io_uring : correct timeout req sequence when waiting timeout

The sequence number of reqs on the timeout_list before the timeout req
should be adjusted in io_timeout_fn(), because the current timeout req
will consumes a slot in the cq_ring and cq_tail pointer will be
increased, otherwise other timeout reqs may return in advance without
waiting for enough wait_nr.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 10 insertions, 1 deletions

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 08c2c428e212..b65a68582a7c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1877,7 +1877,7 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
 {
         struct io_ring_ctx *ctx;
-        struct io_kiocb *req;
+        struct io_kiocb *req, *prev;
         unsigned long flags;
 
         req = container_of(timer, struct io_kiocb, timeout.timer);
@@ -1885,6 +1885,15 @@ static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
         atomic_inc(&ctx->cq_timeouts);
 
         spin_lock_irqsave(&ctx->completion_lock, flags);
+        /*
+         * Adjust the reqs sequence before the current one because it
+         * will consume a slot in the cq_ring and the the cq_tail pointer
+         * will be increased, otherwise other timeout reqs may return in
+         * advance without waiting for enough wait_nr.
+         */
+        prev = req;
+        list_for_each_entry_continue_reverse(prev, &ctx->timeout_list, list)
+                prev->sequence++;
         list_del(&req->list);
 
         io_cqring_fill_event(ctx, req->user_data, -ETIME);