md/raid10: use dereference_rdev_and_rrdev() to get devices

[ 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>

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index ff3c97cde7699c9cf2dd07781f2a80202ba2bf8d..a3a3a02d48b17a5890fa952d3f23dc62df72884e 100644 (file)
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1345,11 +1345,9 @@ retry_wait:
        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;
@@ -1785,10 +1783,9 @@ retry_discard:
         */
        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;