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2276 lines
56 KiB
2276 lines
56 KiB
/* |
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* An async IO implementation for Linux |
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* Written by Benjamin LaHaise <[email protected]> |
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* |
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* Implements an efficient asynchronous io interface. |
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* |
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* Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved. |
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* Copyright 2018 Christoph Hellwig. |
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* |
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* See ../COPYING for licensing terms. |
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*/ |
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#define pr_fmt(fmt) "%s: " fmt, __func__ |
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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/time.h> |
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#include <linux/aio_abi.h> |
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#include <linux/export.h> |
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#include <linux/syscalls.h> |
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#include <linux/backing-dev.h> |
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#include <linux/refcount.h> |
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#include <linux/uio.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/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/timer.h> |
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#include <linux/aio.h> |
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#include <linux/highmem.h> |
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#include <linux/workqueue.h> |
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#include <linux/security.h> |
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#include <linux/eventfd.h> |
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#include <linux/blkdev.h> |
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#include <linux/compat.h> |
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#include <linux/migrate.h> |
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#include <linux/ramfs.h> |
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#include <linux/percpu-refcount.h> |
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#include <linux/mount.h> |
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#include <linux/pseudo_fs.h> |
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|
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#include <linux/uaccess.h> |
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#include <linux/nospec.h> |
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|
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#include "internal.h" |
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|
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#define KIOCB_KEY 0 |
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|
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#define AIO_RING_MAGIC 0xa10a10a1 |
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#define AIO_RING_COMPAT_FEATURES 1 |
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#define AIO_RING_INCOMPAT_FEATURES 0 |
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struct aio_ring { |
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unsigned id; /* kernel internal index number */ |
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unsigned nr; /* number of io_events */ |
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unsigned head; /* Written to by userland or under ring_lock |
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* mutex by aio_read_events_ring(). */ |
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unsigned tail; |
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|
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unsigned magic; |
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unsigned compat_features; |
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unsigned incompat_features; |
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unsigned header_length; /* size of aio_ring */ |
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|
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|
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struct io_event io_events[]; |
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}; /* 128 bytes + ring size */ |
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|
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/* |
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* Plugging is meant to work with larger batches of IOs. If we don't |
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* have more than the below, then don't bother setting up a plug. |
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*/ |
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#define AIO_PLUG_THRESHOLD 2 |
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|
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#define AIO_RING_PAGES 8 |
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|
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struct kioctx_table { |
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struct rcu_head rcu; |
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unsigned nr; |
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struct kioctx __rcu *table[]; |
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}; |
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struct kioctx_cpu { |
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unsigned reqs_available; |
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}; |
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struct ctx_rq_wait { |
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struct completion comp; |
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atomic_t count; |
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}; |
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|
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struct kioctx { |
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struct percpu_ref users; |
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atomic_t dead; |
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struct percpu_ref reqs; |
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|
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unsigned long user_id; |
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struct __percpu kioctx_cpu *cpu; |
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|
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/* |
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* For percpu reqs_available, number of slots we move to/from global |
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* counter at a time: |
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*/ |
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unsigned req_batch; |
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/* |
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* This is what userspace passed to io_setup(), it's not used for |
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* anything but counting against the global max_reqs quota. |
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* |
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* The real limit is nr_events - 1, which will be larger (see |
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* aio_setup_ring()) |
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*/ |
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unsigned max_reqs; |
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|
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/* Size of ringbuffer, in units of struct io_event */ |
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unsigned nr_events; |
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|
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unsigned long mmap_base; |
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unsigned long mmap_size; |
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|
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struct page **ring_pages; |
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long nr_pages; |
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|
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struct rcu_work free_rwork; /* see free_ioctx() */ |
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|
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/* |
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* signals when all in-flight requests are done |
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*/ |
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struct ctx_rq_wait *rq_wait; |
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|
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struct { |
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/* |
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* This counts the number of available slots in the ringbuffer, |
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* so we avoid overflowing it: it's decremented (if positive) |
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* when allocating a kiocb and incremented when the resulting |
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* io_event is pulled off the ringbuffer. |
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* |
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* We batch accesses to it with a percpu version. |
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*/ |
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atomic_t reqs_available; |
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} ____cacheline_aligned_in_smp; |
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struct { |
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spinlock_t ctx_lock; |
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struct list_head active_reqs; /* used for cancellation */ |
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} ____cacheline_aligned_in_smp; |
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struct { |
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struct mutex ring_lock; |
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wait_queue_head_t wait; |
