From: Oleg Nesterov Cache the value of p->signal, and change the code to use while_each_thread() helper. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Cc: Jiri Kosina Signed-off-by: Andrew Morton --- kernel/signal.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) diff -puN kernel/signal.c~handle_stop_signal-use-the-cached-p-signal-value kernel/signal.c --- a/kernel/signal.c~handle_stop_signal-use-the-cached-p-signal-value +++ a/kernel/signal.c @@ -566,9 +566,10 @@ static void do_notify_parent_cldstop(str */ 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, /* * 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, 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, * 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; } } _