask = 0; |
|
|
|
poll_wait(file, &ctx->cq_wait, wait); |
|
/* |
|
* synchronizes with barrier from wq_has_sleeper call in |
|
* io_commit_cqring |
|
*/ |
|
smp_rmb(); |
|
if (!io_sqring_full(ctx)) |
|
mask |= EPOLLOUT | EPOLLWRNORM; |
|
|
|
/* |
|
* Don't flush cqring overflow list here, just do a simple check. |
|
* Otherwise there could possible be ABBA deadlock: |
|
* CPU0 CPU1 |
|
* ---- ---- |
|
* lock(&ctx->uring_lock); |
|
* lock(&ep->mtx); |
|
* lock(&ctx->uring_lock); |
|
* lock(&ep->mtx); |
|
* |
|
* Users may get EPOLLIN meanwhile seeing nothing in cqring, this |
|
* pushs them to do the flush. |
|
*/ |
|
|
|
if (io_cqring_events(ctx) || io_has_work(ctx)) |
|
mask |= EPOLLIN | EPOLLRDNORM; |
|
|
|
return mask; |
|
} |
|
|
|
static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id) |
|
{ |
|
const struct cred *creds; |
|
|
|
creds = xa_erase(&ctx->personalities, id); |
|
if (creds) { |
|
put_cred(creds); |
|
return 0; |
|
} |
|
|
|
return -EINVAL; |
|
} |
|
|
|
struct io_tctx_exit { |
|
struct callback_head task_work; |
|
struct completion completion; |
|
struct io_ring_ctx *ctx; |
|
}; |
|
|
|
static __cold void io_tctx_exit_cb(struct callback_head *cb) |
|
{ |
|
struct io_uring_task *tctx = current->io_uring; |
|
struct io_tctx_exit *work; |
|
|
|
work = container_of(cb, struct io_tctx_exit, task_work); |
|
/* |
|
* When @in_idle, we're in cancellation and it's racy to remove the |
|
* node. It'll be removed by the end of cancellation, just ignore it. |
|
* tctx can be NULL if the queueing of this task_work raced with |
|
* work cancelation off the exec path. |
|
*/ |
|
if (tctx && !atomic_read(&tctx->in_idle)) |
|
io_uring_del_tctx_node((unsigned long)work->ctx); |
|
complete(&work->completion); |
|
} |
|
|
|
static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data) |
|
{ |
|
struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
|
|
|
return req->ctx == data; |
|
} |
|
|
|
static __cold void io_ring_exit_work(struct work_struct *work) |
|
{ |
|
struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work); |
|
unsigned long timeout = jiffies + HZ * 60 * 5; |
|
unsigned long interval = HZ / 20; |
|
struct io_tctx_exit exit; |
|
struct io_tctx_node *node; |
|
int ret; |
|
|
|
/* |
|
* If we're doing polled IO and end up having requests being |
|
* submitted async (out-of-line), then completions can come in while |
|
* we're waiting for refs to drop. We need to reap these manually, |
|
* as nobody else will be looking for them. |
|
*/ |
|
do { |
|
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) |
|
io_move_task_work_from_local(ctx); |
|
|
|
while (io_uring_try_cancel_requests(ctx, NULL, true)) |
|
cond_resched(); |
|
|
|
if (ctx->sq_data) { |
|
struct io_sq_data *sqd = ctx->sq_data; |
|
struct task_struct *tsk; |
|
|
|
io_sq_thread_park(sqd); |
|
tsk = sqd->thread; |
|
if (tsk && tsk->io_uring && tsk->io_uring->io_wq) |
|
io_wq_cancel_cb(tsk->io_uring->io_wq, |
|
io_cancel_ctx_cb, ctx, true); |
|
io_sq_thread_unpark(sqd); |
|
} |
|
|
|
io_req_caches_free(ctx); |
|
|
|
if (WARN_ON_ONCE(time_after(jiffies, timeout))) { |
|
/* there is little hope left, don't run it too often */ |
|
interval = HZ * 60; |
|
} |
|
} while (!wait_for_completion_timeout(&ctx->ref_comp, interval)); |
|
|
|
init_completion(&exit.completion); |
|
init_task_work(&exit.task_work, io_tctx_exit_cb); |
|
exit.ctx = ctx; |
|
/* |
|
* Some may use context even when all refs and requests have been put, |
|
* and they are free to do so while still holding uring_lock or |
|
* completion_lock, see io_req_task_submit(). Apart from other work, |
|
* this lock/unlock section also waits them to finish. |
|
*/ |
|
mutex_lock(&ctx->uring_lock); |
|
while (!list_empty(&ctx->tctx_list)) { |
|
WARN_ON_ONCE(time_after(jiffies, timeout)); |
|
|
|
node = list_first_entry(&ctx->tctx_list, struct io_tctx_node, |
|
ctx_node); |
|
/* don't spin on a single task if cancellation failed */ |
|
list_rotate_left(&ctx->tctx_list); |
|
ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL); |
|
if (WARN_ON_ONCE(ret)) |
|
continue; |
|
|
|
mutex_unlock(&ctx->uring_lock); |
|
wait_for_completion(&exit.completion); |
|
mutex_lock(&ctx->uring_lock); |
|
} |
|
mutex_unlock(&ctx->uring_lock); |
|
spin_lock(&ctx->completion_lock); |
|
spin_unlock(&ctx->completion_lock); |
|
|
|
io_ring_ctx_free(ctx); |
|
} |
|
|
|
static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) |
|
{ |
|
unsigned long index; |
|
struct creds *creds; |
|
|
|
mutex_lock(&ctx->uring_lock); |
|
percpu_ref_kill(&ctx->refs); |
|
if (ctx->rings) |
|
__io_cqring_overflow_flush(ctx, true); |
|
xa_for_each(&ctx->personalities, index, creds) |
|
io_unregister_personality(ctx, index); |
|
if (ctx->rings) |
|
io_poll_remove_all(ctx, NULL, true); |
|
mutex_unlock(&ctx->uring_lock); |
|
|
|
/* |
|
* If we failed setting up the ctx, we might not have any rings |
|
* and therefore did not submit any requests |
|
*/ |
|
if (ctx->rings) |
|
io_kill_timeouts(ctx, NULL, true); |
|
|
|
INIT_WORK(&ctx->exit_work, io_ring_exit_work); |
|
/* |
|
* Use system_unbound_wq to avoid spawning tons of event kworkers |
|
* if we're exiting a ton of rings at the same time. It just adds |
|
* noise and overhead, there's no discernable change in runtime |
|
* over using system_wq. |
|
*/ |
|
queue_work(system_unbound_wq, &ctx->exit_work); |