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} ____cacheline_aligned_in_smp; |
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struct { |
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unsigned tail; |
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unsigned completed_events; |
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spinlock_t completion_lock; |
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} ____cacheline_aligned_in_smp; |
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|
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struct page *internal_pages[AIO_RING_PAGES]; |
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struct file *aio_ring_file; |
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|
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unsigned id; |
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}; |
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|
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/* |
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* First field must be the file pointer in all the |
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* iocb unions! See also 'struct kiocb' in <linux/fs.h> |
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*/ |
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struct fsync_iocb { |
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struct file *file; |
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struct work_struct work; |
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bool datasync; |
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struct cred *creds; |
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}; |
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struct poll_iocb { |
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struct file *file; |
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struct wait_queue_head *head; |
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__poll_t events; |
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bool done; |
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bool cancelled; |
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struct wait_queue_entry wait; |
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struct work_struct work; |
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}; |
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|
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/* |
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* NOTE! Each of the iocb union members has the file pointer |
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* as the first entry in their struct definition. So you can |
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* access the file pointer through any of the sub-structs, |
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* or directly as just 'ki_filp' in this struct. |
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*/ |
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struct aio_kiocb { |
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union { |
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struct file *ki_filp; |
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struct kiocb rw; |
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struct fsync_iocb fsync; |
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struct poll_iocb poll; |
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}; |
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struct kioctx *ki_ctx; |
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kiocb_cancel_fn *ki_cancel; |
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struct io_event ki_res; |
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struct list_head ki_list; /* the aio core uses this |
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* for cancellation */ |
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refcount_t ki_refcnt; |
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|
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/* |
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* If the aio_resfd field of the userspace iocb is not zero, |
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* this is the underlying eventfd context to deliver events to. |
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*/ |
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struct eventfd_ctx *ki_eventfd; |
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}; |
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|
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/*------ sysctl variables----*/ |
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static DEFINE_SPINLOCK(aio_nr_lock); |
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unsigned long aio_nr; /* current system wide number of aio requests */ |
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unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */ |
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/*----end sysctl variables---*/ |
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|
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static struct kmem_cache *kiocb_cachep; |
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static struct kmem_cache *kioctx_cachep; |
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static struct vfsmount *aio_mnt; |
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static const struct file_operations aio_ring_fops; |
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static const struct address_space_operations aio_ctx_aops; |
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static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages) |
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{ |
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struct file *file; |
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struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb); |
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if (IS_ERR(inode)) |
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return ERR_CAST(inode); |
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inode->i_mapping->a_ops = &aio_ctx_aops; |
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inode->i_mapping->private_data = ctx; |
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inode->i_size = PAGE_SIZE * nr_pages; |
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file = alloc_file_pseudo(inode, aio_mnt, "[aio]", |
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O_RDWR, &aio_ring_fops); |
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if (IS_ERR(file)) |
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iput(inode); |
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return file; |
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} |
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static int aio_init_fs_context(struct fs_context *fc) |
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{ |
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if (!init_pseudo(fc, AIO_RING_MAGIC)) |
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return -ENOMEM; |
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fc->s_iflags |= SB_I_NOEXEC; |
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return 0; |
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} |
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|
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/* aio_setup |
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* Creates the slab caches used by the aio routines, panic on |
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* failure as this is done early during the boot sequence. |
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*/ |
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static int __init aio_setup(void) |
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{ |
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static struct file_system_type aio_fs = { |
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.name = "aio", |
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.init_fs_context = aio_init_fs_context, |
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.kill_sb = kill_anon_super, |
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}; |
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aio_mnt = kern_mount(&aio_fs); |
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if (IS_ERR(aio_mnt)) |
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panic("Failed to create aio fs mount."); |
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|
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kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
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kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC); |
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return 0; |
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} |
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__initcall(aio_setup); |
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static void put_aio_ring_file(struct kioctx *ctx) |
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{ |
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struct file *aio_ring_file = ctx->aio_ring_file; |
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struct address_space *i_mapping; |
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|
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if (aio_ring_file) { |
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truncate_setsize(file_inode(aio_ring_file), 0); |
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|
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/* Prevent further access to the kioctx from migratepages */ |
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i_mapping = aio_ring_file->f_mapping; |
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spin_lock(&i_mapping->private_lock); |
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i_mapping->private_data = NULL; |
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ctx->aio_ring_file = NULL; |
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spin_unlock(&i_mapping->private_lock); |
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|
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fput(aio_ring_file); |
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} |
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} |
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static void aio_free_ring(struct kioctx *ctx) |
