diff options
authorNeilBrown <neilb@suse.de>2006-12-08 02:36:17 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-08 08:28:39 -0800
commitd63a5a74dee87883fda6b7d170244acaac5b05e8 (patch)
parent6796bf54a64df36f96a42ae222423fffe36c58a5 (diff)
[PATCH] lockdep: avoid lockdep warning in md
md_open takes ->reconfig_mutex which causes lockdep to complain. This (normally) doesn't have deadlock potential as the possible conflict is with a reconfig_mutex in a different device. I say "normally" because if a loop were created in the array->member hierarchy a deadlock could happen. However that causes bigger problems than a deadlock and should be fixed independently. So we flag the lock in md_open as a nested lock. This requires defining mutex_lock_interruptible_nested. Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
3 files changed, 12 insertions, 1 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c
index d2bcb410e3a..3ce7a5d81d8 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -4423,7 +4423,7 @@ static int md_open(struct inode *inode, struct file *file)
mddev_t *mddev = inode->i_bdev->bd_disk->private_data;
int err;
- if ((err = mddev_lock(mddev)))
+ if ((err = mutex_lock_interruptible_nested(&mddev->reconfig_mutex, 1)))
goto out;
err = 0;
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index b2b91c47756..a7544afd758 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -125,8 +125,10 @@ extern int fastcall mutex_lock_interruptible(struct mutex *lock);
extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass);
+extern int mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass);
# define mutex_lock_nested(lock, subclass) mutex_lock(lock)
+# define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock)
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 8c71cf72a49..e7cbbb82765 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -206,6 +206,15 @@ mutex_lock_nested(struct mutex *lock, unsigned int subclass)
+int __sched
+mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
+ might_sleep();
+ return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass);