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| author |  Guoqing Jiang <gqjiang@suse.com>
| 2016-05-03 22:22:13 -0400 |
|---|---|---|
| committer |  Shaohua Li <shli@fb.com>
| 2016-05-09 09:24:02 -0700 |
| commit | 85ad1d13ee9b3db00615ea24b031c15e5ba14fd1 (patch) | |
| tree | ff8cd0a32ae44fa7d306cee622c9eea96a9de076 /drivers/md/raid5-cache.c | |
| parent | md: raid5: add prerequisite to run underneath dm-raid (diff) | |
| download | linux-85ad1d13ee9b3db00615ea24b031c15e5ba14fd1.tar.gz linux-85ad1d13ee9b3db00615ea24b031c15e5ba14fd1.tar.bz2 linux-85ad1d13ee9b3db00615ea24b031c15e5ba14fd1.zip | |
md: set MD_CHANGE_PENDING in a atomic region
Some code waits for a metadata update by:
1. flagging that it is needed (MD_CHANGE_DEVS or MD_CHANGE_CLEAN)
2. setting MD_CHANGE_PENDING and waking the management thread
3. waiting for MD_CHANGE_PENDING to be cleared
If the first two are done without locking, the code in md_update_sb()
which checks if it needs to repeat might test if an update is needed
before step 1, then clear MD_CHANGE_PENDING after step 2, resulting
in the wait returning early.
So make sure all places that set MD_CHANGE_PENDING are atomicial, and
bit_clear_unless (suggested by Neil) is introduced for the purpose.
Cc: Martin Kepplinger <martink@posteo.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: <linux-kernel@vger.kernel.org>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5-cache.c')
| -rw-r--r-- | drivers/md/raid5-cache.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 9531f5f05b93..ac51bc5ecb16 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -712,8 +712,8 @@ static void r5l_write_super_and_discard_space(struct r5l_log *log, * in_teardown check workaround this issue. */ if (!log->in_teardown) { - set_bit(MD_CHANGE_DEVS, &mddev->flags); - set_bit(MD_CHANGE_PENDING, &mddev->flags); + set_mask_bits(&mddev->flags, 0, + BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING)); md_wakeup_thread(mddev->thread); wait_event(mddev->sb_wait, !test_bit(MD_CHANGE_PENDING, &mddev->flags) || |