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authorPavel Emelyanov <xemul@openvz.org>2008-04-30 09:52:41 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-30 17:29:34 +0200
commit9e3bd6c3fb2334be171e69b432039cd18bce4458 (patch)
tree199963534d6379457d84e6f2ead2b104088182dd /kernel
parentsignals: clean dequeue_signal from excess checks and assignments (diff)
downloadlinux-9e3bd6c3fb2334be171e69b432039cd18bce4458.tar.xz
linux-9e3bd6c3fb2334be171e69b432039cd18bce4458.zip
signals: consolidate send_sigqueue and send_group_sigqueue
Both functions do the same thing after proper locking, but with different sigpending structs, so move the common code into a helper. After this we have 4 places that look very similar: send_sigqueue: calls do_send_sigqueue and signal_wakeup send_group_sigqueue: calls do_send_sigqueue and __group_complete_signal __group_send_sig_info: calls send_signal and __group_complete_signal specific_send_sig_info: calls send_signal and signal_wakeup Besides, send_signal performs actions similar to do_send_sigqueue's and __group_complete_signal - to signal_wakeup. It looks like they can be consolidated gracefully. Oleg said: Personally, I think this change is very good. But send_sigqueue() and send_group_sigqueue() have a very subtle difference which I was never able to understand. Let's suppose that sigqueue is already queued, and the signal is ignored (the latter means we should re-schedule cpu timer or handle overrruns). In that case send_sigqueue() returns 0, but send_group_sigqueue() returns 1. I think this is not the problem (in fact, I think this patch makes the behaviour more correct), but I hope Thomas can take a look and confirm. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/signal.c86
1 files changed, 29 insertions, 57 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 6610a95506b3..f9a52c721274 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1290,10 +1290,33 @@ void sigqueue_free(struct sigqueue *q)
__sigqueue_free(q);
}
+static int do_send_sigqueue(int sig, struct sigqueue *q, struct task_struct *t,
+ struct sigpending *pending)
+{
+ if (unlikely(!list_empty(&q->list))) {
+ /*
+ * If an SI_TIMER entry is already queue just increment
+ * the overrun count.
+ */
+
+ BUG_ON(q->info.si_code != SI_TIMER);
+ q->info.si_overrun++;
+ return 0;
+ }
+
+ if (sig_ignored(t, sig))
+ return 1;
+
+ signalfd_notify(t, sig);
+ list_add_tail(&q->list, &pending->list);
+ sigaddset(&pending->signal, sig);
+ return 0;
+}
+
int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
{
unsigned long flags;
- int ret = 0;
+ int ret = -1;
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
@@ -1307,37 +1330,14 @@ int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
*/
rcu_read_lock();
- if (!likely(lock_task_sighand(p, &flags))) {
- ret = -1;
+ if (!likely(lock_task_sighand(p, &flags)))
goto out_err;
- }
- if (unlikely(!list_empty(&q->list))) {
- /*
- * If an SI_TIMER entry is already queue just increment
- * the overrun count.
- */
- BUG_ON(q->info.si_code != SI_TIMER);
- q->info.si_overrun++;
- goto out;
- }
- /* Short-circuit ignored signals. */
- if (sig_ignored(p, sig)) {
- ret = 1;
- goto out;
- }
- /*
- * Deliver the signal to listening signalfds. This must be called
- * with the sighand lock held.
- */
- signalfd_notify(p, sig);
+ ret = do_send_sigqueue(sig, q, p, &p->pending);
- list_add_tail(&q->list, &p->pending.list);
- sigaddset(&p->pending.signal, sig);
if (!sigismember(&p->blocked, sig))
signal_wake_up(p, sig == SIGKILL);
-out:
unlock_task_sighand(p, &flags);
out_err:
rcu_read_unlock();
@@ -1349,7 +1349,7 @@ int
send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
{
unsigned long flags;
- int ret = 0;
+ int ret;
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
@@ -1358,38 +1358,10 @@ send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p)
spin_lock_irqsave(&p->sighand->siglock, flags);
handle_stop_signal(sig, p);
- /* Short-circuit ignored signals. */
- if (sig_ignored(p, sig)) {
- ret = 1;
- goto out;
- }
-
- if (unlikely(!list_empty(&q->list))) {
- /*
- * If an SI_TIMER entry is already queue just increment
- * the overrun count. Other uses should not try to
- * send the signal multiple times.
- */
- BUG_ON(q->info.si_code != SI_TIMER);
- q->info.si_overrun++;
- goto out;
- }
- /*
- * Deliver the signal to listening signalfds. This must be called
- * with the sighand lock held.
- */
- signalfd_notify(p, sig);
-
- /*
- * Put this signal on the shared-pending queue.
- * We always use the shared queue for process-wide signals,
- * to avoid several races.
- */
- list_add_tail(&q->list, &p->signal->shared_pending.list);
- sigaddset(&p->signal->shared_pending.signal, sig);
+ ret = do_send_sigqueue(sig, q, p, &p->signal->shared_pending);
__group_complete_signal(sig, p);
-out:
+
spin_unlock_irqrestore(&p->sighand->siglock, flags);
read_unlock(&tasklist_lock);
return ret;