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handle_stop_signal: unify partial/full stop handling

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Now that handle_stop_signal() doesn't drop ->siglock, we can't see both
->group_stop_count && SIGNAL_STOP_STOPPED.  Merge two "if" branches.

As Roland pointed out, we never actually needed 2 do_notify_parent_cldstop()
calls.

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>
This commit is contained in:
Oleg Nesterov 2008-04-30 00:52:46 -07:00 committed by Linus Torvalds
parent 6ca25b5513
commit fc321d2e60
1 changed files with 19 additions and 26 deletions
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45
kernel/signal.c
View file

@ -585,33 +585,16 @@ static void handle_stop_signal(int sig, struct task_struct *p)
t = next_thread(t);
} while (t != p);
} else if (sig == SIGCONT) {
unsigned int why;
/*
* Remove all stop signals from all queues,
* and wake all threads.
*/
if (unlikely(p->signal->group_stop_count > 0)) {
/*
* There was a group stop in progress. We'll
* pretend it finished before we got here. We are
* obliged to report it to the parent: if the
* SIGSTOP happened "after" this SIGCONT, then it
* would have cleared this pending SIGCONT. If it
* happened "before" this SIGCONT, then the parent
* got the SIGCHLD about the stop finishing before
* the continue happened. We do the notification
* now, and it's as if the stop had finished and
* the SIGCHLD was pending on entry to this kill.
*/
p->signal->group_stop_count = 0;
p->signal->flags = SIGNAL_STOP_CONTINUED |
SIGNAL_CLD_STOPPED;
}
rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);
t = p;
do {
unsigned int state;
rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
/*
* If there is a handler for SIGCONT, we must make
* sure that no thread returns to user mode before
@ -621,7 +604,7 @@ static void handle_stop_signal(int sig, struct task_struct *p)
* running the handler. With the TIF_SIGPENDING
* flag set, the thread will pause and acquire the
* siglock that we hold now and until we've queued
* the pending signal.
* the pending signal.
*
* Wake up the stopped thread _after_ setting
* TIF_SIGPENDING
@ -636,13 +619,23 @@ static void handle_stop_signal(int sig, struct task_struct *p)
t = next_thread(t);
} while (t != p);
if (p->signal->flags & SIGNAL_STOP_STOPPED) {
/*
* We were in fact stopped, and are now continued.
* Notify the parent with CLD_CONTINUED.
*/
p->signal->flags = SIGNAL_STOP_CONTINUED |
SIGNAL_CLD_CONTINUED;
/*
* Notify the parent with CLD_CONTINUED if we were stopped.
*
* If we were in the middle of a group stop, we pretend it
* was already finished, and then continued. Since SIGCHLD
* doesn't queue we report only CLD_STOPPED, as if the next
* CLD_CONTINUED was dropped.
*/
why = 0;
if (p->signal->flags & SIGNAL_STOP_STOPPED)
why |= SIGNAL_CLD_CONTINUED;
else if (p->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;
} else {
/*