Merge remote-tracking branch 'nfsd/nfsd-next'

[karo-tx-linux.git] / lib / lockref.c

diff --git a/lib/lockref.c b/lib/lockref.c
index e294ae445c9ab4b7e97dd1a46efc7dc7d6a1848d..af6e95d0bed6122bf9fd1e4af2bd76a4e2be62b3 100644 (file)
--- a/lib/lockref.c
+++ b/lib/lockref.c
@@ -11,6 +11,14 @@
 # define cmpxchg64_relaxed cmpxchg64
 #endif
 
+/*
+ * Allow architectures to override the default cpu_relax() within CMPXCHG_LOOP.
+ * This is useful for architectures with an expensive cpu_relax().
+ */
+#ifndef arch_mutex_cpu_relax
+# define arch_mutex_cpu_relax() cpu_relax()
+#endif
+
 /*
  * Note that the "cmpxchg()" reloads the "old" value for the
  * failure case.
@@ -28,7 +36,7 @@
                if (likely(old.lock_count == prev.lock_count)) {                \
                        SUCCESS;                                                \
                }                                                               \
-               cpu_relax();                                                    \
+               arch_mutex_cpu_relax();                                         \
        }                                                                       \
 } while (0)
 
@@ -145,6 +153,7 @@ void lockref_mark_dead(struct lockref *lockref)
        assert_spin_locked(&lockref->lock);
        lockref->count = -128;
 }
+EXPORT_SYMBOL(lockref_mark_dead);
 
 /**
  * lockref_get_not_dead - Increments count unless the ref is dead