From: Satyam Sharma <ssatyam@cse.iitk.ac.in>

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>
---

 include/linux/spinlock.h |    7 +++++++
 1 files changed, 7 insertions(+)

diff -puN include/linux/spinlock.h~introduce-write_trylock_irqsave include/linux/spinlock.h
--- a/include/linux/spinlock.h~introduce-write_trylock_irqsave
+++ a/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.
_