[PATCH 1/6] signals: move the definition of __group_complete_signal() up

From: Oleg Nesterov
Date: Sat Mar 08 2008 - 10:06:34 EST


Move the unchanged definition of __group_complete_signal() so that send_signal
can see it. To simplify the reading of the next patches.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>

--- 25/kernel/signal.c~1_GCS_MOVE 2008-03-08 16:16:22.000000000 +0300
+++ 25/kernel/signal.c 2008-03-08 16:16:52.000000000 +0300
@@ -652,6 +652,102 @@ static void handle_stop_signal(int sig,
}
}

+/*
+ * Test if P wants to take SIG. After we've checked all threads with this,
+ * it's equivalent to finding no threads not blocking SIG. Any threads not
+ * blocking SIG were ruled out because they are not running and already
+ * have pending signals. Such threads will dequeue from the shared queue
+ * as soon as they're available, so putting the signal on the shared queue
+ * will be equivalent to sending it to one such thread.
+ */
+static inline int wants_signal(int sig, struct task_struct *p)
+{
+ if (sigismember(&p->blocked, sig))
+ return 0;
+ if (p->flags & PF_EXITING)
+ return 0;
+ if (sig == SIGKILL)
+ return 1;
+ if (task_is_stopped_or_traced(p))
+ return 0;
+ return task_curr(p) || !signal_pending(p);
+}
+
+static void
+__group_complete_signal(int sig, struct task_struct *p)
+{
+ struct signal_struct *signal = p->signal;
+ struct task_struct *t;
+
+ /*
+ * Now find a thread we can wake up to take the signal off the queue.
+ *
+ * If the main thread wants the signal, it gets first crack.
+ * Probably the least surprising to the average bear.
+ */
+ if (wants_signal(sig, p))
+ t = p;
+ else if (thread_group_empty(p))
+ /*
+ * There is just one thread and it does not need to be woken.
+ * It will dequeue unblocked signals before it runs again.
+ */
+ return;
+ else {
+ /*
+ * Otherwise try to find a suitable thread.
+ */
+ t = signal->curr_target;
+ while (!wants_signal(sig, t)) {
+ t = next_thread(t);
+ if (t == signal->curr_target)
+ /*
+ * No thread needs to be woken.
+ * Any eligible threads will see
+ * the signal in the queue soon.
+ */
+ return;
+ }
+ signal->curr_target = t;
+ }
+
+ /*
+ * Found a killable thread. If the signal will be fatal,
+ * then start taking the whole group down immediately.
+ */
+ if (sig_fatal(p, sig) && !(signal->flags & SIGNAL_GROUP_EXIT) &&
+ !sigismember(&t->real_blocked, sig) &&
+ (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
+ /*
+ * This signal will be fatal to the whole group.
+ */
+ if (!sig_kernel_coredump(sig)) {
+ /*
+ * Start a group exit and wake everybody up.
+ * This way we don't have other threads
+ * running and doing things after a slower
+ * thread has the fatal signal pending.
+ */
+ signal->flags = SIGNAL_GROUP_EXIT;
+ signal->group_exit_code = sig;
+ signal->group_stop_count = 0;
+ t = p;
+ do {
+ sigaddset(&t->pending.signal, SIGKILL);
+ signal_wake_up(t, 1);
+ } while_each_thread(p, t);
+ return;
+ }
+ }
+
+ /*
+ * The signal is already in the shared-pending queue.
+ * Tell the chosen thread to wake up and dequeue it.
+ */
+ signal_wake_up(t, sig == SIGKILL);
+ return;
+}
+
static inline int legacy_queue(struct sigpending *signals, int sig)
{
return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
@@ -817,102 +913,6 @@ force_sig_specific(int sig, struct task_
force_sig_info(sig, SEND_SIG_FORCED, t);
}

-/*
- * Test if P wants to take SIG. After we've checked all threads with this,
- * it's equivalent to finding no threads not blocking SIG. Any threads not
- * blocking SIG were ruled out because they are not running and already
- * have pending signals. Such threads will dequeue from the shared queue
- * as soon as they're available, so putting the signal on the shared queue
- * will be equivalent to sending it to one such thread.
- */
-static inline int wants_signal(int sig, struct task_struct *p)
-{
- if (sigismember(&p->blocked, sig))
- return 0;
- if (p->flags & PF_EXITING)
- return 0;
- if (sig == SIGKILL)
- return 1;
- if (task_is_stopped_or_traced(p))
- return 0;
- return task_curr(p) || !signal_pending(p);
-}
-
-static void
-__group_complete_signal(int sig, struct task_struct *p)
-{
- struct signal_struct *signal = p->signal;
- struct task_struct *t;
-
- /*
- * Now find a thread we can wake up to take the signal off the queue.
- *
- * If the main thread wants the signal, it gets first crack.
- * Probably the least surprising to the average bear.
- */
- if (wants_signal(sig, p))
- t = p;
- else if (thread_group_empty(p))
- /*
- * There is just one thread and it does not need to be woken.
- * It will dequeue unblocked signals before it runs again.
- */
- return;
- else {
- /*
- * Otherwise try to find a suitable thread.
- */
- t = signal->curr_target;
- while (!wants_signal(sig, t)) {
- t = next_thread(t);
- if (t == signal->curr_target)
- /*
- * No thread needs to be woken.
- * Any eligible threads will see
- * the signal in the queue soon.
- */
- return;
- }
- signal->curr_target = t;
- }
-
- /*
- * Found a killable thread. If the signal will be fatal,
- * then start taking the whole group down immediately.
- */
- if (sig_fatal(p, sig) && !(signal->flags & SIGNAL_GROUP_EXIT) &&
- !sigismember(&t->real_blocked, sig) &&
- (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
- /*
- * This signal will be fatal to the whole group.
- */
- if (!sig_kernel_coredump(sig)) {
- /*
- * Start a group exit and wake everybody up.
- * This way we don't have other threads
- * running and doing things after a slower
- * thread has the fatal signal pending.
- */
- signal->flags = SIGNAL_GROUP_EXIT;
- signal->group_exit_code = sig;
- signal->group_stop_count = 0;
- t = p;
- do {
- sigaddset(&t->pending.signal, SIGKILL);
- signal_wake_up(t, 1);
- } while_each_thread(p, t);
- return;
- }
- }
-
- /*
- * The signal is already in the shared-pending queue.
- * Tell the chosen thread to wake up and dequeue it.
- */
- signal_wake_up(t, sig == SIGKILL);
- return;
-}
-
int
__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{

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