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1049 lines
27 KiB
1049 lines
27 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/kernel.h> |
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#include <linux/errno.h> |
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#include <linux/fs.h> |
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#include <linux/file.h> |
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#include <linux/blk-mq.h> |
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#include <linux/mm.h> |
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#include <linux/slab.h> |
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#include <linux/fsnotify.h> |
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#include <linux/poll.h> |
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#include <linux/nospec.h> |
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#include <linux/compat.h> |
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#include <linux/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_uring.h" |
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#include "opdef.h" |
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#include "kbuf.h" |
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#include "rsrc.h" |
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#include "rw.h" |
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struct io_rw { |
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/* NOTE: kiocb has the file as the first member, so don't do it here */ |
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struct kiocb kiocb; |
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u64 addr; |
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u32 len; |
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rwf_t flags; |
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}; |
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|
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static inline bool io_file_supports_nowait(struct io_kiocb *req) |
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{ |
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return req->flags & REQ_F_SUPPORT_NOWAIT; |
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} |
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|
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int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) |
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{ |
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
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unsigned ioprio; |
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int ret; |
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|
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rw->kiocb.ki_pos = READ_ONCE(sqe->off); |
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/* used for fixed read/write too - just read unconditionally */ |
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req->buf_index = READ_ONCE(sqe->buf_index); |
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|
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if (req->opcode == IORING_OP_READ_FIXED || |
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req->opcode == IORING_OP_WRITE_FIXED) { |
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struct io_ring_ctx *ctx = req->ctx; |
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u16 index; |
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|
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if (unlikely(req->buf_index >= ctx->nr_user_bufs)) |
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return -EFAULT; |
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index = array_index_nospec(req->buf_index, ctx->nr_user_bufs); |
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req->imu = ctx->user_bufs[index]; |
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io_req_set_rsrc_node(req, ctx, 0); |
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} |
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ioprio = READ_ONCE(sqe->ioprio); |
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if (ioprio) { |
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ret = ioprio_check_cap(ioprio); |
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if (ret) |
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return ret; |
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|
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rw->kiocb.ki_ioprio = ioprio; |
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} else { |
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rw->kiocb.ki_ioprio = get_current_ioprio(); |
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} |
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rw->addr = READ_ONCE(sqe->addr); |
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rw->len = READ_ONCE(sqe->len); |
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rw->flags = READ_ONCE(sqe->rw_flags); |
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return 0; |
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} |
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|
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void io_readv_writev_cleanup(struct io_kiocb *req) |
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{ |
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struct io_async_rw *io = req->async_data; |
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kfree(io->free_iovec); |
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} |
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static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) |
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{ |
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switch (ret) { |
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case -EIOCBQUEUED: |
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break; |
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case -ERESTARTSYS: |
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case -ERESTARTNOINTR: |
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case -ERESTARTNOHAND: |
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case -ERESTART_RESTARTBLOCK: |
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/* |
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* We can't just restart the syscall, since previously |
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* submitted sqes may already be in progress. Just fail this |
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* IO with EINTR. |
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*/ |
