[media] em28xx: Fix em28xx deplock

When em28xx extensions are loaded/removed, there are two locks:

a single static em28xx_devlist_mutex that registers each extension
and the struct em28xx dev->lock.

When extensions are registered, em28xx_devlist_mutex is taken first,
and then dev->lock.

Be sure that, when extensions are being removed, the same order
will be used.

Reviewed-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index 3012912d..f773017 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -1094,10 +1094,12 @@ void em28xx_close_extension(struct em28xx *dev)
 	const struct em28xx_ops *ops = NULL;
 
 	mutex_lock(&em28xx_devlist_mutex);
+	mutex_lock(&dev->lock);
 	list_for_each_entry(ops, &em28xx_extension_devlist, next) {
 		if (ops->fini)
 			ops->fini(dev);
 	}
+	mutex_unlock(&dev->lock);
 	list_del(&dev->devlist);
 	mutex_unlock(&em28xx_devlist_mutex);
 }