[PATCH] do_sigaction: don't take tasklist_lock
do_sigaction() does not need tasklist_lock anymore, we can simplify the code.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/signal.c b/kernel/signal.c
index e3bdec9..2dfaa50 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2301,8 +2301,7 @@
return kill_proc_info(sig, &info, pid);
}
-int
-do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
+int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
{
struct k_sigaction *k;
sigset_t mask;
@@ -2328,6 +2327,7 @@
if (act) {
sigdelsetmask(&act->sa.sa_mask,
sigmask(SIGKILL) | sigmask(SIGSTOP));
+ *k = *act;
/*
* POSIX 3.3.1.3:
* "Setting a signal action to SIG_IGN for a signal that is
@@ -2340,19 +2340,8 @@
* be discarded, whether or not it is blocked"
*/
if (act->sa.sa_handler == SIG_IGN ||
- (act->sa.sa_handler == SIG_DFL &&
- sig_kernel_ignore(sig))) {
- /*
- * This is a fairly rare case, so we only take the
- * tasklist_lock once we're sure we'll need it.
- * Now we must do this little unlock and relock
- * dance to maintain the lock hierarchy.
- */
+ (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) {
struct task_struct *t = current;
- spin_unlock_irq(&t->sighand->siglock);
- read_lock(&tasklist_lock);
- spin_lock_irq(&t->sighand->siglock);
- *k = *act;
sigemptyset(&mask);
sigaddset(&mask, sig);
rm_from_queue_full(&mask, &t->signal->shared_pending);
@@ -2361,12 +2350,7 @@
recalc_sigpending_tsk(t);
t = next_thread(t);
} while (t != current);
- spin_unlock_irq(¤t->sighand->siglock);
- read_unlock(&tasklist_lock);
- return 0;
}
-
- *k = *act;
}
spin_unlock_irq(¤t->sighand->siglock);