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{ |
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int i; |
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|
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/* Disconnect the kiotx from the ring file. This prevents future |
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* accesses to the kioctx from page migration. |
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*/ |
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put_aio_ring_file(ctx); |
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|
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for (i = 0; i < ctx->nr_pages; i++) { |
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struct page *page; |
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pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i, |
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page_count(ctx->ring_pages[i])); |
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page = ctx->ring_pages[i]; |
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if (!page) |
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continue; |
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ctx->ring_pages[i] = NULL; |
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put_page(page); |
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} |
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if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) { |
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kfree(ctx->ring_pages); |
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ctx->ring_pages = NULL; |
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} |
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} |
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static int aio_ring_mremap(struct vm_area_struct *vma, unsigned long flags) |
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{ |
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struct file *file = vma->vm_file; |
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struct mm_struct *mm = vma->vm_mm; |
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struct kioctx_table *table; |
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int i, res = -EINVAL; |
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if (flags & MREMAP_DONTUNMAP) |
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return -EINVAL; |
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spin_lock(&mm->ioctx_lock); |
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rcu_read_lock(); |
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table = rcu_dereference(mm->ioctx_table); |
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for (i = 0; i < table->nr; i++) { |
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struct kioctx *ctx; |
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ctx = rcu_dereference(table->table[i]); |
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if (ctx && ctx->aio_ring_file == file) { |
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if (!atomic_read(&ctx->dead)) { |
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ctx->user_id = ctx->mmap_base = vma->vm_start; |
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res = 0; |
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} |
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break; |
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} |
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} |
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rcu_read_unlock(); |
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spin_unlock(&mm->ioctx_lock); |
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return res; |
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} |
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static const struct vm_operations_struct aio_ring_vm_ops = { |
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.mremap = aio_ring_mremap, |
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#if IS_ENABLED(CONFIG_MMU) |
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.fault = filemap_fault, |
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.map_pages = filemap_map_pages, |
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.page_mkwrite = filemap_page_mkwrite, |
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#endif |
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}; |
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static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma) |
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{ |
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vma->vm_flags |= VM_DONTEXPAND; |
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vma->vm_ops = &aio_ring_vm_ops; |
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return 0; |
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} |
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|
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static const struct file_operations aio_ring_fops = { |
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.mmap = aio_ring_mmap, |
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}; |
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|
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#if IS_ENABLED(CONFIG_MIGRATION) |
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static int aio_migratepage(struct address_space *mapping, struct page *new, |
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struct page *old, enum migrate_mode mode) |
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{ |
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struct kioctx *ctx; |
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unsigned long flags; |
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pgoff_t idx; |
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int rc; |
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|
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/* |
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* We cannot support the _NO_COPY case here, because copy needs to |
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* happen under the ctx->completion_lock. That does not work with the |
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* migration workflow of MIGRATE_SYNC_NO_COPY. |
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*/ |
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if (mode == MIGRATE_SYNC_NO_COPY) |
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return -EINVAL; |
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rc = 0; |
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|
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/* mapping->private_lock here protects against the kioctx teardown. */ |
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spin_lock(&mapping->private_lock); |
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ctx = mapping->private_data; |
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if (!ctx) { |
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rc = -EINVAL; |
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goto out; |
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} |
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|
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/* The ring_lock mutex. The prevents aio_read_events() from writing |
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* to the ring's head, and prevents page migration from mucking in |
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* a partially initialized kiotx. |
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*/ |
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if (!mutex_trylock(&ctx->ring_lock)) { |
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rc = -EAGAIN; |
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goto out; |
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} |
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|
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idx = old->index; |
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if (idx < (pgoff_t)ctx->nr_pages) { |
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/* Make sure the old page hasn't already been changed */ |
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if (ctx->ring_pages[idx] != old) |
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rc = -EAGAIN; |
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} else |
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rc = -EINVAL; |
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|
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if (rc != 0) |
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goto out_unlock; |
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|
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/* Writeback must be complete */ |
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BUG_ON(PageWriteback(old)); |
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get_page(new); |
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|
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rc = migrate_page_move_mapping(mapping, new, old, 1); |
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if (rc != MIGRATEPAGE_SUCCESS) { |
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put_page(new); |
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goto out_unlock; |
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} |
|
|
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/* Take completion_lock to prevent other writes to the ring buffer |
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* while the old page is copied to the new. This prevents new |
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* events from being lost. |
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*/ |
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spin_lock_irqsave(&ctx->completion_lock, flags); |
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migrate_page_copy(new, old); |
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BUG_ON(ctx->ring_pages[idx] != old); |
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ctx->ring_pages[idx] = new; |
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spin_unlock_irqrestore(&ctx->completion_lock, flags); |
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|
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/* The old page is no longer accessible. */ |
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put_page(old); |
|
|
