[PATCH 4.19 175/243] media: uvcvideo: Abstract streaming object lifetime

Greg Kroah-Hartman
2019-12-11T15:23:25Z

From: Kieran Bingham <kieran.bingham@ideasonboard.com>

[ Upstream commit ece41454c6a5ed8f301ef1c37710ab222e577823 ]

The streaming object is a key part of handling the UVC device. Although
not critical, we are currently missing a call to destroy the mutex on
clean up paths, and we are due to extend the objects complexity in the
near future.

Facilitate easy management of a stream object by creating a pair of
functions to handle creating and destroying the allocation. The new
uvc_stream_delete() function also performs the missing mutex_destroy()
operation.

Previously a failed streaming object allocation would cause
uvc_parse_streaming() to return -EINVAL, which is inappropriate. If the
constructor failes, we will instead return -ENOMEM.

While we're here, fix the trivial spelling error in the function banner
of uvc_delete().

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/usb/uvc/uvc_driver.c | 54 +++++++++++++++++++++---------
1 file changed, 38 insertions(+), 16 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
index cf4feff2a48c1..063e229ead5ef 100644
--- a/drivers/media/usb/uvc/uvc_driver.c
+++ b/drivers/media/usb/uvc/uvc_driver.c
@@ -390,6 +390,39 @@ static struct uvc_streaming *uvc_stream_by_id(struct uvc_device *dev, int id)
return NULL;
}

+/* ------------------------------------------------------------------------
+ * Streaming Object Management
+ */
+
+static void uvc_stream_delete(struct uvc_streaming *stream)
+{
+ mutex_destroy(&stream->mutex);
+
+ usb_put_intf(stream->intf);
+
+ kfree(stream->format);
+ kfree(stream->header.bmaControls);
+ kfree(stream);
+}
+
+static struct uvc_streaming *uvc_stream_new(struct uvc_device *dev,
+ struct usb_interface *intf)
+{
+ struct uvc_streaming *stream;
+
+ stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+ if (stream == NULL)
+ return NULL;
+
+ mutex_init(&stream->mutex);
+
+ stream->dev = dev;
+ stream->intf = usb_get_intf(intf);
+ stream->intfnum = intf->cur_altsetting->desc.bInterfaceNumber;
+
+ return stream;
+}
+
/* ------------------------------------------------------------------------
* Descriptors parsing
*/
@@ -682,17 +715,12 @@ static int uvc_parse_streaming(struct uvc_device *dev,
return -EINVAL;
}

- streaming = kzalloc(sizeof(*streaming), GFP_KERNEL);
+ streaming = uvc_stream_new(dev, intf);
if (streaming == NULL) {
usb_driver_release_interface(&uvc_driver.driver, intf);
- return -EINVAL;
+ return -ENOMEM;
}

- mutex_init(&streaming->mutex);
- streaming->dev = dev;
- streaming->intf = usb_get_intf(intf);
- streaming->intfnum = intf->cur_altsetting->desc.bInterfaceNumber;
-
/* The Pico iMage webcam has its class-specific interface descriptors
* after the endpoint descriptors.
*/
@@ -899,10 +927,7 @@ static int uvc_parse_streaming(struct uvc_device *dev,

error:
usb_driver_release_interface(&uvc_driver.driver, intf);
- usb_put_intf(intf);
- kfree(streaming->format);
- kfree(streaming->header.bmaControls);
- kfree(streaming);
+ uvc_stream_delete(streaming);
return ret;
}

@@ -1818,7 +1843,7 @@ static int uvc_scan_device(struct uvc_device *dev)
* is released.
*
* As this function is called after or during disconnect(), all URBs have
- * already been canceled by the USB core. There is no need to kill the
+ * already been cancelled by the USB core. There is no need to kill the
* interrupt URB manually.
*/
static void uvc_delete(struct kref *kref)
@@ -1856,10 +1881,7 @@ static void uvc_delete(struct kref *kref)
streaming = list_entry(p, struct uvc_streaming, list);
usb_driver_release_interface(&uvc_driver.driver,
streaming->intf);
- usb_put_intf(streaming->intf);
- kfree(streaming->format);
- kfree(streaming->header.bmaControls);
- kfree(streaming);
+ uvc_stream_delete(streaming);
}

kfree(dev);
--
2.20.1