alpha: lock bitops
Alpha can avoid one mb when acquiring a lock with test_and_set_bit_lock.
[bunk@kernel.org: alpha bitops.h must #include <asm/barrier.h>]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-alpha/bitops.h b/include/asm-alpha/bitops.h
index f1bbe6c..381b4f5 100644
--- a/include/asm-alpha/bitops.h
+++ b/include/asm-alpha/bitops.h
@@ -2,6 +2,7 @@
#define _ALPHA_BITOPS_H
#include <asm/compiler.h>
+#include <asm/barrier.h>
/*
* Copyright 1994, Linus Torvalds.
@@ -69,6 +70,13 @@
:"Ir" (1UL << (nr & 31)), "m" (*m));
}
+static inline void
+clear_bit_unlock(unsigned long nr, volatile void * addr)
+{
+ smp_mb();
+ clear_bit(nr, addr);
+}
+
/*
* WARNING: non atomic version.
*/
@@ -81,6 +89,13 @@
}
static inline void
+__clear_bit_unlock(unsigned long nr, volatile void * addr)
+{
+ smp_mb();
+ __clear_bit(nr, addr);
+}
+
+static inline void
change_bit(unsigned long nr, volatile void * addr)
{
unsigned long temp;
@@ -139,6 +154,33 @@
return oldbit != 0;
}
+static inline int
+test_and_set_bit_lock(unsigned long nr, volatile void *addr)
+{
+ unsigned long oldbit;
+ unsigned long temp;
+ int *m = ((int *) addr) + (nr >> 5);
+
+ __asm__ __volatile__(
+ "1: ldl_l %0,%4\n"
+ " and %0,%3,%2\n"
+ " bne %2,2f\n"
+ " xor %0,%3,%0\n"
+ " stl_c %0,%1\n"
+ " beq %0,3f\n"
+ "2:\n"
+#ifdef CONFIG_SMP
+ " mb\n"
+#endif
+ ".subsection 2\n"
+ "3: br 1b\n"
+ ".previous"
+ :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
+ :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
+
+ return oldbit != 0;
+}
+
/*
* WARNING: non atomic version.
*/
@@ -376,7 +418,6 @@
#else
#include <asm-generic/bitops/hweight.h>
#endif
-#include <asm-generic/bitops/lock.h>
#endif /* __KERNEL__ */