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out_unlock: |
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mutex_unlock(&ctx->ring_lock); |
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out: |
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spin_unlock(&mapping->private_lock); |
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return rc; |
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} |
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#endif |
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|
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static const struct address_space_operations aio_ctx_aops = { |
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.set_page_dirty = __set_page_dirty_no_writeback, |
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#if IS_ENABLED(CONFIG_MIGRATION) |
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.migratepage = aio_migratepage, |
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#endif |
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}; |
|
|
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static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events) |
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{ |
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struct aio_ring *ring; |
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struct mm_struct *mm = current->mm; |
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unsigned long size, unused; |
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int nr_pages; |
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int i; |
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struct file *file; |
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|
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/* Compensate for the ring buffer's head/tail overlap entry */ |
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nr_events += 2; /* 1 is required, 2 for good luck */ |
|
|
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size = sizeof(struct aio_ring); |
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size += sizeof(struct io_event) * nr_events; |
|
|
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nr_pages = PFN_UP(size); |
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if (nr_pages < 0) |
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return -EINVAL; |
|
|
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file = aio_private_file(ctx, nr_pages); |
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if (IS_ERR(file)) { |
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ctx->aio_ring_file = NULL; |
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return -ENOMEM; |
|
} |
|
|
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ctx->aio_ring_file = file; |
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nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) |
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/ sizeof(struct io_event); |
|
|
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ctx->ring_pages = ctx->internal_pages; |
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if (nr_pages > AIO_RING_PAGES) { |
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ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *), |
|
GFP_KERNEL); |
|
if (!ctx->ring_pages) { |
|
put_aio_ring_file(ctx); |
|
return -ENOMEM; |
|
} |
|
} |
|
|
|
for (i = 0; i < nr_pages; i++) { |
|
struct page *page; |
|
page = find_or_create_page(file->f_mapping, |
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i, GFP_HIGHUSER | __GFP_ZERO); |
|
if (!page) |
|
break; |
|
pr_debug("pid(%d) page[%d]->count=%d\n", |
|
current->pid, i, page_count(page)); |
|
SetPageUptodate(page); |
|
unlock_page(page); |
|
|
|
ctx->ring_pages[i] = page; |
|
} |
|
ctx->nr_pages = i; |
|
|
|
if (unlikely(i != nr_pages)) { |
|
aio_free_ring(ctx); |
|
return -ENOMEM; |
|
} |
|
|
|
ctx->mmap_size = nr_pages * PAGE_SIZE; |
|
pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size); |
|
|
|
if (mmap_write_lock_killable(mm)) { |
|
ctx->mmap_size = 0; |
|
aio_free_ring(ctx); |
|
return -EINTR; |
|
} |
|
|
|
ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size, |
|
PROT_READ | PROT_WRITE, |
|
MAP_SHARED, 0, &unused, NULL); |
|
mmap_write_unlock(mm); |
|
if (IS_ERR((void *)ctx->mmap_base)) { |
|
ctx->mmap_size = 0; |
|
aio_free_ring(ctx); |
|
return -ENOMEM; |
|
} |
|
|
|
pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base); |
|
|
|
ctx->user_id = ctx->mmap_base; |
|
ctx->nr_events = nr_events; /* trusted copy */ |
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]); |
|
ring->nr = nr_events; /* user copy */ |
|
ring->id = ~0U; |
|
ring->head = ring->tail = 0; |
|
ring->magic = AIO_RING_MAGIC; |
|
ring->compat_features = AIO_RING_COMPAT_FEATURES; |
|
ring->incompat_features = AIO_RING_INCOMPAT_FEATURES; |
|
ring->header_length = sizeof(struct aio_ring); |
|
kunmap_atomic(ring); |
|
flush_dcache_page(ctx->ring_pages[0]); |
|
|
|
return 0; |
|
} |
|
|
|
#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event)) |
|
#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event)) |
|
#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE) |
|
|
|
void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel) |
|
{ |
|
struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, rw); |
|
struct kioctx *ctx = req->ki_ctx; |
|
unsigned long flags; |
|
|
|
if (WARN_ON_ONCE(!list_empty(&req->ki_list))) |
|
return; |
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags); |
|
list_add_tail(&req->ki_list, &ctx->active_reqs); |
|
req->ki_cancel = cancel; |
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
|
} |
|
EXPORT_SYMBOL(kiocb_set_cancel_fn); |
|
|
|
/* |
|
* free_ioctx() should be RCU delayed to synchronize against the RCU |
|
* protected lookup_ioctx() and also needs process context to call |
|
* aio_free_ring(). Use rcu_work. |
|
*/ |
|
static void free_ioctx(struct work_struct *work) |
|
{ |
|
struct kioctx *ctx = container_of(to_rcu_work(work), struct kioctx, |
|
free_rwork); |
|
pr_debug("freeing %p\n", ctx); |
|
|
|
aio_free_ring(ctx); |
|
free_percpu(ctx->cpu); |
|
percpu_ref_exit(&ctx->reqs); |
|
percpu_ref_exit(&ctx->users); |
|
kmem_cache_free(kioctx_cachep, ctx); |
|
} |
|
|
|
static void free_ioctx_reqs(struct percpu_ref *ref) |
|
{ |
|
struct kioctx *ctx = container_of(ref, struct kioctx, reqs); |
|
|
|
/* At this point we know that there are no any in-flight requests */ |
|
if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count)) |
|
complete(&ctx->rq_wait->comp); |
|
|
|
/* Synchronize against RCU protected table->table[] dereferences */ |
|
INIT_RCU_WORK(&ctx->free_rwork, free_ioctx); |
|
queue_rcu_work(system_wq, &ctx->free_rwork); |
|
} |
|
|
|
/* |
|
* When this function runs, the kioctx has been removed from the "hash table" |
|
* and ctx->users has dropped to 0, so we know no more kiocbs can be submitted - |
|
* now it's safe to cancel any that need to be. |
|
*/ |
|
static void free_ioctx_users(struct percpu_ref *ref) |
|
{ |
|
struct kioctx *ctx = container_of(ref, struct kioctx, users); |
|
struct aio_kiocb *req; |
|
|
|
spin_lock_irq(&ctx->ctx_lock); |
|
|
|
while (!list_empty(&ctx->active_reqs)) { |
|
req = list_first_entry(&ctx->active_reqs, |
|
struct aio_kiocb, ki_list); |
|
req->ki_cancel(&req->rw); |
|
list_del_init(&req->ki_list); |
|
} |
|
|
|
spin_unlock_irq(&ctx->ctx_lock); |
|
|
|
percpu_ref_kill(&ctx->reqs); |
|
percpu_ref_put(&ctx->reqs); |
|
} |
|
|
|
static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) |
|
{ |
|
unsigned i, new_nr; |
|
struct kioctx_table *table, *old; |
|
struct aio_ring *ring; |
|
|
|
spin_lock(&mm->ioctx_lock); |
|
table = rcu_dereference_raw(mm->ioctx_table); |
|
|
|
while (1) { |
|
if (table) |
|
for (i = 0; i < table->nr; i++) |
|
if (!rcu_access_pointer(table->table[i])) { |
|
ctx->id = i; |
|
rcu_assign_pointer(table->table[i], ctx); |
|
spin_unlock(&mm->ioctx_lock); |
|
|
|
/* While kioctx setup is in progress, |
|
* we are protected from page migration |
|
* changes ring_pages by ->ring_lock. |
|
*/ |
|
ring = kmap_atomic(ctx->ring_pages[0]); |
|
ring->id = ctx->id; |
|
kunmap_atomic(ring); |
|
return 0; |
|
} |
|
|
|
new_nr = (table ? table->nr : 1) * 4; |
|
spin_unlock(&mm->ioctx_lock); |
|
|
|
table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) * |
|
new_nr, GFP_KERNEL); |
|
if (!table) |
|
return -ENOMEM; |
|
|
|
table->nr = new_nr; |
|
|
|
spin_lock(&mm->ioctx_lock); |
|
old = rcu_dereference_raw(mm->ioctx_table); |
|
|
|
if (!old) { |
|
rcu_assign_pointer(mm->ioctx_table, table); |
|
} else if (table->nr > old->nr) { |
|
memcpy(table->table, old->table, |
|
old->nr * sizeof(struct kioctx *)); |
|
|
|
rcu_assign_pointer(mm->ioctx_table, table); |
|
kfree_rcu(old, rcu); |
|
} else { |
|
kfree(table); |
|
table = old; |
|
} |
|
} |
|
} |
|
|
|
static void aio_nr_sub(unsigned nr) |
|
{ |
|
spin_lock(&aio_nr_lock); |
|
if (WARN_ON(aio_nr - nr > aio_nr)) |
|
aio_nr = 0; |
|
else |
|
aio_nr -= nr; |
|
spin_unlock(&aio_nr_lock); |
|
} |
|
|
|
/* ioctx_alloc |
|
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed. |
|
*/ |
|
static struct kioctx *ioctx_alloc(unsigned nr_events) |
|
{ |
|
struct mm_struct *mm = current->mm; |
|
struct kioctx *ctx; |
|
int err = -ENOMEM; |
|
|
|
/* |
|
* Store the original nr_events -- what userspace passed to io_setup(), |
|
* for counting against the global limit -- before it changes. |
|
*/ |
|
unsigned int max_reqs = nr_events; |
|
|
|
/* |
|
* We keep track of the number of available ringbuffer slots, to prevent |
|
* overflow (reqs_available), and we also use percpu counters for this. |
|
* |
|
* So since up to half the slots might be on other cpu's percpu counters |
|
* and unavailable, double nr_events so userspace sees what they |
|
* expected: additionally, we move req_batch slots to/from percpu |
|
* counters at a time, so make sure that isn't 0: |
|
*/ |
|
nr_events = max(nr_events, num_possible_cpus() * 4); |
|
nr_events *= 2; |
|
|
|
/* Prevent overflows */ |
|
if (nr_events > (0x10000000U / sizeof(struct io_event))) { |
|
pr_debug("ENOMEM: nr_events too high\n"); |
|
return ERR_PTR(-EINVAL); |
|
} |
|
|
|
if (!nr_events || (unsigned long)max_reqs > aio_max_nr) |
|
return ERR_PTR(-EAGAIN); |
|
|
|
ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL); |
|
if (!ctx) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
ctx->max_reqs = max_reqs; |
|
|
|
spin_lock_init(&ctx->ctx_lock); |
|
spin_lock_init(&ctx->completion_lock); |
|
mutex_init(&ctx->ring_lock); |
|
/* Protect against page migration throughout kiotx setup by keeping |
|
* the ring_lock mutex held until setup is complete. */ |
|
