io_uring/io_uring.h - third_party/kernel - Git at Google

 #ifndef IOU_CORE_H
 #define IOU_CORE_H

 #include <linux/errno.h>
 #include <linux/lockdep.h>
 #include <linux/resume_user_mode.h>
 #include <linux/kasan.h>
 #include <linux/io_uring_types.h>
 #include <uapi/linux/eventpoll.h>
 #include "io-wq.h"
 #include "slist.h"
 #include "filetable.h"

 #ifndef CREATE_TRACE_POINTS
 #include <trace/events/io_uring.h>
 #endif

 enum {
 	/*
 	 * A hint to not wake right away but delay until there are enough of
 	 * tw's queued to match the number of CQEs the task is waiting for.
 	 *
 	 * Must not be used wirh requests generating more than one CQE.
 	 * It's also ignored unless IORING_SETUP_DEFER_TASKRUN is set.
 	 */
 	IOU_F_TWQ_LAZY_WAKE			= 1,
 };

 enum {
 	IOU_OK			= 0,
 	IOU_ISSUE_SKIP_COMPLETE	= -EIOCBQUEUED,

 	/*
 	 * Requeue the task_work to restart operations on this request. The
 	 * actual value isn't important, should just be not an otherwise
 	 * valid error code, yet less than -MAX_ERRNO and valid internally.
 	 */
 	IOU_REQUEUE		= -3072,

 	/*
 	 * Intended only when both IO_URING_F_MULTISHOT is passed
 	 * to indicate to the poll runner that multishot should be
 	 * removed and the result is set on req->cqe.res.
 	 */
 	IOU_STOP_MULTISHOT	= -ECANCELED,
 };

 bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
 void io_req_cqe_overflow(struct io_kiocb *req);
 int io_run_task_work_sig(struct io_ring_ctx *ctx);
 void io_req_defer_failed(struct io_kiocb *req, s32 res);
 void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags);
 bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
 bool io_fill_cqe_req_aux(struct io_kiocb *req, bool defer, s32 res, u32 cflags);
 void __io_commit_cqring_flush(struct io_ring_ctx *ctx);

 struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages);
 int io_uring_mmap_pages(struct io_ring_ctx *ctx, struct vm_area_struct *vma,
 			struct page **pages, int npages);

 struct file *io_file_get_normal(struct io_kiocb *req, int fd);
 struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
 			       unsigned issue_flags);

 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
 bool io_alloc_async_data(struct io_kiocb *req);
 void io_req_task_queue(struct io_kiocb *req);
 void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts);
 void io_req_task_queue_fail(struct io_kiocb *req, int ret);
 void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts);
 void tctx_task_work(struct callback_head *cb);
 __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
 int io_uring_alloc_task_context(struct task_struct *task,
 				struct io_ring_ctx *ctx);

 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
 				     int start, int end);

 int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts);
 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
 void __io_submit_flush_completions(struct io_ring_ctx *ctx);
 int io_req_prep_async(struct io_kiocb *req);

 struct io_wq_work *io_wq_free_work(struct io_wq_work *work);
 void io_wq_submit_work(struct io_wq_work *work);

 void io_free_req(struct io_kiocb *req);
 void io_queue_next(struct io_kiocb *req);
 void io_task_refs_refill(struct io_uring_task *tctx);
 bool __io_alloc_req_refill(struct io_ring_ctx *ctx);

 bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
 			bool cancel_all);

 void *io_pages_map(struct page ***out_pages, unsigned short *npages,
 		   size_t size);
 void io_pages_unmap(void *ptr, struct page ***pages, unsigned short *npages,
 		    bool put_pages);

