| Message ID | 20211003201355.24081-1-m.grzeschik@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RESEND,v4] usb: gadget: uvc: fix multiple opens | expand |
Hi Michael, Thank you for resending this. On Sun, Oct 03, 2021 at 10:13:55PM +0200, Michael Grzeschik wrote: > From: Thomas Haemmerle <thomas.haemmerle@wolfvision.net> > > Currently, the UVC function is activated when open on the corresponding > v4l2 device is called. > On another open the activation of the function fails since the > deactivation counter in `usb_function_activate` equals 0. However the > error is not returned to userspace since the open of the v4l2 device is > successful. > > On a close the function is deactivated (since deactivation counter still > equals 0) and the video is disabled in `uvc_v4l2_release`, although the > UVC application potentially is streaming. > > Move activation of UVC function to subscription on UVC_EVENT_SETUP > because there we can guarantee for a userspace application utilizing > UVC. > Block subscription on UVC_EVENT_SETUP while another application already > is subscribed to it, indicated by `bool func_connected` in > `struct uvc_device`. > Extend the `struct uvc_file_handle` with member `bool is_uvc_app_handle` > to tag it as the handle used by the userspace UVC application. Reflowing the paragraph would be nice (this could be done when applying the patch, or not at all). > With this a process is able to check capabilities of the v4l2 device > without deactivating the function for the actual UVC application. > > Reviewed-By: Michael Tretter <m.tretter@pengutronix.de> > Signed-off-by: Thomas Haemmerle <thomas.haemmerle@wolfvision.net> > Signed-off-by: Michael Tretter <m.tretter@pengutronix.de> > Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Felipe, please let me know if you want me to take this in my tree and issue a pull request, otherwise I'll assume you'll pick it up. > --- > v4: > - remove unnecessary inner parentheses > - keep and use the local video variable in `uvc_v4l2_release()` > > v3: > - replace `unsigned int connections` with `bool func_connected` > - rename `bool connected` to `bool is_uvc_app_handle` > > v2: > - fix deadlock in `uvc_v4l2_unsubscribe_event()` (mutex is already > locked in v4l2-core) introduced in v1 > - lock mutex in `uvc_v4l2_release()` to suppress ioctls and protect > connected > --- > drivers/usb/gadget/function/uvc.h | 2 ++ > drivers/usb/gadget/function/uvc_v4l2.c | 49 ++++++++++++++++++++++---- > 2 files changed, 44 insertions(+), 7 deletions(-) > > diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h > index 255a61bd6a6a8..9d5f17b551bbd 100644 > --- a/drivers/usb/gadget/function/uvc.h > +++ b/drivers/usb/gadget/function/uvc.h > @@ -126,6 +126,7 @@ struct uvc_device { > enum uvc_state state; > struct usb_function func; > struct uvc_video video; > + bool func_connected; > > /* Descriptors */ > struct { > @@ -156,6 +157,7 @@ static inline struct uvc_device *to_uvc(struct usb_function *f) > struct uvc_file_handle { > struct v4l2_fh vfh; > struct uvc_video *device; > + bool is_uvc_app_handle; > }; > > #define to_uvc_file_handle(handle) \ > diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c > index 4ca89eab61590..197c26f7aec63 100644 > --- a/drivers/usb/gadget/function/uvc_v4l2.c > +++ b/drivers/usb/gadget/function/uvc_v4l2.c > @@ -227,17 +227,55 @@ static int > uvc_v4l2_subscribe_event(struct v4l2_fh *fh, > const struct v4l2_event_subscription *sub) > { > + struct uvc_device *uvc = video_get_drvdata(fh->vdev); > + struct uvc_file_handle *handle = to_uvc_file_handle(fh); > + int ret; > + > if (sub->type < UVC_EVENT_FIRST || sub->type > UVC_EVENT_LAST) > return -EINVAL; > > - return v4l2_event_subscribe(fh, sub, 2, NULL); > + if (sub->type == UVC_EVENT_SETUP && uvc->func_connected) > + return -EBUSY; > + > + ret = v4l2_event_subscribe(fh, sub, 2, NULL); > + if (ret < 0) > + return ret; > + > + if (sub->type == UVC_EVENT_SETUP) { > + uvc->func_connected = true; > + handle->is_uvc_app_handle = true; > + uvc_function_connect(uvc); > + } > + > + return 0; > +} > + > +static void uvc_v4l2_disable(struct uvc_device *uvc) > +{ > + uvc->func_connected = false; > + uvc_function_disconnect(uvc); > + uvcg_video_enable(&uvc->video, 0); > + uvcg_free_buffers(&uvc->video.queue); > } > > static int > uvc_v4l2_unsubscribe_event(struct v4l2_fh *fh, > const struct v4l2_event_subscription *sub) > { > - return v4l2_event_unsubscribe(fh, sub); > + struct uvc_device *uvc = video_get_drvdata(fh->vdev); > + struct uvc_file_handle *handle = to_uvc_file_handle(fh); > + int ret; > + > + ret = v4l2_event_unsubscribe(fh, sub); > + if (ret < 0) > + return ret; > + > + if (sub->type == UVC_EVENT_SETUP && handle->is_uvc_app_handle) { > + uvc_v4l2_disable(uvc); > + handle->is_uvc_app_handle = false; > + } > + > + return 0; > } > > static long > @@ -292,7 +330,6 @@ uvc_v4l2_open(struct file *file) > handle->device = &uvc->video; > file->private_data = &handle->vfh; > > - uvc_function_connect(uvc); > return 0; > } > > @@ -304,11 +341,9 @@ uvc_v4l2_release(struct file *file) > struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data); > struct uvc_video *video = handle->device; > > - uvc_function_disconnect(uvc); > - > mutex_lock(&video->mutex); > - uvcg_video_enable(video, 0); > - uvcg_free_buffers(&video->queue); > + if (handle->is_uvc_app_handle) > + uvc_v4l2_disable(uvc); > mutex_unlock(&video->mutex); > > file->private_data = NULL;
On Tue, Oct 05, 2021 at 02:53:48AM +0300, Laurent Pinchart wrote: > Hi Michael, > > Thank you for resending this. > > On Sun, Oct 03, 2021 at 10:13:55PM +0200, Michael Grzeschik wrote: > > From: Thomas Haemmerle <thomas.haemmerle@wolfvision.net> > > > > Currently, the UVC function is activated when open on the corresponding > > v4l2 device is called. > > On another open the activation of the function fails since the > > deactivation counter in `usb_function_activate` equals 0. However the > > error is not returned to userspace since the open of the v4l2 device is > > successful. > > > > On a close the function is deactivated (since deactivation counter still > > equals 0) and the video is disabled in `uvc_v4l2_release`, although the > > UVC application potentially is streaming. > > > > Move activation of UVC function to subscription on UVC_EVENT_SETUP > > because there we can guarantee for a userspace application utilizing > > UVC. > > Block subscription on UVC_EVENT_SETUP while another application already > > is subscribed to it, indicated by `bool func_connected` in > > `struct uvc_device`. > > Extend the `struct uvc_file_handle` with member `bool is_uvc_app_handle` > > to tag it as the handle used by the userspace UVC application. > > Reflowing the paragraph would be nice (this could be done when applying > the patch, or not at all). > > > With this a process is able to check capabilities of the v4l2 device > > without deactivating the function for the actual UVC application. > > > > Reviewed-By: Michael Tretter <m.tretter@pengutronix.de> > > Signed-off-by: Thomas Haemmerle <thomas.haemmerle@wolfvision.net> > > Signed-off-by: Michael Tretter <m.tretter@pengutronix.de> > > Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> > > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > > Felipe, please let me know if you want me to take this in my tree and > issue a pull request, otherwise I'll assume you'll pick it up. I'll pick it up now, thanks. greg k-h
