The asm-generic/local.h BITS_PER_LONG == 64 case can best be described
as, uh, creative use of in_irq() and in_interrupt()... Now that Christoph
Lameter's atomic_long_t support is merged in mainline, might as well
convert asm-generic/local.h to use it, so the same code can be used
for both sizes of unsigned long.
Signed-off-by: Kyle McMartin <[email protected]>
---
Is there any particular reason why these routines weren't simply
implemented with local_save/restore_flags, if they are only meant to
guarantee atomicity to the local cpu? I'm sure on most platforms
this would be more efficient than using an atomic...
local.h | 80 +++++++---------------------------------------------------------
1 file changed, 9 insertions(+), 71 deletions(-)
diff --git a/include/asm-generic/local.h b/include/asm-generic/local.h
index 16fc003..de46148 100644
--- a/include/asm-generic/local.h
+++ b/include/asm-generic/local.h
@@ -4,28 +4,28 @@
#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. */
-#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) ((unsigned long)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 +34,6 @@ 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.
-
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