handle_stop_signal: use the cached p->signal value

Cache the value of p->signal, and change the code to use while_each_thread()
helper.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 13 insertions, 15 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index dee8cc927a63..b266fa46402a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -566,9 +566,10 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why);
  */
 static void handle_stop_signal(int sig, struct task_struct *p)
 {
+        struct signal_struct *signal = p->signal;
         struct task_struct *t;
 
-        if (p->signal->flags & SIGNAL_GROUP_EXIT)
+        if (signal->flags & SIGNAL_GROUP_EXIT)
                 /*
                  * The process is in the middle of dying already.
                  */
@@ -578,19 +579,18 @@ static void handle_stop_signal(int sig, struct task_struct *p)
                 /*
                  * This is a stop signal.  Remove SIGCONT from all queues.
                  */
-                rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending);
+                rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
                 t = p;
                 do {
                         rm_from_queue(sigmask(SIGCONT), &t->pending);
-                        t = next_thread(t);
-                } while (t != p);
+                } while_each_thread(p, t);
         } else if (sig == SIGCONT) {
                 unsigned int why;
                 /*
                  * Remove all stop signals from all queues,
                  * and wake all threads.
                  */
-                rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
+                rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
                 t = p;
                 do {
                         unsigned int state;
@@ -615,9 +615,7 @@ static void handle_stop_signal(int sig, struct task_struct *p)
                                 state |= TASK_INTERRUPTIBLE;
                         }
                         wake_up_state(t, state);
-
-                        t = next_thread(t);
-                } while (t != p);
+                } while_each_thread(p, t);
 
                 /*
                  * Notify the parent with CLD_CONTINUED if we were stopped.
@@ -628,29 +626,29 @@ static void handle_stop_signal(int sig, struct task_struct *p)
                  * CLD_CONTINUED was dropped.
                  */
                 why = 0;
-                if (p->signal->flags & SIGNAL_STOP_STOPPED)
+                if (signal->flags & SIGNAL_STOP_STOPPED)
                         why |= SIGNAL_CLD_CONTINUED;
-                else if (p->signal->group_stop_count)
+                else if (signal->group_stop_count)
                         why |= SIGNAL_CLD_STOPPED;
 
                 if (why) {
-                        p->signal->flags = why | SIGNAL_STOP_CONTINUED;
-                        p->signal->group_stop_count = 0;
-                        p->signal->group_exit_code = 0;
+                        signal->flags = why | SIGNAL_STOP_CONTINUED;
+                        signal->group_stop_count = 0;
+                        signal->group_exit_code = 0;
                 } else {
                         /*
                          * We are not stopped, but there could be a stop
                          * signal in the middle of being processed after
                          * being removed from the queue.  Clear that too.
                          */
-                        p->signal->flags &= ~SIGNAL_STOP_DEQUEUED;
+                        signal->flags &= ~SIGNAL_STOP_DEQUEUED;
                 }
         } else if (sig == SIGKILL) {
                 /*
                  * Make sure that any pending stop signal already dequeued
                  * is undone by the wakeup for SIGKILL.
                  */
-                p->signal->flags &= ~SIGNAL_STOP_DEQUEUED;
+                signal->flags &= ~SIGNAL_STOP_DEQUEUED;
         }
 }