 #if defined(CONFIG_PROVE_LOCKING)
 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
 {
 	lockdep_assert(in_task());

 	if (ctx->flags & IORING_SETUP_IOPOLL) {
 		lockdep_assert_held(&ctx->uring_lock);
 	} else if (!ctx->task_complete) {
 		lockdep_assert_held(&ctx->completion_lock);
 	} else if (ctx->submitter_task) {
 		/*
 		 * ->submitter_task may be NULL and we can still post a CQE,
 		 * if the ring has been setup with IORING_SETUP_R_DISABLED.
 		 * Not from an SQE, as those cannot be submitted, but via
 		 * updating tagged resources.
 		 */
 		if (ctx->submitter_task->flags & PF_EXITING)
 			lockdep_assert(current_work());
 		else
 			lockdep_assert(current == ctx->submitter_task);
 	}
 }
 #else
 static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
 {
 }
 #endif

 static inline void io_req_task_work_add(struct io_kiocb *req)
 {
 	__io_req_task_work_add(req, 0);
 }

 #define io_for_each_link(pos, head) \
 	for (pos = (head); pos; pos = pos->link)

 static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
 					struct io_uring_cqe **ret,
 					bool overflow)
 {
 	io_lockdep_assert_cq_locked(ctx);

 	if (unlikely(ctx->cqe_cached >= ctx->cqe_sentinel)) {
 		if (unlikely(!io_cqe_cache_refill(ctx, overflow)))
 			return false;
 	}
 	*ret = ctx->cqe_cached;
 	ctx->cached_cq_tail++;
 	ctx->cqe_cached++;
 	if (ctx->flags & IORING_SETUP_CQE32)
 		ctx->cqe_cached++;
 	return true;
 }

 static inline bool io_get_cqe(struct io_ring_ctx *ctx, struct io_uring_cqe **ret)
 {
 	return io_get_cqe_overflow(ctx, ret, false);
 }

 static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
 					    struct io_kiocb *req)
 {
 	struct io_uring_cqe *cqe;

 	/*
 	 * If we can't get a cq entry, userspace overflowed the
 	 * submission (by quite a lot). Increment the overflow count in
 	 * the ring.
 	 */
 	if (unlikely(!io_get_cqe(ctx, &cqe)))
 		return false;

 	if (trace_io_uring_complete_enabled())
 		trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
 					req->cqe.res, req->cqe.flags,
 					req->big_cqe.extra1, req->big_cqe.extra2);

 	memcpy(cqe, &req->cqe, sizeof(*cqe));
 	if (ctx->flags & IORING_SETUP_CQE32) {
 		memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
 		memset(&req->big_cqe, 0, sizeof(req->big_cqe));
 	}
 	return true;
 }

 static inline void req_set_fail(struct io_kiocb *req)
 {
 	req->flags |= REQ_F_FAIL;
 	if (req->flags & REQ_F_CQE_SKIP) {
 		req->flags &= ~REQ_F_CQE_SKIP;
 		req->flags |= REQ_F_SKIP_LINK_CQES;
 	}
 }

 static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
 {
 	req->cqe.res = res;
 	req->cqe.flags = cflags;
 }

 static inline bool req_has_async_data(struct io_kiocb *req)
 {
 	return req->flags & REQ_F_ASYNC_DATA;
 }

 static inline void io_put_file(struct io_kiocb *req)
 {
 	if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
 		fput(req->file);
 }

 static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
 					 unsigned issue_flags)
 {
 	lockdep_assert_held(&ctx->uring_lock);
 	if (issue_flags & IO_URING_F_UNLOCKED)
 		mutex_unlock(&ctx->uring_lock);
 }

 static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
 				       unsigned issue_flags)
 {
 	/*
 	 * "Normal" inline submissions always hold the uring_lock, since we
 	 * grab it from the system call. Same is true for the SQPOLL offload.
 	 * The only exception is when we've detached the request and issue it
 	 * from an async worker thread, grab the lock for that case.
 	 */
 	if (issue_flags & IO_URING_F_UNLOCKED)
 		mutex_lock(&ctx->uring_lock);
 	lockdep_assert_held(&ctx->uring_lock);
 }

 static inline void io_commit_cqring(struct io_ring_ctx *ctx)
 {
 	/* order cqe stores with ring update */
 	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
 }

