Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / include / asm-generic / local.h

diff --git a/include/asm-generic/local.h b/include/asm-generic/local.h
index 16fc003..9291c24 100644 (file)
--- a/include/asm-generic/local.h
+++ b/include/asm-generic/local.h
@@ -4,28 +4,35 @@
 #include <linux/config.h>
 #include <linux/percpu.h>
 #include <linux/hardirq.h>
+#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.
+ */
 
-#if BITS_PER_LONG == 32
 /* Implement in terms of atomics. */
 
 /* Don't use typedef: don't want them to be mixed with atomic_t's. */
 typedef struct
 {
-       atomic_t a;
+       atomic_long_t a;
 } local_t;
 
-#define LOCAL_INIT(i)  { ATOMIC_INIT(i) }
+#define LOCAL_INIT(i)  { ATOMIC_LONG_INIT(i) }
 
-#define local_read(l)  ((unsigned long)atomic_read(&(l)->a))
-#define local_set(l,i) atomic_set((&(l)->a),(i))
-#define local_inc(l)   atomic_inc(&(l)->a)
-#define local_dec(l)   atomic_dec(&(l)->a)
-#define local_add(i,l) atomic_add((i),(&(l)->a))
-#define local_sub(i,l) atomic_sub((i),(&(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)
+#define local_add(i,l) atomic_long_add((i),(&(l)->a))
+#define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
 
 /* Non-atomic variants, ie. preemption disabled and won't be touched
  * in interrupt, etc.  Some archs can optimize this case well. */
@@ -34,68 +41,6 @@ typedef struct
 #define __local_add(i,l)       local_set((l), local_read(l) + (i))
 #define __local_sub(i,l)       local_set((l), local_read(l) - (i))
 
-#else /* ... can't use atomics. */
-/* Implement in terms of three variables.
-   Another option would be to use local_irq_save/restore. */
-
-typedef struct
-{
-       /* 0 = in hardirq, 1 = in softirq, 2 = usermode. */
-       unsigned long v[3];
-} local_t;
-
-#define _LOCAL_VAR(l)  ((l)->v[!in_interrupt() + !in_irq()])
-
-#define LOCAL_INIT(i)  { { (i), 0, 0 } }
-
-static inline unsigned long local_read(local_t *l)
-{
-       return l->v[0] + l->v[1] + l->v[2];
-}
-
-static inline void local_set(local_t *l, unsigned long v)
-{
-       l->v[0] = v;
-       l->v[1] = l->v[2] = 0;
-}
-
-static inline void local_inc(local_t *l)
-{
-       preempt_disable();
-       _LOCAL_VAR(l)++;
-       preempt_enable();
-}
-
-static inline void local_dec(local_t *l)
-{
-       preempt_disable();
-       _LOCAL_VAR(l)--;
-       preempt_enable();
-}
-
-static inline void local_add(unsigned long v, local_t *l)
-{
-       preempt_disable();
-       _LOCAL_VAR(l) += v;
-       preempt_enable();
-}
-
-static inline void local_sub(unsigned long v, local_t *l)
-{
-       preempt_disable();
-       _LOCAL_VAR(l) -= v;
-       preempt_enable();
-}
-
-/* Non-atomic variants, ie. preemption disabled and won't be touched
- * in interrupt, etc.  Some archs can optimize this case well. */
-#define __local_inc(l)         ((l)->v[0]++)
-#define __local_dec(l)         ((l)->v[0]--)
-#define __local_add(i,l)       ((l)->v[0] += (i))
-#define __local_sub(i,l)       ((l)->v[0] -= (i))
-
-#endif /* Non-atomic implementation */
-
 /* Use these for per-cpu local_t variables: on some archs they are
  * much more efficient than these naive implementations.  Note they take
  * a variable (eg. mystruct.foo), not an address.