Merge branch 'for-3.16' of git://linux-nfs.org/~bfields/linux

[karo-tx-linux.git] / kernel / locking / rwsem.c

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index cfff1435bdfb2f1e6d8a88d797c2a205f9145daf..42f806de49d421092a7bd077c8efb4df9546cb94 100644 (file)
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -12,6 +12,27 @@
 
 #include <linux/atomic.h>
 
+#if defined(CONFIG_SMP) && defined(CONFIG_RWSEM_XCHGADD_ALGORITHM)
+static inline void rwsem_set_owner(struct rw_semaphore *sem)
+{
+       sem->owner = current;
+}
+
+static inline void rwsem_clear_owner(struct rw_semaphore *sem)
+{
+       sem->owner = NULL;
+}
+
+#else
+static inline void rwsem_set_owner(struct rw_semaphore *sem)
+{
+}
+
+static inline void rwsem_clear_owner(struct rw_semaphore *sem)
+{
+}
+#endif
+
 /*
  * lock for reading
  */
@@ -48,6 +69,7 @@ void __sched down_write(struct rw_semaphore *sem)
        rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
 
        LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
+       rwsem_set_owner(sem);
 }
 
 EXPORT_SYMBOL(down_write);
@@ -59,8 +81,11 @@ int down_write_trylock(struct rw_semaphore *sem)
 {
        int ret = __down_write_trylock(sem);
 
-       if (ret == 1)
+       if (ret == 1) {
                rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_);
+               rwsem_set_owner(sem);
+       }
+
        return ret;
 }
 
@@ -85,6 +110,7 @@ void up_write(struct rw_semaphore *sem)
 {
        rwsem_release(&sem->dep_map, 1, _RET_IP_);
 
+       rwsem_clear_owner(sem);
        __up_write(sem);
 }
 
@@ -99,6 +125,7 @@ void downgrade_write(struct rw_semaphore *sem)
         * lockdep: a downgraded write will live on as a write
         * dependency.
         */
+       rwsem_clear_owner(sem);
        __downgrade_write(sem);
 }
 
@@ -122,6 +149,7 @@ void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest)
        rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_);
 
        LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
+       rwsem_set_owner(sem);
 }
 
 EXPORT_SYMBOL(_down_write_nest_lock);
@@ -141,6 +169,7 @@ void down_write_nested(struct rw_semaphore *sem, int subclass)
        rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
 
        LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
+       rwsem_set_owner(sem);
 }
 
 EXPORT_SYMBOL(down_write_nested);