|
} |
|
|
|
static int io_uring_release(struct inode *inode, struct file *file) |
|
{ |
|
struct io_ring_ctx *ctx = file->private_data; |
|
|
|
file->private_data = NULL; |
|
io_ring_ctx_wait_and_kill(ctx); |
|
return 0; |
|
} |
|
|
|
struct io_task_cancel { |
|
struct task_struct *task; |
|
bool all; |
|
}; |
|
|
|
static bool io_cancel_task_cb(struct io_wq_work *work, void *data) |
|
{ |
|
struct io_kiocb *req = container_of(work, struct io_kiocb, work); |
|
struct io_task_cancel *cancel = data; |
|
|
|
return io_match_task_safe(req, cancel->task, cancel->all); |
|
} |
|
|
|
static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx, |
|
struct task_struct *task, |
|
bool cancel_all) |
|
{ |
|
struct io_defer_entry *de; |
|
LIST_HEAD(list); |
|
|
|
spin_lock(&ctx->completion_lock); |
|
list_for_each_entry_reverse(de, &ctx->defer_list, list) { |
|
if (io_match_task_safe(de->req, task, cancel_all)) { |
|
list_cut_position(&list, &ctx->defer_list, &de->list); |
|
break; |
|
} |
|
} |
|
spin_unlock(&ctx->completion_lock); |
|
if (list_empty(&list)) |
|
return false; |
|
|
|
while (!list_empty(&list)) { |
|
de = list_first_entry(&list, struct io_defer_entry, list); |
|
list_del_init(&de->list); |
|
io_req_complete_failed(de->req, -ECANCELED); |
|
kfree(de); |
|
} |
|
return true; |
|
} |
|
|
|
static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx) |
|
{ |
|
struct io_tctx_node *node; |
|
enum io_wq_cancel cret; |
|
bool ret = false; |
|
|
|
mutex_lock(&ctx->uring_lock); |
|
list_for_each_entry(node, &ctx->tctx_list, ctx_node) { |
|
struct io_uring_task *tctx = node->task->io_uring; |
|
|
|
/* |
|
* io_wq will stay alive while we hold uring_lock, because it's |
|
* killed after ctx nodes, which requires to take the lock. |
|
*/ |
|
if (!tctx || !tctx->io_wq) |
|
continue; |
|
cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true); |
|
ret |= (cret != IO_WQ_CANCEL_NOTFOUND); |
|
} |
|
mutex_unlock(&ctx->uring_lock); |
|
|
|
return ret; |
|
} |
|
|
|
static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx, |
|
struct task_struct *task, |
|
bool cancel_all) |
|
{ |
|
struct io_task_cancel cancel = { .task = task, .all = cancel_all, }; |
|
struct io_uring_task *tctx = task ? task->io_uring : NULL; |
|
enum io_wq_cancel cret; |
|
bool ret = false; |
|
|
|
/* failed during ring init, it couldn't have issued any requests */ |
|
if (!ctx->rings) |
|
return false; |
|
|
|
if (!task) { |
|
ret |= io_uring_try_cancel_iowq(ctx); |
|
} else if (tctx && tctx->io_wq) { |
|
/* |
|
* Cancels requests of all rings, not only @ctx, but |
|
* it's fine as the task is in exit/exec. |
|
*/ |
|
cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb, |
|
&cancel, true); |
|
ret |= (cret != IO_WQ_CANCEL_NOTFOUND); |
|
} |
|
|
|
/* SQPOLL thread does its own polling */ |
|
if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) || |
|
(ctx->sq_data && ctx->sq_data->thread == current)) { |
|
while (!wq_list_empty(&ctx->iopoll_list)) { |
|
io_iopoll_try_reap_events(ctx); |
|
ret = true; |
|
} |
|
} |
|
|
|
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) |
|
ret |= io_run_local_work(ctx) > 0; |
|
ret |= io_cancel_defer_files(ctx, task, cancel_all); |
|
mutex_lock(&ctx->uring_lock); |
|
ret |= io_poll_remove_all(ctx, task, cancel_all); |
|
mutex_unlock(&ctx->uring_lock); |
|
ret |= io_kill_timeouts(ctx, task, cancel_all); |
|
if (task) |
|
ret |= io_run_task_work() > 0; |
|
return ret; |
|
} |
|
|
|
static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked) |
|
{ |
|
if (tracked) |
|
return atomic_read(&tctx->inflight_tracked); |
|
return percpu_counter_sum(&tctx->inflight); |
|
} |
|
|
|
/* |
|
* Find any io_uring ctx that this task has registered or done IO on, and cancel |
|
* requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation. |
|
*/ |
|
__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd) |
|
{ |
|
struct io_uring_task *tctx = current->io_uring; |
|
struct io_ring_ctx *ctx; |
|
s64 inflight; |
|
DEFINE_WAIT(wait); |
|
|
|
WARN_ON_ONCE(sqd && sqd->thread != current); |
|
|
|
if (!current->io_uring) |
|
return; |
|
if (tctx->io_wq) |
|
io_wq_exit_start(tctx->io_wq); |
|
|
|
atomic_inc(&tctx->in_idle); |
|
do { |
|
bool loop = false; |
|
|
|
io_uring_drop_tctx_refs(current); |
|
/* read completions before cancelations */ |
|
inflight = tctx_inflight(tctx, !cancel_all); |
|
if (!inflight) |
|
break; |
|
|
|
if (!sqd) { |
|
struct io_tctx_node *node; |
|
unsigned long index; |
|
|
|
xa_for_each(&tctx->xa, index, node) { |
|
/* sqpoll task will cancel all its requests */ |
|
if (node->ctx->sq_data) |
|
continue; |
|
loop |= io_uring_try_cancel_requests(node->ctx, |
|
current, cancel_all); |
|
} |
|
} else { |
|
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) |
|
loop |= io_uring_try_cancel_requests(ctx, |
|
current, |
|
cancel_all); |
|
} |
|
|
|
if (loop) { |
|
cond_resched(); |
|
continue; |
|
} |
|
|
|
prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE); |
|
io_run_task_work(); |
|
io_uring_drop_tctx_refs(current); |
|
|
|
/* |
|
* If we've seen completions, retry without waiting. This |
|
* avoids a race where a completion comes in before we did |
|
* prepare_to_wait(). |
|
*/ |
|
if (inflight == tctx_inflight(tctx, !cancel_all)) |
|
schedule(); |
|
finish_wait(&tctx->wait, &wait); |
|
} while (1); |
