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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-04-30 09:53:00 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-30 17:29:36 +0200 |
| commit | 021e1ae3d85a76ce962a300c96813f04ae50c87c (patch) | |
| tree | 1c3cfbf8151c339baa3b35a4a78fa50ccc7594ab /kernel/signal.c | |
| parent | signals: fold sig_ignored() into handle_stop_signal() (diff) | |
| download | linux-021e1ae3d85a76ce962a300c96813f04ae50c87c.tar.xz linux-021e1ae3d85a76ce962a300c96813f04ae50c87c.zip | |
signals: document CLD_CONTINUED notification mechanics
A couple of small comments about how CLD_CONTINUED notification works.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 359c4de7c772..8423867f7d8f 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -633,6 +633,11 @@ static int prepare_signal(int sig, struct task_struct *p) why |= SIGNAL_CLD_STOPPED; if (why) { + /* + * The first thread which returns from finish_stop() + * will take ->siglock, notice SIGNAL_CLD_MASK, and + * notify its parent. See get_signal_to_deliver(). + */ signal->flags = why | SIGNAL_STOP_CONTINUED; signal->group_stop_count = 0; signal->group_exit_code = 0; @@ -1694,7 +1699,11 @@ relock: try_to_freeze(); spin_lock_irq(&sighand->siglock); - + /* + * Every stopped thread goes here after wakeup. Check to see if + * we should notify the parent, prepare_signal(SIGCONT) encodes + * the CLD_ si_code into SIGNAL_CLD_MASK bits. + */ if (unlikely(signal->flags & SIGNAL_CLD_MASK)) { int why = (signal->flags & SIGNAL_STOP_CONTINUED) ? CLD_CONTINUED : CLD_STOPPED; |