vt: sort out locking for font handling

The font methods are console_lock covered. Unfortunately they don't extend
the lock over all the needed tests.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/vt.c

@@ -3969,9 +3969,6 @@ static int con_font_get(struct vc_data *vc, struct console_font_op *op)
 	int rc = -EINVAL;
 	int c;
 
-	if (vc->vc_mode != KD_TEXT)
-		return -EINVAL;
-
 	if (op->data) {
 		font.data = kmalloc(max_font_size, GFP_KERNEL);
 		if (!font.data)
@@ -3980,7 +3977,9 @@ static int con_font_get(struct vc_data *vc, struct console_font_op *op)
 		font.data = NULL;
 
 	console_lock();
-	if (vc->vc_sw->con_font_get)
+	if (vc->vc_mode != KD_TEXT)
+		rc = -EINVAL;
+	else if (vc->vc_sw->con_font_get)
 		rc = vc->vc_sw->con_font_get(vc, &font);
 	else
 		rc = -ENOSYS;
@@ -4062,7 +4061,9 @@ static int con_font_set(struct vc_data *vc, struct console_font_op *op)
 	if (IS_ERR(font.data))
 		return PTR_ERR(font.data);
 	console_lock();
-	if (vc->vc_sw->con_font_set)
+	if (vc->vc_mode != KD_TEXT)
+		rc = -EINVAL;
+	else if (vc->vc_sw->con_font_set)
 		rc = vc->vc_sw->con_font_set(vc, &font, op->flags);
 	else
 		rc = -ENOSYS;
@@ -4078,8 +4079,6 @@ static int con_font_default(struct vc_data *vc, struct console_font_op *op)
 	char *s = name;
 	int rc;
 
-	if (vc->vc_mode != KD_TEXT)
-		return -EINVAL;
 
 	if (!op->data)
 		s = NULL;
@@ -4089,6 +4088,10 @@ static int con_font_default(struct vc_data *vc, struct console_font_op *op)
 		name[MAX_FONT_NAME - 1] = 0;
 
 	console_lock();
+	if (vc->vc_mode != KD_TEXT) {
+		console_unlock();
+		return -EINVAL;
+	}
 	if (vc->vc_sw->con_font_default)
 		rc = vc->vc_sw->con_font_default(vc, &font, s);
 	else
@@ -4106,11 +4109,11 @@ static int con_font_copy(struct vc_data *vc, struct console_font_op *op)
 	int con = op->height;
 	int rc;
 
-	if (vc->vc_mode != KD_TEXT)
-		return -EINVAL;
 
 	console_lock();
-	if (!vc->vc_sw->con_font_copy)
+	if (vc->vc_mode != KD_TEXT)
+		rc = -EINVAL;
+	else if (!vc->vc_sw->con_font_copy)
 		rc = -ENOSYS;
 	else if (con < 0 || !vc_cons_allocated(con))
 		rc = -ENOTTY;