introduce write_trylock_irqsave()

Introduce a write_trylock_irqsave() implementation.  Similar in style to
the implementation of spin_trylock_irqsave() in mainline.

Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: Sripathi Kodi <sripathik@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
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 a946176db638c7198705a20a7d2fd715279dfc2d..c376f3b36c8980c9b434cabc693e7ef9b4ab43f3 100644 (file)
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -282,6 +282,13 @@ do {                                               \
        1 : ({ local_irq_restore(flags); 0; }); \
 })
 
+#define write_trylock_irqsave(lock, flags) \
+({ \
+       local_irq_save(flags); \
+       write_trylock(lock) ? \
+       1 : ({ local_irq_restore(flags); 0; }); \
+})
+
 /*
  * Locks two spinlocks l1 and l2.
  * l1_first indicates if spinlock l1 should be taken first.