[PATCH AUTOSEL 5.6 11/47] io_uring: don't prepare DRAIN reqs twice

Sasha Levin
2020-05-28T11:56:29Z

From: Pavel Begunkov <asml.silence@gmail.com>

[ Upstream commit 650b548129b60b0d23508351800108196f4aa89f ]

If req->io is not NULL, it's already prepared. Don't do it again,
it's dangerous.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/io_uring.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 8bdf2629f7fd..aa800f70c55e 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4262,12 +4262,13 @@ static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (!req_need_defer(req) && list_empty_careful(&ctx->defer_list))
return 0;

- if (!req->io && io_alloc_async_ctx(req))
- return -EAGAIN;
-
- ret = io_req_defer_prep(req, sqe);
- if (ret < 0)
- return ret;
+ if (!req->io) {
+ if (io_alloc_async_ctx(req))
+ return -EAGAIN;
+ ret = io_req_defer_prep(req, sqe);
+ if (ret < 0)
+ return ret;
+ }

spin_lock_irq(&ctx->completion_lock);
if (!req_need_defer(req) && list_empty(&ctx->defer_list)) {
--
2.25.1