 static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
 {
 	if (wq_has_sleeper(&ctx->poll_wq))
 		__wake_up(&ctx->poll_wq, TASK_NORMAL, 0,
 				poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 }

 static inline void io_cqring_wake(struct io_ring_ctx *ctx)
 {
 	/*
 	 * Trigger waitqueue handler on all waiters on our waitqueue. This
 	 * won't necessarily wake up all the tasks, io_should_wake() will make
 	 * that decision.
 	 *
 	 * Pass in EPOLLIN|EPOLL_URING_WAKE as the poll wakeup key. The latter
 	 * set in the mask so that if we recurse back into our own poll
 	 * waitqueue handlers, we know we have a dependency between eventfd or
 	 * epoll and should terminate multishot poll at that point.
 	 */
 	if (wq_has_sleeper(&ctx->cq_wait))
 		__wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
 				poll_to_key(EPOLL_URING_WAKE | EPOLLIN));
 }

 static inline bool io_sqring_full(struct io_ring_ctx *ctx)
 {
 	struct io_rings *r = ctx->rings;

 	/*
 	 * SQPOLL must use the actual sqring head, as using the cached_sq_head
 	 * is race prone if the SQPOLL thread has grabbed entries but not yet
 	 * committed them to the ring. For !SQPOLL, this doesn't matter, but
 	 * since this helper is just used for SQPOLL sqring waits (or POLLOUT),
 	 * just read the actual sqring head unconditionally.
 	 */
 	return READ_ONCE(r->sq.tail) - READ_ONCE(r->sq.head) == ctx->sq_entries;
 }

 static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
 {
 	struct io_rings *rings = ctx->rings;
 	unsigned int entries;

 	/* make sure SQ entry isn't read before tail */
 	entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
 	return min(entries, ctx->sq_entries);
 }

 static inline int io_run_task_work(void)
 {
 	/*
 	 * Always check-and-clear the task_work notification signal. With how
 	 * signaling works for task_work, we can find it set with nothing to
 	 * run. We need to clear it for that case, like get_signal() does.
 	 */
 	if (test_thread_flag(TIF_NOTIFY_SIGNAL))
 		clear_notify_signal();
 	/*
 	 * PF_IO_WORKER never returns to userspace, so check here if we have
 	 * notify work that needs processing.
 	 */
 	if (current->flags & PF_IO_WORKER &&
 	    test_thread_flag(TIF_NOTIFY_RESUME)) {
 		__set_current_state(TASK_RUNNING);
 		resume_user_mode_work(NULL);
 	}
 	if (task_work_pending(current)) {
 		__set_current_state(TASK_RUNNING);
 		task_work_run();
 		return 1;
 	}

 	return 0;
 }

 static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
 {
 	return task_work_pending(current) || !llist_empty(&ctx->work_llist);
 }

 static inline void io_tw_lock(struct io_ring_ctx *ctx, struct io_tw_state *ts)
 {
 	if (!ts->locked) {
 		mutex_lock(&ctx->uring_lock);
 		ts->locked = true;
 	}
 }

 /*
  * Don't complete immediately but use deferred completion infrastructure.
  * Protected by ->uring_lock and can only be used either with
  * IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
  */
 static inline void io_req_complete_defer(struct io_kiocb *req)
 	__must_hold(&req->ctx->uring_lock)
 {
 	struct io_submit_state *state = &req->ctx->submit_state;

 	lockdep_assert_held(&req->ctx->uring_lock);

 	wq_list_add_tail(&req->comp_list, &state->compl_reqs);
 }

 static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
 {
 	if (unlikely(ctx->off_timeout_used || ctx->drain_active ||
 		     ctx->has_evfd || ctx->poll_activated))
 		__io_commit_cqring_flush(ctx);
 }

 static inline void io_get_task_refs(int nr)
 {
 	struct io_uring_task *tctx = current->io_uring;

 	tctx->cached_refs -= nr;
 	if (unlikely(tctx->cached_refs < 0))
 		io_task_refs_refill(tctx);
 }

 static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
 {
 	return !ctx->submit_state.free_list.next;
 }

