signals: inline __fatal_signal_pending

__fatal_signal_pending inlines to one instruction on x86, probably two
instructions on other machines.  It takes two longer x86 instructions just
to call it and test its return value, not to mention the function itself.

On my random x86_64 config, this saved 70 bytes of text (59 of those being
__fatal_signal_pending itself).
Signed-off-by: NRoland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/sched.h

@@ -2337,7 +2337,10 @@ static inline int signal_pending(struct task_struct *p)
 	return unlikely(test_tsk_thread_flag(p,TIF_SIGPENDING));
 }
 
-extern int __fatal_signal_pending(struct task_struct *p);
+static inline int __fatal_signal_pending(struct task_struct *p)
+{
+	return unlikely(sigismember(&p->pending.signal, SIGKILL));
+}
 
 static inline int fatal_signal_pending(struct task_struct *p)
 {

kernel/signal.c

@@ -1050,12 +1050,6 @@ void zap_other_threads(struct task_struct *p)
 	}
 }
 
-int __fatal_signal_pending(struct task_struct *tsk)
-{
-	return sigismember(&tsk->pending.signal, SIGKILL);
-}
-EXPORT_SYMBOL(__fatal_signal_pending);
-
 struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags)
 {
 	struct sighand_struct *sighand;