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authorNick Piggin <nickpiggin@yahoo.com.au>2005-11-13 16:07:25 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-13 18:14:16 -0800
commit8426e1f6af0fd7f44d040af7263750c5a52f3cc3 (patch)
tree827bd2588c2b73d11cea6869de8ff42dba134375 /include/asm-m68knommu
parent4a6dae6d382e9edf3ff440b819e554ed706359bc (diff)
[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-m68knommu')
-rw-r--r--include/asm-m68knommu/atomic.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/asm-m68knommu/atomic.h b/include/asm-m68knommu/atomic.h
index 2fd33a56b60..3c1cc153c41 100644
--- a/include/asm-m68knommu/atomic.h
+++ b/include/asm-m68knommu/atomic.h
@@ -130,6 +130,16 @@ static inline int atomic_sub_return(int i, atomic_t * v)
#define atomic_cmpxchg(v, o, n) ((int)cmpxchg(&((v)->counter), (o), (n)))
+#define atomic_add_unless(v, a, u) \
+({ \
+ int c, old; \
+ c = atomic_read(v); \
+ while (c != (u) && (old = atomic_cmpxchg((v), c, c + (a))) != c) \
+ c = old; \
+ c != (u); \
+})
+#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
+
#define atomic_dec_return(v) atomic_sub_return(1,(v))
#define atomic_inc_return(v) atomic_add_return(1,(v))