6.4-stable review patch. If anyone has any objections, please let me know.
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From: Li Nan linan122@huawei.com
[ Upstream commit 673643490b9a0eb3b25633abe604f62b8f63dba1 ]
Commit 2ae6aaf76912 ("md/raid10: fix io loss while replacement replace rdev") reads replacement first to prevent io loss. However, there are same issue in wait_blocked_dev() and raid10_handle_discard(), too. Fix it by using dereference_rdev_and_rrdev() to get devices.
Fixes: d30588b2731f ("md/raid10: improve raid10 discard request") Fixes: f2e7e269a752 ("md/raid10: pull the code that wait for blocked dev into one function") Signed-off-by: Li Nan linan122@huawei.com Link: https://lore.kernel.org/r/20230701080529.2684932-4-linan666@huaweicloud.com Signed-off-by: Song Liu song@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/raid10.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index f47fd50651c45..925ab30c15d49 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -1350,11 +1350,9 @@ static void wait_blocked_dev(struct mddev *mddev, struct r10bio *r10_bio) blocked_rdev = NULL; rcu_read_lock(); for (i = 0; i < conf->copies; i++) { - struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev); - struct md_rdev *rrdev = rcu_dereference( - conf->mirrors[i].replacement); - if (rdev == rrdev) - rrdev = NULL; + struct md_rdev *rdev, *rrdev; + + rdev = dereference_rdev_and_rrdev(&conf->mirrors[i], &rrdev); if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) { atomic_inc(&rdev->nr_pending); blocked_rdev = rdev; @@ -1790,10 +1788,9 @@ static int raid10_handle_discard(struct mddev *mddev, struct bio *bio) */ rcu_read_lock(); for (disk = 0; disk < geo->raid_disks; disk++) { - struct md_rdev *rdev = rcu_dereference(conf->mirrors[disk].rdev); - struct md_rdev *rrdev = rcu_dereference( - conf->mirrors[disk].replacement); + struct md_rdev *rdev, *rrdev;
+ rdev = dereference_rdev_and_rrdev(&conf->mirrors[disk], &rrdev); r10_bio->devs[disk].bio = NULL; r10_bio->devs[disk].repl_bio = NULL;