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-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 de4614840c2c..9291c24f5819 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)