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* [PATCH 5.12 v3] io_uring: fix rw req completion
@ 2021-04-08 18:28 Pavel Begunkov
  2021-04-08 18:33 ` Pavel Begunkov
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Pavel Begunkov @ 2021-04-08 18:28 UTC (permalink / raw)
  To: Jens Axboe, io-uring

WARNING: at fs/io_uring.c:8578 io_ring_exit_work.cold+0x0/0x18

As reissuing is now passed back by REQ_F_REISSUE and kiocb_done()
internally uses __io_complete_rw(), it may stop after setting the flag
so leaving a dangling request.

There are tricky edge cases, e.g. reading beyound file, boundary, so
the easiest way is to hand code reissue in kiocb_done() as
__io_complete_rw() was doing for us before.

Fixes: 230d50d448ac ("io_uring: move reissue into regular IO path")
Signed-off-by: Pavel Begunkov <[email protected]>
Link: https://lore.kernel.org/r/f602250d292f8a84cca9a01d747744d1e797be26.1617842918.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <[email protected]>
---


v2: io_rw_reissue() may fail, check return code
v3: adjust commit message

 fs/io_uring.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index f1881ac0744b..f2df0569a60a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2762,6 +2762,7 @@ static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
 {
 	struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
 	struct io_async_rw *io = req->async_data;
+	bool check_reissue = (kiocb->ki_complete == io_complete_rw);
 
 	/* add previously done IO, if any */
 	if (io && io->bytes_done > 0) {
@@ -2777,6 +2778,18 @@ static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
 		__io_complete_rw(req, ret, 0, issue_flags);
 	else
 		io_rw_done(kiocb, ret);
+
+	if (check_reissue && req->flags & REQ_F_REISSUE) {
+		req->flags &= ~REQ_F_REISSUE;
+		if (!io_rw_reissue(req)) {
+			int cflags = 0;
+
+			req_set_fail_links(req);
+			if (req->flags & REQ_F_BUFFER_SELECTED)
+				cflags = io_put_rw_kbuf(req);
+			__io_req_complete(req, issue_flags, ret, cflags);
+		}
+	}
 }
 
 static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter)
-- 
2.24.0


^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2021-04-11  2:30 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-04-08 18:28 [PATCH 5.12 v3] io_uring: fix rw req completion Pavel Begunkov
2021-04-08 18:33 ` Pavel Begunkov
2021-04-08 19:33 ` Jens Axboe
2021-04-11  0:31 ` Pavel Begunkov
2021-04-11  2:30   ` Jens Axboe

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