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ret = -EINTR; |
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fallthrough; |
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default: |
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kiocb->ki_complete(kiocb, ret); |
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} |
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} |
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static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req) |
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{ |
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
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|
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if (rw->kiocb.ki_pos != -1) |
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return &rw->kiocb.ki_pos; |
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|
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if (!(req->file->f_mode & FMODE_STREAM)) { |
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req->flags |= REQ_F_CUR_POS; |
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rw->kiocb.ki_pos = req->file->f_pos; |
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return &rw->kiocb.ki_pos; |
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} |
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rw->kiocb.ki_pos = 0; |
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return NULL; |
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} |
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static void io_req_task_queue_reissue(struct io_kiocb *req) |
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{ |
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req->io_task_work.func = io_queue_iowq; |
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io_req_task_work_add(req); |
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} |
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#ifdef CONFIG_BLOCK |
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static bool io_resubmit_prep(struct io_kiocb *req) |
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{ |
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struct io_async_rw *io = req->async_data; |
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|
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if (!req_has_async_data(req)) |
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return !io_req_prep_async(req); |
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iov_iter_restore(&io->s.iter, &io->s.iter_state); |
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return true; |
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} |
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static bool io_rw_should_reissue(struct io_kiocb *req) |
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{ |
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umode_t mode = file_inode(req->file)->i_mode; |
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struct io_ring_ctx *ctx = req->ctx; |
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|
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if (!S_ISBLK(mode) && !S_ISREG(mode)) |
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return false; |
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if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() && |
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!(ctx->flags & IORING_SETUP_IOPOLL))) |
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return false; |
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/* |
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* If ref is dying, we might be running poll reap from the exit work. |
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* Don't attempt to reissue from that path, just let it fail with |
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* -EAGAIN. |
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*/ |
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if (percpu_ref_is_dying(&ctx->refs)) |
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return false; |
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/* |
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* Play it safe and assume not safe to re-import and reissue if we're |
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* not in the original thread group (or in task context). |
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*/ |
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if (!same_thread_group(req->task, current) || !in_task()) |
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return false; |
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return true; |
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} |
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#else |
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static bool io_resubmit_prep(struct io_kiocb *req) |
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{ |
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return false; |
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} |
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static bool io_rw_should_reissue(struct io_kiocb *req) |
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{ |
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return false; |
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} |
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#endif |
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static void kiocb_end_write(struct io_kiocb *req) |
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{ |
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/* |
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* Tell lockdep we inherited freeze protection from submission |
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* thread. |
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*/ |
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if (req->flags & REQ_F_ISREG) { |
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struct super_block *sb = file_inode(req->file)->i_sb; |
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|
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__sb_writers_acquired(sb, SB_FREEZE_WRITE); |
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sb_end_write(sb); |
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} |
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} |
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static bool __io_complete_rw_common(struct io_kiocb *req, long res) |
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{ |
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
