Merge tag 'devicetree-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/robh...

[cascardo/linux.git] / lib / lockref.c

diff --git a/lib/lockref.c b/lib/lockref.c
index e2cd2c0..e294ae4 100644 (file)
--- a/lib/lockref.c
+++ b/lib/lockref.c
@@ -3,6 +3,14 @@
 
 #ifdef CONFIG_CMPXCHG_LOCKREF
 
+/*
+ * Allow weakly-ordered memory architectures to provide barrier-less
+ * cmpxchg semantics for lockref updates.
+ */
+#ifndef cmpxchg64_relaxed
+# define cmpxchg64_relaxed cmpxchg64
+#endif
+
 /*
  * Note that the "cmpxchg()" reloads the "old" value for the
  * failure case.
@@ -14,8 +22,9 @@
        while (likely(arch_spin_value_unlocked(old.lock.rlock.raw_lock))) {     \
                struct lockref new = old, prev = old;                           \
                CODE                                                            \
-               old.lock_count = cmpxchg(&lockref->lock_count,                  \
-                                        old.lock_count, new.lock_count);       \
+               old.lock_count = cmpxchg64_relaxed(&lockref->lock_count,        \
+                                                  old.lock_count,              \
+                                                  new.lock_count);             \
                if (likely(old.lock_count == prev.lock_count)) {                \
                        SUCCESS;                                                \
                }                                                               \