 extern struct kmem_cache *req_cachep;

 static inline struct io_kiocb *io_extract_req(struct io_ring_ctx *ctx)
 {
 	struct io_kiocb *req;

 	req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
 	wq_stack_extract(&ctx->submit_state.free_list);
 	return req;
 }

 static inline bool io_alloc_req(struct io_ring_ctx *ctx, struct io_kiocb **req)
 {
 	if (unlikely(io_req_cache_empty(ctx))) {
 		if (!__io_alloc_req_refill(ctx))
 			return false;
 	}
 	*req = io_extract_req(ctx);
 	return true;
 }

 static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx)
 {
 	return likely(ctx->submitter_task == current);
 }

 static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
 {
 	return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) ||
 		      ctx->submitter_task == current);
 }

 static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
 {
 	io_req_set_res(req, res, 0);
 	req->io_task_work.func = io_req_task_complete;
 	io_req_task_work_add(req);
 }

 /*
  * IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
  * slot.
  */
 static inline size_t uring_sqe_size(struct io_ring_ctx *ctx)
 {
 	if (ctx->flags & IORING_SETUP_SQE128)
 		return 2 * sizeof(struct io_uring_sqe);
 	return sizeof(struct io_uring_sqe);
 }
 #endif
	#ifndef IOU_CORE_H
	#define IOU_CORE_H

	#include <linux/errno.h>
	#include <linux/lockdep.h>
	#include <linux/resume_user_mode.h>
	#include <linux/kasan.h>
	#include <linux/io_uring_types.h>
	#include <uapi/linux/eventpoll.h>
	#include "io-wq.h"
	#include "slist.h"
	#include "filetable.h"

	#ifndef CREATE_TRACE_POINTS
	#include <trace/events/io_uring.h>
	#endif

	enum {
	/*
	* A hint to not wake right away but delay until there are enough of
	* tw's queued to match the number of CQEs the task is waiting for.
	*
	* Must not be used wirh requests generating more than one CQE.
	* It's also ignored unless IORING_SETUP_DEFER_TASKRUN is set.
	*/
	IOU_F_TWQ_LAZY_WAKE = 1,
	};

	enum {
	IOU_OK = 0,
	IOU_ISSUE_SKIP_COMPLETE = -EIOCBQUEUED,

	/*
	* Requeue the task_work to restart operations on this request. The
	* actual value isn't important, should just be not an otherwise
	* valid error code, yet less than -MAX_ERRNO and valid internally.
	*/
	IOU_REQUEUE = -3072,

	/*
	* Intended only when both IO_URING_F_MULTISHOT is passed
	* to indicate to the poll runner that multishot should be
	* removed and the result is set on req->cqe.res.
	*/
	IOU_STOP_MULTISHOT = -ECANCELED,
	};

	bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow);
	void io_req_cqe_overflow(struct io_kiocb *req);
	int io_run_task_work_sig(struct io_ring_ctx *ctx);
	void io_req_defer_failed(struct io_kiocb *req, s32 res);
	void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags);
	bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags);
	bool io_fill_cqe_req_aux(struct io_kiocb *req, bool defer, s32 res, u32 cflags);
	void __io_commit_cqring_flush(struct io_ring_ctx *ctx);

	struct page *io_pin_pages(unsigned long ubuf, unsigned long len, int npages);
	int io_uring_mmap_pages(struct io_ring_ctx ctx, struct vm_area_struct vma,
	struct page **pages, int npages);

	struct file io_file_get_normal(struct io_kiocb req, int fd);
	struct file io_file_get_fixed(struct io_kiocb req, int fd,
	unsigned issue_flags);

	void __io_req_task_work_add(struct io_kiocb *req, unsigned flags);
	bool io_alloc_async_data(struct io_kiocb *req);
	void io_req_task_queue(struct io_kiocb *req);
	void io_req_task_complete(struct io_kiocb req, struct io_tw_state ts);
	void io_req_task_queue_fail(struct io_kiocb *req, int ret);
	void io_req_task_submit(struct io_kiocb req, struct io_tw_state ts);
	void tctx_task_work(struct callback_head *cb);
	__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd);
	int io_uring_alloc_task_context(struct task_struct *task,
	struct io_ring_ctx *ctx);

