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>

1 files changed, 17 insertions, 25 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 772aa011dad8..fb8ffd468854 100644
--- 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);