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|
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if (rw->kiocb.ki_flags & IOCB_WRITE) { |
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kiocb_end_write(req); |
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fsnotify_modify(req->file); |
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} else { |
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fsnotify_access(req->file); |
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} |
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if (unlikely(res != req->cqe.res)) { |
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if ((res == -EAGAIN || res == -EOPNOTSUPP) && |
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io_rw_should_reissue(req)) { |
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req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO; |
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return true; |
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} |
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req_set_fail(req); |
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req->cqe.res = res; |
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} |
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return false; |
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} |
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static void io_complete_rw(struct kiocb *kiocb, long res) |
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{ |
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struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); |
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struct io_kiocb *req = cmd_to_io_kiocb(rw); |
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|
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if (__io_complete_rw_common(req, res)) |
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return; |
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io_req_set_res(req, res, 0); |
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req->io_task_work.func = io_req_task_complete; |
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io_req_task_work_add(req); |
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} |
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static void io_complete_rw_iopoll(struct kiocb *kiocb, long res) |
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{ |
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struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); |
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struct io_kiocb *req = cmd_to_io_kiocb(rw); |
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if (kiocb->ki_flags & IOCB_WRITE) |
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kiocb_end_write(req); |
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if (unlikely(res != req->cqe.res)) { |
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if (res == -EAGAIN && io_rw_should_reissue(req)) { |
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req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO; |
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return; |
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} |
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req->cqe.res = res; |
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} |
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|
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/* order with io_iopoll_complete() checking ->iopoll_completed */ |
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smp_store_release(&req->iopoll_completed, 1); |
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} |
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static int kiocb_done(struct io_kiocb *req, ssize_t ret, |
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unsigned int issue_flags) |
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{ |
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struct io_async_rw *io = req->async_data; |
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
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|
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/* add previously done IO, if any */ |
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if (req_has_async_data(req) && io->bytes_done > 0) { |
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if (ret < 0) |
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ret = io->bytes_done; |
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else |
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ret += io->bytes_done; |
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} |
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if (req->flags & REQ_F_CUR_POS) |
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req->file->f_pos = rw->kiocb.ki_pos; |
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if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) { |
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if (!__io_complete_rw_common(req, ret)) { |
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io_req_set_res(req, req->cqe.res, |
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io_put_kbuf(req, issue_flags)); |
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return IOU_OK; |
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} |
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} else { |
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io_rw_done(&rw->kiocb, ret); |
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} |
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|
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if (req->flags & REQ_F_REISSUE) { |
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req->flags &= ~REQ_F_REISSUE; |
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if (io_resubmit_prep(req)) |
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io_req_task_queue_reissue(req); |
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else |
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io_req_task_queue_fail(req, ret); |
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} |
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return IOU_ISSUE_SKIP_COMPLETE; |
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} |
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#ifdef CONFIG_COMPAT |
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static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov, |
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unsigned int issue_flags) |
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{ |
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