|
|
|
io_uring_clean_tctx(tctx); |
|
if (cancel_all) { |
|
/* |
|
* We shouldn't run task_works after cancel, so just leave |
|
* ->in_idle set for normal exit. |
|
*/ |
|
atomic_dec(&tctx->in_idle); |
|
/* for exec all current's requests should be gone, kill tctx */ |
|
__io_uring_free(current); |
|
} |
|
} |
|
|
|
void __io_uring_cancel(bool cancel_all) |
|
{ |
|
io_uring_cancel_generic(cancel_all, NULL); |
|
} |
|
|
|
static void *io_uring_validate_mmap_request(struct file *file, |
|
loff_t pgoff, size_t sz) |
|
{ |
|
struct io_ring_ctx *ctx = file->private_data; |
|
loff_t offset = pgoff << PAGE_SHIFT; |
|
struct page *page; |
|
void *ptr; |
|
|
|
switch (offset) { |
|
case IORING_OFF_SQ_RING: |
|
case IORING_OFF_CQ_RING: |
|
ptr = ctx->rings; |
|
break; |
|
case IORING_OFF_SQES: |
|
ptr = ctx->sq_sqes; |
|
break; |
|
default: |
|
return ERR_PTR(-EINVAL); |
|
} |
|
|
|
page = virt_to_head_page(ptr); |
|
if (sz > page_size(page)) |
|
return ERR_PTR(-EINVAL); |
|
|
|
return ptr; |
|
} |
|
|
|
#ifdef CONFIG_MMU |
|
|
|
static __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma) |
|
{ |
|
size_t sz = vma->vm_end - vma->vm_start; |
|
unsigned long pfn; |
|
void *ptr; |
|
|
|
ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz); |
|
if (IS_ERR(ptr)) |
|
return PTR_ERR(ptr); |
|
|
|
pfn = virt_to_phys(ptr) >> PAGE_SHIFT; |
|
return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); |
|
} |
|
|
|
#else /* !CONFIG_MMU */ |
|
|
|
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) |
|
{ |
|
return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL; |
|
} |
|
|
|
static unsigned int io_uring_nommu_mmap_capabilities(struct file *file) |
|
{ |
|
return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; |
|
} |
|
|
|
static unsigned long io_uring_nommu_get_unmapped_area(struct file *file, |
|
unsigned long addr, unsigned long len, |
|
unsigned long pgoff, unsigned long flags) |
|
{ |
|
void *ptr; |
|
|
|
ptr = io_uring_validate_mmap_request(file, pgoff, len); |
|
if (IS_ERR(ptr)) |
|
return PTR_ERR(ptr); |
|
|
|
return (unsigned long) ptr; |
|
} |
|
|
|
#endif /* !CONFIG_MMU */ |
|
|
|
static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t argsz) |
|
{ |
|
if (flags & IORING_ENTER_EXT_ARG) { |
|
struct io_uring_getevents_arg arg; |
|
|
|
if (argsz != sizeof(arg)) |
|
return -EINVAL; |
|
if (copy_from_user(&arg, argp, sizeof(arg))) |
|
return -EFAULT; |
|
} |
|
return 0; |
|
} |
|
|
|
static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz, |
|
struct __kernel_timespec __user **ts, |
|
const sigset_t __user **sig) |
|
{ |
|
struct io_uring_getevents_arg arg; |
|
|
|
/* |
|
* If EXT_ARG isn't set, then we have no timespec and the argp pointer |
|
* is just a pointer to the sigset_t. |
|
*/ |
|
if (!(flags & IORING_ENTER_EXT_ARG)) { |
|
*sig = (const sigset_t __user *) argp; |
|
*ts = NULL; |
|
return 0; |
|
} |
|
|
|
/* |
|
* EXT_ARG is set - ensure we agree on the size of it and copy in our |
|
* timespec and sigset_t pointers if good. |
|
*/ |
|
if (*argsz != sizeof(arg)) |
|
return -EINVAL; |
|
if (copy_from_user(&arg, argp, sizeof(arg))) |
|
return -EFAULT; |
|
if (arg.pad) |
|
return -EINVAL; |
|
*sig = u64_to_user_ptr(arg.sigmask); |
|
*argsz = arg.sigmask_sz; |
|
*ts = u64_to_user_ptr(arg.ts); |
|
return 0; |
|
} |
|
|
|
SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, |
|
u32, min_complete, u32, flags, const void __user *, argp, |
|
size_t, argsz) |
|
{ |
|
struct io_ring_ctx *ctx; |
|
struct fd f; |
|
long ret; |
|
|
|
if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP | |
|
IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG | |
|
IORING_ENTER_REGISTERED_RING))) |
|
return -EINVAL; |
|
|
|
/* |
|
* Ring fd has been registered via IORING_REGISTER_RING_FDS, we |
|
* need only dereference our task private array to find it. |
|
*/ |
|
if (flags & IORING_ENTER_REGISTERED_RING) { |
|
struct io_uring_task *tctx = current->io_uring; |
|
|
|
if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX)) |
|
return -EINVAL; |
|
fd = array_index_nospec(fd, IO_RINGFD_REG_MAX); |
|
f.file = tctx->registered_rings[fd]; |
|
f.flags = 0; |
|
if (unlikely(!f.file)) |
|
return -EBADF; |
|
} else { |
|
f = fdget(fd); |
|
if (unlikely(!f.file)) |
|
return -EBADF; |
|
ret = -EOPNOTSUPP; |
|
if (unlikely(!io_is_uring_fops(f.file))) |
|
goto out; |
|
} |
|
|
|
ctx = f.file->private_data; |
|
ret = -EBADFD; |
|
if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED)) |
|
goto out; |
|
|
|
/* |
|
* For SQ polling, the thread will do all submissions and completions. |
|
* Just return the requested submit count, and wake the thread if |
|
* we were asked to. |
|
*/ |
|
ret = 0; |
|
if (ctx->flags & IORING_SETUP_SQPOLL) { |
|
io_cqring_overflow_flush(ctx); |
|
|
|
if (unlikely(ctx->sq_data->thread == NULL)) { |
|
ret = -EOWNERDEAD; |
|
goto out; |
|
} |
|
if (flags & IORING_ENTER_SQ_WAKEUP) |
|
wake_up(&ctx->sq_data->wait); |
|
if (flags & IORING_ENTER_SQ_WAIT) { |
|
ret = io_sqpoll_wait_sq(ctx); |
|
if (ret) |
|
goto out; |
|
} |
|
ret = to_submit; |
|
} else if (to_submit) { |
|
ret = io_uring_add_tctx_node(ctx); |
|
if (unlikely(ret)) |
|
goto out; |
|
|
|
mutex_lock(&ctx->uring_lock); |
|
ret = io_submit_sqes(ctx, to_submit); |
|
if (ret != to_submit) { |
|
mutex_unlock(&ctx->uring_lock); |
|
goto out; |
|
} |
|
