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authorOleg Nesterov <oleg@tv-sign.ru>2008-04-30 00:52:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 08:29:34 -0700
commitfc321d2e60d6f4eee17206612d0b50519f526daf (patch)
tree79dd03d347ccee2f5a538823f7434dfd40e302be
parent6ca25b551309eb1b1b41f83414a92f7472e0b23d (diff)
handle_stop_signal: unify partial/full stop handling
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>
-rw-r--r--kernel/signal.c45
1 files changed, 19 insertions, 26 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index ce53ab19c21..dee8cc927a6 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -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 {
/*