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struct compat_iovec __user *uiov; |
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compat_ssize_t clen; |
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void __user *buf; |
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size_t len; |
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uiov = u64_to_user_ptr(rw->addr); |
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if (!access_ok(uiov, sizeof(*uiov))) |
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return -EFAULT; |
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if (__get_user(clen, &uiov->iov_len)) |
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return -EFAULT; |
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if (clen < 0) |
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return -EINVAL; |
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len = clen; |
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buf = io_buffer_select(req, &len, issue_flags); |
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if (!buf) |
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return -ENOBUFS; |
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rw->addr = (unsigned long) buf; |
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iov[0].iov_base = buf; |
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rw->len = iov[0].iov_len = (compat_size_t) len; |
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return 0; |
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} |
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#endif |
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static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, |
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unsigned int issue_flags) |
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{ |
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
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struct iovec __user *uiov = u64_to_user_ptr(rw->addr); |
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void __user *buf; |
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ssize_t len; |
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if (copy_from_user(iov, uiov, sizeof(*uiov))) |
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return -EFAULT; |
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len = iov[0].iov_len; |
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if (len < 0) |
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return -EINVAL; |
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buf = io_buffer_select(req, &len, issue_flags); |
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if (!buf) |
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return -ENOBUFS; |
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rw->addr = (unsigned long) buf; |
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iov[0].iov_base = buf; |
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rw->len = iov[0].iov_len = len; |
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return 0; |
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} |
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static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, |
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unsigned int issue_flags) |
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{ |
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
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|
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if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) { |
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iov[0].iov_base = u64_to_user_ptr(rw->addr); |
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iov[0].iov_len = rw->len; |
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return 0; |
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} |
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if (rw->len != 1) |
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return -EINVAL; |
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#ifdef CONFIG_COMPAT |
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if (req->ctx->compat) |
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return io_compat_import(req, iov, issue_flags); |
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#endif |
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return __io_iov_buffer_select(req, iov, issue_flags); |
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} |
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static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req, |
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struct io_rw_state *s, |
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unsigned int issue_flags) |
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{ |
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struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
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struct iov_iter *iter = &s->iter; |
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u8 opcode = req->opcode; |
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struct iovec *iovec; |
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void __user *buf; |
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size_t sqe_len; |
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ssize_t ret; |
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if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { |
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ret = io_import_fixed(ddir, iter, req->imu, rw->addr, rw->len); |
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if (ret) |
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return ERR_PTR(ret); |
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return NULL; |
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} |
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buf = u64_to_user_ptr(rw->addr); |
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sqe_len = rw->len; |
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|
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if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) { |
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if (io_do_buffer_select(req)) { |
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buf = io_buffer_select(req, &sqe_len, issue_flags); |
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if (!buf) |
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return ERR_PTR(-ENOBUFS); |
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rw->addr = (unsigned long) buf; |
