This is a note to let you know that I've just added the patch titled
md/raid10: factor out dereference_rdev_and_rrdev()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-raid10-factor-out-dereference_rdev_and_rrdev.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 19e87d4599990d2c3eca74b69608ef6c55887ec6
Author: Li Nan <linan122@xxxxxxxxxx>
Date: Sat Jul 1 16:05:28 2023 +0800
md/raid10: factor out dereference_rdev_and_rrdev()
[ Upstream commit b99f8fd2d91eb734f13098aa1cf337edaca454b7 ]
Factor out a helper to get 'rdev' and 'replacement' from config->mirrors.
Just to make code cleaner and prepare to fix the bug of io loss while
'replacement' replace 'rdev'.
There is no functional change.
Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230701080529.2684932-3-linan666@xxxxxxxxxxxxxxx
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Stable-dep-of: 673643490b9a ("md/raid10: use dereference_rdev_and_rrdev() to get devices")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index edd3b65c447db..ff3c97cde7699 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1316,6 +1316,25 @@ static void raid10_write_one_disk(struct mddev *mddev, struct r10bio *r10_bio,
}
}
+static struct md_rdev *dereference_rdev_and_rrdev(struct raid10_info *mirror,
+ struct md_rdev **prrdev)
+{
+ struct md_rdev *rdev, *rrdev;
+
+ rrdev = rcu_dereference(mirror->replacement);
+ /*
+ * Read replacement first to prevent reading both rdev and
+ * replacement as NULL during replacement replace rdev.
+ */
+ smp_mb();
+ rdev = rcu_dereference(mirror->rdev);
+ if (rdev == rrdev)
+ rrdev = NULL;
+
+ *prrdev = rrdev;
+ return rdev;
+}
+
static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio)
{
int i;
@@ -1459,15 +1478,7 @@ static void raid10_write_request(struct mddev *mddev, struct bio *bio,
int d = r10_bio->devs[i].devnum;
struct md_rdev *rdev, *rrdev;
- rrdev = rcu_dereference(conf->mirrors[d].replacement);
- /*
- * Read replacement first to prevent reading both rdev and
- * replacement as NULL during replacement replace rdev.
- */
- smp_mb();
- rdev = rcu_dereference(conf->mirrors[d].rdev);
- if (rdev == rrdev)
- rrdev = NULL;
+ rdev = dereference_rdev_and_rrdev(&conf->mirrors[d], &rrdev);
if (rdev && (test_bit(Faulty, &rdev->flags)))
rdev = NULL;
if (rrdev && (test_bit(Faulty, &rrdev->flags)))