if (flags & IORING_ENTER_GETEVENTS) { |
|
if (ctx->syscall_iopoll) |
|
goto iopoll_locked; |
|
/* |
|
* Ignore errors, we'll soon call io_cqring_wait() and |
|
* it should handle ownership problems if any. |
|
*/ |
|
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) |
|
(void)io_run_local_work_locked(ctx); |
|
} |
|
mutex_unlock(&ctx->uring_lock); |
|
} |
|
|
|
if (flags & IORING_ENTER_GETEVENTS) { |
|
int ret2; |
|
|
|
if (ctx->syscall_iopoll) { |
|
/* |
|
* We disallow the app entering submit/complete with |
|
* polling, but we still need to lock the ring to |
|
* prevent racing with polled issue that got punted to |
|
* a workqueue. |
|
*/ |
|
mutex_lock(&ctx->uring_lock); |
|
iopoll_locked: |
|
ret2 = io_validate_ext_arg(flags, argp, argsz); |
|
if (likely(!ret2)) { |
|
min_complete = min(min_complete, |
|
ctx->cq_entries); |
|
ret2 = io_iopoll_check(ctx, min_complete); |
|
} |
|
mutex_unlock(&ctx->uring_lock); |
|
} else { |
|
const sigset_t __user *sig; |
|
struct __kernel_timespec __user *ts; |
|
|
|
ret2 = io_get_ext_arg(flags, argp, &argsz, &ts, &sig); |
|
if (likely(!ret2)) { |
|
min_complete = min(min_complete, |
|
ctx->cq_entries); |
|
ret2 = io_cqring_wait(ctx, min_complete, sig, |
|
argsz, ts); |
|
} |
|
} |
|
|
|
if (!ret) { |
|
ret = ret2; |
|
|
|
/* |
|
* EBADR indicates that one or more CQE were dropped. |
|
* Once the user has been informed we can clear the bit |
|
* as they are obviously ok with those drops. |
|
*/ |
|
if (unlikely(ret2 == -EBADR)) |
|
clear_bit(IO_CHECK_CQ_DROPPED_BIT, |
|
&ctx->check_cq); |
|
} |
|
} |
|
out: |
|
fdput(f); |
|
return ret; |
|
} |
|
|
|
static const struct file_operations io_uring_fops = { |
|
.release = io_uring_release, |
|
.mmap = io_uring_mmap, |
|
#ifndef CONFIG_MMU |
|
.get_unmapped_area = io_uring_nommu_get_unmapped_area, |
|
.mmap_capabilities = io_uring_nommu_mmap_capabilities, |
|
#endif |
|
.poll = io_uring_poll, |
|
#ifdef CONFIG_PROC_FS |
|
.show_fdinfo = io_uring_show_fdinfo, |
|
#endif |
|
}; |
|
|
|
bool io_is_uring_fops(struct file *file) |
|
{ |
|
return file->f_op == &io_uring_fops; |
|
} |
|
|
|
static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx, |
|
struct io_uring_params *p) |
|
{ |
|
struct io_rings *rings; |
|
size_t size, sq_array_offset; |
|
|
|
/* make sure these are sane, as we already accounted them */ |
|
ctx->sq_entries = p->sq_entries; |
|
ctx->cq_entries = p->cq_entries; |
|
|
|
size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset); |
|
if (size == SIZE_MAX) |
|
return -EOVERFLOW; |
|
|
|
rings = io_mem_alloc(size); |
|
if (!rings) |
|
return -ENOMEM; |
|
|
|
ctx->rings = rings; |
|
ctx->sq_array = (u32 *)((char *)rings + sq_array_offset); |
|
rings->sq_ring_mask = p->sq_entries - 1; |
|
rings->cq_ring_mask = p->cq_entries - 1; |
|
rings->sq_ring_entries = p->sq_entries; |
|
rings->cq_ring_entries = p->cq_entries; |
|
|
|
if (p->flags & IORING_SETUP_SQE128) |
|
size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries); |
|
else |
|
size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); |
|
if (size == SIZE_MAX) { |
|
io_mem_free(ctx->rings); |
|
ctx->rings = NULL; |
|
return -EOVERFLOW; |
|
} |
|
|
|
ctx->sq_sqes = io_mem_alloc(size); |
|
if (!ctx->sq_sqes) { |
|
io_mem_free(ctx->rings); |
|
ctx->rings = NULL; |
|
return -ENOMEM; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file) |
|
{ |
|
int ret, fd; |
|
|
|
fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC); |
|
if (fd < 0) |
|
return fd; |
|
|
|
ret = __io_uring_add_tctx_node(ctx); |
|
if (ret) { |
|
put_unused_fd(fd); |
|
return ret; |
|
} |
|
fd_install(fd, file); |
|
return fd; |
|
} |
|
|
|
/* |
|
* Allocate an anonymous fd, this is what constitutes the application |
|
* visible backing of an io_uring instance. The application mmaps this |
|
* fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled, |
|
* we have to tie this fd to a socket for file garbage collection purposes. |
|
*/ |
|
static struct file *io_uring_get_file(struct io_ring_ctx *ctx) |
|
{ |
|
struct file *file; |
|
#if defined(CONFIG_UNIX) |
|
int ret; |
|
|
|
ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP, |
|
&ctx->ring_sock); |
|
if (ret) |
|
return ERR_PTR(ret); |
|
#endif |
|
|
|
file = anon_inode_getfile_secure("[io_uring]", &io_uring_fops, ctx, |
|
O_RDWR | O_CLOEXEC, NULL); |
|
#if defined(CONFIG_UNIX) |
|
if (IS_ERR(file)) { |
|
sock_release(ctx->ring_sock); |
|
ctx->ring_sock = NULL; |
|
} else { |
|
ctx->ring_sock->file = file; |
|
} |
|
#endif |
|
return file; |
|
} |
|
|
|
static __cold int io_uring_create(unsigned entries, struct io_uring_params *p, |
|
struct io_uring_params __user *params) |
|
{ |
|
struct io_ring_ctx *ctx; |
|
struct file *file; |
|
int ret; |
|
|
|
if (!entries) |
|
return -EINVAL; |
|
if (entries > IORING_MAX_ENTRIES) { |
|
if (!(p->flags & IORING_SETUP_CLAMP)) |
|
return -EINVAL; |
|
entries = IORING_MAX_ENTRIES; |
|
} |
|
|
|
/* |
|
* Use twice as many entries for the CQ ring. It's possible for the |
|
* application to drive a higher depth than the size of the SQ ring, |
|
* since the sqes are only used at submission time. This allows for |
|
* some flexibility in overcommitting a bit. If the application has |
|
* set IORING_SETUP_CQSIZE, it will have passed in the desired number |
|
* of CQ ring entries manually. |
|
*/ |
|
