| Message ID | 20090407235902.196040156@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, 8 Apr 2009, Jan Blunck wrote: > This patch removes the stupid "Read locks within the self-held write lock > succeed" behaviour. This is breaking in mm_take_all_locks() since it is quite > common to ensure that a lock is taken with BUG_ON(down_read_trylock(&mm->mmap_sem)). Good catch. There are some more oddballs in that file, which we missed when we moved from 26 to 29 - we dropped the rwlocks stuff and that cleaned up that area. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: b/kernel/rt.c =================================================================== --- a/kernel/rt.c +++ b/kernel/rt.c @@ -381,18 +381,6 @@ int rt_down_read_trylock(struct rw_sema unsigned long flags; int ret; - /* - * Read locks within the self-held write lock succeed. - */ - spin_lock_irqsave(&rwsem->lock.wait_lock, flags); - if (rt_mutex_real_owner(&rwsem->lock) == current) { - spin_unlock_irqrestore(&rwsem->lock.wait_lock, flags); - rwsem_acquire_read(&rwsem->dep_map, 0, 1, _RET_IP_); - rwsem->read_depth++; - return 1; - } - spin_unlock_irqrestore(&rwsem->lock.wait_lock, flags); - ret = rt_mutex_trylock(&rwsem->lock); if (ret) rwsem_acquire(&rwsem->dep_map, 0, 1, _RET_IP_);
This patch removes the stupid "Read locks within the self-held write lock succeed" behaviour. This is breaking in mm_take_all_locks() since it is quite common to ensure that a lock is taken with BUG_ON(down_read_trylock(&mm->mmap_sem)). Signed-off-by: Jan Blunck <jblunck@suse.de> --- kernel/rt.c | 12 ------------ 1 file changed, 12 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html