signals: consolidate checking for ignored/legacy signals

Two callers for send_signal() - the specific_send_sig_info and the
__group_send_sig_info - both check for sig to be ignored or already queued.

Move these checks into send_signal() and make it return 1 to indicate that the
signal is dropped, but there's no error in this.

Besides, merge comments and spell-check them.

[oleg@tv-sign.ru: simplifications]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/signal.c b/kernel/signal.c
index 772aa01..fb8ffd4 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -668,6 +668,14 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
        struct sigqueue * q = NULL;
 
        /*
+        * Short-circuit ignored signals and support queuing
+        * exactly one non-rt signal, so that we can get more
+        * detailed information about the cause of the signal.
+        */
+       if (sig_ignored(t, sig) || legacy_queue(signals, sig))
+               return 0;
+
+       /*
         * Deliver the signal to listening signalfds. This must be called
         * with the sighand lock held.
         */
@@ -723,7 +731,7 @@ static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
 
 out_set:
        sigaddset(&signals->signal, sig);
-       return 0;
+       return 1;
 }
 
 int print_fatal_signals;
@@ -761,26 +769,18 @@ __setup("print-fatal-signals=", setup_print_fatal_signals);
 static int
 specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t)
 {
-       int ret = 0;
+       int ret;
 
        BUG_ON(!irqs_disabled());
        assert_spin_locked(&t->sighand->siglock);
 
-       /* Short-circuit ignored signals.  */
-       if (sig_ignored(t, sig))
-               goto out;
-
-       /* Support queueing exactly one non-rt signal, so that we
-          can get more detailed information about the cause of
-          the signal. */
-       if (legacy_queue(&t->pending, sig))
-               goto out;
-
        ret = send_signal(sig, info, t, &t->pending);
-       if (!ret && !sigismember(&t->blocked, sig))
+       if (ret <= 0)
+               return ret;
+
+       if (!sigismember(&t->blocked, sig))
                signal_wake_up(t, sig == SIGKILL);
-out:
-       return ret;
+       return 0;
 }
 
 /*
@@ -925,26 +925,18 @@ __group_complete_signal(int sig, struct task_struct *p)
 int
 __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
 {
-       int ret = 0;
+       int ret;
 
        assert_spin_locked(&p->sighand->siglock);
        handle_stop_signal(sig, p);
 
-       /* Short-circuit ignored signals.  */
-       if (sig_ignored(p, sig))
-               return ret;
-
-       if (legacy_queue(&p->signal->shared_pending, sig))
-               /* This is a non-RT signal and we already have one queued.  */
-               return ret;
-
        /*
         * Put this signal on the shared-pending queue, or fail with EAGAIN.
         * We always use the shared queue for process-wide signals,
         * to avoid several races.
         */
        ret = send_signal(sig, info, p, &p->signal->shared_pending);
-       if (unlikely(ret))
+       if (ret <= 0)
                return ret;
 
        __group_complete_signal(sig, p);