	int io_ring_add_registered_file(struct io_uring_task tctx, struct file file,
	int start, int end);

	int io_poll_issue(struct io_kiocb req, struct io_tw_state ts);
	int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
	int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
	void __io_submit_flush_completions(struct io_ring_ctx *ctx);
	int io_req_prep_async(struct io_kiocb *req);

	struct io_wq_work io_wq_free_work(struct io_wq_work work);
	void io_wq_submit_work(struct io_wq_work *work);

	void io_free_req(struct io_kiocb *req);
	void io_queue_next(struct io_kiocb *req);
	void io_task_refs_refill(struct io_uring_task *tctx);
	bool __io_alloc_req_refill(struct io_ring_ctx *ctx);

	bool io_match_task_safe(struct io_kiocb head, struct task_struct task,
	bool cancel_all);

	void io_pages_map(struct page *out_pages, unsigned short npages,
	size_t size);
	void io_pages_unmap(void ptr, struct page *pages, unsigned short npages,
	bool put_pages);

	#if defined(CONFIG_PROVE_LOCKING)
	static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
	{
	lockdep_assert(in_task());

	if (ctx->flags & IORING_SETUP_IOPOLL) {
	lockdep_assert_held(&ctx->uring_lock);
	} else if (!ctx->task_complete) {
	lockdep_assert_held(&ctx->completion_lock);
	} else if (ctx->submitter_task) {
	/*
	* ->submitter_task may be NULL and we can still post a CQE,
	* if the ring has been setup with IORING_SETUP_R_DISABLED.
	* Not from an SQE, as those cannot be submitted, but via
	* updating tagged resources.
	*/
	if (ctx->submitter_task->flags & PF_EXITING)
	lockdep_assert(current_work());
	else
	lockdep_assert(current == ctx->submitter_task);
	}
	}
	#else
	static inline void io_lockdep_assert_cq_locked(struct io_ring_ctx *ctx)
	{
	}
	#endif

	static inline void io_req_task_work_add(struct io_kiocb *req)
	{
	__io_req_task_work_add(req, 0);
	}

	#define io_for_each_link(pos, head) \
	for (pos = (head); pos; pos = pos->link)

	static inline bool io_get_cqe_overflow(struct io_ring_ctx *ctx,
	struct io_uring_cqe **ret,
	bool overflow)
	{
	io_lockdep_assert_cq_locked(ctx);

	if (unlikely(ctx->cqe_cached >= ctx->cqe_sentinel)) {
	if (unlikely(!io_cqe_cache_refill(ctx, overflow)))
	return false;
	}
	*ret = ctx->cqe_cached;
	ctx->cached_cq_tail++;
	ctx->cqe_cached++;
	if (ctx->flags & IORING_SETUP_CQE32)
	ctx->cqe_cached++;
	return true;
	}

	static inline bool io_get_cqe(struct io_ring_ctx ctx, struct io_uring_cqe *ret)
	{
	return io_get_cqe_overflow(ctx, ret, false);
	}

	static __always_inline bool io_fill_cqe_req(struct io_ring_ctx *ctx,
	struct io_kiocb *req)
	{
	struct io_uring_cqe *cqe;

	/*
	* If we can't get a cq entry, userspace overflowed the
	* submission (by quite a lot). Increment the overflow count in
	* the ring.
	*/
	if (unlikely(!io_get_cqe(ctx, &cqe)))
	return false;

	if (trace_io_uring_complete_enabled())
	trace_io_uring_complete(req->ctx, req, req->cqe.user_data,
	req->cqe.res, req->cqe.flags,
	req->big_cqe.extra1, req->big_cqe.extra2);

