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authorZhengyuan Liu <liuzhengyuan@kylinos.cn>2019-07-13 11:58:26 +0800
committerJens Axboe <axboe@kernel.dk>2019-07-16 08:27:09 -0600
commitdbd0f6d6c2a11eb9c31ca9cd454f95bb5713e92e (patch)
treebf49250d4c59d6b4ed45b9075cf9c3d793872064 /fs/io_uring.c
parent9637d517347e80ee2fe1c5d8ce45ba1b88d8b5cd (diff)
io_uring: fix the sequence comparison in io_sequence_defer
sq->cached_sq_head and cq->cached_cq_tail are both unsigned int. If cached_sq_head overflows before cached_cq_tail, then we may miss a barrier req. As cached_cq_tail always follows cached_sq_head, the NQ should be enough. Cc: stable@vger.kernel.org Fixes: de0617e46717 ("io_uring: add support for marking commands as draining") Signed-off-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
-rw-r--r--fs/io_uring.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index d682049c07b2..708d133492a1 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -429,7 +429,7 @@ static inline bool io_sequence_defer(struct io_ring_ctx *ctx,
if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) != REQ_F_IO_DRAIN)
return false;
- return req->sequence > ctx->cached_cq_tail + ctx->sq_ring->dropped;
+ return req->sequence != ctx->cached_cq_tail + ctx->sq_ring->dropped;
}
static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx)