[PATCH] sched: Turn lock_task_sighand() into a static inline

[Anton Vorontsov <anton.vorontsov@linaro.org>]

It appears that sparse tool understands static inline functions for
context balance checking, so let's turn the macros into an inline func.

This makes the code a little bit more robust.

Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
---

On Wed, Feb 08, 2012 at 04:27:50PM +0100, Oleg Nesterov wrote:
> On 02/07, Anton Vorontsov wrote:
> >
> > On Mon, Feb 06, 2012 at 04:27:32PM -0500, KOSAKI Motohiro wrote:
> > >
> > > Some __cond_lock() caller are inline functions. Is this bad?
> >
> > No, that's great, actually. :-) Not obvious, but seems like
> > sparse understands __cond_lock in inline functions, so I'd
> > better use it.
> 
> Hmm, great...
> 
> may be you can update lock_task_sighand() too ? (in a separate
> patch of course).

Sure thing. Here it goes...

 include/linux/sched.h |   15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index e82f721..22ae10e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2394,12 +2394,15 @@ static inline void task_unlock(struct task_struct *p)
 extern struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
 							unsigned long *flags);
 
-#define lock_task_sighand(tsk, flags)					\
-({	struct sighand_struct *__ss;					\
-	__cond_lock(&(tsk)->sighand->siglock,				\
-		    (__ss = __lock_task_sighand(tsk, flags)));		\
-	__ss;								\
-})									\
+static inline struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
+						       unsigned long *flags)
+{
+	struct sighand_struct *ret;
+
+	ret = __lock_task_sighand(tsk, flags);
+	(void)__cond_lock(&tsk->sighand->siglock, ret);
+	return ret;
+}
 
 static inline void unlock_task_sighand(struct task_struct *tsk,
 						unsigned long *flags)
-- 
1.7.8.3