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authorNamhyung Kim <namhyung@gmail.com>2010-10-27 15:34:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-10-27 18:03:12 -0700
commitb8ed374e202e23caaf9bd77dcadc9de6447faaa8 (patch)
treeea97fe186c7e0c0ee8cd61e0fc94dc42f635fd3b
parent5ef45079dd9c8f2e9c7aa788dc3121835ae52863 (diff)
signals: annotate lock_task_sighand()
lock_task_sighand() grabs sighand->siglock in case of returning non-NULL but unlock_task_sighand() releases it unconditionally. This leads sparse to complain about the lock context imbalance. Rename and wrap lock_task_sighand() using __cond_lock() macro to make sparse happy. Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/sched.h9
-rw-r--r--kernel/signal.c3
2 files changed, 10 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 393ce94e54b..3ff5c8519ab 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2236,9 +2236,16 @@ static inline void task_unlock(struct task_struct *p)
spin_unlock(&p->alloc_lock);
}
-extern struct sighand_struct *lock_task_sighand(struct task_struct *tsk,
+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 void unlock_task_sighand(struct task_struct *tsk,
unsigned long *flags)
{
diff --git a/kernel/signal.c b/kernel/signal.c
index 919562c3d6b..e921409b85a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1105,7 +1105,8 @@ int zap_other_threads(struct task_struct *p)
return count;
}
-struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)
+struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
+ unsigned long *flags)
{
struct sighand_struct *sighand;