[PATCH] might_sleep() improvements

From: Mitchell Blank Jr <mitch@sfgoth.com>

This patch makes the following improvements to might_sleep():

 o Add a "might_sleep_if()" macro for when we might sleep only if some
   condition is met.  It's a bit tidier, and has an unlikely() in it.

 o Add might_sleep checks to skb_share_check() and skb_unshare() which
   sometimes need to allocate memory.

 o Make all architectures call might_sleep() in both down() and
   down_interruptible().  Before only ppc, ppc64, and i386 did this check.
   (sh did the check on down() but not down_interruptible())

1 files changed, 6 insertions, 2 deletions

diff --git a/include/asm-alpha/semaphore.h b/include/asm-alpha/semaphore.h
index ab26cfbaddbf..a363f018a35f 100644
--- a/include/asm-alpha/semaphore.h
+++ b/include/asm-alpha/semaphore.h
@@ -88,14 +88,18 @@ extern void __up_wakeup(struct semaphore *);
 
 static inline void __down(struct semaphore *sem)
 {
-	long count = atomic_dec_return(&sem->count);
+	long count;
+	might_sleep();
+	count = atomic_dec_return(&sem->count);
 	if (unlikely(count < 0))
 		__down_failed(sem);
 }
 
 static inline int __down_interruptible(struct semaphore *sem)
 {
-	long count = atomic_dec_return(&sem->count);
+	long count;
+	might_sleep();
+	count = atomic_dec_return(&sem->count);
 	if (unlikely(count < 0))
 		return __down_failed_interruptible(sem);
 	return 0;