signal: Define __ARCH_HAS_SA_RESTORER so we know whether to clear sa_restorer

[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 7b9cd2c..c04e0db 100644 (file)
--- a/include/asm-generic/mutex-xchg.h
+++ b/include/asm-generic/mutex-xchg.h
@@ -26,9 +26,13 @@ static inline void
 __mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
 {
        if (unlikely(atomic_xchg(count, 0) != 1))
-               fail_fn(count);
-       else
-               smp_mb();
+               /*
+                * We failed to acquire the lock, so mark it contended
+                * to ensure that any waiting tasks are woken up by the
+                * unlock slow path.
+                */
+               if (likely(atomic_xchg(count, -1) != 1))
+                       fail_fn(count);
 }
 
 /**
@@ -45,11 +49,9 @@ static inline int
 __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;
-       }
+               if (likely(atomic_xchg(count, -1) != 1))
+                       return fail_fn(count);
+       return 0;
 }
 
 /**
@@ -67,7 +69,6 @@ __mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
 static inline void
 __mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
 {
-       smp_mb();
        if (unlikely(atomic_xchg(count, 1) != 0))
                fail_fn(count);
 }
@@ -110,7 +111,6 @@ __mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
                if (prev < 0)
                        prev = 0;
        }
-       smp_mb();
 
        return prev;
 }