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authorNick Piggin <nickpiggin@yahoo.com.au>2005-11-14 01:07:25 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-14 03:14:16 +0100
commit8426e1f6af0fd7f44d040af7263750c5a52f3cc3 (patch)
tree827bd2588c2b73d11cea6869de8ff42dba134375 /include/asm-v850
parent[PATCH] atomic: cmpxchg (diff)
downloadlinux-8426e1f6af0fd7f44d040af7263750c5a52f3cc3.tar.xz
linux-8426e1f6af0fd7f44d040af7263750c5a52f3cc3.zip
[PATCH] atomic: inc_not_zero
Introduce an atomic_inc_not_zero operation. Make this a special case of atomic_add_unless because lockless pagecache actually wants atomic_inc_not_negativeone due to its offset refcount. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-v850')
-rw-r--r--include/asm-v850/atomic.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/include/asm-v850/atomic.h b/include/asm-v850/atomic.h
index e497166ca42b..bede3172ce7f 100644
--- a/include/asm-v850/atomic.h
+++ b/include/asm-v850/atomic.h
@@ -104,6 +104,22 @@ static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
return ret;
}
+static inline int atomic_add_unless(atomic_t *v, int a, int u)
+{
+ int ret;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ ret = v->counter;
+ if (ret != u)
+ v->counter += a;
+ local_irq_restore(flags);
+
+ return ret != u;
+}
+
+#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+
/* Atomic operations are already serializing on ARM */
#define smp_mb__before_atomic_dec() barrier()
#define smp_mb__after_atomic_dec() barrier()