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>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 08c2c428e21293618ab639b396e52f0205edc8be..b65a68582a7c193f32454cb540e9bf524a4f56ed 100644 (file)
--- 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);