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rw->len = sqe_len; |
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} |
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|
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ret = import_single_range(ddir, buf, sqe_len, s->fast_iov, iter); |
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if (ret) |
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return ERR_PTR(ret); |
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return NULL; |
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} |
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iovec = s->fast_iov; |
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if (req->flags & REQ_F_BUFFER_SELECT) { |
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ret = io_iov_buffer_select(req, iovec, issue_flags); |
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if (ret) |
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return ERR_PTR(ret); |
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iov_iter_init(iter, ddir, iovec, 1, iovec->iov_len); |
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return NULL; |
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} |
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|
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ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter, |
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req->ctx->compat); |
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if (unlikely(ret < 0)) |
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return ERR_PTR(ret); |
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return iovec; |
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} |
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|
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static inline int io_import_iovec(int rw, struct io_kiocb *req, |
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struct iovec **iovec, struct io_rw_state *s, |
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unsigned int issue_flags) |
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{ |
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*iovec = __io_import_iovec(rw, req, s, issue_flags); |
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if (unlikely(IS_ERR(*iovec))) |
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return PTR_ERR(*iovec); |
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|
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iov_iter_save_state(&s->iter, &s->iter_state); |
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return 0; |
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} |
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|
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static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb) |
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{ |
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return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos; |
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} |
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|
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/* |
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* For files that don't have ->read_iter() and ->write_iter(), handle them |
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* by looping over ->read() or ->write() manually. |
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*/ |
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static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter) |
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{ |
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struct kiocb *kiocb = &rw->kiocb; |
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struct file *file = kiocb->ki_filp; |
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ssize_t ret = 0; |
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loff_t *ppos; |
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|
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/* |
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* Don't support polled IO through this interface, and we can't |
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* support non-blocking either. For the latter, this just causes |
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* the kiocb to be handled from an async context. |
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*/ |
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if (kiocb->ki_flags & IOCB_HIPRI) |
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return -EOPNOTSUPP; |
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if ((kiocb->ki_flags & IOCB_NOWAIT) && |
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!(kiocb->ki_filp->f_flags & O_NONBLOCK)) |
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return -EAGAIN; |
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|
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ppos = io_kiocb_ppos(kiocb); |
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|
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while (iov_iter_count(iter)) { |
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struct iovec iovec; |
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ssize_t nr; |
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|
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if (!iov_iter_is_bvec(iter)) { |
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iovec = iov_iter_iovec(iter); |
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} else { |
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iovec.iov_base = u64_to_user_ptr(rw->addr); |
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iovec.iov_len = rw->len; |
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} |
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|
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if (ddir == READ) { |
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nr = file->f_op->read(file, iovec.iov_base, |
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iovec.iov_len, ppos); |
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} else { |
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nr = file->f_op->write(file, iovec.iov_base, |
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iovec.iov_len, ppos); |
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} |
|
|
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if (nr < 0) { |
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if (!ret) |
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ret = nr; |
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break; |
