From 9e413497c7f5ab6da77270315788a5f279d10e02 Mon Sep 17 00:00:00 2001
From: David Mosberger <davidm@tiger.hpl.hp.com>
Date: Tue, 4 Mar 2003 02:38:51 -0800
Subject: [PATCH] ia64: Implement _raw_write_trylock().  Based on patch by Joel
 Guillet.

---
 include/asm-ia64/spinlock.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/asm-ia64/spinlock.h b/include/asm-ia64/spinlock.h
index 46c473d80d442..7478ee58fb9fd 100644
--- a/include/asm-ia64/spinlock.h
+++ b/include/asm-ia64/spinlock.h
@@ -183,6 +183,19 @@ do {										\
 		:: "r"(rw) : "ar.ccv", "p7", "r2", "r29", "memory");		\
 } while(0)
 
+#define _raw_write_trylock(rw)							\
+({										\
+	register long result;							\
+										\
+	__asm__ __volatile__ (							\
+		"mov ar.ccv = r0\n"						\
+		"dep r29 = -1, r0, 31, 1\n"					\
+		";;\n"								\
+		"cmpxchg4.acq %0 = [%1], r29, ar.ccv\n"				\
+		: "=r"(result) : "r"(rw) : "ar.ccv", "r29", "memory");		\
+	(result == 0);								\
+})
+
 #define _raw_write_unlock(x)								\
 ({											\
 	smp_mb__before_clear_bit();	/* need barrier before releasing lock... */	\
-- 
2.53.0