diff options
| author | NeilBrown <neilb@suse.de> | 2006-12-08 02:36:17 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.osdl.org> | 2006-12-08 08:28:39 -0800 |
| commit | d63a5a74dee87883fda6b7d170244acaac5b05e8 (patch) | |
| tree | 8b12bc626b8f1507b7b550865c5f8282bcac6c27 | |
| parent | 6796bf54a64df36f96a42ae222423fffe36c58a5 (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>
| -rw-r--r-- | drivers/md/md.c | 2 | ||||
| -rw-r--r-- | include/linux/mutex.h | 2 | ||||
| -rw-r--r-- | kernel/mutex.c | 9 |
3 files changed, 12 insertions, 1 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index d2bcb410e3ab..3ce7a5d81d81 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 b2b91c477563..a7544afd7582 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -125,8 +125,10 @@ extern int fastcall mutex_lock_interruptible(struct mutex *lock); #ifdef CONFIG_DEBUG_LOCK_ALLOC extern void mutex_lock_nested(struct mutex *lock, unsigned int subclass); +extern int mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass); #else # define mutex_lock_nested(lock, subclass) mutex_lock(lock) +# define mutex_lock_interruptible_nested(lock, subclass) mutex_lock_interruptible(lock) #endif /* diff --git a/kernel/mutex.c b/kernel/mutex.c index 8c71cf72a497..e7cbbb82765b 100644 --- a/kernel/mutex.c +++ b/kernel/mutex.c @@ -206,6 +206,15 @@ mutex_lock_nested(struct mutex *lock, unsigned int subclass) } EXPORT_SYMBOL_GPL(mutex_lock_nested); + +int __sched +mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass) +{ + might_sleep(); + return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass); +} + +EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested); #endif /* |