diff options
Diffstat (limited to 'lib/lockref.c')
| -rw-r--r-- | lib/lockref.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/lib/lockref.c b/lib/lockref.c index 677d036cf3c7..f07a40d33871 100644 --- a/lib/lockref.c +++ b/lib/lockref.c @@ -1,7 +1,16 @@ #include <linux/export.h> #include <linux/lockref.h> +#include <linux/mutex.h> -#ifdef CONFIG_CMPXCHG_LOCKREF +#if USE_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 @@ -14,12 +23,13 @@ while (likely(arch_spin_value_unlocked(old.lock.rlock.raw_lock))) { \ struct lockref new = old, prev = old; \ CODE \ - old.lock_count = cmpxchg64(&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; \ } \ - cpu_relax(); \ + arch_mutex_cpu_relax(); \ } \ } while (0) @@ -136,6 +146,7 @@ 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 |