Re: [patchlet] locking/rt: fix rt_read_lock() lockdep annotation.

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

* Mike Galbraith | 2014-05-07 16:20:15 [+0200]:

>> > This looks like it reverse applies?
>> Nope, I thought Thomas's whacked the one he did on purpose.  
>I should learn to speak lockdep.  How about this instead?
>
>locking/rt: fix rt_read_trylock() lockdep annotation.
>
>rt-rw-lockdep-annotations.patch dropped a rwlock_acquire_read
>
>Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
>---
> kernel/locking/rt.c |    3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
>--- a/kernel/locking/rt.c
>+++ b/kernel/locking/rt.c
>@@ -217,7 +217,7 @@ int __lockfunc rt_read_trylock(rwlock_t
> 		migrate_disable();
> 		ret = rt_mutex_trylock(lock);
> 		if (ret)
>-			rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
>+			rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);

Think we should drop rwlock_acquire_read() and use rwlock_acquire()
instead (like the previous patch) because on -RT there is no difference
between a read and a write lock. Or is there more to it?

> 		else
> 			migrate_enable();
> 

Sebastian