[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>
diff --git a/arch/sparc/lib/atomic32.c b/arch/sparc/lib/atomic32.c
index be46f65..cb3cf0f 100644
--- a/arch/sparc/lib/atomic32.c
+++ b/arch/sparc/lib/atomic32.c
@@ -53,6 +53,21 @@
return ret;
}
+int atomic_add_unless(atomic_t *v, int a, int u)
+{
+ int ret;
+ unsigned long flags;
+
+ spin_lock_irqsave(ATOMIC_HASH(v), flags);
+ ret = v->counter;
+ if (ret != u)
+ v->counter += a;
+ spin_unlock_irqrestore(ATOMIC_HASH(v), flags);
+ return ret != u;
+}
+
+static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+/* Atomic operations are already serializing */
void atomic_set(atomic_t *v, int i)
{
unsigned long flags;