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![Dylan Yudaken](/assets/img/avatar_default.png)
It is possible for tw to lock the ring, and this was not propogated out to
io_run_local_work. This can cause an unlock to be missed.
Instead pass a pointer to locked into __io_run_local_work.
Fixes: 8ac5d85a89
("io_uring: add local task_work run helper that is entered locked")
Signed-off-by: Dylan Yudaken <dylany@meta.com>
Link: https://lore.kernel.org/r/20221027144429.3971400-3-dylany@meta.com
[axboe: WARN_ON() -> WARN_ON_ONCE() and add a minor comment]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
367 lines
9.8 KiB
C
367 lines
9.8 KiB
C
#ifndef IOU_CORE_H
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#define IOU_CORE_H
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#include <linux/errno.h>
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#include <linux/lockdep.h>
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#include <linux/io_uring_types.h>
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#include "io-wq.h"
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#include "slist.h"
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#include "filetable.h"
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#ifndef CREATE_TRACE_POINTS
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#include <trace/events/io_uring.h>
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#endif
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enum {
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IOU_OK = 0,
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IOU_ISSUE_SKIP_COMPLETE = -EIOCBQUEUED,
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/*
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* Intended only when both REQ_F_POLLED and REQ_F_APOLL_MULTISHOT
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* are set to indicate to the poll runner that multishot should be
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* removed and the result is set on req->cqe.res.
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*/
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IOU_STOP_MULTISHOT = -ECANCELED,
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};
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struct io_uring_cqe *__io_get_cqe(struct io_ring_ctx *ctx, bool overflow);
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bool io_req_cqe_overflow(struct io_kiocb *req);
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int io_run_task_work_sig(struct io_ring_ctx *ctx);
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int __io_run_local_work(struct io_ring_ctx *ctx, bool *locked);
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int io_run_local_work(struct io_ring_ctx *ctx);
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void io_req_complete_failed(struct io_kiocb *req, s32 res);
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void __io_req_complete(struct io_kiocb *req, unsigned issue_flags);
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void io_req_complete_post(struct io_kiocb *req);
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void __io_req_complete_post(struct io_kiocb *req);
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bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags,
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bool allow_overflow);
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bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags,
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bool allow_overflow);
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void __io_commit_cqring_flush(struct io_ring_ctx *ctx);
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struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages);
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struct file *io_file_get_normal(struct io_kiocb *req, int fd);
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struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
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unsigned issue_flags);
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static inline bool io_req_ffs_set(struct io_kiocb *req)
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{
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return req->flags & REQ_F_FIXED_FILE;
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}
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bool io_is_uring_fops(struct file *file);
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bool io_alloc_async_data(struct io_kiocb *req);
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void io_req_task_work_add(struct io_kiocb *req);
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void io_req_tw_post_queue(struct io_kiocb *req, s32 res, u32 cflags);
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void io_req_task_queue(struct io_kiocb *req);
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void io_queue_iowq(struct io_kiocb *req, bool *dont_use);
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void io_req_task_complete(struct io_kiocb *req, bool *locked);
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void io_req_task_queue_fail(struct io_kiocb *req, int ret);
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void io_req_task_submit(struct io_kiocb *req, bool *locked);
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void tctx_task_work(struct callback_head *cb);
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__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
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int io_uring_alloc_task_context(struct task_struct *task,
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struct io_ring_ctx *ctx);
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int io_poll_issue(struct io_kiocb *req, bool *locked);
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int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
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int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
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void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node);
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int io_req_prep_async(struct io_kiocb *req);
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struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
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void io_wq_submit_work(struct io_wq_work *work);
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void io_free_req(struct io_kiocb *req);
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void io_queue_next(struct io_kiocb *req);
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void __io_put_task(struct task_struct *task, int nr);
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void io_task_refs_refill(struct io_uring_task *tctx);
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bool __io_alloc_req_refill(struct io_ring_ctx *ctx);
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bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
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bool cancel_all);
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#define io_for_each_link(pos, head) \
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for (pos = (head); pos; pos = pos->link)
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static inline void io_cq_lock(struct io_ring_ctx *ctx)
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__acquires(ctx->completion_lock)
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{
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spin_lock(&ctx->completion_lock);
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}
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void io_cq_unlock_post(struct io_ring_ctx *ctx);