p->sq_entries = roundup_pow_of_two(entries); |
|
if (p->flags & IORING_SETUP_CQSIZE) { |
|
/* |
|
* If IORING_SETUP_CQSIZE is set, we do the same roundup |
|
* to a power-of-two, if it isn't already. We do NOT impose |
|
* any cq vs sq ring sizing. |
|
*/ |
|
if (!p->cq_entries) |
|
return -EINVAL; |
|
if (p->cq_entries > IORING_MAX_CQ_ENTRIES) { |
|
if (!(p->flags & IORING_SETUP_CLAMP)) |
|
return -EINVAL; |
|
p->cq_entries = IORING_MAX_CQ_ENTRIES; |
|
} |
|
p->cq_entries = roundup_pow_of_two(p->cq_entries); |
|
if (p->cq_entries < p->sq_entries) |
|
return -EINVAL; |
|
} else { |
|
p->cq_entries = 2 * p->sq_entries; |
|
} |
|
|
|
ctx = io_ring_ctx_alloc(p); |
|
if (!ctx) |
|
return -ENOMEM; |
|
|
|
/* |
|
* When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user |
|
* space applications don't need to do io completion events |
|
* polling again, they can rely on io_sq_thread to do polling |
|
* work, which can reduce cpu usage and uring_lock contention. |
|
*/ |
|
if (ctx->flags & IORING_SETUP_IOPOLL && |
|
!(ctx->flags & IORING_SETUP_SQPOLL)) |
|
ctx->syscall_iopoll = 1; |
|
|
|
ctx->compat = in_compat_syscall(); |
|
if (!capable(CAP_IPC_LOCK)) |
|
ctx->user = get_uid(current_user()); |
|
|
|
/* |
|
* For SQPOLL, we just need a wakeup, always. For !SQPOLL, if |
|
* COOP_TASKRUN is set, then IPIs are never needed by the app. |
|
*/ |
|
ret = -EINVAL; |
|
if (ctx->flags & IORING_SETUP_SQPOLL) { |
|
/* IPI related flags don't make sense with SQPOLL */ |
|
if (ctx->flags & (IORING_SETUP_COOP_TASKRUN | |
|
IORING_SETUP_TASKRUN_FLAG | |
|
IORING_SETUP_DEFER_TASKRUN)) |
|
goto err; |
|
ctx->notify_method = TWA_SIGNAL_NO_IPI; |
|
} else if (ctx->flags & IORING_SETUP_COOP_TASKRUN) { |
|
ctx->notify_method = TWA_SIGNAL_NO_IPI; |
|
} else { |
|
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG && |
|
!(ctx->flags & IORING_SETUP_DEFER_TASKRUN)) |
|
goto err; |
|
ctx->notify_method = TWA_SIGNAL; |
|
} |
|
|
|
/* |
|
* For DEFER_TASKRUN we require the completion task to be the same as the |
|
* submission task. This implies that there is only one submitter, so enforce |
|
* that. |
|
*/ |
|
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN && |
|
!(ctx->flags & IORING_SETUP_SINGLE_ISSUER)) { |
|
goto err; |
|
} |
|
|
|
/* |
|
* This is just grabbed for accounting purposes. When a process exits, |
|
* the mm is exited and dropped before the files, hence we need to hang |
|
* on to this mm purely for the purposes of being able to unaccount |
|
* memory (locked/pinned vm). It's not used for anything else. |
|
*/ |
|
mmgrab(current->mm); |
|
ctx->mm_account = current->mm; |
|
|
|
ret = io_allocate_scq_urings(ctx, p); |
|
if (ret) |
|
goto err; |
|
|
|
ret = io_sq_offload_create(ctx, p); |
|
if (ret) |
|
goto err; |
|
/* always set a rsrc node */ |
|
ret = io_rsrc_node_switch_start(ctx); |
|
if (ret) |
|
goto err; |
|
io_rsrc_node_switch(ctx, NULL); |
|
|
|
memset(&p->sq_off, 0, sizeof(p->sq_off)); |
|
p->sq_off.head = offsetof(struct io_rings, sq.head); |
|
p->sq_off.tail = offsetof(struct io_rings, sq.tail); |
|
p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask); |
|
p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries); |
|
p->sq_off.flags = offsetof(struct io_rings, sq_flags); |
|
p->sq_off.dropped = offsetof(struct io_rings, sq_dropped); |
|
p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings; |
|
|
|
memset(&p->cq_off, 0, sizeof(p->cq_off)); |
|
p->cq_off.head = offsetof(struct io_rings, cq.head); |
|
p->cq_off.tail = offsetof(struct io_rings, cq.tail); |
|
p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask); |
|
p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries); |
|
p->cq_off.overflow = offsetof(struct io_rings, cq_overflow); |
|
p->cq_off.cqes = offsetof(struct io_rings, cqes); |
|
p->cq_off.flags = offsetof(struct io_rings, cq_flags); |
|
|
|
p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP | |
|
IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS | |
|
IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL | |
|
IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED | |
|
IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS | |
|
IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP | |
|
IORING_FEAT_LINKED_FILE; |
|
|
|
if (copy_to_user(params, p, sizeof(*p))) { |
|
ret = -EFAULT; |
|
goto err; |
|
} |
|
|
|
if (ctx->flags & IORING_SETUP_SINGLE_ISSUER |
|
&& !(ctx->flags & IORING_SETUP_R_DISABLED)) |
|
ctx->submitter_task = get_task_struct(current); |
|
|
|
file = io_uring_get_file(ctx); |
|
if (IS_ERR(file)) { |
|
ret = PTR_ERR(file); |
|
goto err; |
|
} |
|
|
|
/* |
|
* Install ring fd as the very last thing, so we don't risk someone |
|
* having closed it before we finish setup |
|
*/ |
|
ret = io_uring_install_fd(ctx, file); |
|
if (ret < 0) { |
|
/* fput will clean it up */ |
|
fput(file); |
|
return ret; |
|
} |
|
|
|
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); |
|
return ret; |
|
err: |
|
io_ring_ctx_wait_and_kill(ctx); |
|
return ret; |
|
} |
|
|
|
/* |
|
* Sets up an aio uring context, and returns the fd. Applications asks for a |
|
* ring size, we return the actual sq/cq ring sizes (among other things) in the |
|
* params structure passed in. |
|
*/ |
|
static long io_uring_setup(u32 entries, struct io_uring_params __user *params) |
|
{ |
|
struct io_uring_params p; |
