signals: kill rm_from_queue(), change prepare_signal() to use for_each_thread()

rm_from_queue() doesn't make sense.  The only caller, prepare_signal(),
can use rm_from_queue_full() with the same effect.

While at it, change prepare_signal() to use for_each_thread() instead of
do/while_each_thread.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 33 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 251ca9c9d666..19316dc3eb0b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -728,29 +728,6 @@ static int rm_from_queue_full(sigset_t *mask, struct sigpending *s)
         }
         return 1;
 }
-/*
- * Remove signals in mask from the pending set and queue.
- * Returns 1 if any signals were found.
- *
- * All callers must be holding the siglock.
- */
-static int rm_from_queue(unsigned long mask, struct sigpending *s)
-{
-        struct sigqueue *q, *n;
-
-        if (!sigtestsetmask(&s->signal, mask))
-                return 0;
-
-        sigdelsetmask(&s->signal, mask);
-        list_for_each_entry_safe(q, n, &s->list, list) {
-                if (q->info.si_signo < SIGRTMIN &&
-                    (mask & sigmask(q->info.si_signo))) {
-                        list_del_init(&q->list);
-                        __sigqueue_free(q);
-                }
-        }
-        return 1;
-}
 
 static inline int is_si_special(const struct siginfo *info)
 {
@@ -862,6 +839,7 @@ static bool prepare_signal(int sig, struct task_struct *p, bool force)
 {
         struct signal_struct *signal = p->signal;
         struct task_struct *t;
+        sigset_t flush;
 
         if (signal->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) {
                 if (signal->flags & SIGNAL_GROUP_COREDUMP)
@@ -873,26 +851,25 @@ static bool prepare_signal(int sig, struct task_struct *p, bool force)
                 /*
                  * This is a stop signal.  Remove SIGCONT from all queues.
                  */
-                rm_from_queue(sigmask(SIGCONT), &signal->shared_pending);
-                t = p;
-                do {
-                        rm_from_queue(sigmask(SIGCONT), &t->pending);
-                } while_each_thread(p, t);
+                siginitset(&flush, sigmask(SIGCONT));
+                rm_from_queue_full(&flush, &signal->shared_pending);
+                for_each_thread(p, t)
+                        rm_from_queue_full(&flush, &t->pending);
         } else if (sig == SIGCONT) {
                 unsigned int why;
                 /*
                  * Remove all stop signals from all queues, wake all threads.
                  */
-                rm_from_queue(SIG_KERNEL_STOP_MASK, &signal->shared_pending);
-                t = p;
-                do {
+                siginitset(&flush, SIG_KERNEL_STOP_MASK);
+                rm_from_queue_full(&flush, &signal->shared_pending);
+                for_each_thread(p, t) {
+                        rm_from_queue_full(&flush, &t->pending);
                         task_clear_jobctl_pending(t, JOBCTL_STOP_PENDING);
-                        rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);
                         if (likely(!(t->ptrace & PT_SEIZED)))
                                 wake_up_state(t, __TASK_STOPPED);
                         else
                                 ptrace_trap_notify(t);
-                } while_each_thread(p, t);
+                }
 
                 /*
                  * Notify the parent with CLD_CONTINUED if we were stopped.