ptrace_signal subroutine

This breaks out the ptrace handling from get_signal_to_deliver into a
new subroutine.  The actual code there doesn't change, and it gets
inlined into nearly identical compiled code.  This makes the function
substantially shorter and thus easier to read, and it nicely isolates
the ptrace magic.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Acked-by: NKyle McMartin <kyle@mcmartin.ca>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/signal.c

@@ -1757,35 +1757,12 @@ static int do_signal_stop(int signr)
 	return 1;
 }
 
-int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
+static int ptrace_signal(int signr, siginfo_t *info,
 			 struct pt_regs *regs, void *cookie)
 {
-	sigset_t *mask = &current->blocked;
-	int signr = 0;
-
-relock:
-	/*
-	 * We'll jump back here after any time we were stopped in TASK_STOPPED.
-	 * While in TASK_STOPPED, we were considered "frozen enough".
-	 * Now that we woke up, it's crucial if we're supposed to be
-	 * frozen that we freeze now before running anything substantial.
-	 */
-	try_to_freeze();
-
-	spin_lock_irq(&current->sighand->siglock);
-	for (;;) {
-		struct k_sigaction *ka;
-
-		if (unlikely(current->signal->group_stop_count > 0) &&
-		    do_signal_stop(0))
-			goto relock;
-
-		signr = dequeue_signal(current, mask, info);
-
-		if (!signr)
-			break; /* will return 0 */
+	if (!(current->ptrace & PT_PTRACED))
+		return signr;
 
-		if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
 	ptrace_signal_deliver(regs, cookie);
 
 	/* Let the debugger run.  */
@@ -1794,7 +1771,7 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
 	/* We're back.  Did the debugger cancel the sig?  */
 	signr = current->exit_code;
 	if (signr == 0)
-				continue;
+		return signr;
 
 	current->exit_code = 0;
 
@@ -1813,8 +1790,44 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
 	/* If the (new) signal is now blocked, requeue it.  */
 	if (sigismember(&current->blocked, signr)) {
 		specific_send_sig_info(signr, info, current);
-				continue;
+		signr = 0;
 	}
+
+	return signr;
+}
+
+int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
+			  struct pt_regs *regs, void *cookie)
+{
+	sigset_t *mask = &current->blocked;
+	int signr = 0;
+
+relock:
+	/*
+	 * We'll jump back here after any time we were stopped in TASK_STOPPED.
+	 * While in TASK_STOPPED, we were considered "frozen enough".
+	 * Now that we woke up, it's crucial if we're supposed to be
+	 * frozen that we freeze now before running anything substantial.
+	 */
+	try_to_freeze();
+
+	spin_lock_irq(&current->sighand->siglock);
+	for (;;) {
+		struct k_sigaction *ka;
+
+		if (unlikely(current->signal->group_stop_count > 0) &&
+		    do_signal_stop(0))
+			goto relock;
+
+		signr = dequeue_signal(current, mask, info);
+
+		if (!signr)
+			break; /* will return 0 */
+
+		if (signr != SIGKILL) {
+			signr = ptrace_signal(signr, info, regs, cookie);
+			if (!signr)
+				continue;
 		}
 
 		ka = &current->sighand->action[signr-1];