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>

diff --git a/kernel/signal.c b/kernel/signal.c
index dee8cc9..b266fa4 100644 (file)
--- 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;
        }
 }