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static inline struct io_uring_cqe *io_get_cqe_overflow(struct io_ring_ctx *ctx,
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bool overflow)
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{
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if (likely(ctx->cqe_cached < ctx->cqe_sentinel)) {
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struct io_uring_cqe *cqe = ctx->cqe_cached;
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ctx->cached_cq_tail++;
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ctx->cqe_cached++;
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if (ctx->flags & IORING_SETUP_CQE32)
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ctx->cqe_cached++;
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return cqe;
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}
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return __io_get_cqe(ctx, overflow);
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}
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static inline struct io_uring_cqe *io_get_cqe(struct io_ring_ctx *ctx)
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{
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return io_get_cqe_overflow(ctx, false);
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}
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static inline bool __io_fill_cqe_req(struct io_ring_ctx *ctx,
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struct io_kiocb *req)
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{
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struct io_uring_cqe *cqe;
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/*
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* If we can't get a cq entry, userspace overflowed the
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* submission (by quite a lot). Increment the overflow count in
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* the ring.
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*/
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cqe = io_get_cqe(ctx);
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if (unlikely(!cqe))
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return io_req_cqe_overflow(req);
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trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
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req->cqe.res, req->cqe.flags,
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(req->flags & REQ_F_CQE32_INIT) ? req->extra1 : 0,
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(req->flags & REQ_F_CQE32_INIT) ? req->extra2 : 0);
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memcpy(cqe, &req->cqe, sizeof(*cqe));
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if (ctx->flags & IORING_SETUP_CQE32) {
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u64 extra1 = 0, extra2 = 0;
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if (req->flags & REQ_F_CQE32_INIT) {
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extra1 = req->extra1;
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extra2 = req->extra2;
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}
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WRITE_ONCE(cqe->big_cqe[0], extra1);
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WRITE_ONCE(cqe->big_cqe[1], extra2);
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}
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return true;
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}
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static inline void req_set_fail(struct io_kiocb *req)
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{
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req->flags |= REQ_F_FAIL;
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if (req->flags & REQ_F_CQE_SKIP) {
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req->flags &= ~REQ_F_CQE_SKIP;
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req->flags |= REQ_F_SKIP_LINK_CQES;
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}
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}
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static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
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{
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req->cqe.res = res;
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req->cqe.flags = cflags;
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}
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static inline bool req_has_async_data(struct io_kiocb *req)
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{
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return req->flags & REQ_F_ASYNC_DATA;
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}
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static inline void io_put_file(struct file *file)
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{
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if (file)
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fput(file);
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}
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static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
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unsigned issue_flags)
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{
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lockdep_assert_held(&ctx->uring_lock);
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if (issue_flags & IO_URING_F_UNLOCKED)
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mutex_unlock(&ctx->uring_lock);
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}
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static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
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unsigned issue_flags)
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{
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/*
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* "Normal" inline submissions always hold the uring_lock, since we
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* grab it from the system call. Same is true for the SQPOLL offload.
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* The only exception is when we've detached the request and issue it
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* from an async worker thread, grab the lock for that case.
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*/
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if (issue_flags & IO_URING_F_UNLOCKED)
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mutex_lock(&ctx->uring_lock);
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lockdep_assert_held(&ctx->uring_lock);
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}
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static inline void io_commit_cqring(struct io_ring_ctx *ctx)
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{
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/* order cqe stores with ring update */
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smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
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}
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/* requires smb_mb() prior, see wq_has_sleeper() */
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static inline void __io_cqring_wake(struct io_ring_ctx *ctx)
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{
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/*
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* wake_up_all() may seem excessive, but io_wake_function() and
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* io_should_wake() handle the termination of the loop and only
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* wake as many waiters as we need to.
