1 files changed, 22 insertions, 15 deletions

diff --git a/lib/rwsem-spinlock.c b/lib/rwsem-spinlock.c
index 9df3ca56db11..ffc9fc7f3b05 100644
--- a/lib/rwsem-spinlock.c
+++ b/lib/rwsem-spinlock.c
@@ -17,6 +17,19 @@ struct rwsem_waiter {
 #define RWSEM_WAITING_FOR_WRITE 0x00000002
 };
 
+int rwsem_is_locked(struct rw_semaphore *sem)
+{
+        int ret = 1;
+        unsigned long flags;
+
+        if (spin_trylock_irqsave(&sem->wait_lock, flags)) {
+                ret = (sem->activity != 0);
+                spin_unlock_irqrestore(&sem->wait_lock, flags);
+        }
+        return ret;
+}
+EXPORT_SYMBOL(rwsem_is_locked);
+
 /*
  * initialise the semaphore
  */
@@ -34,6 +47,7 @@ void __init_rwsem(struct rw_semaphore *sem, const char *name,
         spin_lock_init(&sem->wait_lock);
         INIT_LIST_HEAD(&sem->wait_list);
 }
+EXPORT_SYMBOL(__init_rwsem);
 
 /*
  * handle the lock release when processes blocked on it that can now run
@@ -129,13 +143,14 @@ void __sched __down_read(struct rw_semaphore *sem)
 {
         struct rwsem_waiter waiter;
         struct task_struct *tsk;
+        unsigned long flags;
 
-        spin_lock_irq(&sem->wait_lock);
+        spin_lock_irqsave(&sem->wait_lock, flags);
 
         if (sem->activity >= 0 && list_empty(&sem->wait_list)) {
                 /* granted */
                 sem->activity++;
-                spin_unlock_irq(&sem->wait_lock);
+                spin_unlock_irqrestore(&sem->wait_lock, flags);
                 goto out;
         }
 
@@ -150,7 +165,7 @@ void __sched __down_read(struct rw_semaphore *sem)
         list_add_tail(&waiter.list, &sem->wait_list);
 
         /* we don't need to touch the semaphore struct anymore */
-        spin_unlock_irq(&sem->wait_lock);
+        spin_unlock_irqrestore(&sem->wait_lock, flags);
 
         /* wait to be given the lock */
         for (;;) {
@@ -195,13 +210,14 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
 {
         struct rwsem_waiter waiter;
         struct task_struct *tsk;
+        unsigned long flags;
 
-        spin_lock_irq(&sem->wait_lock);
+        spin_lock_irqsave(&sem->wait_lock, flags);
 
         if (sem->activity == 0 && list_empty(&sem->wait_list)) {
                 /* granted */
                 sem->activity = -1;
-                spin_unlock_irq(&sem->wait_lock);
+                spin_unlock_irqrestore(&sem->wait_lock, flags);
                 goto out;
         }
 
@@ -216,7 +232,7 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
         list_add_tail(&waiter.list, &sem->wait_list);
 
         /* we don't need to touch the semaphore struct anymore */
-        spin_unlock_irq(&sem->wait_lock);
+        spin_unlock_irqrestore(&sem->wait_lock, flags);
 
         /* wait to be given the lock */
         for (;;) {
@@ -305,12 +321,3 @@ void __downgrade_write(struct rw_semaphore *sem)
         spin_unlock_irqrestore(&sem->wait_lock, flags);
 }
 
-EXPORT_SYMBOL(__init_rwsem);
-EXPORT_SYMBOL(__down_read);
-EXPORT_SYMBOL(__down_read_trylock);
-EXPORT_SYMBOL(__down_write_nested);
-EXPORT_SYMBOL(__down_write);
-EXPORT_SYMBOL(__down_write_trylock);
-EXPORT_SYMBOL(__up_read);
-EXPORT_SYMBOL(__up_write);
-EXPORT_SYMBOL(__downgrade_write);