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} |
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ret += nr; |
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if (!iov_iter_is_bvec(iter)) { |
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iov_iter_advance(iter, nr); |
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} else { |
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rw->addr += nr; |
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rw->len -= nr; |
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if (!rw->len) |
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break; |
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} |
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if (nr != iovec.iov_len) |
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break; |
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} |
|
|
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return ret; |
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} |
|
|
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static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec, |
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const struct iovec *fast_iov, struct iov_iter *iter) |
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{ |
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struct io_async_rw *io = req->async_data; |
|
|
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memcpy(&io->s.iter, iter, sizeof(*iter)); |
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io->free_iovec = iovec; |
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io->bytes_done = 0; |
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/* can only be fixed buffers, no need to do anything */ |
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if (iov_iter_is_bvec(iter)) |
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return; |
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if (!iovec) { |
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unsigned iov_off = 0; |
|
|
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io->s.iter.iov = io->s.fast_iov; |
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if (iter->iov != fast_iov) { |
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iov_off = iter->iov - fast_iov; |
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io->s.iter.iov += iov_off; |
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} |
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if (io->s.fast_iov != fast_iov) |
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memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off, |
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sizeof(struct iovec) * iter->nr_segs); |
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} else { |
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req->flags |= REQ_F_NEED_CLEANUP; |
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} |
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} |
|
|
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static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, |
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struct io_rw_state *s, bool force) |
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{ |
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if (!force && !io_op_defs[req->opcode].prep_async) |
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return 0; |
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if (!req_has_async_data(req)) { |
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struct io_async_rw *iorw; |
|
|
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if (io_alloc_async_data(req)) { |
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kfree(iovec); |
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return -ENOMEM; |
|
} |
|
|
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io_req_map_rw(req, iovec, s->fast_iov, &s->iter); |
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iorw = req->async_data; |
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/* we've copied and mapped the iter, ensure state is saved */ |
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iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state); |
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} |
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return 0; |
|
} |
|
|
|
static inline int io_rw_prep_async(struct io_kiocb *req, int rw) |
|
{ |
|
struct io_async_rw *iorw = req->async_data; |
|
struct iovec *iov; |
|
int ret; |
|
|
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/* submission path, ->uring_lock should already be taken */ |
|
ret = io_import_iovec(rw, req, &iov, &iorw->s, 0); |
|
if (unlikely(ret < 0)) |
|
return ret; |
|
|
|
iorw->bytes_done = 0; |
|
iorw->free_iovec = iov; |
|
if (iov) |
|
req->flags |= REQ_F_NEED_CLEANUP; |
|
return 0; |
|
} |
|
|
|
int io_readv_prep_async(struct io_kiocb *req) |
|
{ |
|
return io_rw_prep_async(req, READ); |
|
} |
|
|
|
int io_writev_prep_async(struct io_kiocb *req) |
|
{ |
|
return io_rw_prep_async(req, WRITE); |
|
} |
|
|
|
/* |
|
* This is our waitqueue callback handler, registered through __folio_lock_async() |
|
* when we initially tried to do the IO with the iocb armed our waitqueue. |
|
* This gets called when the page is unlocked, and we generally expect that to |
|
* happen when the page IO is completed and the page is now uptodate. This will |
|
* queue a task_work based retry of the operation, attempting to copy the data |
|
* again. If the latter fails because the page was NOT uptodate, then we will |
|
* do a thread based blocking retry of the operation. That's the unexpected |
|
* slow path. |
|
*/ |
|
static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode, |
|
int sync, void *arg) |
|
{ |
|
struct wait_page_queue *wpq; |
|
struct io_kiocb *req = wait->private; |
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
|
struct wait_page_key *key = arg; |
|
|
|
wpq = container_of(wait, struct wait_page_queue, wait); |
|
|
|
if (!wake_page_match(wpq, key)) |
|
return 0; |
|
|
|
rw->kiocb.ki_flags &= ~IOCB_WAITQ; |
|
list_del_init(&wait->entry); |
|
io_req_task_queue(req); |
|
return 1; |
|
} |
|
|
|
/* |
|
* This controls whether a given IO request should be armed for async page |
|
* based retry. If we return false here, the request is handed to the async |
|
* worker threads for retry. If we're doing buffered reads on a regular file, |
|
* we prepare a private wait_page_queue entry and retry the operation. This |
|
* will either succeed because the page is now uptodate and unlocked, or it |
|
* will register a callback when the page is unlocked at IO completion. Through |
|
