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Date: Fri, 27 Oct 2023 13:56:12 +0100
From: Dan Scally <dan.scally@...asonboard.com>
To: Avichal Rakesh <arakesh@...gle.com>, gregkh@...uxfoundation.org,
laurent.pinchart@...asonboard.com
Cc: etalvala@...gle.com, jchowdhary@...gle.com,
linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
m.grzeschik@...gutronix.de
Subject: Re: [PATCH v8 1/4] usb: gadget: uvc: prevent use of disabled endpoint
Hi Avichal
On 24/10/2023 19:36, Avichal Rakesh wrote:
> Currently the set_alt callback immediately disables the endpoint and queues
> the v4l2 streamoff event. However, as the streamoff event is processed
> asynchronously, it is possible that the video_pump thread attempts to queue
> requests to an already disabled endpoint.
>
> This change moves disabling usb endpoint to the end of streamoff event
> callback. As the endpoint's state can no longer be used, video_pump is
> now guarded by uvc->state as well. To be consistent with the actual
> streaming state, uvc->state is now toggled between CONNECTED and STREAMING
> from the v4l2 event callback only.
>
> Link: https://lore.kernel.org/20230615171558.GK741@pendragon.ideasonboard.com/
> Link: https://lore.kernel.org/20230531085544.253363-1-dan.scally@ideasonboard.com/
Thank you for picking this up! And I'm sorry to have been so remiss looking at your patches - I will
try to be more responsive to them. I spotted a typo below, but otherwise:
Reviewed-by: Daniel Scally <dan.scally@...asonboard.com>
> Reviewed-by: Michael Grzeschik <m.grzeschik@...gutronix.de>
> Tested-by: Michael Grzeschik <m.grzeschik@...gutronix.de>
> Signed-off-by: Avichal Rakesh <arakesh@...gle.com>
> ---
> v1 -> v2: Rebased to ToT and reworded commit message.
> v2 -> v3: Fix email threading goof-up
> v3 -> v4: Address review comments & re-rebase to ToT
> v4 -> v5: Add Reviewed-by & Tested-by
> v5 -> v6: No change
> v6 -> v7: No change
> v7 -> v8: No change. Getting back in review queue
>
> drivers/usb/gadget/function/f_uvc.c | 11 +++++------
> drivers/usb/gadget/function/f_uvc.h | 2 +-
> drivers/usb/gadget/function/uvc.h | 2 +-
> drivers/usb/gadget/function/uvc_v4l2.c | 20 +++++++++++++++++---
> drivers/usb/gadget/function/uvc_video.c | 3 ++-
> 5 files changed, 26 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
> index faa398109431..ae08341961eb 100644
> --- a/drivers/usb/gadget/function/f_uvc.c
> +++ b/drivers/usb/gadget/function/f_uvc.c
> @@ -263,10 +263,13 @@ uvc_function_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
> return 0;
> }
>
> -void uvc_function_setup_continue(struct uvc_device *uvc)
> +void uvc_function_setup_continue(struct uvc_device *uvc, int disable_ep)
> {
> struct usb_composite_dev *cdev = uvc->func.config->cdev;
>
> + if (disable_ep && uvc->video.ep)
> + usb_ep_disable(uvc->video.ep);
> +
> usb_composite_setup_continue(cdev);
> }
>
> @@ -337,15 +340,11 @@ uvc_function_set_alt(struct usb_function *f, unsigned interface, unsigned alt)
> if (uvc->state != UVC_STATE_STREAMING)
> return 0;
>
> - if (uvc->video.ep)
> - usb_ep_disable(uvc->video.ep);
> -
> memset(&v4l2_event, 0, sizeof(v4l2_event));
> v4l2_event.type = UVC_EVENT_STREAMOFF;
> v4l2_event_queue(&uvc->vdev, &v4l2_event);
>
> - uvc->state = UVC_STATE_CONNECTED;
> - return 0;
> + return USB_GADGET_DELAYED_STATUS;
>
> case 1:
> if (uvc->state != UVC_STATE_CONNECTED)
> diff --git a/drivers/usb/gadget/function/f_uvc.h b/drivers/usb/gadget/function/f_uvc.h
> index 1db972d4beeb..e7f9f13f14dc 100644
