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authorAndrew Morton <akpm@osdl.org>2006-03-31 02:30:49 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-31 12:18:55 -0800
commit2cf8d82d63807c2c68adf20bb28bf502496186dd (patch)
tree13cafaa87dafa639f3876bcda6d302266a349c88 /include/asm-generic
parent09ce3512dcad0ad1d07eee0dc5ebb6d037c39c16 (diff)
downloadop-kernel-dev-2cf8d82d63807c2c68adf20bb28bf502496186dd.zip
op-kernel-dev-2cf8d82d63807c2c68adf20bb28bf502496186dd.tar.gz
[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>
Diffstat (limited to 'include/asm-generic')
-rw-r--r--include/asm-generic/local.h13
1 files changed, 10 insertions, 3 deletions
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 @@ typedef struct
#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)
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