[PATCH] make local_t signed
local_t's were defined to be unsigned. This increases confusion because
atomic_t's are signed. The patch goes through and changes all implementations
to use signed longs throughout.
Also, x86-64 was using 32-bit quantities for the value passed into local_add()
and local_sub(). Fixed.
All (actually, both) existing users have been audited.
(Also s/__inline__/inline/ in x86_64/local.h)
Cc: Andi Kleen <ak@muc.de>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-generic/local.h b/include/asm-generic/local.h
index de46148..9291c24 100644
--- a/include/asm-generic/local.h
+++ b/include/asm-generic/local.h
@@ -7,8 +7,15 @@
#include <asm/atomic.h>
#include <asm/types.h>
-/* An unsigned long type for operations which are atomic for a single
- * CPU. Usually used in combination with per-cpu variables. */
+/*
+ * A signed long type for operations which are atomic for a single CPU.
+ * Usually used in combination with per-cpu variables.
+ *
+ * This is the default implementation, which uses atomic_long_t. Which is
+ * rather pointless. The whole point behind local_t is that some processors
+ * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs
+ * running on this CPU. local_t allows exploitation of such capabilities.
+ */
/* Implement in terms of atomics. */
@@ -20,7 +27,7 @@
#define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
-#define local_read(l) ((unsigned long)atomic_long_read(&(l)->a))
+#define local_read(l) atomic_long_read(&(l)->a)
#define local_set(l,i) atomic_long_set((&(l)->a),(i))
#define local_inc(l) atomic_long_inc(&(l)->a)
#define local_dec(l) atomic_long_dec(&(l)->a)