new helper: sigsuspend()

guts of saved_sigmask-based sigsuspend/rt_sigsuspend.  Takes
kernel sigset_t *.

Open-coded instances replaced with calling it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/kernel/compat.c b/kernel/compat.c
index d2c67aa..c28a306 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -1073,15 +1073,7 @@
 	if (copy_from_user(&newset32, unewset, sizeof(compat_sigset_t)))
 		return -EFAULT;
 	sigset_from_compat(&newset, &newset32);
-	sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));
-
-	current->saved_sigmask = current->blocked;
-	set_current_blocked(&newset);
-
-	current->state = TASK_INTERRUPTIBLE;
-	schedule();
-	set_restore_sigmask();
-	return -ERESTARTNOHAND;
+	return sigsuspend(&newset);
 }
 #endif /* __ARCH_WANT_COMPAT_SYS_RT_SIGSUSPEND */
 
diff --git a/kernel/signal.c b/kernel/signal.c
index 17afcaf..3ad220a 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3236,6 +3236,21 @@
 
 #endif
 
+#ifdef HAVE_SET_RESTORE_SIGMASK
+int sigsuspend(sigset_t *set)
+{
+	sigdelsetmask(set, sigmask(SIGKILL)|sigmask(SIGSTOP));
+
+	current->saved_sigmask = current->blocked;
+	set_current_blocked(set);
+
+	current->state = TASK_INTERRUPTIBLE;
+	schedule();
+	set_restore_sigmask();
+	return -ERESTARTNOHAND;
+}
+#endif
+
 #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
 /**
  *  sys_rt_sigsuspend - replace the signal mask for a value with the
@@ -3253,15 +3268,7 @@
 
 	if (copy_from_user(&newset, unewset, sizeof(newset)))
 		return -EFAULT;
-	sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP));
-
-	current->saved_sigmask = current->blocked;
-	set_current_blocked(&newset);
-
-	current->state = TASK_INTERRUPTIBLE;
-	schedule();
-	set_restore_sigmask();
-	return -ERESTARTNOHAND;
+	return sigsuspend(&newset);
 }
 #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */