Commit 93bd25bb authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring: make timeout sequence == 0 mean no sequence 



Currently we make sequence == 0 be the same as sequence == 1, but that's
not super useful if the intent is really to have a timeout that's just
a pure timeout.

If the user passes in sqe->off == 0, then don't apply any sequence logic
to the request, let it purely be driven by the timeout specified.

Reported-by: default avatar李通洲 <carter.li@eoitek.com>
Reviewed-by: default avatar李通洲 <carter.li@eoitek.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 65de03e2

fs/io_uring.c

+22 −7
Original line number Diff line number Diff line
@@ -326,6 +326,7 @@ struct io_kiocb { 
#define REQ_F_TIMEOUT		1024	/* timeout request */

#define REQ_F_ISREG		2048	/* regular file */

#define REQ_F_MUST_PUNT		4096	/* must be punted even for NONBLOCK */

#define REQ_F_TIMEOUT_NOSEQ	8192	/* no timeout sequence */

	u64			user_data;

	u32			result;

	u32			sequence;
@@ -453,10 +454,14 @@ static struct io_kiocb *io_get_timeout_req(struct io_ring_ctx *ctx) 
	struct io_kiocb *req;



	req = list_first_entry_or_null(&ctx->timeout_list, struct io_kiocb, list);

	if (req && !__io_sequence_defer(ctx, req)) {

	if (req) {

		if (req->flags & REQ_F_TIMEOUT_NOSEQ)

			return NULL;

		if (!__io_sequence_defer(ctx, req)) {

			list_del_init(&req->list);

			return req;

		}

	}



	return NULL;

}
@@ -1941,18 +1946,24 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	if (get_timespec64(&ts, u64_to_user_ptr(sqe->addr)))

		return -EFAULT;



	req->flags |= REQ_F_TIMEOUT;



	/*

	 * sqe->off holds how many events that need to occur for this

	 * timeout event to be satisfied.

	 * timeout event to be satisfied. If it isn't set, then this is

	 * a pure timeout request, sequence isn't used.

	 */

	count = READ_ONCE(sqe->off);

	if (!count)

		count = 1;

	if (!count) {

		req->flags |= REQ_F_TIMEOUT_NOSEQ;

		spin_lock_irq(&ctx->completion_lock);

		entry = ctx->timeout_list.prev;

		goto add;

	}



	req->sequence = ctx->cached_sq_head + count - 1;

	/* reuse it to store the count */

	req->submit.sequence = count;

	req->flags |= REQ_F_TIMEOUT;



	/*

	 * Insertion sort, ensuring the first entry in the list is always
@@ -1964,6 +1975,9 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
		unsigned nxt_sq_head;

		long long tmp, tmp_nxt;



		if (nxt->flags & REQ_F_TIMEOUT_NOSEQ)

			continue;



		/*

		 * Since cached_sq_head + count - 1 can overflow, use type long

		 * long to store it.
@@ -1990,6 +2004,7 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
		nxt->sequence++;

	}

	req->sequence -= span;

add:

	list_add(&req->list, entry);

	spin_unlock_irq(&ctx->completion_lock);

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