mutex: speed up generic mutex implementations

[pandora-kernel.git] / include / asm-generic / mutex-xchg.h

diff --git a/include/asm-generic/mutex-xchg.h b/include/asm-generic/mutex-xchg.h
index 1d24f47..580a6d3 100644 (file)
--- a/include/asm-generic/mutex-xchg.h
+++ b/include/asm-generic/mutex-xchg.h
@@ -1,9 +1,9 @@
 /*
- * asm-generic/mutex-xchg.h
+ * include/asm-generic/mutex-xchg.h
  *
  * Generic implementation of the mutex fastpath, based on xchg().
  *
- * NOTE: An xchg based implementation is less optimal than an atomic
+ * NOTE: An xchg based implementation might be less optimal than an atomic
  *       decrement/increment based implementation. If your architecture
  *       has a reasonable atomic dec/inc then you should probably use
  *      asm-generic/mutex-dec.h instead, or you could open-code an
@@ -22,14 +22,12 @@
  * wasn't 1 originally. This function MUST leave the value lower than 1
  * even when the "1" assertion wasn't true.
  */
-#define __mutex_fastpath_lock(count, fail_fn)                          \
-do {                                                                   \
-       if (unlikely(atomic_xchg(count, 0) != 1))                       \
-               fail_fn(count);                                         \
-       else                                                            \
-               smp_mb();                                               \
-} while (0)
-
+static inline void
+__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
+{
+       if (unlikely(atomic_xchg(count, 0) != 1))
+               fail_fn(count);
+}
 
 /**
  *  __mutex_fastpath_lock_retval - try to take the lock by moving the count
@@ -46,10 +44,7 @@ __mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
 {
        if (unlikely(atomic_xchg(count, 0) != 1))
                return fail_fn(count);
-       else {
-               smp_mb();
-               return 0;
-       }
+       return 0;
 }
 
 /**
@@ -64,12 +59,12 @@ __mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
  * __mutex_slowpath_needs_to_unlock() macro needs to return 1, it needs
  * to return 0 otherwise.
  */
-#define __mutex_fastpath_unlock(count, fail_fn)                                \
-do {                                                                   \
-       smp_mb();                                                       \
-       if (unlikely(atomic_xchg(count, 1) != 0))                       \
-               fail_fn(count);                                         \
-} while (0)
+static inline void
+__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
+{
+       if (unlikely(atomic_xchg(count, 1) != 0))
+               fail_fn(count);
+}
 
 #define __mutex_slowpath_needs_to_unlock()             0
 
@@ -109,7 +104,6 @@ __mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
                if (prev < 0)
                        prev = 0;
        }
-       smp_mb();
 
        return prev;
 }