|
int i; |
|
|
|
if (copy_from_user(&p, params, sizeof(p))) |
|
return -EFAULT; |
|
for (i = 0; i < ARRAY_SIZE(p.resv); i++) { |
|
if (p.resv[i]) |
|
return -EINVAL; |
|
} |
|
|
|
if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | |
|
IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE | |
|
IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ | |
|
IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL | |
|
IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG | |
|
IORING_SETUP_SQE128 | IORING_SETUP_CQE32 | |
|
IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN)) |
|
return -EINVAL; |
|
|
|
return io_uring_create(entries, &p, params); |
|
} |
|
|
|
SYSCALL_DEFINE2(io_uring_setup, u32, entries, |
|
struct io_uring_params __user *, params) |
|
{ |
|
return io_uring_setup(entries, params); |
|
} |
|
|
|
static __cold int io_probe(struct io_ring_ctx *ctx, void __user *arg, |
|
unsigned nr_args) |
|
{ |
|
struct io_uring_probe *p; |
|
size_t size; |
|
int i, ret; |
|
|
|
size = struct_size(p, ops, nr_args); |
|
if (size == SIZE_MAX) |
|
return -EOVERFLOW; |
|
p = kzalloc(size, GFP_KERNEL); |
|
if (!p) |
|
return -ENOMEM; |
|
|
|
ret = -EFAULT; |
|
if (copy_from_user(p, arg, size)) |
|
goto out; |
|
ret = -EINVAL; |
|
if (memchr_inv(p, 0, size)) |
|
goto out; |
|
|
|
p->last_op = IORING_OP_LAST - 1; |
|
if (nr_args > IORING_OP_LAST) |
|
nr_args = IORING_OP_LAST; |
|
|
|
for (i = 0; i < nr_args; i++) { |
|
p->ops[i].op = i; |
|
if (!io_op_defs[i].not_supported) |
|
p->ops[i].flags = IO_URING_OP_SUPPORTED; |
|
} |
|
p->ops_len = i; |
|
|
|
ret = 0; |
|
if (copy_to_user(arg, p, size)) |
|
ret = -EFAULT; |
|
out: |
|
kfree(p); |
|
return ret; |
|
} |
|
|
|
static int io_register_personality(struct io_ring_ctx *ctx) |
|
{ |
|
const struct cred *creds; |
|
u32 id; |
|
int ret; |
|
|
|
creds = get_current_cred(); |
|
|
|
ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds, |
|
XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL); |
|
if (ret < 0) { |
|
put_cred(creds); |
|
return ret; |
|
} |
|
return id; |
|
} |
|
|
|
static __cold int io_register_restrictions(struct io_ring_ctx *ctx, |
|
void __user *arg, unsigned int nr_args) |
|
{ |
|
struct io_uring_restriction *res; |
|
size_t size; |
|
int i, ret; |
|
|
|
/* Restrictions allowed only if rings started disabled */ |
|
if (!(ctx->flags & IORING_SETUP_R_DISABLED)) |
|
return -EBADFD; |
|
|
|
/* We allow only a single restrictions registration */ |
|
if (ctx->restrictions.registered) |
|
return -EBUSY; |
|
|
|
if (!arg || nr_args > IORING_MAX_RESTRICTIONS) |
|
return -EINVAL; |
|
|
|
size = array_size(nr_args, sizeof(*res)); |
|
if (size == SIZE_MAX) |
|
return -EOVERFLOW; |
|
|
|
res = memdup_user(arg, size); |
|
if (IS_ERR(res)) |
|
return PTR_ERR(res); |
|
|
|
ret = 0; |
|
|
|
for (i = 0; i < nr_args; i++) { |
|
switch (res[i].opcode) { |
|
case IORING_RESTRICTION_REGISTER_OP: |
|
if (res[i].register_op >= IORING_REGISTER_LAST) { |
|
ret = -EINVAL; |
|
goto out; |
|
} |
|
|
|
__set_bit(res[i].register_op, |
|
ctx->restrictions.register_op); |
|
break; |
|
case IORING_RESTRICTION_SQE_OP: |
|
if (res[i].sqe_op >= IORING_OP_LAST) { |
|
ret = -EINVAL; |
|
goto out; |
|
} |
|
|
|
__set_bit(res[i].sqe_op, ctx->restrictions.sqe_op); |
|
break; |
|
case IORING_RESTRICTION_SQE_FLAGS_ALLOWED: |
|
ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags; |
|
break; |
|
case IORING_RESTRICTION_SQE_FLAGS_REQUIRED: |
|
ctx->restrictions.sqe_flags_required = res[i].sqe_flags; |
|
break; |
|
default: |
|
ret = -EINVAL; |
|
goto out; |
|
} |
|
} |
|
|
|
out: |
|
/* Reset all restrictions if an error happened */ |
|
if (ret != 0) |
|
memset(&ctx->restrictions, 0, sizeof(ctx->restrictions)); |
|
else |
|
ctx->restrictions.registered = true; |
|
|
|
kfree(res); |
|
return ret; |
|
} |
|
|
|
static int io_register_enable_rings(struct io_ring_ctx *ctx) |
|
{ |
|
if (!(ctx->flags & IORING_SETUP_R_DISABLED)) |
|
return -EBADFD; |
|
|
|
if (ctx->flags & IORING_SETUP_SINGLE_ISSUER && !ctx->submitter_task) |
|
ctx->submitter_task = get_task_struct(current); |
|
|
|
if (ctx->restrictions.registered) |
|
ctx->restricted = 1; |
|
|
|
ctx->flags &= ~IORING_SETUP_R_DISABLED; |
|
if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait)) |
|
wake_up(&ctx->sq_data->wait); |
|
return 0; |
|
} |
|
|
|
static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx, |
|
void __user *arg, unsigned len) |
|
{ |
|
struct io_uring_task *tctx = current->io_uring; |
|
cpumask_var_t new_mask; |
|
int ret; |
|
|
|
if (!tctx || !tctx->io_wq) |
|
return -EINVAL; |
|
|
|
if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) |
|
return -ENOMEM; |
|
|
|
cpumask_clear(new_mask); |
|
if (len > cpumask_size()) |
|
len = cpumask_size(); |
|
|
|
if (in_compat_syscall()) { |
|
ret = compat_get_bitmap(cpumask_bits(new_mask), |
|
(const compat_ulong_t __user *)arg, |
|
len * 8 /* CHAR_BIT */); |
|
} else { |
|
ret = copy_from_user(new_mask, arg, len); |
|
} |
|
|
|
if (ret) { |
|
free_cpumask_var(new_mask); |
|
return -EFAULT; |
|
} |
|
|
|
ret = io_wq_cpu_affinity(tctx->io_wq, new_mask); |
|
free_cpumask_var(new_mask); |
|
return ret; |
|
} |
|
|
|
static __cold int io_unregister_iowq_aff(struct io_ring_ctx *ctx) |
|
{ |
|
struct io_uring_task *tctx = current->io_uring; |
|
|
|
if (!tctx || !tctx->io_wq) |
|
return -EINVAL; |