mutex_lock(&ctx->ring_lock); |
|
init_waitqueue_head(&ctx->wait); |
|
|
|
INIT_LIST_HEAD(&ctx->active_reqs); |
|
|
|
if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL)) |
|
goto err; |
|
|
|
if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL)) |
|
goto err; |
|
|
|
ctx->cpu = alloc_percpu(struct kioctx_cpu); |
|
if (!ctx->cpu) |
|
goto err; |
|
|
|
err = aio_setup_ring(ctx, nr_events); |
|
if (err < 0) |
|
goto err; |
|
|
|
atomic_set(&ctx->reqs_available, ctx->nr_events - 1); |
|
ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4); |
|
if (ctx->req_batch < 1) |
|
ctx->req_batch = 1; |
|
|
|
/* limit the number of system wide aios */ |
|
spin_lock(&aio_nr_lock); |
|
if (aio_nr + ctx->max_reqs > aio_max_nr || |
|
aio_nr + ctx->max_reqs < aio_nr) { |
|
spin_unlock(&aio_nr_lock); |
|
err = -EAGAIN; |
|
goto err_ctx; |
|
} |
|
aio_nr += ctx->max_reqs; |
|
spin_unlock(&aio_nr_lock); |
|
|
|
percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */ |
|
percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */ |
|
|
|
err = ioctx_add_table(ctx, mm); |
|
if (err) |
|
goto err_cleanup; |
|
|
|
/* Release the ring_lock mutex now that all setup is complete. */ |
|
mutex_unlock(&ctx->ring_lock); |
|
|
|
pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n", |
|
ctx, ctx->user_id, mm, ctx->nr_events); |
|
return ctx; |
|
|
|
err_cleanup: |
|
aio_nr_sub(ctx->max_reqs); |
|
err_ctx: |
|
atomic_set(&ctx->dead, 1); |
|
if (ctx->mmap_size) |
|
vm_munmap(ctx->mmap_base, ctx->mmap_size); |
|
aio_free_ring(ctx); |
|
err: |
|
mutex_unlock(&ctx->ring_lock); |
|
free_percpu(ctx->cpu); |
|
percpu_ref_exit(&ctx->reqs); |
|
percpu_ref_exit(&ctx->users); |
|
kmem_cache_free(kioctx_cachep, ctx); |
|
pr_debug("error allocating ioctx %d\n", err); |
|
return ERR_PTR(err); |
|
} |
|
|
|
/* kill_ioctx |
|
* Cancels all outstanding aio requests on an aio context. Used |
|
* when the processes owning a context have all exited to encourage |
|
* the rapid destruction of the kioctx. |
|
*/ |
|
static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx, |
|
struct ctx_rq_wait *wait) |
|
{ |
|
struct kioctx_table *table; |
|
|
|
spin_lock(&mm->ioctx_lock); |
|
if (atomic_xchg(&ctx->dead, 1)) { |
|
spin_unlock(&mm->ioctx_lock); |
|
return -EINVAL; |
|
} |
|
|
|
table = rcu_dereference_raw(mm->ioctx_table); |
|
WARN_ON(ctx != rcu_access_pointer(table->table[ctx->id])); |
|
RCU_INIT_POINTER(table->table[ctx->id], NULL); |
|
spin_unlock(&mm->ioctx_lock); |
|
|
|
/* free_ioctx_reqs() will do the necessary RCU synchronization */ |
|
wake_up_all(&ctx->wait); |
|
|
|
/* |
|
* It'd be more correct to do this in free_ioctx(), after all |
|
* the outstanding kiocbs have finished - but by then io_destroy |
|
* has already returned, so io_setup() could potentially return |
|
* -EAGAIN with no ioctxs actually in use (as far as userspace |
|
* could tell). |
|
*/ |
|
aio_nr_sub(ctx->max_reqs); |
|
|
|
if (ctx->mmap_size) |
|
vm_munmap(ctx->mmap_base, ctx->mmap_size); |
|
|
|
ctx->rq_wait = wait; |
|
percpu_ref_kill(&ctx->users); |
|
return 0; |
|
} |
|
|
|
/* |
|
* exit_aio: called when the last user of mm goes away. At this point, there is |
|
* no way for any new requests to be submited or any of the io_* syscalls to be |
|
* called on the context. |
|
* |
|
* There may be outstanding kiocbs, but free_ioctx() will explicitly wait on |
|
* them. |
|
*/ |
|
void exit_aio(struct mm_struct *mm) |
|
{ |
|
struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table); |
|
struct ctx_rq_wait wait; |
|
int i, skipped; |
|
|
|
if (!table) |
|
return; |
|
|
|
atomic_set(&wait.count, table->nr); |
|
init_completion(&wait.comp); |
|
|
|
skipped = 0; |
|
for (i = 0; i < table->nr; ++i) { |
|
struct kioctx *ctx = |
|
rcu_dereference_protected(table->table[i], true); |
|
|
|
if (!ctx) { |
|
skipped++; |
|
continue; |
|
} |
|
|
|
/* |
|
* We don't need to bother with munmap() here - exit_mmap(mm) |
|
* is coming and it'll unmap everything. And we simply can't, |
|
* this is not necessarily our ->mm. |
|
* Since kill_ioctx() uses non-zero ->mmap_size as indicator |
|
* that it needs to unmap the area, just set it to 0. |
|
*/ |
|
ctx->mmap_size = 0; |
|
kill_ioctx(mm, ctx, &wait); |
|
} |
|
|
|
if (!atomic_sub_and_test(skipped, &wait.count)) { |
|
/* Wait until all IO for the context are done. */ |
|
wait_for_completion(&wait.comp); |
|
} |
|
|
|
RCU_INIT_POINTER(mm->ioctx_table, NULL); |
|
kfree(table); |
|
} |
|
|
|
static void put_reqs_available(struct kioctx *ctx, unsigned nr) |
|
{ |
|
struct kioctx_cpu *kcpu; |
|
unsigned long flags; |
|
|
|
local_irq_save(flags); |
|
kcpu = this_cpu_ptr(ctx->cpu); |
|
kcpu->reqs_available += nr; |
|
|
|
while (kcpu->reqs_available >= ctx->req_batch * 2) { |
|
kcpu->reqs_available -= ctx->req_batch; |
|
atomic_add(ctx->req_batch, &ctx->reqs_available); |
|
} |
|
|
|
local_irq_restore(flags); |
|
} |
|
|
|
static bool __get_reqs_available(struct kioctx *ctx) |
|
{ |
|
struct kioctx_cpu *kcpu; |
|
bool ret = false; |
|
unsigned long flags; |
|
|
|
local_irq_save(flags); |
|
kcpu = this_cpu_ptr(ctx->cpu); |
|
if (!kcpu->reqs_available) { |
|
int old, avail = atomic_read(&ctx->reqs_available); |
|
|
|
do { |
|
if (avail < ctx->req_batch) |
|
goto out; |
|
|
|
old = avail; |
|
avail = atomic_cmpxchg(&ctx->reqs_available, |
|
avail, avail - ctx->req_batch); |
|
} while (avail != old); |
|
|
|
kcpu->reqs_available += ctx->req_batch; |
|
} |
|
|
|
ret = true; |
|
kcpu->reqs_available--; |
|
out: |
|
local_irq_restore(flags); |
|
return ret; |
|
} |
|
|
|
/* refill_reqs_available |
|
* Updates the reqs_available reference counts used for tracking the |
|
* number of free slots in the completion ring. This can be called |
|
* from aio_complete() (to optimistically update reqs_available) or |
|
* from aio_get_req() (the we're out of events case). It must be |
|
* called holding ctx->completion_lock. |
|
*/ |
|
static void refill_reqs_available(struct kioctx *ctx, unsigned head, |
|
unsigned tail) |
|
{ |
|
unsigned events_in_ring, completed; |
|
|
|
/* Clamp head since userland can write to it. */ |
|
head %= ctx->nr_events; |
|
if (head <= tail) |
|
events_in_ring = tail - head; |
|
else |
|
events_in_ring = ctx->nr_events - (head - tail); |
|
|
|
completed = ctx->completed_events; |
|
if (events_in_ring < completed) |
|
completed -= events_in_ring; |
|
else |
|
completed = 0; |
|
|
|
if (!completed) |
|
return; |
|
|
|
ctx->completed_events -= completed; |
|
put_reqs_available(ctx, completed); |
|
} |
|
|
|
/* user_refill_reqs_available |
|
* Called to refill reqs_available when aio_get_req() encounters an |
|
* out of space in the completion ring. |
|
*/ |
|
static void user_refill_reqs_available(struct kioctx *ctx) |
|
{ |
|
spin_lock_irq(&ctx->completion_lock); |
|
if (ctx->completed_events) { |
|
struct aio_ring *ring; |
|
unsigned head; |
|
|
|
/* Access of ring->head may race with aio_read_events_ring() |
|
* here, but that's okay since whether we read the old version |
|
* or the new version, and either will be valid. The important |
|
* part is that head cannot pass tail since we prevent |
|
* aio_complete() from updating tail by holding |
|
* ctx->completion_lock. Even if head is invalid, the check |
|
* against ctx->completed_events below will make sure we do the |
|
* safe/right thing. |
|
*/ |
|
ring = kmap_atomic(ctx->ring_pages[0]); |
|
head = ring->head; |
|
kunmap_atomic(ring); |
|
|
|
refill_reqs_available(ctx, head, ctx->tail); |
|
} |
|
|
|
spin_unlock_irq(&ctx->completion_lock); |
|
} |
|
|
|
static bool get_reqs_available(struct kioctx *ctx) |
|
{ |
|
if (__get_reqs_available(ctx)) |
|
return true; |
|
user_refill_reqs_available(ctx); |
|
return __get_reqs_available(ctx); |
|
} |
|
|
|
/* aio_get_req |
|
* Allocate a slot for an aio request. |
|
* Returns NULL if no requests are free. |
|
* |
|
* The refcount is initialized to 2 - one for the async op completion, |
|
* one for the synchronous code that does this. |
|
*/ |
|
static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx) |
|
{ |
|
struct aio_kiocb *req; |
|
|
|
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL); |
|
if (unlikely(!req)) |
|
return NULL; |
|
|
|
if (unlikely(!get_reqs_available(ctx))) { |
|
kmem_cache_free(kiocb_cachep, req); |
|
return NULL; |
|
} |
|
|
|
percpu_ref_get(&ctx->reqs); |
|
req->ki_ctx = ctx; |
|
INIT_LIST_HEAD(&req->ki_list); |
|
refcount_set(&req->ki_refcnt, 2); |
|
req->ki_eventfd = NULL; |
|
return req; |
|
} |
|
|
|
static struct kioctx *lookup_ioctx(unsigned long ctx_id) |
|
{ |
|
struct aio_ring __user *ring = (void __user *)ctx_id; |
|
struct mm_struct *mm = current->mm; |
|
struct kioctx *ctx, *ret = NULL; |
|
struct kioctx_table *table; |
|
unsigned id; |
|
|
|
if (get_user(id, &ring->id)) |
|
return NULL; |
|
|
|
rcu_read_lock(); |
|
table = rcu_dereference(mm->ioctx_table); |
|
|
|
if (!table || id >= table->nr) |
|
goto out; |
|
|
|
id = array_index_nospec(id, table->nr); |
|
ctx = rcu_dereference(table->table[id]); |
|
if (ctx && ctx->user_id == ctx_id) { |
|
if (percpu_ref_tryget_live(&ctx->users)) |
|
ret = ctx; |
|
} |
|
out: |
|
rcu_read_unlock(); |
|
return ret; |
|
} |
|
|
|
static inline void iocb_destroy(struct aio_kiocb *iocb) |
|
{ |
|
if (iocb->ki_eventfd) |
|
eventfd_ctx_put(iocb->ki_eventfd); |
|
if (iocb->ki_filp) |
|
fput(iocb->ki_filp); |
|
percpu_ref_put(&iocb->ki_ctx->reqs); |
|
kmem_cache_free(kiocb_cachep, iocb); |
|
} |
|
|
|
/* aio_complete |
|
* Called when the io request on the given iocb is complete. |
|
*/ |
|
static void aio_complete(struct aio_kiocb *iocb) |
|
{ |
|
struct kioctx *ctx = iocb->ki_ctx; |
|
struct aio_ring *ring; |
|
struct io_event *ev_page, *event; |
|
unsigned tail, pos, head; |
|
unsigned long flags; |
|
|
|
/* |
|
* Add a completion event to the ring buffer. Must be done holding |
|
* ctx->completion_lock to prevent other code from messing with the tail |
|
* pointer since we might be called from irq context. |
|
*/ |
|
spin_lock_irqsave(&ctx->completion_lock, flags); |
|
|
|
tail = ctx->tail; |
|
pos = tail + AIO_EVENTS_OFFSET; |
|
|
|
if (++tail >= ctx->nr_events) |
|
tail = 0; |
|
|
|
ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); |
|
event = ev_page + pos % AIO_EVENTS_PER_PAGE; |
|
|
|
*event = iocb->ki_res; |
|
|
|
kunmap_atomic(ev_page); |
|
flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]); |
|
|
|
pr_debug("%p[%u]: %p: %p %Lx %Lx %Lx\n", ctx, tail, iocb, |
|
(void __user *)(unsigned long)iocb->ki_res.obj, |
|
iocb->ki_res.data, iocb->ki_res.res, iocb->ki_res.res2); |
|
|
|
/* after flagging the request as done, we |
|
* must never even look at it again |
|
*/ |
|
smp_wmb(); /* make event visible before updating tail */ |
|
|
|
