signals: clean dequeue_signal from excess checks and assignments

The signr variable may be declared without initialization - it is set ro the
return value from __dequeue_signal() right at the function beginning.

Besides, after recalc_sigpending() two checks for signr to be not 0 may be
merged into one.  Both if-s become easier to read.

Thanks to Oleg for pointing out mistakes in the first version of this patch.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 24ee53b7f60c..6610a95506b3 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -377,7 +377,7 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
  */
 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
 {
-        int signr = 0;
+        int signr;
 
         /* We only dequeue private signals from ourselves, we don't let
          * signalfd steal them
@@ -410,8 +410,12 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
                         }
                 }
         }
+
         recalc_sigpending();
-        if (signr && unlikely(sig_kernel_stop(signr))) {
+        if (!signr)
+                return 0;
+
+        if (unlikely(sig_kernel_stop(signr))) {
                 /*
                  * Set a marker that we have dequeued a stop signal.  Our
                  * caller might release the siglock and then the pending
@@ -427,9 +431,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
                 if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT))
                         tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
         }
-        if (signr &&
-             ((info->si_code & __SI_MASK) == __SI_TIMER) &&
-             info->si_sys_private) {
+        if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
                 /*
                  * Release the siglock to ensure proper locking order
                  * of timer locks outside of siglocks.  Note, we leave