rwsem: Test for no active locks in __rwsem_do_wake undo code

[sfrench/cifs-2.6.git] / lib / rwsem.c

diff --git a/lib/rwsem.c b/lib/rwsem.c
index 7d02700a4b0e131ae0dfba2e6da6ecf75b6a8d2c..ceba8e28807a81c09c551e4f782091efa9bebccf 100644 (file)
--- a/lib/rwsem.c
+++ b/lib/rwsem.c
@@ -136,9 +136,10 @@ __rwsem_do_wake(struct rw_semaphore *sem, int downgrading)
  out:
        return sem;
 
-       /* undo the change to count, but check for a transition 1->0 */
+       /* undo the change to the active count, but check for a transition
+        * 1->0 */
  undo:
-       if (rwsem_atomic_update(-RWSEM_ACTIVE_BIAS, sem) != 0)
+       if (rwsem_atomic_update(-RWSEM_ACTIVE_BIAS, sem) & RWSEM_ACTIVE_MASK)
                goto out;
        goto try_again;
 }
@@ -187,7 +188,7 @@ rwsem_down_failed_common(struct rw_semaphore *sem,
 /*
  * wait for the read lock to be granted
  */
-struct rw_semaphore fastcall __sched *
+asmregparm struct rw_semaphore __sched *
 rwsem_down_read_failed(struct rw_semaphore *sem)
 {
        struct rwsem_waiter waiter;
@@ -201,7 +202,7 @@ rwsem_down_read_failed(struct rw_semaphore *sem)
 /*
  * wait for the write lock to be granted
  */
-struct rw_semaphore fastcall __sched *
+asmregparm struct rw_semaphore __sched *
 rwsem_down_write_failed(struct rw_semaphore *sem)
 {
        struct rwsem_waiter waiter;
@@ -216,7 +217,7 @@ rwsem_down_write_failed(struct rw_semaphore *sem)
  * handle waking up a waiter on the semaphore
  * - up_read/up_write has decremented the active part of count if we come here
  */
-struct rw_semaphore fastcall *rwsem_wake(struct rw_semaphore *sem)
+asmregparm struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem)
 {
        unsigned long flags;
 
@@ -236,7 +237,7 @@ struct rw_semaphore fastcall *rwsem_wake(struct rw_semaphore *sem)
  * - caller incremented waiting part of count and discovered it still negative
  * - just wake up any readers at the front of the queue
  */
-struct rw_semaphore fastcall *rwsem_downgrade_wake(struct rw_semaphore *sem)
+asmregparm struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem)
 {
        unsigned long flags;