|
|
|
return io_wq_cpu_affinity(tctx->io_wq, NULL); |
|
} |
|
|
|
static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx, |
|
void __user *arg) |
|
__must_hold(&ctx->uring_lock) |
|
{ |
|
struct io_tctx_node *node; |
|
struct io_uring_task *tctx = NULL; |
|
struct io_sq_data *sqd = NULL; |
|
__u32 new_count[2]; |
|
int i, ret; |
|
|
|
if (copy_from_user(new_count, arg, sizeof(new_count))) |
|
return -EFAULT; |
|
for (i = 0; i < ARRAY_SIZE(new_count); i++) |
|
if (new_count[i] > INT_MAX) |
|
return -EINVAL; |
|
|
|
if (ctx->flags & IORING_SETUP_SQPOLL) { |
|
sqd = ctx->sq_data; |
|
if (sqd) { |
|
/* |
|
* Observe the correct sqd->lock -> ctx->uring_lock |
|
* ordering. Fine to drop uring_lock here, we hold |
|
* a ref to the ctx. |
|
*/ |
|
refcount_inc(&sqd->refs); |
|
mutex_unlock(&ctx->uring_lock); |
|
mutex_lock(&sqd->lock); |
|
mutex_lock(&ctx->uring_lock); |
|
if (sqd->thread) |
|
tctx = sqd->thread->io_uring; |
|
} |
|
} else { |
|
tctx = current->io_uring; |
|
} |
|
|
|
BUILD_BUG_ON(sizeof(new_count) != sizeof(ctx->iowq_limits)); |
|
|
|
for (i = 0; i < ARRAY_SIZE(new_count); i++) |
|
if (new_count[i]) |
|
ctx->iowq_limits[i] = new_count[i]; |
|
ctx->iowq_limits_set = true; |
|
|
|
if (tctx && tctx->io_wq) { |
|
ret = io_wq_max_workers(tctx->io_wq, new_count); |
|
if (ret) |
|
goto err; |
|
} else { |
|
memset(new_count, 0, sizeof(new_count)); |
|
} |
|
|
|
if (sqd) { |
|
mutex_unlock(&sqd->lock); |
|
io_put_sq_data(sqd); |
|
} |
|
|
|
if (copy_to_user(arg, new_count, sizeof(new_count))) |
|
return -EFAULT; |
|
|
|
/* that's it for SQPOLL, only the SQPOLL task creates requests */ |
|
if (sqd) |
|
return 0; |
|
|
|
/* now propagate the restriction to all registered users */ |
|
list_for_each_entry(node, &ctx->tctx_list, ctx_node) { |
|
struct io_uring_task *tctx = node->task->io_uring; |
|
|
|
if (WARN_ON_ONCE(!tctx->io_wq)) |
|
continue; |
|
|
|
for (i = 0; i < ARRAY_SIZE(new_count); i++) |
|
new_count[i] = ctx->iowq_limits[i]; |
|
/* ignore errors, it always returns zero anyway */ |
|
(void)io_wq_max_workers(tctx->io_wq, new_count); |
|
} |
|
return 0; |
|
err: |
|
if (sqd) { |
|
mutex_unlock(&sqd->lock); |
|
io_put_sq_data(sqd); |
|
} |
|
return ret; |
|
} |
|
|
|
static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, |
|
void __user *arg, unsigned nr_args) |
|
__releases(ctx->uring_lock) |
|
__acquires(ctx->uring_lock) |
|
{ |
|
int ret; |
|
|
|
/* |
|
* We don't quiesce the refs for register anymore and so it can't be |
|
* dying as we're holding a file ref here. |
|
*/ |
|
if (WARN_ON_ONCE(percpu_ref_is_dying(&ctx->refs))) |
|
return -ENXIO; |
|
|
|
if (ctx->submitter_task && ctx->submitter_task != current) |
|
return -EEXIST; |
|
|
|
if (ctx->restricted) { |
|
if (opcode >= IORING_REGISTER_LAST) |
|
return -EINVAL; |
|
opcode = array_index_nospec(opcode, IORING_REGISTER_LAST); |
|
if (!test_bit(opcode, ctx->restrictions.register_op)) |
|
return -EACCES; |
|
} |
|
|
|
switch (opcode) { |
|
case IORING_REGISTER_BUFFERS: |
|
ret = -EFAULT; |
|
if (!arg) |
|
break; |
|
ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL); |
|
break; |
|
case IORING_UNREGISTER_BUFFERS: |
|
ret = -EINVAL; |
|
if (arg || nr_args) |
|
break; |
|
ret = io_sqe_buffers_unregister(ctx); |
|
break; |
|
case IORING_REGISTER_FILES: |
|
ret = -EFAULT; |
|
if (!arg) |
|
break; |
|
ret = io_sqe_files_register(ctx, arg, nr_args, NULL); |
|
break; |
|
case IORING_UNREGISTER_FILES: |
|
ret = -EINVAL; |
|
if (arg || nr_args) |
|
break; |
|
ret = io_sqe_files_unregister(ctx); |
|
break; |
|
case IORING_REGISTER_FILES_UPDATE: |
|
ret = io_register_files_update(ctx, arg, nr_args); |
|
break; |
|
case IORING_REGISTER_EVENTFD: |
|
ret = -EINVAL; |
|
if (nr_args != 1) |
|
break; |
|
ret = io_eventfd_register(ctx, arg, 0); |
|
break; |
|
case IORING_REGISTER_EVENTFD_ASYNC: |
|
ret = -EINVAL; |
|
if (nr_args != 1) |
|
break; |
|
ret = io_eventfd_register(ctx, arg, 1); |
|
break; |
|
case IORING_UNREGISTER_EVENTFD: |
|
ret = -EINVAL; |
|
if (arg || nr_args) |
|
break; |
|
ret = io_eventfd_unregister(ctx); |
|
break; |
|
case IORING_REGISTER_PROBE: |
|
ret = -EINVAL; |
|
if (!arg || nr_args > 256) |
|
break; |
|
ret = io_probe(ctx, arg, nr_args); |
|
break; |
|
case IORING_REGISTER_PERSONALITY: |
|
ret = -EINVAL; |
|
if (arg || nr_args) |
|
break; |
|
ret = io_register_personality(ctx); |
|
break; |
|
case IORING_UNREGISTER_PERSONALITY: |
|
ret = -EINVAL; |
|
if (arg) |
|
break; |
|
ret = io_unregister_personality(ctx, nr_args); |
|
break; |
|
case IORING_REGISTER_ENABLE_RINGS: |
|
ret = -EINVAL; |
|
if (arg || nr_args) |
|
break; |
|
ret = io_register_enable_rings(ctx); |
|
break; |
|
case IORING_REGISTER_RESTRICTIONS: |
|
ret = io_register_restrictions(ctx, arg, nr_args); |
|
break; |
|
case IORING_REGISTER_FILES2: |
|
ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_FILE); |
|
break; |
|
case IORING_REGISTER_FILES_UPDATE2: |
|
ret = io_register_rsrc_update(ctx, arg, nr_args, |
|
IORING_RSRC_FILE); |
|
break; |
|
case IORING_REGISTER_BUFFERS2: |
|
ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_BUFFER); |
|
break; |
|
case IORING_REGISTER_BUFFERS_UPDATE: |
|
ret = io_register_rsrc_update(ctx, arg, nr_args, |
|
IORING_RSRC_BUFFER); |
|
break; |
|
case IORING_REGISTER_IOWQ_AFF: |
|
ret = -EINVAL; |
|
if (!arg || !nr_args) |
|
break; |
|
