V4L/DVB: em28xx: fix locks during dvb init sequence

Serialize DVB initialization, to avoid it to happen while analog
initialization is still happening.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/em28xx/em28xx-core.c

@@ -1178,21 +1178,18 @@ void em28xx_add_into_devlist(struct em28xx *dev)
  */
 
 static LIST_HEAD(em28xx_extension_devlist);
-static DEFINE_MUTEX(em28xx_extension_devlist_lock);
 
 int em28xx_register_extension(struct em28xx_ops *ops)
 {
 	struct em28xx *dev = NULL;
 
 	mutex_lock(&em28xx_devlist_mutex);
-	mutex_lock(&em28xx_extension_devlist_lock);
 	list_add_tail(&ops->next, &em28xx_extension_devlist);
 	list_for_each_entry(dev, &em28xx_devlist, devlist) {
 		if (dev)
 			ops->init(dev);
 	}
 	printk(KERN_INFO "Em28xx: Initialized (%s) extension\n", ops->name);
-	mutex_unlock(&em28xx_extension_devlist_lock);
 	mutex_unlock(&em28xx_devlist_mutex);
 	return 0;
 }
@@ -1208,10 +1205,8 @@ void em28xx_unregister_extension(struct em28xx_ops *ops)
 			ops->fini(dev);
 	}
 
-	mutex_lock(&em28xx_extension_devlist_lock);
 	printk(KERN_INFO "Em28xx: Removed (%s) extension\n", ops->name);
 	list_del(&ops->next);
-	mutex_unlock(&em28xx_extension_devlist_lock);
 	mutex_unlock(&em28xx_devlist_mutex);
 }
 EXPORT_SYMBOL(em28xx_unregister_extension);
@@ -1220,26 +1215,26 @@ void em28xx_init_extension(struct em28xx *dev)
 {
 	struct em28xx_ops *ops = NULL;
 
-	mutex_lock(&em28xx_extension_devlist_lock);
+	mutex_lock(&em28xx_devlist_mutex);
 	if (!list_empty(&em28xx_extension_devlist)) {
 		list_for_each_entry(ops, &em28xx_extension_devlist, next) {
 			if (ops->init)
 				ops->init(dev);
 		}
 	}
-	mutex_unlock(&em28xx_extension_devlist_lock);
+	mutex_unlock(&em28xx_devlist_mutex);
 }
 
 void em28xx_close_extension(struct em28xx *dev)
 {
 	struct em28xx_ops *ops = NULL;
 
-	mutex_lock(&em28xx_extension_devlist_lock);
+	mutex_lock(&em28xx_devlist_mutex);
 	if (!list_empty(&em28xx_extension_devlist)) {
 		list_for_each_entry(ops, &em28xx_extension_devlist, next) {
 			if (ops->fini)
 				ops->fini(dev);
 		}
 	}
-	mutex_unlock(&em28xx_extension_devlist_lock);
+	mutex_unlock(&em28xx_devlist_mutex);
 }

drivers/media/video/em28xx/em28xx-dvb.c

@@ -467,6 +467,7 @@ static int dvb_init(struct em28xx *dev)
 	}
 	dev->dvb = dvb;
 
+	mutex_lock(&dev->lock);
 	em28xx_set_mode(dev, EM28XX_DIGITAL_MODE);
 	/* init frontend */
 	switch (dev->model) {
@@ -590,15 +591,16 @@ static int dvb_init(struct em28xx *dev)
 	if (result < 0)
 		goto out_free;
 
-	em28xx_set_mode(dev, EM28XX_SUSPEND);
 	em28xx_info("Successfully loaded em28xx-dvb\n");
-	return 0;
+ret:
+	em28xx_set_mode(dev, EM28XX_SUSPEND);
+	mutex_unlock(&dev->lock);
+	return result;
 
 out_free:
-	em28xx_set_mode(dev, EM28XX_SUSPEND);
 	kfree(dvb);
 	dev->dvb = NULL;
-	return result;
+	goto ret;
 }
 
 static int dvb_fini(struct em28xx *dev)