* that callback, io_uring uses task_work to setup a retry of the operation. |
|
* That retry will attempt the buffered read again. The retry will generally |
|
* succeed, or in rare cases where it fails, we then fall back to using the |
|
* async worker threads for a blocking retry. |
|
*/ |
|
static bool io_rw_should_retry(struct io_kiocb *req) |
|
{ |
|
struct io_async_rw *io = req->async_data; |
|
struct wait_page_queue *wait = &io->wpq; |
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
|
struct kiocb *kiocb = &rw->kiocb; |
|
|
|
/* never retry for NOWAIT, we just complete with -EAGAIN */ |
|
if (req->flags & REQ_F_NOWAIT) |
|
return false; |
|
|
|
/* Only for buffered IO */ |
|
if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI)) |
|
return false; |
|
|
|
/* |
|
* just use poll if we can, and don't attempt if the fs doesn't |
|
* support callback based unlocks |
|
*/ |
|
if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC)) |
|
return false; |
|
|
|
wait->wait.func = io_async_buf_func; |
|
wait->wait.private = req; |
|
wait->wait.flags = 0; |
|
INIT_LIST_HEAD(&wait->wait.entry); |
|
kiocb->ki_flags |= IOCB_WAITQ; |
|
kiocb->ki_flags &= ~IOCB_NOWAIT; |
|
kiocb->ki_waitq = wait; |
|
return true; |
|
} |
|
|
|
static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter) |
|
{ |
|
struct file *file = rw->kiocb.ki_filp; |
|
|
|
if (likely(file->f_op->read_iter)) |
|
return call_read_iter(file, &rw->kiocb, iter); |
|
else if (file->f_op->read) |
|
return loop_rw_iter(READ, rw, iter); |
|
else |
|
return -EINVAL; |
|
} |
|
|
|
static bool need_complete_io(struct io_kiocb *req) |
|
{ |
|
return req->flags & REQ_F_ISREG || |
|
S_ISBLK(file_inode(req->file)->i_mode); |
|
} |
|
|
|
static int io_rw_init_file(struct io_kiocb *req, fmode_t mode) |
|
{ |
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
|
struct kiocb *kiocb = &rw->kiocb; |
|
struct io_ring_ctx *ctx = req->ctx; |
|
struct file *file = req->file; |
|
int ret; |
|
|
|
if (unlikely(!file || !(file->f_mode & mode))) |
|
return -EBADF; |
|
|
|
if (!io_req_ffs_set(req)) |
|
req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT; |
|
|
|
kiocb->ki_flags = file->f_iocb_flags; |
|
ret = kiocb_set_rw_flags(kiocb, rw->flags); |
|
if (unlikely(ret)) |
|
return ret; |
|
|
|
/* |
|
* If the file is marked O_NONBLOCK, still allow retry for it if it |
|
* supports async. Otherwise it's impossible to use O_NONBLOCK files |
|
* reliably. If not, or it IOCB_NOWAIT is set, don't retry. |
|
*/ |
|
if ((kiocb->ki_flags & IOCB_NOWAIT) || |
|
((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req))) |
|
req->flags |= REQ_F_NOWAIT; |
|
|
|
if (ctx->flags & IORING_SETUP_IOPOLL) { |
|
if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll) |
|
return -EOPNOTSUPP; |
|
|
|
kiocb->private = NULL; |
|
kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE; |
|
kiocb->ki_complete = io_complete_rw_iopoll; |
|
req->iopoll_completed = 0; |
|
} else { |
|
if (kiocb->ki_flags & IOCB_HIPRI) |
|
return -EINVAL; |
|
kiocb->ki_complete = io_complete_rw; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
int io_read(struct io_kiocb *req, unsigned int issue_flags) |
|
{ |
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
|
struct io_rw_state __s, *s = &__s; |
|
struct iovec *iovec; |
|
struct kiocb *kiocb = &rw->kiocb; |
|
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; |
|
struct io_async_rw *io; |
|
ssize_t ret, ret2; |
|
loff_t *ppos; |
|
|
|
if (!req_has_async_data(req)) { |
|
ret = io_import_iovec(READ, req, &iovec, s, issue_flags); |
|
if (unlikely(ret < 0)) |
|
return ret; |
|
} else { |
|
io = req->async_data; |
|
s = &io->s; |
|
|
|
/* |
|
* Safe and required to re-import if we're using provided |
|
* buffers, as we dropped the selected one before retry. |
|
*/ |
|
if (io_do_buffer_select(req)) { |
|
ret = io_import_iovec(READ, req, &iovec, s, issue_flags); |
|
if (unlikely(ret < 0)) |
|
return ret; |
|
} |
|
|
|
/* |
|
* We come here from an earlier attempt, restore our state to |
|
* match in case it doesn't. It's cheap enough that we don't |
|
* need to make this conditional. |
|
*/ |
|
iov_iter_restore(&s->iter, &s->iter_state); |
|
iovec = NULL; |
|
} |
|
ret = io_rw_init_file(req, FMODE_READ); |
|
if (unlikely(ret)) { |
|
kfree(iovec); |
|
return ret; |
|
} |
|
req->cqe.res = iov_iter_count(&s->iter); |
|
|
|
if (force_nonblock) { |
|
/* If the file doesn't support async, just async punt */ |
|
if (unlikely(!io_file_supports_nowait(req))) { |
|
ret = io_setup_async_rw(req, iovec, s, true); |
|
return ret ?: -EAGAIN; |
|
} |
|
kiocb->ki_flags |= IOCB_NOWAIT; |
|
} else { |
|
/* Ensure we clear previously set non-block flag */ |
|
kiocb->ki_flags &= ~IOCB_NOWAIT; |
|
} |
|
|
|
ppos = io_kiocb_update_pos(req); |
|
|
|
ret = rw_verify_area(READ, req->file, ppos, req->cqe.res); |
|
if (unlikely(ret)) { |
|
kfree(iovec); |
|
return ret; |
|
} |
|
|
|
ret = io_iter_do_read(rw, &s->iter); |
|
|
|
if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) { |
|
req->flags &= ~REQ_F_REISSUE; |
|
/* if we can poll, just do that */ |
|
if (req->opcode == IORING_OP_READ && file_can_poll(req->file)) |
|
return -EAGAIN; |
|
/* IOPOLL retry should happen for io-wq threads */ |
|
if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL)) |
|
goto done; |
|
/* no retry on NONBLOCK nor RWF_NOWAIT */ |
|
if (req->flags & REQ_F_NOWAIT) |
|
goto done; |
|
ret = 0; |
|
} else if (ret == -EIOCBQUEUED) { |
|
if (iovec) |
|
kfree(iovec); |
|
return IOU_ISSUE_SKIP_COMPLETE; |
|
} else if (ret == req->cqe.res || ret <= 0 || !force_nonblock || |
|
(req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) { |
|
/* read all, failed, already did sync or don't want to retry */ |
|
goto done; |
|
} |
|
|
|
/* |
|
* Don't depend on the iter state matching what was consumed, or being |
|
* untouched in case of error. Restore it and we'll advance it |
|
* manually if we need to. |
|
*/ |
|
iov_iter_restore(&s->iter, &s->iter_state); |
|
|
|
ret2 = io_setup_async_rw(req, iovec, s, true); |
|
if (ret2) |
|
return ret2; |
|
|
|
iovec = NULL; |
|
io = req->async_data; |
|
s = &io->s; |
|
/* |
|
* Now use our persistent iterator and state, if we aren't already. |
|
* We've restored and mapped the iter to match. |
|
*/ |
|
|
|
do { |
|
/* |
|
* We end up here because of a partial read, either from |
|
* above or inside this loop. Advance the iter by the bytes |
|
* that were consumed. |
|
*/ |
|
iov_iter_advance(&s->iter, ret); |
|
if (!iov_iter_count(&s->iter)) |
|
break; |
|
io->bytes_done += ret; |
|
iov_iter_save_state(&s->iter, &s->iter_state); |
|
|
|
/* if we can retry, do so with the callbacks armed */ |
|
if (!io_rw_should_retry(req)) { |
|
kiocb->ki_flags &= ~IOCB_WAITQ; |
|
return -EAGAIN; |
