linux-kernel - [PATCH] block: clear iocb->private in blkdev_bio_end_io

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Date:   Fri, 11 Feb 2022 10:01:36 +0100
From:   Stefano Garzarella <sgarzare@...hat.com>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     linux-kernel@...r.kernel.org,
        Pavel Begunkov <asml.silence@...il.com>,
        linux-block@...r.kernel.org
Subject: [PATCH] block: clear iocb->private in blkdev_bio_end_io_async()

iocb_bio_iopoll() expects iocb->private to be cleared before
releasing the bio.

We already do this in blkdev_bio_end_io(), but we forgot in the
recently added blkdev_bio_end_io_async().

Fixes: 54a88eb838d3 ("block: add single bio async direct IO helper")
Cc: asml.silence@...il.com
Signed-off-by: Stefano Garzarella <sgarzare@...hat.com>
---
I haven't seen a failure, I was just reading the code to understand iopoll,
so IIUC we should clean iocb->private in blkdev_bio_end_io_async().

Thanks,
Stefano
---
 block/fops.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/fops.c b/block/fops.c
index 4f59e0f5bf30..a18e7fbd97b8 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -289,6 +289,8 @@ static void blkdev_bio_end_io_async(struct bio *bio)
 	struct kiocb *iocb = dio->iocb;
 	ssize_t ret;
 
+	WRITE_ONCE(iocb->private, NULL);
+
 	if (likely(!bio->bi_status)) {
 		ret = dio->size;
 		iocb->ki_pos += ret;
-- 
2.34.1