um: don't restore current->blocked on error

If we fail to setup the signal stack frame then we don't need to restore
current->blocked because it is not modified by setup_signal_stack_*.

Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Richard Weinberger <richard@nod.at>
Tested-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/um/kernel/signal.c

@@ -65,13 +65,9 @@ static int handle_signal(struct pt_regs *regs, unsigned long signr,
 #endif
 		err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
 
-	if (err) {
-		spin_lock_irq(&current->sighand->siglock);
-		current->blocked = *oldset;
-		recalc_sigpending();
-		spin_unlock_irq(&current->sighand->siglock);
+	if (err)
 		force_sigsegv(signr, current);
-	} else {
+	else {
 		spin_lock_irq(&current->sighand->siglock);
 		sigorsets(&current->blocked, &current->blocked,
 			  &ka->sa.sa_mask);