|
} |
|
|
|
/* |
|
* Now retry read with the IOCB_WAITQ parts set in the iocb. If |
|
* we get -EIOCBQUEUED, then we'll get a notification when the |
|
* desired page gets unlocked. We can also get a partial read |
|
* here, and if we do, then just retry at the new offset. |
|
*/ |
|
ret = io_iter_do_read(rw, &s->iter); |
|
if (ret == -EIOCBQUEUED) |
|
return IOU_ISSUE_SKIP_COMPLETE; |
|
/* we got some bytes, but not all. retry. */ |
|
kiocb->ki_flags &= ~IOCB_WAITQ; |
|
iov_iter_restore(&s->iter, &s->iter_state); |
|
} while (ret > 0); |
|
done: |
|
/* it's faster to check here then delegate to kfree */ |
|
if (iovec) |
|
kfree(iovec); |
|
return kiocb_done(req, ret, issue_flags); |
|
} |
|
|
|
int io_write(struct io_kiocb *req, unsigned int issue_flags) |
|
{ |
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
|
struct io_rw_state __s, *s = &__s; |
|
struct iovec *iovec; |
|
struct kiocb *kiocb = &rw->kiocb; |
|
bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; |
|
ssize_t ret, ret2; |
|
loff_t *ppos; |
|
|
|
if (!req_has_async_data(req)) { |
|
ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags); |
|
if (unlikely(ret < 0)) |
|
return ret; |
|
} else { |
|
struct io_async_rw *io = req->async_data; |
|
|
|
s = &io->s; |
|
iov_iter_restore(&s->iter, &s->iter_state); |
|
iovec = NULL; |
|
} |
|
ret = io_rw_init_file(req, FMODE_WRITE); |
|
if (unlikely(ret)) { |
|
kfree(iovec); |
|
return ret; |
|
} |
|
req->cqe.res = iov_iter_count(&s->iter); |
|
|
|
if (force_nonblock) { |
|
/* If the file doesn't support async, just async punt */ |
|
if (unlikely(!io_file_supports_nowait(req))) |
|
goto copy_iov; |
|
|
|
/* File path supports NOWAIT for non-direct_IO only for block devices. */ |
|
if (!(kiocb->ki_flags & IOCB_DIRECT) && |
|
!(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) && |
|
(req->flags & REQ_F_ISREG)) |
|
goto copy_iov; |
|
|
|
kiocb->ki_flags |= IOCB_NOWAIT; |
|
} else { |
|
/* Ensure we clear previously set non-block flag */ |
|
kiocb->ki_flags &= ~IOCB_NOWAIT; |
|
} |
|
|
|
ppos = io_kiocb_update_pos(req); |
|
|
|
ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res); |
|
if (unlikely(ret)) { |
|
kfree(iovec); |
|
return ret; |
|
} |
|
|
|
/* |
|
* Open-code file_start_write here to grab freeze protection, |
|
* which will be released by another thread in |
|
* io_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 (req->flags & REQ_F_ISREG) { |
|
sb_start_write(file_inode(req->file)->i_sb); |
|
__sb_writers_release(file_inode(req->file)->i_sb, |
|
SB_FREEZE_WRITE); |
|
} |
|
kiocb->ki_flags |= IOCB_WRITE; |
|
|
|
if (likely(req->file->f_op->write_iter)) |
|
ret2 = call_write_iter(req->file, kiocb, &s->iter); |
|
else if (req->file->f_op->write) |
|
ret2 = loop_rw_iter(WRITE, rw, &s->iter); |
|
else |
|
ret2 = -EINVAL; |
|
|
|
if (req->flags & REQ_F_REISSUE) { |
|
req->flags &= ~REQ_F_REISSUE; |
|
ret2 = -EAGAIN; |
|
} |
|
|
|
/* |
|
* Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just |
|
* retry them without IOCB_NOWAIT. |
|
*/ |
|
if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) |
|
ret2 = -EAGAIN; |
|
/* no retry on NONBLOCK nor RWF_NOWAIT */ |
|
if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT)) |
|
goto done; |
|
if (!force_nonblock || ret2 != -EAGAIN) { |
|
/* IOPOLL retry should happen for io-wq threads */ |
|
if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL)) |
|
goto copy_iov; |
|
|
|
if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) { |
|
struct io_async_rw *rw; |
|
|
|
trace_io_uring_short_write(req->ctx, kiocb->ki_pos - ret2, |
|
req->cqe.res, ret2); |
|
|
|
/* This is a partial write. The file pos has already been |
|
* updated, setup the async struct to complete the request |
|
* in the worker. Also update bytes_done to account for |
|
* the bytes already written. |
|
*/ |
|
iov_iter_save_state(&s->iter, &s->iter_state); |
|
ret = io_setup_async_rw(req, iovec, s, true); |
|
|
|
rw = req->async_data; |
|
if (rw) |
|
rw->bytes_done += ret2; |
|
|
|
if (kiocb->ki_flags & IOCB_WRITE) |
|
kiocb_end_write(req); |
|
return ret ? ret : -EAGAIN; |
|
} |
|
done: |
|
ret = kiocb_done(req, ret2, issue_flags); |
|
} else { |
|
copy_iov: |
|
iov_iter_restore(&s->iter, &s->iter_state); |
|
ret = io_setup_async_rw(req, iovec, s, false); |
|
if (!ret) { |
|
if (kiocb->ki_flags & IOCB_WRITE) |
|
kiocb_end_write(req); |
|
return -EAGAIN; |
|
} |
|
return ret; |
|
} |
|
/* it's reportedly faster than delegating the null check to kfree() */ |
|
if (iovec) |
|
kfree(iovec); |
|
return ret; |
|
} |
|
|
|
static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx) |
|
{ |
|
io_commit_cqring_flush(ctx); |
|
if (ctx->flags & IORING_SETUP_SQPOLL) |
|
io_cqring_wake(ctx); |
|
} |
|
|
|
int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) |
|
{ |
|
struct io_wq_work_node *pos, *start, *prev; |
|
unsigned int poll_flags = BLK_POLL_NOSLEEP; |
|
DEFINE_IO_COMP_BATCH(iob); |
|
int nr_events = 0; |
|
|
|
/* |
|
* Only spin for completions if we don't have multiple devices hanging |
|
* off our complete list. |
|
*/ |
|
if (ctx->poll_multi_queue || force_nonspin) |
|
poll_flags |= BLK_POLL_ONESHOT; |
|
|
|
wq_list_for_each(pos, start, &ctx->iopoll_list) { |
|
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); |
|
struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); |
|
int ret; |
|
|
|
/* |
|
* Move completed and retryable entries to our local lists. |
|
* If we find a request that requires polling, break out |
|
* and complete those lists first, if we have entries there. |
|
*/ |
|
if (READ_ONCE(req->iopoll_completed)) |
|
break; |
|
|
|
ret = rw->kiocb.ki_filp->f_op->iopoll(&rw->kiocb, &iob, poll_flags); |
|
if (unlikely(ret < 0)) |
|
return ret; |
|
else if (ret) |
|
poll_flags |= BLK_POLL_ONESHOT; |
|
|
|
/* iopoll may have completed current req */ |
|
if (!rq_list_empty(iob.req_list) || |
|
READ_ONCE(req->iopoll_completed)) |
|
break; |
|
} |
|
|
|
if (!rq_list_empty(iob.req_list)) |
|
iob.complete(&iob); |
|
else if (!pos) |
|
return 0; |
|
|
|
prev = start; |
|
wq_list_for_each_resume(pos, prev) { |
|
struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); |
|
|
|
/* order with io_complete_rw_iopoll(), e.g. ->result updates */ |
|
if (!smp_load_acquire(&req->iopoll_completed)) |
|
break; |
|
nr_events++; |
|
if (unlikely(req->flags & REQ_F_CQE_SKIP)) |
|
continue; |
|
|
|
req->cqe.flags = io_put_kbuf(req, 0); |
|
__io_fill_cqe_req(req->ctx, req); |
|
} |
|
|
|
if (unlikely(!nr_events)) |
|
return 0; |
|
|
|
io_commit_cqring(ctx); |
|
io_cqring_ev_posted_iopoll(ctx); |
|
pos = start ? start->next : ctx->iopoll_list.first; |
|
wq_list_cut(&ctx->iopoll_list, prev, start); |
|
io_free_batch_list(ctx, pos); |
|
return nr_events; |
|
}
|
|
|