ret = io_register_iowq_aff(ctx, arg, nr_args); |
|
break; |
|
case IORING_UNREGISTER_IOWQ_AFF: |
|
ret = -EINVAL; |
|
if (arg || nr_args) |
|
break; |
|
ret = io_unregister_iowq_aff(ctx); |
|
break; |
|
case IORING_REGISTER_IOWQ_MAX_WORKERS: |
|
ret = -EINVAL; |
|
if (!arg || nr_args != 2) |
|
break; |
|
ret = io_register_iowq_max_workers(ctx, arg); |
|
break; |
|
case IORING_REGISTER_RING_FDS: |
|
ret = io_ringfd_register(ctx, arg, nr_args); |
|
break; |
|
case IORING_UNREGISTER_RING_FDS: |
|
ret = io_ringfd_unregister(ctx, arg, nr_args); |
|
break; |
|
case IORING_REGISTER_PBUF_RING: |
|
ret = -EINVAL; |
|
if (!arg || nr_args != 1) |
|
break; |
|
ret = io_register_pbuf_ring(ctx, arg); |
|
break; |
|
case IORING_UNREGISTER_PBUF_RING: |
|
ret = -EINVAL; |
|
if (!arg || nr_args != 1) |
|
break; |
|
ret = io_unregister_pbuf_ring(ctx, arg); |
|
break; |
|
case IORING_REGISTER_SYNC_CANCEL: |
|
ret = -EINVAL; |
|
if (!arg || nr_args != 1) |
|
break; |
|
ret = io_sync_cancel(ctx, arg); |
|
break; |
|
case IORING_REGISTER_FILE_ALLOC_RANGE: |
|
ret = -EINVAL; |
|
if (!arg || nr_args) |
|
break; |
|
ret = io_register_file_alloc_range(ctx, arg); |
|
break; |
|
default: |
|
ret = -EINVAL; |
|
break; |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, |
|
void __user *, arg, unsigned int, nr_args) |
|
{ |
|
struct io_ring_ctx *ctx; |
|
long ret = -EBADF; |
|
struct fd f; |
|
|
|
f = fdget(fd); |
|
if (!f.file) |
|
return -EBADF; |
|
|
|
ret = -EOPNOTSUPP; |
|
if (!io_is_uring_fops(f.file)) |
|
goto out_fput; |
|
|
|
ctx = f.file->private_data; |
|
|
|
io_run_task_work_ctx(ctx); |
|
|
|
mutex_lock(&ctx->uring_lock); |
|
ret = __io_uring_register(ctx, opcode, arg, nr_args); |
|
mutex_unlock(&ctx->uring_lock); |
|
trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ret); |
|
out_fput: |
|
fdput(f); |
|
return ret; |
|
} |
|
|
|
static int __init io_uring_init(void) |
|
{ |
|
#define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \ |
|
BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \ |
|
BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \ |
|
} while (0) |
|
|
|
#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \ |
|
__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename) |
|
#define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \ |
|
__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename) |
|
BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64); |
|
BUILD_BUG_SQE_ELEM(0, __u8, opcode); |
|
BUILD_BUG_SQE_ELEM(1, __u8, flags); |
|
BUILD_BUG_SQE_ELEM(2, __u16, ioprio); |
|
BUILD_BUG_SQE_ELEM(4, __s32, fd); |
|
BUILD_BUG_SQE_ELEM(8, __u64, off); |
|
BUILD_BUG_SQE_ELEM(8, __u64, addr2); |
|
BUILD_BUG_SQE_ELEM(8, __u32, cmd_op); |
|
BUILD_BUG_SQE_ELEM(12, __u32, __pad1); |
|
BUILD_BUG_SQE_ELEM(16, __u64, addr); |
|
BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in); |
|
BUILD_BUG_SQE_ELEM(24, __u32, len); |
|
BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags); |
|
BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags); |
|
BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags); |
|
BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events); |
|
BUILD_BUG_SQE_ELEM(28, __u32, poll32_events); |
|
BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, msg_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, accept_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, open_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, statx_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice); |
|
BUILD_BUG_SQE_ELEM(28, __u32, splice_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, rename_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, unlink_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, hardlink_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, xattr_flags); |
|
BUILD_BUG_SQE_ELEM(28, __u32, msg_ring_flags); |
|
BUILD_BUG_SQE_ELEM(32, __u64, user_data); |
|
BUILD_BUG_SQE_ELEM(40, __u16, buf_index); |
|
BUILD_BUG_SQE_ELEM(40, __u16, buf_group); |
|
BUILD_BUG_SQE_ELEM(42, __u16, personality); |
|
BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in); |
|
BUILD_BUG_SQE_ELEM(44, __u32, file_index); |
|
BUILD_BUG_SQE_ELEM(44, __u16, addr_len); |
|
BUILD_BUG_SQE_ELEM(46, __u16, __pad3[0]); |
|
BUILD_BUG_SQE_ELEM(48, __u64, addr3); |
|
BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd); |
|
BUILD_BUG_SQE_ELEM(56, __u64, __pad2); |
|
|
|
BUILD_BUG_ON(sizeof(struct io_uring_files_update) != |
|
sizeof(struct io_uring_rsrc_update)); |
|
BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) > |
|
sizeof(struct io_uring_rsrc_update2)); |
|
|
|
/* ->buf_index is u16 */ |
|
BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0); |
|
BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) != |
|
offsetof(struct io_uring_buf_ring, tail)); |
|
|
|
/* should fit into one byte */ |
|
BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8)); |
|
BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8)); |
|
BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS); |
|
|
|
BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int)); |
|
|
|
BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32)); |
|
|
|
io_uring_optable_init(); |
|
|
|
req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC | |
|
SLAB_ACCOUNT); |
|
return 0; |
|
}; |
|
__initcall(io_uring_init);
|
|
|