	memcpy(cqe, &req->cqe, sizeof(*cqe));
	if (ctx->flags & IORING_SETUP_CQE32) {
	memcpy(cqe->big_cqe, &req->big_cqe, sizeof(*cqe));
	memset(&req->big_cqe, 0, sizeof(req->big_cqe));
	}
	return true;
	}

	static inline void req_set_fail(struct io_kiocb *req)
	{
	req->flags \|= REQ_F_FAIL;
	if (req->flags & REQ_F_CQE_SKIP) {
	req->flags &= ~REQ_F_CQE_SKIP;
	req->flags \|= REQ_F_SKIP_LINK_CQES;
	}
	}

	static inline void io_req_set_res(struct io_kiocb *req, s32 res, u32 cflags)
	{
	req->cqe.res = res;
	req->cqe.flags = cflags;
	}

	static inline bool req_has_async_data(struct io_kiocb *req)
	{
	return req->flags & REQ_F_ASYNC_DATA;
	}

	static inline void io_put_file(struct io_kiocb *req)
	{
	if (!(req->flags & REQ_F_FIXED_FILE) && req->file)
	fput(req->file);
	}

	static inline void io_ring_submit_unlock(struct io_ring_ctx *ctx,
	unsigned issue_flags)
	{
	lockdep_assert_held(&ctx->uring_lock);
	if (issue_flags & IO_URING_F_UNLOCKED)
	mutex_unlock(&ctx->uring_lock);
	}

	static inline void io_ring_submit_lock(struct io_ring_ctx *ctx,
	unsigned issue_flags)
	{
	/*
	* "Normal" inline submissions always hold the uring_lock, since we
	* grab it from the system call. Same is true for the SQPOLL offload.
	* The only exception is when we've detached the request and issue it
	* from an async worker thread, grab the lock for that case.
	*/
	if (issue_flags & IO_URING_F_UNLOCKED)
	mutex_lock(&ctx->uring_lock);
	lockdep_assert_held(&ctx->uring_lock);
	}

	static inline void io_commit_cqring(struct io_ring_ctx *ctx)
	{
	/* order cqe stores with ring update */
	smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail);
	}

	static inline void io_poll_wq_wake(struct io_ring_ctx *ctx)
	{
	if (wq_has_sleeper(&ctx->poll_wq))
	__wake_up(&ctx->poll_wq, TASK_NORMAL, 0,
	poll_to_key(EPOLL_URING_WAKE \| EPOLLIN));
	}

	static inline void io_cqring_wake(struct io_ring_ctx *ctx)
	{
	/*
	* Trigger waitqueue handler on all waiters on our waitqueue. This
	* won't necessarily wake up all the tasks, io_should_wake() will make
	* that decision.
	*
	* Pass in EPOLLIN\|EPOLL_URING_WAKE as the poll wakeup key. The latter
	* set in the mask so that if we recurse back into our own poll
	* waitqueue handlers, we know we have a dependency between eventfd or
	* epoll and should terminate multishot poll at that point.
	*/
	if (wq_has_sleeper(&ctx->cq_wait))
	__wake_up(&ctx->cq_wait, TASK_NORMAL, 0,
	poll_to_key(EPOLL_URING_WAKE \| EPOLLIN));
	}

	static inline bool io_sqring_full(struct io_ring_ctx *ctx)
	{
	struct io_rings *r = ctx->rings;

	/*
	* SQPOLL must use the actual sqring head, as using the cached_sq_head
	* is race prone if the SQPOLL thread has grabbed entries but not yet
	* committed them to the ring. For !SQPOLL, this doesn't matter, but
	* since this helper is just used for SQPOLL sqring waits (or POLLOUT),
	* just read the actual sqring head unconditionally.
	*/
	return READ_ONCE(r->sq.tail) - READ_ONCE(r->sq.head) == ctx->sq_entries;
	}

	static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
	{
	struct io_rings *rings = ctx->rings;
	unsigned int entries;