ctx->tail = tail; |
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]); |
|
head = ring->head; |
|
ring->tail = tail; |
|
kunmap_atomic(ring); |
|
flush_dcache_page(ctx->ring_pages[0]); |
|
|
|
ctx->completed_events++; |
|
if (ctx->completed_events > 1) |
|
refill_reqs_available(ctx, head, tail); |
|
spin_unlock_irqrestore(&ctx->completion_lock, flags); |
|
|
|
pr_debug("added to ring %p at [%u]\n", iocb, tail); |
|
|
|
/* |
|
* Check if the user asked us to deliver the result through an |
|
* eventfd. The eventfd_signal() function is safe to be called |
|
* from IRQ context. |
|
*/ |
|
if (iocb->ki_eventfd) |
|
eventfd_signal(iocb->ki_eventfd, 1); |
|
|
|
/* |
|
* We have to order our ring_info tail store above and test |
|
* of the wait list below outside the wait lock. This is |
|
* like in wake_up_bit() where clearing a bit has to be |
|
* ordered with the unlocked test. |
|
*/ |
|
smp_mb(); |
|
|
|
if (waitqueue_active(&ctx->wait)) |
|
wake_up(&ctx->wait); |
|
} |
|
|
|
static inline void iocb_put(struct aio_kiocb *iocb) |
|
{ |
|
if (refcount_dec_and_test(&iocb->ki_refcnt)) { |
|
aio_complete(iocb); |
|
iocb_destroy(iocb); |
|
} |
|
} |
|
|
|
/* aio_read_events_ring |
|
* Pull an event off of the ioctx's event ring. Returns the number of |
|
* events fetched |
|
*/ |
|
static long aio_read_events_ring(struct kioctx *ctx, |
|
struct io_event __user *event, long nr) |
|
{ |
|
struct aio_ring *ring; |
|
unsigned head, tail, pos; |
|
long ret = 0; |
|
int copy_ret; |
|
|
|
/* |
|
* The mutex can block and wake us up and that will cause |
|
* wait_event_interruptible_hrtimeout() to schedule without sleeping |
|
* and repeat. This should be rare enough that it doesn't cause |
|
* peformance issues. See the comment in read_events() for more detail. |
|
*/ |
|
sched_annotate_sleep(); |
|
mutex_lock(&ctx->ring_lock); |
|
|
|
/* Access to ->ring_pages here is protected by ctx->ring_lock. */ |
|
ring = kmap_atomic(ctx->ring_pages[0]); |
|
head = ring->head; |
|
tail = ring->tail; |
|
kunmap_atomic(ring); |
|
|
|
/* |
|
* Ensure that once we've read the current tail pointer, that |
|
* we also see the events that were stored up to the tail. |
|
*/ |
|
smp_rmb(); |
|
|
|
pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events); |
|
|
|
if (head == tail) |
|
goto out; |
|
|
|
head %= ctx->nr_events; |
|
tail %= ctx->nr_events; |
|
|
|
while (ret < nr) { |
|
long avail; |
|
struct io_event *ev; |
|
struct page *page; |
|
|
|
avail = (head <= tail ? tail : ctx->nr_events) - head; |
|
if (head == tail) |
|
break; |
|
|
|
pos = head + AIO_EVENTS_OFFSET; |
|
page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]; |
|
pos %= AIO_EVENTS_PER_PAGE; |
|
|
|
avail = min(avail, nr - ret); |
|
avail = min_t(long, avail, AIO_EVENTS_PER_PAGE - pos); |
|
|
|
ev = kmap(page); |
|
copy_ret = copy_to_user(event + ret, ev + pos, |
|
sizeof(*ev) * avail); |
|
kunmap(page); |
|
|
|
if (unlikely(copy_ret)) { |
|
ret = -EFAULT; |
|
goto out; |
|
} |
|
|
|
ret += avail; |
|
head += avail; |
|
head %= ctx->nr_events; |
|
} |
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]); |
|
ring->head = head; |
|
kunmap_atomic(ring); |
|
flush_dcache_page(ctx->ring_pages[0]); |
|
|
|
pr_debug("%li h%u t%u\n", ret, head, tail); |
|
out: |
|
mutex_unlock(&ctx->ring_lock); |
|
|
|
return ret; |
|
} |
|
|
|
static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr, |
|
struct io_event __user *event, long *i) |
|
{ |
|
long ret = aio_read_events_ring(ctx, event + *i, nr - *i); |
|
|
|
if (ret > 0) |
|
*i += ret; |
|
|
|
if (unlikely(atomic_read(&ctx->dead))) |
|
ret = -EINVAL; |
|
|
|
if (!*i) |
|
*i = ret; |
|
|
|
return ret < 0 || *i >= min_nr; |
|
} |
|
|
|
static long read_events(struct kioctx *ctx, long min_nr, long nr, |
|
struct io_event __user *event, |
|
ktime_t until) |
|
{ |
|
long ret = 0; |
|
|
|
/* |
|
* Note that aio_read_events() is being called as the conditional - i.e. |
|
* we're calling it after prepare_to_wait() has set task state to |
|
* TASK_INTERRUPTIBLE. |
|
* |
|
* But aio_read_events() can block, and if it blocks it's going to flip |
|
* the task state back to TASK_RUNNING. |
|
* |
|
* This should be ok, provided it doesn't flip the state back to |
|
* TASK_RUNNING and return 0 too much - that causes us to spin. That |
|
* will only happen if the mutex_lock() call blocks, and we then find |
|
* the ringbuffer empty. So in practice we should be ok, but it's |
|
* something to be aware of when touching this code. |
|
*/ |
|
if (until == 0) |
|
aio_read_events(ctx, min_nr, nr, event, &ret); |
|
else |
|
wait_event_interruptible_hrtimeout(ctx->wait, |
|
aio_read_events(ctx, min_nr, nr, event, &ret), |
|
until); |
|
return ret; |
|
} |
|
|
|
/* sys_io_setup: |
|
* Create an aio_context capable of receiving at least nr_events. |
|
* ctxp must not point to an aio_context that already exists, and |
|
* must be initialized to 0 prior to the call. On successful |
|
* creation of the aio_context, *ctxp is filled in with the resulting |
|
* handle. May fail with -EINVAL if *ctxp is not initialized, |
|
* if the specified nr_events exceeds internal limits. May fail |
|
* with -EAGAIN if the specified nr_events exceeds the user's limit |
|
* of available events. May fail with -ENOMEM if insufficient kernel |
|
* resources are available. May fail with -EFAULT if an invalid |
|
* pointer is passed for ctxp. Will fail with -ENOSYS if not |
|
* implemented. |
|
*/ |
|
SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp) |
|
{ |
|
struct kioctx *ioctx = NULL; |
|
unsigned long ctx; |
|
long ret; |
|
|
|
ret = get_user(ctx, ctxp); |
|
if (unlikely(ret)) |
|
goto out; |
|
|
|
ret = -EINVAL; |
|
if (unlikely(ctx || nr_events == 0)) { |
|
pr_debug("EINVAL: ctx %lu nr_events %u\n", |
|
ctx, nr_events); |
|
goto out; |
|
} |
|
|
|
ioctx = ioctx_alloc(nr_events); |
|
ret = PTR_ERR(ioctx); |
|
if (!IS_ERR(ioctx)) { |
|
ret = put_user(ioctx->user_id, ctxp); |
|
if (ret) |
|
kill_ioctx(current->mm, ioctx, NULL); |
|
percpu_ref_put(&ioctx->users); |
|
} |
|
|
|
out: |
|
return ret; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p) |
|
{ |
|
struct kioctx *ioctx = NULL; |
|
unsigned long ctx; |
|
long ret; |
|
|
|
ret = get_user(ctx, ctx32p); |
|
if (unlikely(ret)) |
|
goto out; |
|
|
|
ret = -EINVAL; |
|
if (unlikely(ctx || nr_events == 0)) { |
|
pr_debug("EINVAL: ctx %lu nr_events %u\n", |
|
ctx, nr_events); |
|
goto out; |
|
} |
|
|
|
ioctx = ioctx_alloc(nr_events); |
|
ret = PTR_ERR(ioctx); |
|
if (!IS_ERR(ioctx)) { |
|
/* truncating is ok because it's a user address */ |
|
ret = put_user((u32)ioctx->user_id, ctx32p); |
|
if (ret) |
|
kill_ioctx(current->mm, ioctx, NULL); |
|
percpu_ref_put(&ioctx->users); |
|
} |
|
|
|
out: |
|
return ret; |
|
} |
|
#endif |
|
|
|
/* sys_io_destroy: |
|
* Destroy the aio_context specified. May cancel any outstanding |
|
* AIOs and block on completion. Will fail with -ENOSYS if not |
|
* implemented. May fail with -EINVAL if the context pointed to |
|
* is invalid. |
|
*/ |
|
SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx) |
|
{ |
|
struct kioctx *ioctx = lookup_ioctx(ctx); |
|
if (likely(NULL != ioctx)) { |
|
struct ctx_rq_wait wait; |
|
int ret; |
|
|
|
init_completion(&wait.comp); |
|
atomic_set(&wait.count, 1); |
|
|
|
/* Pass requests_done to kill_ioctx() where it can be set |
|
* in a thread-safe way. If we try to set it here then we have |
|
* a race condition if two io_destroy() called simultaneously. |
|
*/ |
|
ret = kill_ioctx(current->mm, ioctx, &wait); |
|
percpu_ref_put(&ioctx->users); |
|
|
|
/* Wait until all IO for the context are done. Otherwise kernel |
|
* keep using user-space buffers even if user thinks the context |
|
* is destroyed. |
|
*/ |
|
if (!ret) |
|
wait_for_completion(&wait.comp); |
|
|
|
return ret; |
|
} |
|
pr_debug("EINVAL: invalid context id\n"); |
|
return -EINVAL; |
|
} |
|
|
|
static void aio_remove_iocb(struct aio_kiocb *iocb) |
|
{ |
|
struct kioctx *ctx = iocb->ki_ctx; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags); |
|
list_del(&iocb->ki_list); |
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
|
} |
|
|
|
static void aio_complete_rw(struct kiocb *kiocb, long res, long res2) |
|
{ |
|
struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, rw); |
|
|
|
if (!list_empty_careful(&iocb->ki_list)) |
|
aio_remove_iocb(iocb); |
|
|
|
if (kiocb->ki_flags & IOCB_WRITE) { |
|
struct inode *inode = file_inode(kiocb->ki_filp); |
|
|
|
/* |
|
* Tell lockdep we inherited freeze protection from submission |
|
* thread. |
|
*/ |
|
if (S_ISREG(inode->i_mode)) |
|
__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); |
|
file_end_write(kiocb->ki_filp); |
|
} |
|
|
|
iocb->ki_res.res = res; |
|
iocb->ki_res.res2 = res2; |
|
iocb_put(iocb); |
|
} |
|
|
|
static int aio_prep_rw(struct kiocb *req, const struct iocb *iocb) |
|
{ |
|
int ret; |
|
|
|
req->ki_complete = aio_complete_rw; |
|
req->private = NULL; |
|
req->ki_pos = iocb->aio_offset; |
|
req->ki_flags = iocb_flags(req->ki_filp); |
|
if (iocb->aio_flags & IOCB_FLAG_RESFD) |
|
req->ki_flags |= IOCB_EVENTFD; |
|
req->ki_hint = ki_hint_validate(file_write_hint(req->ki_filp)); |
|
if (iocb->aio_flags & IOCB_FLAG_IOPRIO) { |
|
/* |
|
* If the IOCB_FLAG_IOPRIO flag of aio_flags is set, then |
|
* aio_reqprio is interpreted as an I/O scheduling |
|
* class and priority. |
|
*/ |
|
ret = ioprio_check_cap(iocb->aio_reqprio); |
|
if (ret) { |
|
pr_debug("aio ioprio check cap error: %d\n", ret); |
|
return ret; |
|
} |
|
|
|
req->ki_ioprio = iocb->aio_reqprio; |
|
} else |
|
req->ki_ioprio = get_current_ioprio(); |
|
|
|
ret = kiocb_set_rw_flags(req, iocb->aio_rw_flags); |
|
if (unlikely(ret)) |
|
return ret; |
|
|
|
req->ki_flags &= ~IOCB_HIPRI; /* no one is going to poll for this I/O */ |
|
return 0; |
|
} |
|
|
|
static ssize_t aio_setup_rw(int rw, const struct iocb *iocb, |
|
struct iovec **iovec, bool vectored, bool compat, |
|
struct iov_iter *iter) |
|
{ |
|
void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf; |
|
size_t len = iocb->aio_nbytes; |
|
|
|
if (!vectored) { |
|
ssize_t ret = import_single_range(rw, buf, len, *iovec, iter); |
|
*iovec = NULL; |
|
return ret; |
|
} |
|
|
|
return __import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter, compat); |
|
} |
|
|
|
static inline void aio_rw_done(struct kiocb *req, ssize_t ret) |
|
{ |
|
switch (ret) { |
|
case -EIOCBQUEUED: |
|
break; |
|
case -ERESTARTSYS: |
|
case -ERESTARTNOINTR: |
|
case -ERESTARTNOHAND: |
|
case -ERESTART_RESTARTBLOCK: |
|
/* |
|
* There's no easy way to restart the syscall since other AIO's |
|
* may be already running. Just fail this IO with EINTR. |
|
*/ |
|
ret = -EINTR; |
|
fallthrough; |
|
default: |