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*/
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if (waitqueue_active(&ctx->cq_wait))
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wake_up_all(&ctx->cq_wait);
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}
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static inline void io_cqring_wake(struct io_ring_ctx *ctx)
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{
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smp_mb();
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__io_cqring_wake(ctx);
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}
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static inline bool io_sqring_full(struct io_ring_ctx *ctx)
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{
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struct io_rings *r = ctx->rings;
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return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries;
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}
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static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
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{
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struct io_rings *rings = ctx->rings;
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/* make sure SQ entry isn't read before tail */
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return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
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}
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static inline int io_run_task_work(void)
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{
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if (task_work_pending(current)) {
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if (test_thread_flag(TIF_NOTIFY_SIGNAL))
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clear_notify_signal();
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__set_current_state(TASK_RUNNING);
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task_work_run();
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return 1;
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}
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return 0;
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}
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static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
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{
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return test_thread_flag(TIF_NOTIFY_SIGNAL) ||
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!wq_list_empty(&ctx->work_llist);
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}
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static inline int io_run_task_work_ctx(struct io_ring_ctx *ctx)
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{
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int ret = 0;
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int ret2;
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if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
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ret = io_run_local_work(ctx);
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/* want to run this after in case more is added */
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ret2 = io_run_task_work();
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/* Try propagate error in favour of if tasks were run,
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* but still make sure to run them if requested
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*/
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if (ret >= 0)
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ret += ret2;
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return ret;
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}
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static inline int io_run_local_work_locked(struct io_ring_ctx *ctx)
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{
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bool locked;
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int ret;
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if (llist_empty(&ctx->work_llist))
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return 0;
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locked = true;
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ret = __io_run_local_work(ctx, &locked);
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/* shouldn't happen! */
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if (WARN_ON_ONCE(!locked))
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mutex_lock(&ctx->uring_lock);
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return ret;
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}
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static inline void io_tw_lock(struct io_ring_ctx *ctx, bool *locked)
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{
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if (!*locked) {
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mutex_lock(&ctx->uring_lock);
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*locked = true;
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}
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}
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/*
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* Don't complete immediately but use deferred completion infrastructure.
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* Protected by ->uring_lock and can only be used either with
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* IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
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*/
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static inline void io_req_complete_defer(struct io_kiocb *req)
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__must_hold(&req->ctx->uring_lock)
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{
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struct io_submit_state *state = &req->ctx->submit_state;
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lockdep_assert_held(&req->ctx->uring_lock);
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wq_list_add_tail(&req->comp_list, &state->compl_reqs);
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}
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static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
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{
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if (unlikely(ctx->off_timeout_used || ctx->drain_active || ctx->has_evfd))
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__io_commit_cqring_flush(ctx);
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}
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/* must to be called somewhat shortly after putting a request */
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static inline void io_put_task(struct task_struct *task, int nr)
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{
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if (likely(task == current))
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task->io_uring->cached_refs += nr;
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else
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__io_put_task(task, nr);
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}
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static inline void io_get_task_refs(int nr)
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{
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struct io_uring_task *tctx = current->io_uring;
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tctx->cached_refs -= nr;
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if (unlikely(tctx->cached_refs < 0))
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io_task_refs_refill(tctx);
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}
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static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
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{
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return !ctx->submit_state.free_list.next;
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}
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static inline bool io_alloc_req_refill(struct io_ring_ctx *ctx)
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{
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if (unlikely(io_req_cache_empty(ctx)))
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return __io_alloc_req_refill(ctx);
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return true;
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}
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static inline struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
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{
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struct io_wq_work_node *node;
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node = wq_stack_extract(&ctx->submit_state.free_list);
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return container_of(node, struct io_kiocb, comp_list);
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}
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static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
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{
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return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
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ctx->submitter_task == current);
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}
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#endif
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