Allow rwlocks to re-enable interrupts

Pass the original flags to rwlock arch-code, so that it can re-enable
interrupts if implemented for that architecture.

Initially, make __raw_read_lock_flags and __raw_write_lock_flags stubs
which just do the same thing as non-flags variants.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index a0c66a2..252b245 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -153,9 +153,11 @@
  extern int _raw_spin_trylock(spinlock_t *lock);
  extern void _raw_spin_unlock(spinlock_t *lock);
  extern void _raw_read_lock(rwlock_t *lock);
+#define _raw_read_lock_flags(lock, flags) _raw_read_lock(lock)
  extern int _raw_read_trylock(rwlock_t *lock);
  extern void _raw_read_unlock(rwlock_t *lock);
  extern void _raw_write_lock(rwlock_t *lock);
+#define _raw_write_lock_flags(lock, flags) _raw_write_lock(lock)
  extern int _raw_write_trylock(rwlock_t *lock);
  extern void _raw_write_unlock(rwlock_t *lock);
 #else
@@ -165,9 +167,13 @@
 # define _raw_spin_trylock(lock)	__raw_spin_trylock(&(lock)->raw_lock)
 # define _raw_spin_unlock(lock)		__raw_spin_unlock(&(lock)->raw_lock)
 # define _raw_read_lock(rwlock)		__raw_read_lock(&(rwlock)->raw_lock)
+# define _raw_read_lock_flags(lock, flags) \
+		__raw_read_lock_flags(&(lock)->raw_lock, *(flags))
 # define _raw_read_trylock(rwlock)	__raw_read_trylock(&(rwlock)->raw_lock)
 # define _raw_read_unlock(rwlock)	__raw_read_unlock(&(rwlock)->raw_lock)
 # define _raw_write_lock(rwlock)	__raw_write_lock(&(rwlock)->raw_lock)
+# define _raw_write_lock_flags(lock, flags) \
+		__raw_write_lock_flags(&(lock)->raw_lock, *(flags))
 # define _raw_write_trylock(rwlock)	__raw_write_trylock(&(rwlock)->raw_lock)
 # define _raw_write_unlock(rwlock)	__raw_write_unlock(&(rwlock)->raw_lock)
 #endif