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io_uring: correct timeout req sequence when inserting a new entry

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The sequence number of the timeout req (req->sequence) indicate the
expected completion request. Because of each timeout req consume a
sequence number, so the sequence of each timeout req on the timeout
list shouldn't be the same. But now, we may get the same number (also
incorrect) if we insert a new entry before the last one, such as submit
such two timeout reqs on a new ring instance below.

                    req->sequence
 req_1 (count = 2):       2
 req_2 (count = 1):       2

Then, if we submit a nop req, req_2 will still timeout even the nop req
finished. This patch fix this problem by adjust the sequence number of
each reordered reqs when inserting a new entry.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
zhangyi (F) 2019-10-23 15:10:09 +08:00 committed by Jens Axboe
parent ef03681ae8
commit a1f58ba46f
1 changed files with 10 additions and 1 deletions
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11
fs/io_uring.c
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@ -1912,6 +1912,7 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe)
struct io_ring_ctx *ctx = req->ctx;
struct list_head *entry;
struct timespec64 ts;
unsigned span = 0;
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
@ -1960,9 +1961,17 @@ static int io_timeout(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (ctx->cached_sq_head < nxt_sq_head)
tmp += UINT_MAX;
if (tmp >= tmp_nxt)
if (tmp > tmp_nxt)
break;
/*
* Sequence of reqs after the insert one and itself should
* be adjusted because each timeout req consumes a slot.
*/
span++;
nxt->sequence++;
}
req->sequence -= span;
list_add(&req->list, entry);
spin_unlock_irq(&ctx->completion_lock);