vt_ioctl: move vt_reldisp out of vt_ioctl

It's too long to be inlined.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200615074910.19267-34-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/vt_ioctl.c

@@ -633,6 +633,42 @@ static int vt_io_ioctl(struct vc_data *vc, unsigned int cmd, void __user *up,
 	return 0;
 }
 
+static int vt_reldisp(struct vc_data *vc, unsigned int swtch)
+{
+	int newvt, ret;
+
+	if (vc->vt_mode.mode != VT_PROCESS)
+		return -EINVAL;
+
+	/* Switched-to response */
+	if (vc->vt_newvt < 0) {
+		 /* If it's just an ACK, ignore it */
+		return swtch == VT_ACKACQ ? 0 : -EINVAL;
+	}
+
+	/* Switching-from response */
+	if (swtch == 0) {
+		/* Switch disallowed, so forget we were trying to do it. */
+		vc->vt_newvt = -1;
+		return 0;
+	}
+
+	/* The current vt has been released, so complete the switch. */
+	newvt = vc->vt_newvt;
+	vc->vt_newvt = -1;
+	ret = vc_allocate(newvt);
+	if (ret)
+		return ret;
+
+	/*
+	 * When we actually do the console switch, make sure we are atomic with
+	 * respect to other console switches..
+	 */
+	complete_change_console(vc_cons[newvt].d);
+
+	return 0;
+}
+
 static int vt_setactivate(struct vt_setactivate __user *sa)
 {
 	struct vt_setactivate vsa;
@@ -865,55 +901,11 @@ int vt_ioctl(struct tty_struct *tty,
 			return -EPERM;
 
 		console_lock();
-		if (vc->vt_mode.mode != VT_PROCESS) {
-			console_unlock();
-			return -EINVAL;
-		}
-		/*
-		 * Switching-from response
-		 */
-		if (vc->vt_newvt >= 0) {
-			if (arg == 0)
-				/*
-				 * Switch disallowed, so forget we were trying
-				 * to do it.
-				 */
-				vc->vt_newvt = -1;
-
-			else {
-				/*
-				 * The current vt has been released, so
-				 * complete the switch.
-				 */
-				int newvt;
-				newvt = vc->vt_newvt;
-				vc->vt_newvt = -1;
-				ret = vc_allocate(newvt);
-				if (ret) {
-					console_unlock();
-					return ret;
-				}
-				/*
-				 * When we actually do the console switch,
-				 * make sure we are atomic with respect to
-				 * other console switches..
-				 */
-				complete_change_console(vc_cons[newvt].d);
-			}
-		} else {
-			/*
-			 * Switched-to response
-			 */
-			/*
-			 * If it's just an ACK, ignore it
-			 */
-			if (arg != VT_ACKACQ) {
-				console_unlock();
-				return -EINVAL;
-			}
-		}
+		ret = vt_reldisp(vc, arg);
 		console_unlock();
-		break;
+
+		return ret;
+
 
 	 /*
 	  * Disallocate memory associated to VT (but leave VT1)