|
req->ki_complete(req, ret, 0); |
|
} |
|
} |
|
|
|
static int aio_read(struct kiocb *req, const struct iocb *iocb, |
|
bool vectored, bool compat) |
|
{ |
|
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; |
|
struct iov_iter iter; |
|
struct file *file; |
|
int ret; |
|
|
|
ret = aio_prep_rw(req, iocb); |
|
if (ret) |
|
return ret; |
|
file = req->ki_filp; |
|
if (unlikely(!(file->f_mode & FMODE_READ))) |
|
return -EBADF; |
|
ret = -EINVAL; |
|
if (unlikely(!file->f_op->read_iter)) |
|
return -EINVAL; |
|
|
|
ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter); |
|
if (ret < 0) |
|
return ret; |
|
ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter)); |
|
if (!ret) |
|
aio_rw_done(req, call_read_iter(file, req, &iter)); |
|
kfree(iovec); |
|
return ret; |
|
} |
|
|
|
static int aio_write(struct kiocb *req, const struct iocb *iocb, |
|
bool vectored, bool compat) |
|
{ |
|
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; |
|
struct iov_iter iter; |
|
struct file *file; |
|
int ret; |
|
|
|
ret = aio_prep_rw(req, iocb); |
|
if (ret) |
|
return ret; |
|
file = req->ki_filp; |
|
|
|
if (unlikely(!(file->f_mode & FMODE_WRITE))) |
|
return -EBADF; |
|
if (unlikely(!file->f_op->write_iter)) |
|
return -EINVAL; |
|
|
|
ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter); |
|
if (ret < 0) |
|
return ret; |
|
ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter)); |
|
if (!ret) { |
|
/* |
|
* Open-code file_start_write here to grab freeze protection, |
|
* which will be released by another thread in |
|
* aio_complete_rw(). Fool lockdep by telling it the lock got |
|
* released so that it doesn't complain about the held lock when |
|
* we return to userspace. |
|
*/ |
|
if (S_ISREG(file_inode(file)->i_mode)) { |
|
sb_start_write(file_inode(file)->i_sb); |
|
__sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE); |
|
} |
|
req->ki_flags |= IOCB_WRITE; |
|
aio_rw_done(req, call_write_iter(file, req, &iter)); |
|
} |
|
kfree(iovec); |
|
return ret; |
|
} |
|
|
|
static void aio_fsync_work(struct work_struct *work) |
|
{ |
|
struct aio_kiocb *iocb = container_of(work, struct aio_kiocb, fsync.work); |
|
const struct cred *old_cred = override_creds(iocb->fsync.creds); |
|
|
|
iocb->ki_res.res = vfs_fsync(iocb->fsync.file, iocb->fsync.datasync); |
|
revert_creds(old_cred); |
|
put_cred(iocb->fsync.creds); |
|
iocb_put(iocb); |
|
} |
|
|
|
static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb, |
|
bool datasync) |
|
{ |
|
if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes || |
|
iocb->aio_rw_flags)) |
|
return -EINVAL; |
|
|
|
if (unlikely(!req->file->f_op->fsync)) |
|
return -EINVAL; |
|
|
|
req->creds = prepare_creds(); |
|
if (!req->creds) |
|
return -ENOMEM; |
|
|
|
req->datasync = datasync; |
|
INIT_WORK(&req->work, aio_fsync_work); |
|
schedule_work(&req->work); |
|
return 0; |
|
} |
|
|
|
static void aio_poll_put_work(struct work_struct *work) |
|
{ |
|
struct poll_iocb *req = container_of(work, struct poll_iocb, work); |
|
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); |
|
|
|
iocb_put(iocb); |
|
} |
|
|
|
static void aio_poll_complete_work(struct work_struct *work) |
|
{ |
|
struct poll_iocb *req = container_of(work, struct poll_iocb, work); |
|
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); |
|
struct poll_table_struct pt = { ._key = req->events }; |
|
struct kioctx *ctx = iocb->ki_ctx; |
|
__poll_t mask = 0; |
|
|
|
if (!READ_ONCE(req->cancelled)) |
|
mask = vfs_poll(req->file, &pt) & req->events; |
|
|
|
/* |
|
* Note that ->ki_cancel callers also delete iocb from active_reqs after |
|
* calling ->ki_cancel. We need the ctx_lock roundtrip here to |
|
* synchronize with them. In the cancellation case the list_del_init |
|
* itself is not actually needed, but harmless so we keep it in to |
|
* avoid further branches in the fast path. |
|
*/ |
|
spin_lock_irq(&ctx->ctx_lock); |
|
if (!mask && !READ_ONCE(req->cancelled)) { |
|
add_wait_queue(req->head, &req->wait); |
|
spin_unlock_irq(&ctx->ctx_lock); |
|
return; |
|
} |
|
list_del_init(&iocb->ki_list); |
|
iocb->ki_res.res = mangle_poll(mask); |
|
req->done = true; |
|
spin_unlock_irq(&ctx->ctx_lock); |
|
|
|
iocb_put(iocb); |
|
} |
|
|
|
/* assumes we are called with irqs disabled */ |
|
static int aio_poll_cancel(struct kiocb *iocb) |
|
{ |
|
struct aio_kiocb *aiocb = container_of(iocb, struct aio_kiocb, rw); |
|
struct poll_iocb *req = &aiocb->poll; |
|
|
|
spin_lock(&req->head->lock); |
|
WRITE_ONCE(req->cancelled, true); |
|
if (!list_empty(&req->wait.entry)) { |
|
list_del_init(&req->wait.entry); |
|
schedule_work(&aiocb->poll.work); |
|
} |
|
spin_unlock(&req->head->lock); |
|
|
|
return 0; |
|
} |
|
|
|
static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, |
|
void *key) |
|
{ |
|
struct poll_iocb *req = container_of(wait, struct poll_iocb, wait); |
|
struct aio_kiocb *iocb = container_of(req, struct aio_kiocb, poll); |
|
__poll_t mask = key_to_poll(key); |
|
unsigned long flags; |
|
|
|
/* for instances that support it check for an event match first: */ |
|
if (mask && !(mask & req->events)) |
|
return 0; |
|
|
|
list_del_init(&req->wait.entry); |
|
|
|
if (mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) { |
|
struct kioctx *ctx = iocb->ki_ctx; |
|
|
|
/* |
|
* Try to complete the iocb inline if we can. Use |
|
* irqsave/irqrestore because not all filesystems (e.g. fuse) |
|
* call this function with IRQs disabled and because IRQs |
|
* have to be disabled before ctx_lock is obtained. |
|
*/ |
|
list_del(&iocb->ki_list); |
|
iocb->ki_res.res = mangle_poll(mask); |
|
req->done = true; |
|
if (iocb->ki_eventfd && eventfd_signal_count()) { |
|
iocb = NULL; |
|
INIT_WORK(&req->work, aio_poll_put_work); |
|
schedule_work(&req->work); |
|
} |
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags); |
|
if (iocb) |
|
iocb_put(iocb); |
|
} else { |
|
schedule_work(&req->work); |
|
} |
|
return 1; |
|
} |
|
|
|
struct aio_poll_table { |
|
struct poll_table_struct pt; |
|
struct aio_kiocb *iocb; |
|
int error; |
|
}; |
|
|
|
static void |
|
aio_poll_queue_proc(struct file *file, struct wait_queue_head *head, |
|
struct poll_table_struct *p) |
|
{ |
|
struct aio_poll_table *pt = container_of(p, struct aio_poll_table, pt); |
|
|
|
/* multiple wait queues per file are not supported */ |
|
if (unlikely(pt->iocb->poll.head)) { |
|
pt->error = -EINVAL; |
|
return; |
|
} |
|
|
|
pt->error = 0; |
|
pt->iocb->poll.head = head; |
|
add_wait_queue(head, &pt->iocb->poll.wait); |
|
} |
|
|
|
static int aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb) |
|
{ |
|
struct kioctx *ctx = aiocb->ki_ctx; |
|
struct poll_iocb *req = &aiocb->poll; |
|
struct aio_poll_table apt; |
|
bool cancel = false; |
|
__poll_t mask; |
|
|
|
/* reject any unknown events outside the normal event mask. */ |
|
if ((u16)iocb->aio_buf != iocb->aio_buf) |
|
return -EINVAL; |
|
/* reject fields that are not defined for poll */ |
|
if (iocb->aio_offset || iocb->aio_nbytes || iocb->aio_rw_flags) |
|
return -EINVAL; |
|
|
|
INIT_WORK(&req->work, aio_poll_complete_work); |
|
req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP; |
|
|
|
req->head = NULL; |
|
req->done = false; |
|
req->cancelled = false; |
|
|
|
apt.pt._qproc = aio_poll_queue_proc; |
|
apt.pt._key = req->events; |
|
apt.iocb = aiocb; |
|
apt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */ |
|
|
|
/* initialized the list so that we can do list_empty checks */ |
|
INIT_LIST_HEAD(&req->wait.entry); |
|
init_waitqueue_func_entry(&req->wait, aio_poll_wake); |
|
|
|
mask = vfs_poll(req->file, &apt.pt) & req->events; |
|
spin_lock_irq(&ctx->ctx_lock); |
|
if (likely(req->head)) { |
|
spin_lock(&req->head->lock); |
|
if (unlikely(list_empty(&req->wait.entry))) { |
|
if (apt.error) |
|
cancel = true; |
|
apt.error = 0; |
|
mask = 0; |
|
} |
|
if (mask || apt.error) { |
|
list_del_init(&req->wait.entry); |
|
} else if (cancel) { |
|
WRITE_ONCE(req->cancelled, true); |
|
} else if (!req->done) { /* actually waiting for an event */ |
|
list_add_tail(&aiocb->ki_list, &ctx->active_reqs); |
|
aiocb->ki_cancel = aio_poll_cancel; |
|
} |
|
spin_unlock(&req->head->lock); |
|
} |
|
if (mask) { /* no async, we'd stolen it */ |
|
aiocb->ki_res.res = mangle_poll(mask); |
|
apt.error = 0; |
|
} |
|
spin_unlock_irq(&ctx->ctx_lock); |
|
if (mask) |
|
iocb_put(aiocb); |
|
return apt.error; |
|
} |
|
|
|
static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb, |
|
struct iocb __user *user_iocb, struct aio_kiocb *req, |
|
bool compat) |
|
{ |
|
req->ki_filp = fget(iocb->aio_fildes); |
|
if (unlikely(!req->ki_filp)) |
|
return -EBADF; |
|
|
|
if (iocb->aio_flags & IOCB_FLAG_RESFD) { |
|
struct eventfd_ctx *eventfd; |
|
/* |
|
* If the IOCB_FLAG_RESFD flag of aio_flags is set, get an |
|
* instance of the file* now. The file descriptor must be |
|
* an eventfd() fd, and will be signaled for each completed |
|
* event using the eventfd_signal() function. |
|
*/ |
|
eventfd = eventfd_ctx_fdget(iocb->aio_resfd); |
|
if (IS_ERR(eventfd)) |
|
return PTR_ERR(eventfd); |
|
|
|
req->ki_eventfd = eventfd; |
|
} |
|
|
|
if (unlikely(put_user(KIOCB_KEY, &user_iocb->aio_key))) { |
|
pr_debug("EFAULT: aio_key\n"); |
|
return -EFAULT; |
|
} |
|
|
|
req->ki_res.obj = (u64)(unsigned long)user_iocb; |
|
req->ki_res.data = iocb->aio_data; |
|
req->ki_res.res = 0; |
|
req->ki_res.res2 = 0; |
|
|
|
switch (iocb->aio_lio_opcode) { |
|
case IOCB_CMD_PREAD: |
|
return aio_read(&req->rw, iocb, false, compat); |
|
case IOCB_CMD_PWRITE: |
|
return aio_write(&req->rw, iocb, false, compat); |
|
case IOCB_CMD_PREADV: |
|
return aio_read(&req->rw, iocb, true, compat); |
|
case IOCB_CMD_PWRITEV: |
|
return aio_write(&req->rw, iocb, true, compat); |
|
case IOCB_CMD_FSYNC: |
|
return aio_fsync(&req->fsync, iocb, false); |
|
case IOCB_CMD_FDSYNC: |
|
return aio_fsync(&req->fsync, iocb, true); |
|
case IOCB_CMD_POLL: |
|
return aio_poll(req, iocb); |
|
default: |
|
pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode); |
|
return -EINVAL; |
|
} |
|
} |
|
|
|
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, |
|
bool compat) |
|
{ |
|
struct aio_kiocb *req; |
|
struct iocb iocb; |
|
int err; |
|
|
|
if (unlikely(copy_from_user(&iocb, user_iocb, sizeof(iocb)))) |
|
return -EFAULT; |
|
|
|
/* enforce forwards compatibility on users */ |
|
if (unlikely(iocb.aio_reserved2)) { |
|
pr_debug("EINVAL: reserve field set\n"); |
|
return -EINVAL; |
|
} |
|
|
|
/* prevent overflows */ |
|
if (unlikely( |
|
(iocb.aio_buf != (unsigned long)iocb.aio_buf) || |
|
(iocb.aio_nbytes != (size_t)iocb.aio_nbytes) || |
|
((ssize_t)iocb.aio_nbytes < 0) |
|
)) { |
|
pr_debug("EINVAL: overflow check\n"); |
|
return -EINVAL; |