	/* make sure SQ entry isn't read before tail */
	entries = smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
	return min(entries, ctx->sq_entries);
	}

	static inline int io_run_task_work(void)
	{
	/*
	* Always check-and-clear the task_work notification signal. With how
	* signaling works for task_work, we can find it set with nothing to
	* run. We need to clear it for that case, like get_signal() does.
	*/
	if (test_thread_flag(TIF_NOTIFY_SIGNAL))
	clear_notify_signal();
	/*
	* PF_IO_WORKER never returns to userspace, so check here if we have
	* notify work that needs processing.
	*/
	if (current->flags & PF_IO_WORKER &&
	test_thread_flag(TIF_NOTIFY_RESUME)) {
	__set_current_state(TASK_RUNNING);
	resume_user_mode_work(NULL);
	}
	if (task_work_pending(current)) {
	__set_current_state(TASK_RUNNING);
	task_work_run();
	return 1;
	}

	return 0;
	}

	static inline bool io_task_work_pending(struct io_ring_ctx *ctx)
	{
	return task_work_pending(current) \|\| !llist_empty(&ctx->work_llist);
	}

	static inline void io_tw_lock(struct io_ring_ctx ctx, struct io_tw_state ts)
	{
	if (!ts->locked) {
	mutex_lock(&ctx->uring_lock);
	ts->locked = true;
	}
	}

	/*
	* Don't complete immediately but use deferred completion infrastructure.
	* Protected by ->uring_lock and can only be used either with
	* IO_URING_F_COMPLETE_DEFER or inside a tw handler holding the mutex.
	*/
	static inline void io_req_complete_defer(struct io_kiocb *req)
	__must_hold(&req->ctx->uring_lock)
	{
	struct io_submit_state *state = &req->ctx->submit_state;

	lockdep_assert_held(&req->ctx->uring_lock);

	wq_list_add_tail(&req->comp_list, &state->compl_reqs);
	}

	static inline void io_commit_cqring_flush(struct io_ring_ctx *ctx)
	{
	if (unlikely(ctx->off_timeout_used \|\| ctx->drain_active \|\|
	ctx->has_evfd \|\| ctx->poll_activated))
	__io_commit_cqring_flush(ctx);
	}

	static inline void io_get_task_refs(int nr)
	{
	struct io_uring_task *tctx = current->io_uring;

	tctx->cached_refs -= nr;
	if (unlikely(tctx->cached_refs < 0))
	io_task_refs_refill(tctx);
	}

	static inline bool io_req_cache_empty(struct io_ring_ctx *ctx)
	{
	return !ctx->submit_state.free_list.next;
	}

	extern struct kmem_cache *req_cachep;

	static inline struct io_kiocb io_extract_req(struct io_ring_ctx ctx)
	{
	struct io_kiocb *req;

	req = container_of(ctx->submit_state.free_list.next, struct io_kiocb, comp_list);
	wq_stack_extract(&ctx->submit_state.free_list);
	return req;
	}

	static inline bool io_alloc_req(struct io_ring_ctx ctx, struct io_kiocb *req)
	{
	if (unlikely(io_req_cache_empty(ctx))) {
	if (!__io_alloc_req_refill(ctx))
	return false;
	}
	*req = io_extract_req(ctx);
	return true;
	}

	static inline bool io_allowed_defer_tw_run(struct io_ring_ctx *ctx)
	{
	return likely(ctx->submitter_task == current);
	}

	static inline bool io_allowed_run_tw(struct io_ring_ctx *ctx)
	{
	return likely(!(ctx->flags & IORING_SETUP_DEFER_TASKRUN) \|\|
	ctx->submitter_task == current);
	}

	static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res)
	{
	io_req_set_res(req, res, 0);
	req->io_task_work.func = io_req_task_complete;
	io_req_task_work_add(req);
	}

	/*
	* IORING_SETUP_SQE128 contexts allocate twice the normal SQE size for each
	* slot.
	*/
	static inline size_t uring_sqe_size(struct io_ring_ctx *ctx)
	{
	if (ctx->flags & IORING_SETUP_SQE128)
	return 2 * sizeof(struct io_uring_sqe);
	return sizeof(struct io_uring_sqe);
	}
	#endif