[LV-k25-commit] CVS: kernel-2.5/include/asm-vax system.h,1.9,1.10

[Kenn H. <ke...@us...>]

Update of /cvsroot/linux-vax/kernel-2.5/include/asm-vax
In directory sc8-pr-cvs1:/tmp/cvs-serv5158/include/asm-vax

Modified Files:
	system.h 
Log Message:
Need a definition of cmpxchg() in 2.5.37


Index: system.h
===================================================================
RCS file: /cvsroot/linux-vax/kernel-2.5/include/asm-vax/system.h,v
retrieving revision 1.9
retrieving revision 1.10
diff -u -r1.9 -r1.10
--- system.h	14 Feb 2003 02:21:02 -0000	1.9
+++ system.h	17 Feb 2003 20:04:17 -0000	1.10
@@ -38,6 +38,24 @@
 extern void __switch_to(struct task_struct*, struct task_struct*);
 #define switch_to(prev, next, last)	__switch_to((prev), (next))
 
+/*
+ * Atomic compare and exchange.  Compare OLD with MEM, if identical,
+ * store NEW in MEM.  Return the initial value in MEM.  Success is
+ * indicated by comparing RETURN with OLD.
+ */
+
+#define cmpxchg(ptr, old, new) ({ \
+	unsigned long flags;		\
+	__typeof__(*(ptr)) cur;		\
+	local_irq_save(flags);		\
+	cur = *(ptr);			\
+	if (cur == (old)) {		\
+		*(ptr) = (new);		\
+	}				\
+	local_irq_restore(flags);	\
+	cur;				\
+})
+
 /* mb is the alpha instruction to cause serialisation of memory
    operations. According to a software note in section 5.5.4 of 
    part I of the alpha arch handbook (p/no ey-l520e-dp) we dont