Gitweb: http://git.kernel.org/linus/6d69cb87f05eef3b02370b2f7bae608ad2301a00
Commit: 6d69cb87f05eef3b02370b2f7bae608ad2301a00
Parent: 95c3eb76dc07fd81289888ffc42948196b34b444
Author: Oleg Nesterov <oleg@redhat.com>
AuthorDate: Thu Apr 2 16:58:12 2009 -0700
Committer: Linus Torvalds <torvalds@linux-foundation.org>
CommitDate: Thu Apr 2 19:04:59 2009 -0700
ptrace: simplify ptrace_exit()->ignoring_children() path
ignoring_children() takes parent->sighand->siglock and checks
k_sigaction[SIGCHLD] atomically. But this buys nothing, we can't get the
"really" wrong result even if we race with sigaction(SIGCHLD). If we read
the "stale" sa_handler/sa_flags we can pretend it was changed right after
the check.
Remove spin_lock(->siglock), and kill "int ign" which caches the result of
ignoring_children() which becomes rather trivial.
Perhaps it makes sense to export this helper, do_notify_parent() can use
it too.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
kernel/exit.c | 25 ++++++++-----------------
1 files changed, 8 insertions(+), 17 deletions(-)
diff --git a/kernel/exit.c b/kernel/exit.c
index 0c06b9e..7a83114 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -732,19 +732,15 @@ static void exit_mm(struct task_struct * tsk)
}
/*
- * Return nonzero if @parent's children should reap themselves.
- *
- * Called with write_lock_irq(&tasklist_lock) held.
+ * Called with irqs disabled, returns true if childs should reap themselves.
*/
-static int ignoring_children(struct task_struct *parent)
+static int ignoring_children(struct sighand_struct *sigh)
{
int ret;
- struct sighand_struct *psig = ...
