md/bitmap: protect clearing of ->bitmap by mddev->lock
This makes it safe to inspect the struct while holding only
the spinlock.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 1695ee5..3424b19 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -1619,7 +1619,9 @@
return;
mutex_lock(&mddev->bitmap_info.mutex);
+ spin_lock(&mddev->lock);
mddev->bitmap = NULL; /* disconnect from the md device */
+ spin_unlock(&mddev->lock);
mutex_unlock(&mddev->bitmap_info.mutex);
if (mddev->thread)
mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
diff --git a/drivers/md/md.h b/drivers/md/md.h
index e41559d..8770308 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -392,6 +392,7 @@
* clearing MD_CHANGE_*
* in_sync - and related safemode and MD_CHANGE changes
* pers (also protected by reconfig_mutex and pending IO).
+ * clearing ->bitmap
*/
spinlock_t lock;
wait_queue_head_t sb_wait; /* for waiting on superblock updates */