Greg KH <gregkh@linuxfoundation.org> writes: > On Tue, Oct 05, 2021 at 02:53:48AM +0300, Laurent Pinchart wrote: >> Hi Michael, >> >> Thank you for resending this. >> >> On Sun, Oct 03, 2021 at 10:13:55PM +0200, Michael Grzeschik wrote: >> > From: Thomas Haemmerle <thomas.haemmerle@wolfvision.net> >> > >> > Currently, the UVC function is activated when open on the corresponding >> > v4l2 device is called. >> > On another open the activation of the function fails since the >> > deactivation counter in `usb_function_activate` equals 0. However the >> > error is not returned to userspace since the open of the v4l2 device is >> > successful. >> > >> > On a close the function is deactivated (since deactivation counter still >> > equals 0) and the video is disabled in `uvc_v4l2_release`, although the >> > UVC application potentially is streaming. >> > >> > Move activation of UVC function to subscription on UVC_EVENT_SETUP >> > because there we can guarantee for a userspace application utilizing >> > UVC. >> > Block subscription on UVC_EVENT_SETUP while another application already >> > is subscribed to it, indicated by `bool func_connected` in >> > `struct uvc_device`. >> > Extend the `struct uvc_file_handle` with member `bool is_uvc_app_handle` >> > to tag it as the handle used by the userspace UVC application. >> >> Reflowing the paragraph would be nice (this could be done when applying >> the patch, or not at all). >> >> > With this a process is able to check capabilities of the v4l2 device >> > without deactivating the function for the actual UVC application. >> > >> > Reviewed-By: Michael Tretter <m.tretter@pengutronix.de> >> > Signed-off-by: Thomas Haemmerle <thomas.haemmerle@wolfvision.net> >> > Signed-off-by: Michael Tretter <m.tretter@pengutronix.de> >> > Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> >> >> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> >> >> Felipe, please let me know if you want me to take this in my tree and >> issue a pull request, otherwise I'll assume you'll pick it up. > > I'll pick it up now, thanks. I guess it's too late for an Ack. FWIW: Acked-by: Felipe Balbi <balbi@kernel.org>
On Tue, Oct 05, 2021 at 02:06:22PM +0300, Felipe Balbi wrote: > > Greg KH <gregkh@linuxfoundation.org> writes: > > > On Tue, Oct 05, 2021 at 02:53:48AM +0300, Laurent Pinchart wrote: > >> Hi Michael, > >> > >> Thank you for resending this. > >> > >> On Sun, Oct 03, 2021 at 10:13:55PM +0200, Michael Grzeschik wrote: > >> > From: Thomas Haemmerle <thomas.haemmerle@wolfvision.net> > >> > > >> > Currently, the UVC function is activated when open on the corresponding > >> > v4l2 device is called. > >> > On another open the activation of the function fails since the > >> > deactivation counter in `usb_function_activate` equals 0. However the > >> > error is not returned to userspace since the open of the v4l2 device is > >> > successful. > >> > > >> > On a close the function is deactivated (since deactivation counter still > >> > equals 0) and the video is disabled in `uvc_v4l2_release`, although the > >> > UVC application potentially is streaming. > >> > > >> > Move activation of UVC function to subscription on UVC_EVENT_SETUP > >> > because there we can guarantee for a userspace application utilizing > >> > UVC. > >> > Block subscription on UVC_EVENT_SETUP while another application already > >> > is subscribed to it, indicated by `bool func_connected` in > >> > `struct uvc_device`. > >> > Extend the `struct uvc_file_handle` with member `bool is_uvc_app_handle` > >> > to