Commit b0dd8a41 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: correct poll cancel and linked timeout expiration completion 



Currently a poll request fills a completion entry of 0, even if it got
cancelled. This is odd, and it makes it harder to support with chains.
Ensure that it returns -ECANCELED in the completions events if it got
cancelled, and furthermore ensure that the linked timeout that triggered
it completes with -ETIME if we did indeed trigger the completions
through a timeout.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent e0e328c4

fs/io_uring.c

+22 −11
Original line number Diff line number Diff line
@@ -2066,11 +2066,14 @@ static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	return 0;

}



static void io_poll_complete(struct io_kiocb *req, __poll_t mask)

static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)

{

	struct io_ring_ctx *ctx = req->ctx;



	req->poll.done = true;

	if (error)

		io_cqring_fill_event(req, error);

	else

		io_cqring_fill_event(req, mangle_poll(mask));

	io_commit_cqring(ctx);

}
@@ -2084,11 +2087,16 @@ static void io_poll_complete_work(struct io_wq_work **workptr) 
	struct io_ring_ctx *ctx = req->ctx;

	struct io_kiocb *nxt = NULL;

	__poll_t mask = 0;

	int ret = 0;



	if (work->flags & IO_WQ_WORK_CANCEL)

	if (work->flags & IO_WQ_WORK_CANCEL) {

		WRITE_ONCE(poll->canceled, true);

		ret = -ECANCELED;

	} else if (READ_ONCE(poll->canceled)) {

		ret = -ECANCELED;

	}



	if (!READ_ONCE(poll->canceled))

	if (ret != -ECANCELED)

		mask = vfs_poll(poll->file, &pt) & poll->events;



	/*
@@ -2099,13 +2107,13 @@ static void io_poll_complete_work(struct io_wq_work **workptr) 
	 * avoid further branches in the fast path.

	 */

	spin_lock_irq(&ctx->completion_lock);

	if (!mask && !READ_ONCE(poll->canceled)) {

	if (!mask && ret != -ECANCELED) {

		add_wait_queue(poll->head, &poll->wait);

		spin_unlock_irq(&ctx->completion_lock);

		return;

	}

	io_poll_remove_req(req);

	io_poll_complete(req, mask);

	io_poll_complete(req, mask, ret);

	spin_unlock_irq(&ctx->completion_lock);



	io_cqring_ev_posted(ctx);
@@ -2139,7 +2147,7 @@ static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, 
	 */

	if (mask && spin_trylock_irqsave(&ctx->completion_lock, flags)) {

		io_poll_remove_req(req);

		io_poll_complete(req, mask);

		io_poll_complete(req, mask, 0);

		req->flags |= REQ_F_COMP_LOCKED;

		io_put_req(req);

		spin_unlock_irqrestore(&ctx->completion_lock, flags);
@@ -2251,7 +2259,7 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe, 
	}

	if (mask) { /* no async, we'd stolen it */

		ipt.error = 0;

		io_poll_complete(req, mask);

		io_poll_complete(req, mask, 0);

	}

	spin_unlock_irq(&ctx->completion_lock);
@@ -2503,7 +2511,7 @@ static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr) 


static void io_async_find_and_cancel(struct io_ring_ctx *ctx,

				     struct io_kiocb *req, __u64 sqe_addr,

				     struct io_kiocb **nxt)

				     struct io_kiocb **nxt, int success_ret)

{

	unsigned long flags;

	int ret;
@@ -2520,6 +2528,8 @@ static void io_async_find_and_cancel(struct io_ring_ctx *ctx, 
		goto done;

	ret = io_poll_cancel(ctx, sqe_addr);

done:

	if (!ret)

		ret = success_ret;

	io_cqring_fill_event(req, ret);

	io_commit_cqring(ctx);

	spin_unlock_irqrestore(&ctx->completion_lock, flags);
@@ -2541,7 +2551,7 @@ static int io_async_cancel(struct io_kiocb *req, const struct io_uring_sqe *sqe, 
	    sqe->cancel_flags)

		return -EINVAL;



	io_async_find_and_cancel(ctx, req, READ_ONCE(sqe->addr), nxt);

	io_async_find_and_cancel(ctx, req, READ_ONCE(sqe->addr), nxt, 0);

	return 0;

}
@@ -2831,7 +2841,8 @@ static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer) 
	spin_unlock_irqrestore(&ctx->completion_lock, flags);



	if (prev) {

		io_async_find_and_cancel(ctx, req, prev->user_data, NULL);

		io_async_find_and_cancel(ctx, req, prev->user_data, NULL,

						-ETIME);

		io_put_req(prev);

	} else {

		io_cqring_add_event(req, -ETIME);

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