> --- a/drivers/usb/gadget/function/f_uvc.h
> +++ b/drivers/usb/gadget/function/f_uvc.h
> @@ -11,7 +11,7 @@
>
> struct uvc_device;
>
> -void uvc_function_setup_continue(struct uvc_device *uvc);
> +void uvc_function_setup_continue(struct uvc_device *uvc, int disale_ep);
s/disale_ep/disable_ep
>
> void uvc_function_connect(struct uvc_device *uvc);
>
> diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h
> index 6751de8b63ad..989bc6b4e93d 100644
> --- a/drivers/usb/gadget/function/uvc.h
> +++ b/drivers/usb/gadget/function/uvc.h
> @@ -177,7 +177,7 @@ struct uvc_file_handle {
> * Functions
> */
>
> -extern void uvc_function_setup_continue(struct uvc_device *uvc);
> +extern void uvc_function_setup_continue(struct uvc_device *uvc, int disable_ep);
> extern void uvc_function_connect(struct uvc_device *uvc);
> extern void uvc_function_disconnect(struct uvc_device *uvc);
>
> diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
> index 3f0a9795c0d4..7cb8d027ff0c 100644
> --- a/drivers/usb/gadget/function/uvc_v4l2.c
> +++ b/drivers/usb/gadget/function/uvc_v4l2.c
> @@ -451,7 +451,7 @@ uvc_v4l2_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
> * Complete the alternate setting selection setup phase now that
> * userspace is ready to provide video frames.
> */
> - uvc_function_setup_continue(uvc);
> + uvc_function_setup_continue(uvc, 0);
> uvc->state = UVC_STATE_STREAMING;
>
> return 0;
> @@ -463,11 +463,18 @@ uvc_v4l2_streamoff(struct file *file, void *fh, enum v4l2_buf_type type)
> struct video_device *vdev = video_devdata(file);
> struct uvc_device *uvc = video_get_drvdata(vdev);
> struct uvc_video *video = &uvc->video;
> + int ret = 0;
>
> if (type != video->queue.queue.type)
> return -EINVAL;
>
> - return uvcg_video_enable(video, 0);
> + uvc->state = UVC_STATE_CONNECTED;
> + ret = uvcg_video_enable(video, 0);
> + if (ret < 0)
> + return ret;
> +
> + uvc_function_setup_continue(uvc, 1);
> + return 0;
> }
>
> static int
> @@ -500,6 +507,14 @@ uvc_v4l2_subscribe_event(struct v4l2_fh *fh,
> static void uvc_v4l2_disable(struct uvc_device *uvc)
> {
> uvc_function_disconnect(uvc);
> + /*
> + * Drop uvc->state to CONNECTED if it was streaming before.
> + * This ensures that the usb_requests are no longer queued
> + * to the controller.
> + */
> + if (uvc->state == UVC_STATE_STREAMING)
> + uvc->state = UVC_STATE_CONNECTED;
> +
> uvcg_video_enable(&uvc->video, 0);
> uvcg_free_buffers(&uvc->video.queue);
> uvc->func_connected = false;
> @@ -647,4 +662,3 @@ const struct v4l2_file_operations uvc_v4l2_fops = {
> .get_unmapped_area = uvcg_v4l2_get_unmapped_area,
> #endif
> };
> -
> diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
> index 91af3b1ef0d4..c334802ac0a4 100644
> --- a/drivers/usb/gadget/function/uvc_video.c
> +++ b/drivers/usb/gadget/function/uvc_video.c
> @@ -384,13 +384,14 @@ static void uvcg_video_pump(struct work_struct *work)
> struct uvc_video_queue *queue = &video->queue;
> /* video->max_payload_size is only set when using bulk transfer */
> bool is_bulk = video->max_payload_size;
> + struct uvc_device *uvc = video->uvc;
> struct usb_request *req = NULL;
> struct uvc_buffer *buf;
> unsigned long flags;
> bool buf_done;
> int ret;
>
> - while (video->ep->enabled) {
> + while (uvc->state == UVC_STATE_STREAMING && video->ep->enabled) {
> /*
> * Retrieve the first available USB request, protected by the
> * request lock.
> --
> 2.42.0.758.gaed0368e0e-goog
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