tag it as the handle used by the userspace UVC application. > >> > >> Reflowing the paragraph would be nice (this could be done when applying > >> the patch, or not at all). > >> > >> > With this a process is able to check capabilities of the v4l2 device > >> > without deactivating the function for the actual UVC application. > >> > > >> > Reviewed-By: Michael Tretter <m.tretter@pengutronix.de> > >> > Signed-off-by: Thomas Haemmerle <thomas.haemmerle@wolfvision.net> > >> > Signed-off-by: Michael Tretter <m.tretter@pengutronix.de> > >> > Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de> > >> > >> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > >> > >> Felipe, please let me know if you want me to take this in my tree and > >> issue a pull request, otherwise I'll assume you'll pick it up. > > > > I'll pick it up now, thanks. > > I guess it's too late for an Ack. FWIW: > > Acked-by: Felipe Balbi <balbi@kernel.org> Nope, not too late, just added, thanks! greg k-h
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index 255a61bd6a6a8..9d5f17b551bbd 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -126,6 +126,7 @@ struct uvc_device { enum uvc_state state; struct usb_function func; struct uvc_video video; + bool func_connected; /* Descriptors */ struct { @@ -156,6 +157,7 @@ static inline struct uvc_device *to_uvc(struct usb_function *f) struct uvc_file_handle { struct v4l2_fh vfh; struct uvc_video *device; + bool is_uvc_app_handle; }; #define to_uvc_file_handle(handle) \ diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c index 4ca89eab61590..197c26f7aec63 100644 --- a/drivers/usb/gadget/function/uvc_v4l2.c +++ b/drivers/usb/gadget/function/uvc_v4l2.c @@ -227,17 +227,55 @@ static int uvc_v4l2_subscribe_event(struct v4l2_fh *fh, const struct v4l2_event_subscription *sub) { + struct uvc_device *uvc = video_get_drvdata(fh->vdev); + struct uvc_file_handle *handle = to_uvc_file_handle(fh); + int ret; + if (sub->type < UVC_EVENT_FIRST || sub->type > UVC_EVENT_LAST) return -EINVAL; - return v4l2_event_subscribe(fh, sub, 2, NULL); + if (sub->type == UVC_EVENT_SETUP && uvc->func_connected) + return -EBUSY; + + ret = v4l2_event_subscribe(fh, sub, 2, NULL); + if (ret < 0) + return ret; + + if (sub->type == UVC_EVENT_SETUP) { + uvc->func_connected = true; + handle->is_uvc_app_handle = true; + uvc_function_connect(uvc); + } + + return 0; +} + +static void uvc_v4l2_disable(struct uvc_device *uvc) +{ + uvc->func_connected = false; + uvc_function_disconnect(uvc); + uvcg_video_enable(&uvc->video, 0); + uvcg_free_buffers(&uvc->video.queue); } static int uvc_v4l2_unsubscribe_event(struct v4l2_fh *fh, const struct v4l2_event_subscription *sub) { - return v4l2_event_unsubscribe(fh, sub); + struct uvc_device *uvc = video_get_drvdata(fh->vdev); + struct uvc_file_handle *handle = to_uvc_file_handle(fh); + int ret; + + ret = v4l2_event_unsubscribe(fh, sub); + if (ret < 0) + return ret; + + if (sub->type == UVC_EVENT_SETUP && handle->is_uvc_app_handle) { + uvc_v4l2_disable(uvc); + handle->is_uvc_app_handle = false; + } + + return 0; } static long @@ -292,7 +330,6 @@ uvc_v4l2_open(struct file *file) handle->device = &uvc->video; file->private_data = &handle->vfh; - uvc_function_connect(uvc); return 0; } @@ -304,11 +341,9 @@ uvc_v4l2_release(struct file *file) struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data); struct uvc_video *video = handle->device; - uvc_function_disconnect(uvc); - mutex_lock(&video->mutex); - uvcg_video_enable(video, 0); - uvcg_free_buffers(&video->queue); + if (handle->is_uvc_app_handle) + uvc_v4l2_disable(uvc); mutex_unlock(&video->mutex); file->private_data = NULL;