1 files changed, 63 insertions, 0 deletions

diff --git a/arch/blackfin/include/asm/mutex.h b/arch/blackfin/include/asm/mutex.h
index 458c1f7fbc18..5d399256bf06 100644
--- a/arch/blackfin/include/asm/mutex.h
+++ b/arch/blackfin/include/asm/mutex.h
@@ -6,4 +6,67 @@
  * implementation. (see asm-generic/mutex-xchg.h for details)
  */
 
+#ifndef _ASM_MUTEX_H
+#define _ASM_MUTEX_H
+
+#ifndef CONFIG_SMP
 #include <asm-generic/mutex-dec.h>
+#else
+
+static inline void
+__mutex_fastpath_lock(atomic_t *count, void (*fail_fn)(atomic_t *))
+{
+        if (unlikely(atomic_dec_return(count) < 0))
+                fail_fn(count);
+        else
+                smp_mb();
+}
+
+static inline int
+__mutex_fastpath_lock_retval(atomic_t *count, int (*fail_fn)(atomic_t *))
+{
+        if (unlikely(atomic_dec_return(count) < 0))
+                return fail_fn(count);
+        else {
+                smp_mb();
+                return 0;
+        }
+}
+
+static inline void
+__mutex_fastpath_unlock(atomic_t *count, void (*fail_fn)(atomic_t *))
+{
+        smp_mb();
+        if (unlikely(atomic_inc_return(count) <= 0))
+                fail_fn(count);
+}
+
+#define __mutex_slowpath_needs_to_unlock()              1
+
+static inline int
+__mutex_fastpath_trylock(atomic_t *count, int (*fail_fn)(atomic_t *))
+{
+        /*
+         * We have two variants here. The cmpxchg based one is the best one
+         * because it never induce a false contention state.  It is included
+         * here because architectures using the inc/dec algorithms over the
+         * xchg ones are much more likely to support cmpxchg natively.
+         *
+         * If not we fall back to the spinlock based variant - that is
+         * just as efficient (and simpler) as a 'destructive' probing of
+         * the mutex state would be.
+         */
+#ifdef __HAVE_ARCH_CMPXCHG
+        if (likely(atomic_cmpxchg(count, 1, 0) == 1)) {
+                smp_mb();
+                return 1;
+        }
+        return 0;
+#else
+        return fail_fn(count);
+#endif
+}
+
+#endif
+
+#endif