diff options
| author | Yu Kuai <yukuai3@huawei.com> | 2023-11-24 10:59:53 +0300 |
|---|---|---|
| committer | Mike Snitzer <snitzer@kernel.org> | 2023-12-18 21:05:21 +0300 |
| commit | db29d79b34d9593179de5f868be45c650923e7b4 (patch) | |
| tree | 0594db7328418a993dd1a9aff8120cda9ade4887 /drivers/md | |
| parent | ceb6a6f023fd3e8b07761ed900352ef574010bcb (diff) | |
| download | linux-db29d79b34d9593179de5f868be45c650923e7b4.tar.xz | |
dm-raid: delay flushing event_work() after reconfig_mutex is released
After commit db5e653d7c9f ("md: delay choosing sync action to
md_start_sync()"), md_start_sync() will hold 'reconfig_mutex', however,
in order to make sure event_work is done, __md_stop() will flush
workqueue with reconfig_mutex grabbed, hence if sync_work is still
pending, deadlock will be triggered.
Fortunately, former pacthes to fix stopping sync_thread already make sure
all sync_work is done already, hence such deadlock is not possible
anymore. However, in order not to cause confusions for people by this
implicit dependency, delay flushing event_work to dm-raid where
'reconfig_mutex' is not held, and add some comments to emphasize that
the workqueue can't be flushed with 'reconfig_mutex'.
Fixes: db5e653d7c9f ("md: delay choosing sync action to md_start_sync()")
Depends-on: f52f5c71f3d4 ("md: fix stopping sync thread")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-raid.c | 3 | ||||
| -rw-r--r-- | drivers/md/md.c | 11 |
2 files changed, 11 insertions, 3 deletions
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c index 91ebdcc6e9a8..eb009d6bb03a 100644 --- a/drivers/md/dm-raid.c +++ b/drivers/md/dm-raid.c @@ -3317,6 +3317,9 @@ static void raid_dtr(struct dm_target *ti) mddev_lock_nointr(&rs->md); md_stop(&rs->md); mddev_unlock(&rs->md); + + if (work_pending(&rs->md.event_work)) + flush_work(&rs->md.event_work); raid_set_free(rs); } diff --git a/drivers/md/md.c b/drivers/md/md.c index b066abbffd10..9bdd57324c37 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -82,6 +82,14 @@ static struct module *md_cluster_mod; static DECLARE_WAIT_QUEUE_HEAD(resync_wait); static struct workqueue_struct *md_wq; + +/* + * This workqueue is used for sync_work to register new sync_thread, and for + * del_work to remove rdev, and for event_work that is only set by dm-raid. + * + * Noted that sync_work will grab reconfig_mutex, hence never flush this + * workqueue whith reconfig_mutex grabbed. + */ static struct workqueue_struct *md_misc_wq; struct workqueue_struct *md_bitmap_wq; @@ -6330,9 +6338,6 @@ static void __md_stop(struct mddev *mddev) struct md_personality *pers = mddev->pers; md_bitmap_destroy(mddev); mddev_detach(mddev); - /* Ensure ->event_work is done */ - if (mddev->event_work.func) - flush_workqueue(md_misc_wq); spin_lock(&mddev->lock); mddev->pers = NULL; spin_unlock(&mddev->lock); |