|
} |
|
|
|
req = aio_get_req(ctx); |
|
if (unlikely(!req)) |
|
return -EAGAIN; |
|
|
|
err = __io_submit_one(ctx, &iocb, user_iocb, req, compat); |
|
|
|
/* Done with the synchronous reference */ |
|
iocb_put(req); |
|
|
|
/* |
|
* If err is 0, we'd either done aio_complete() ourselves or have |
|
* arranged for that to be done asynchronously. Anything non-zero |
|
* means that we need to destroy req ourselves. |
|
*/ |
|
if (unlikely(err)) { |
|
iocb_destroy(req); |
|
put_reqs_available(ctx, 1); |
|
} |
|
return err; |
|
} |
|
|
|
/* sys_io_submit: |
|
* Queue the nr iocbs pointed to by iocbpp for processing. Returns |
|
* the number of iocbs queued. May return -EINVAL if the aio_context |
|
* specified by ctx_id is invalid, if nr is < 0, if the iocb at |
|
* *iocbpp[0] is not properly initialized, if the operation specified |
|
* is invalid for the file descriptor in the iocb. May fail with |
|
* -EFAULT if any of the data structures point to invalid data. May |
|
* fail with -EBADF if the file descriptor specified in the first |
|
* iocb is invalid. May fail with -EAGAIN if insufficient resources |
|
* are available to queue any iocbs. Will return 0 if nr is 0. Will |
|
* fail with -ENOSYS if not implemented. |
|
*/ |
|
SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr, |
|
struct iocb __user * __user *, iocbpp) |
|
{ |
|
struct kioctx *ctx; |
|
long ret = 0; |
|
int i = 0; |
|
struct blk_plug plug; |
|
|
|
if (unlikely(nr < 0)) |
|
return -EINVAL; |
|
|
|
ctx = lookup_ioctx(ctx_id); |
|
if (unlikely(!ctx)) { |
|
pr_debug("EINVAL: invalid context id\n"); |
|
return -EINVAL; |
|
} |
|
|
|
if (nr > ctx->nr_events) |
|
nr = ctx->nr_events; |
|
|
|
if (nr > AIO_PLUG_THRESHOLD) |
|
blk_start_plug(&plug); |
|
for (i = 0; i < nr; i++) { |
|
struct iocb __user *user_iocb; |
|
|
|
if (unlikely(get_user(user_iocb, iocbpp + i))) { |
|
ret = -EFAULT; |
|
break; |
|
} |
|
|
|
ret = io_submit_one(ctx, user_iocb, false); |
|
if (ret) |
|
break; |
|
} |
|
if (nr > AIO_PLUG_THRESHOLD) |
|
blk_finish_plug(&plug); |
|
|
|
percpu_ref_put(&ctx->users); |
|
return i ? i : ret; |
|
} |
|
|
|
#ifdef CONFIG_COMPAT |
|
COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id, |
|
int, nr, compat_uptr_t __user *, iocbpp) |
|
{ |
|
struct kioctx *ctx; |
|
long ret = 0; |
|
int i = 0; |
|
struct blk_plug plug; |
|
|
|
if (unlikely(nr < 0)) |
|
return -EINVAL; |
|
|
|
ctx = lookup_ioctx(ctx_id); |
|
if (unlikely(!ctx)) { |
|
pr_debug("EINVAL: invalid context id\n"); |
|
return -EINVAL; |
|
} |
|
|
|
if (nr > ctx->nr_events) |
|
nr = ctx->nr_events; |
|
|
|
if (nr > AIO_PLUG_THRESHOLD) |
|
blk_start_plug(&plug); |
|
for (i = 0; i < nr; i++) { |
|
compat_uptr_t user_iocb; |
|
|
|
if (unlikely(get_user(user_iocb, iocbpp + i))) { |
|
ret = -EFAULT; |
|
break; |
|
} |
|
|
|
ret = io_submit_one(ctx, compat_ptr(user_iocb), true); |
|
if (ret) |
|
break; |
|
} |
|
if (nr > AIO_PLUG_THRESHOLD) |
|
blk_finish_plug(&plug); |
|
|
|
percpu_ref_put(&ctx->users); |
|
return i ? i : ret; |
|
} |
|
#endif |
|
|
|
/* sys_io_cancel: |
|
* Attempts to cancel an iocb previously passed to io_submit. If |
|
* the operation is successfully cancelled, the resulting event is |
|
* copied into the memory pointed to by result without being placed |
|
* into the completion queue and 0 is returned. May fail with |
|
* -EFAULT if any of the data structures pointed to are invalid. |
|
* May fail with -EINVAL if aio_context specified by ctx_id is |
|
* invalid. May fail with -EAGAIN if the iocb specified was not |
|
* cancelled. Will fail with -ENOSYS if not implemented. |
|
*/ |
|
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb, |
|
struct io_event __user *, result) |
|
{ |
|
struct kioctx *ctx; |
|
struct aio_kiocb *kiocb; |
|
int ret = -EINVAL; |
|
u32 key; |
|
u64 obj = (u64)(unsigned long)iocb; |
|
|
|
if (unlikely(get_user(key, &iocb->aio_key))) |
|
return -EFAULT; |
|
if (unlikely(key != KIOCB_KEY)) |
|
return -EINVAL; |
|
|
|
ctx = lookup_ioctx(ctx_id); |
|
if (unlikely(!ctx)) |
|
return -EINVAL; |
|
|
|
spin_lock_irq(&ctx->ctx_lock); |
|
/* TODO: use a hash or array, this sucks. */ |
|
list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) { |
|
if (kiocb->ki_res.obj == obj) { |
|
ret = kiocb->ki_cancel(&kiocb->rw); |
|
list_del_init(&kiocb->ki_list); |
|
break; |
|
} |
|
} |
|
spin_unlock_irq(&ctx->ctx_lock); |
|
|
|
if (!ret) { |
|
/* |
|
* The result argument is no longer used - the io_event is |
|
* always delivered via the ring buffer. -EINPROGRESS indicates |
|
* cancellation is progress: |
|
*/ |
|
ret = -EINPROGRESS; |
|
} |
|
|
|
percpu_ref_put(&ctx->users); |
|
|
|
return ret; |
|
} |
|
|
|
static long do_io_getevents(aio_context_t ctx_id, |
|
long min_nr, |
|
long nr, |
|
struct io_event __user *events, |
|
struct timespec64 *ts) |
|
{ |
|
ktime_t until = ts ? timespec64_to_ktime(*ts) : KTIME_MAX; |
|
struct kioctx *ioctx = lookup_ioctx(ctx_id); |
|
long ret = -EINVAL; |
|
|
|
if (likely(ioctx)) { |
|
if (likely(min_nr <= nr && min_nr >= 0)) |
|
ret = read_events(ioctx, min_nr, nr, events, until); |
|
percpu_ref_put(&ioctx->users); |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
/* io_getevents: |
|
* Attempts to read at least min_nr events and up to nr events from |
|
* the completion queue for the aio_context specified by ctx_id. If |
|
* it succeeds, the number of read events is returned. May fail with |
|
* -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is |
|
* out of range, if timeout is out of range. May fail with -EFAULT |
|
* if any of the memory specified is invalid. May return 0 or |
|
* < min_nr if the timeout specified by timeout has elapsed |
|
* before sufficient events are available, where timeout == NULL |
|
* specifies an infinite timeout. Note that the timeout pointed to by |
|
* timeout is relative. Will fail with -ENOSYS if not implemented. |
|
*/ |
|
#ifdef CONFIG_64BIT |
|
|
|
SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id, |
|
long, min_nr, |
|
long, nr, |
|
struct io_event __user *, events, |
|
struct __kernel_timespec __user *, timeout) |
|
{ |
|
struct timespec64 ts; |
|
int ret; |
|
|
|
if (timeout && unlikely(get_timespec64(&ts, timeout))) |
|
return -EFAULT; |
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); |
|
if (!ret && signal_pending(current)) |
|
ret = -EINTR; |
|
return ret; |
|
} |
|
|
|
#endif |
|
|
|
struct __aio_sigset { |
|
const sigset_t __user *sigmask; |
|
size_t sigsetsize; |
|
}; |
|
|
|
SYSCALL_DEFINE6(io_pgetevents, |
|
aio_context_t, ctx_id, |
|
long, min_nr, |
|
long, nr, |
|
struct io_event __user *, events, |
|
struct __kernel_timespec __user *, timeout, |
|
const struct __aio_sigset __user *, usig) |
|
{ |
|
struct __aio_sigset ksig = { NULL, }; |
|
struct timespec64 ts; |
|
bool interrupted; |
|
int ret; |
|
|
|
if (timeout && unlikely(get_timespec64(&ts, timeout))) |
|
return -EFAULT; |
|
|
|
if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) |
|
return -EFAULT; |
|
|
|
ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize); |
|
if (ret) |
|
return ret; |
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); |
|
|
|
interrupted = signal_pending(current); |
|
restore_saved_sigmask_unless(interrupted); |
|
if (interrupted && !ret) |
|
ret = -ERESTARTNOHAND; |
|
|
|
return ret; |
|
} |
|
|
|
#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT) |
|
|
|
SYSCALL_DEFINE6(io_pgetevents_time32, |
|
aio_context_t, ctx_id, |
|
long, min_nr, |
|
long, nr, |
|
struct io_event __user *, events, |
|
struct old_timespec32 __user *, timeout, |
|
const struct __aio_sigset __user *, usig) |
|
{ |
|
struct __aio_sigset ksig = { NULL, }; |
|
struct timespec64 ts; |
|
bool interrupted; |
|
int ret; |
|
|
|
if (timeout && unlikely(get_old_timespec32(&ts, timeout))) |
|
return -EFAULT; |
|
|
|
if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) |
|
return -EFAULT; |
|
|
|
|
|
ret = set_user_sigmask(ksig.sigmask, ksig.sigsetsize); |
|
if (ret) |
|
return ret; |
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &ts : NULL); |
|
|
|
interrupted = signal_pending(current); |
|
restore_saved_sigmask_unless(interrupted); |
|
if (interrupted && !ret) |
|
ret = -ERESTARTNOHAND; |
|
|
|
return ret; |
|
} |
|
|
|
#endif |
|
|
|
#if defined(CONFIG_COMPAT_32BIT_TIME) |
|
|
|
SYSCALL_DEFINE5(io_getevents_time32, __u32, ctx_id, |
|
__s32, min_nr, |
|
__s32, nr, |
|
struct io_event __user *, events, |
|
struct old_timespec32 __user *, timeout) |
|
{ |
|
struct timespec64 t; |
|
int ret; |
|
|
|
if (timeout && get_old_timespec32(&t, timeout)) |
|
return -EFAULT; |
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); |
|
if (!ret && signal_pending(current)) |
|
ret = -EINTR; |
|
return ret; |
|
} |
|
|
|
#endif |
|
|
|
#ifdef CONFIG_COMPAT |
|
|
|
struct __compat_aio_sigset { |
|
compat_uptr_t sigmask; |
|
compat_size_t sigsetsize; |
|
}; |
|
|
|
#if defined(CONFIG_COMPAT_32BIT_TIME) |
|
|
|
COMPAT_SYSCALL_DEFINE6(io_pgetevents, |
|
compat_aio_context_t, ctx_id, |
|
compat_long_t, min_nr, |
|
compat_long_t, nr, |
|
struct io_event __user *, events, |
|
struct old_timespec32 __user *, timeout, |
|
const struct __compat_aio_sigset __user *, usig) |
|
{ |
|
struct __compat_aio_sigset ksig = { 0, }; |
|
struct timespec64 t; |
|
bool interrupted; |
|
int ret; |
|
|
|
if (timeout && get_old_timespec32(&t, timeout)) |
|
return -EFAULT; |
|
|
|
if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) |
|
return -EFAULT; |
|
|
|
ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize); |
|
if (ret) |
|
return ret; |
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); |
|
|
|
interrupted = signal_pending(current); |
|
restore_saved_sigmask_unless(interrupted); |
|
if (interrupted && !ret) |
|
ret = -ERESTARTNOHAND; |
|
|
|
return ret; |
|
} |
|
|
|
#endif |
|
|
|
COMPAT_SYSCALL_DEFINE6(io_pgetevents_time64, |
|
compat_aio_context_t, ctx_id, |
|
compat_long_t, min_nr, |
|
compat_long_t, nr, |
|
struct io_event __user *, events, |
|
struct __kernel_timespec __user *, timeout, |
|
const struct __compat_aio_sigset __user *, usig) |
|
{ |
|
struct __compat_aio_sigset ksig = { 0, }; |
|
struct timespec64 t; |
|
bool interrupted; |
|
int ret; |
|
|
|
if (timeout && get_timespec64(&t, timeout)) |
|
return -EFAULT; |
|
|
|
if (usig && copy_from_user(&ksig, usig, sizeof(ksig))) |
|
return -EFAULT; |
|
|
|
ret = set_compat_user_sigmask(compat_ptr(ksig.sigmask), ksig.sigsetsize); |
|
if (ret) |
|
return ret; |
|
|
|
ret = do_io_getevents(ctx_id, min_nr, nr, events, timeout ? &t : NULL); |
|
|
|
interrupted = signal_pending(current); |
|
restore_saved_sigmask_unless(interrupted); |
|
if (interrupted && !ret) |
|
ret = -ERESTARTNOHAND; |
|
|
|
return ret; |
|
} |
|
#endif
|
|
|