usb: gadget: uvc: prevent use of disabled endpoint

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/
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Tested-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Avichal Rakesh <arakesh@google.com>
Link: https://lore.kernel.org/r/20231109004104.3467968-1-arakesh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 786379f1b7b72457a6bc9e303e47b7f62c6eecae..77999ed53d33e3298fc5ea7c4f7d7f814b9e6d84 100644 (file)
--- 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 1db972d4beebe13875974a9708f41ae8d29ecd12..083aef0c65c6a6edcf12f4398c78d004978e9ab8 100644 (file)
--- 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 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 6751de8b63ad9437bbaa08ad47412048e8e79b29..989bc6b4e93d36ab4d7ab691855fc18cbbb33d5b 100644 (file)
--- 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 3f0a9795c0d45d150f2371f77554f558e23b812b..7cb8d027ff0c359b9fe3edbe0aede1b8dd23b303 100644 (file)
--- 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 91af3b1ef0d412e9d71720afb38f24a703ec4e6e..c334802ac0a43f332a20b5aacf116bc45fecfc08 100644 (file)
--- 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.