1 files changed, 30 insertions, 34 deletions

diff --git a/kernel/semaphore.c b/kernel/semaphore.c
index 5c2942e768cd..5e41217239e8 100644
--- a/kernel/semaphore.c
+++ b/kernel/semaphore.c
@@ -54,10 +54,9 @@ void down(struct semaphore *sem)
         unsigned long flags;
 
         spin_lock_irqsave(&sem->lock, flags);
-        if (likely(sem->count > 0))
-                sem->count--;
-        else
+        if (unlikely(!sem->count))
                 __down(sem);
+        sem->count--;
         spin_unlock_irqrestore(&sem->lock, flags);
 }
 EXPORT_SYMBOL(down);
@@ -77,10 +76,10 @@ int down_interruptible(struct semaphore *sem)
         int result = 0;
 
         spin_lock_irqsave(&sem->lock, flags);
-        if (likely(sem->count > 0))
-                sem->count--;
-        else
+        if (unlikely(!sem->count))
                 result = __down_interruptible(sem);
+        if (!result)
+                sem->count--;
         spin_unlock_irqrestore(&sem->lock, flags);
 
         return result;
@@ -103,10 +102,10 @@ int down_killable(struct semaphore *sem)
         int result = 0;
 
         spin_lock_irqsave(&sem->lock, flags);
-        if (likely(sem->count > 0))
-                sem->count--;
-        else
+        if (unlikely(!sem->count))
                 result = __down_killable(sem);
+        if (!result)
+                sem->count--;
         spin_unlock_irqrestore(&sem->lock, flags);
 
         return result;
@@ -157,10 +156,10 @@ int down_timeout(struct semaphore *sem, long jiffies)
         int result = 0;
 
         spin_lock_irqsave(&sem->lock, flags);
-        if (likely(sem->count > 0))
-                sem->count--;
-        else
+        if (unlikely(!sem->count))
                 result = __down_timeout(sem, jiffies);
+        if (!result)
+                sem->count--;
         spin_unlock_irqrestore(&sem->lock, flags);
 
         return result;
@@ -179,9 +178,8 @@ void up(struct semaphore *sem)
         unsigned long flags;
 
         spin_lock_irqsave(&sem->lock, flags);
-        if (likely(list_empty(&sem->wait_list)))
-                sem->count++;
-        else
+        sem->count++;
+        if (unlikely(!list_empty(&sem->wait_list)))
                 __up(sem);
         spin_unlock_irqrestore(&sem->lock, flags);
 }
@@ -192,7 +190,6 @@ EXPORT_SYMBOL(up);
 struct semaphore_waiter {
         struct list_head list;
         struct task_struct *task;
-        int up;
 };
 
 /*
@@ -205,33 +202,34 @@ static inline int __sched __down_common(struct semaphore *sem, long state,
 {
         struct task_struct *task = current;
         struct semaphore_waiter waiter;
+        int ret = 0;
 
-        list_add_tail(&waiter.list, &sem->wait_list);
         waiter.task = task;
-        waiter.up = 0;
+        list_add_tail(&waiter.list, &sem->wait_list);
 
         for (;;) {
-                if (state == TASK_INTERRUPTIBLE && signal_pending(task))
-                        goto interrupted;
-                if (state == TASK_KILLABLE && fatal_signal_pending(task))
-                        goto interrupted;
-                if (timeout <= 0)
-                        goto timed_out;
+                if (state == TASK_INTERRUPTIBLE && signal_pending(task)) {
+                        ret = -EINTR;
+                        break;
+                }
+                if (state == TASK_KILLABLE && fatal_signal_pending(task)) {
+                        ret = -EINTR;
+                        break;
+                }
+                if (timeout <= 0) {
+                        ret = -ETIME;
+                        break;
+                }
                 __set_task_state(task, state);
                 spin_unlock_irq(&sem->lock);
                 timeout = schedule_timeout(timeout);
                 spin_lock_irq(&sem->lock);
-                if (waiter.up)
-                        return 0;
+                if (sem->count > 0)
+                        break;
         }
 
- timed_out:
-        list_del(&waiter.list);
-        return -ETIME;
-
- interrupted:
         list_del(&waiter.list);
-        return -EINTR;
+        return ret;
 }
 
 static noinline void __sched __down(struct semaphore *sem)
@@ -258,7 +256,5 @@ static noinline void __sched __up(struct semaphore *sem)
 {
         struct semaphore_waiter *waiter = list_first_entry(&sem->wait_list,
                                                 struct semaphore_waiter, list);
-        list_del(&waiter->list);
-        waiter->up = 1;
         wake_up_process(waiter->task);
 }