| Message ID | 20240614-guenter-mini-v6-2-7b7fdc3b21b3@chromium.org |
|---|---|
| State | New |
| Headers | show |
| Series | uvcvideo: Attempt N to land UVC race conditions fixes | expand |
Hi Ricardo, Thank you for the patch. On Fri, Jun 14, 2024 at 12:41:28PM +0000, Ricardo Ribalda wrote: > There are two different use-cases of uvc_status(): I'd add a blank line here, and remove the leading tabs from the next two lines. > - adding/removing a user when the camera is open/closed > - stopping/starting when the camera is suspended/resumed > > Make the API reflect these two use-cases and move all the refcounting > and locking logic to the uvc_status.c file. If my understanding is correct, this doesn't introduce any functional change, and is not a dependency of further patches in the series. I don't have a strong opinion on the refactoring itself, so I'm fine with it, but I'd like a mention in the commit message that no functional change is introduced. > Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org> > --- > drivers/media/usb/uvc/uvc_driver.c | 13 ++------- > drivers/media/usb/uvc/uvc_status.c | 55 ++++++++++++++++++++++++++++++++++++-- > drivers/media/usb/uvc/uvc_v4l2.c | 22 +++++---------- > drivers/media/usb/uvc/uvcvideo.h | 10 ++++--- > 4 files changed, 67 insertions(+), 33 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > index 55132688e363..c8c0352af1e5 100644 > --- a/drivers/media/usb/uvc/uvc_driver.c > +++ b/drivers/media/usb/uvc/uvc_driver.c > @@ -2135,7 +2135,6 @@ static int uvc_probe(struct usb_interface *intf, > INIT_LIST_HEAD(&dev->streams); > kref_init(&dev->ref); > atomic_set(&dev->nmappings, 0); > - mutex_init(&dev->lock); > > dev->udev = usb_get_dev(udev); > dev->intf = usb_get_intf(intf); > @@ -2301,10 +2300,7 @@ static int uvc_suspend(struct usb_interface *intf, pm_message_t message) > /* Controls are cached on the fly so they don't need to be saved. */ > if (intf->cur_altsetting->desc.bInterfaceSubClass == > UVC_SC_VIDEOCONTROL) { > - mutex_lock(&dev->lock); > - if (dev->users) > - uvc_status_stop(dev); > - mutex_unlock(&dev->lock); > + uvc_status_suspend(dev); > return 0; > } > > @@ -2335,12 +2331,7 @@ static int __uvc_resume(struct usb_interface *intf, int reset) > return ret; > } > > - mutex_lock(&dev->lock); > - if (dev->users) > - ret = uvc_status_start(dev, GFP_NOIO); > - mutex_unlock(&dev->lock); > - > - return ret; > + return uvc_status_resume(dev); > } > > list_for_each_entry(stream, &dev->streams, list) { > diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c > index a78a88c710e2..375a95dd3011 100644 > --- a/drivers/media/usb/uvc/uvc_status.c > +++ b/drivers/media/usb/uvc/uvc_status.c > @@ -257,6 +257,8 @@ int uvc_status_init(struct uvc_device *dev) > unsigned int pipe; > int interval; > > + mutex_init(&dev->status_lock); > + > if (ep == NULL) > return 0; > > @@ -302,18 +304,22 @@ void uvc_status_cleanup(struct uvc_device *dev) > kfree(dev->status); > } > > -int uvc_status_start(struct uvc_device *dev, gfp_t flags) > +static int __uvc_status_start(struct uvc_device *dev, gfp_t flags) Do we need a double underscore prefix here and for the stop() function ? > { > + lockdep_assert_held(&dev->status_lock); > + > if (dev->int_urb == NULL) > return 0; > > return usb_submit_urb(dev->int_urb, flags); > } > > -void uvc_status_stop(struct uvc_device *dev) > +static void __uvc_status_stop(struct uvc_device *dev) > { > struct uvc_ctrl_work *w = &dev->async_ctrl; > > + lockdep_assert_held(&dev->status_lock); > + > /* > * Prevent the asynchronous control handler from requeing the URB. The > * barrier is needed so the flush_status change is visible to other > @@ -350,3 +356,48 @@ void uvc_status_stop(struct uvc_device *dev) > */ > smp_store_release(&dev->flush_status, false); > } > + > +int uvc_status_resume(struct uvc_device *dev) > +{ > + int ret = 0; > + > + mutex_lock(&dev->status_lock); > + if (dev->status_users) > + ret = __uvc_status_start(dev, GFP_NOIO); > + mutex_unlock(&dev->status_lock); > + > + return ret; Now that we have scoped guards, this can be written as guard(mutex)(&dev->status_lock); if (!dev->status_users) return 0; return __uvc_status_start(dev, GFP_NOIO); > +} > + > +void uvc_status_suspend(struct uvc_device *dev) > +{ > + mutex_lock(&dev->status_lock); > + if (dev->status_users) > + __uvc_status_stop(dev); > + mutex_unlock(&dev->status_lock); guard(mutex)(&dev->status_lock); if (dev->status_users) __uvc_status_stop(dev); Same below. > +} > + > +int uvc_status_get(struct uvc_device *dev) > +{ > + int ret = 0; > + > + mutex_lock(&dev->status_lock); > + if (!dev->status_users) > + ret = __uvc_status_start(dev, GFP_KERNEL); > + if (!ret) > + dev->status_users++; > + mutex_unlock(&dev->status_lock); > + > + return ret; > +} > + > +void uvc_status_put(struct uvc_device *dev) > +{ > + mutex_lock(&dev->status_lock); > + if (dev->status_users == 1) > + __uvc_status_stop(dev); > + WARN_ON(!dev->status_users); Is this needed, or could we keep the original code ? if (--dev->status_users == 0) __uvc_status_stop(dev); All those comments are quite minor, the next version will have my R-b. > + if (dev->status_users) > + dev->status_users--; > + mutex_unlock(&dev->status_lock); > +} > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c > index f4988f03640a..97c5407f6603 100644 > --- a/drivers/media/usb/uvc/uvc_v4l2.c > +++ b/drivers/media/usb/uvc/uvc_v4l2.c > @@ -628,20 +628,13 @@ static int uvc_v4l2_open(struct file *file) > return -ENOMEM; > } > > - mutex_lock(&stream->dev->lock); > - if (stream->dev->users == 0) { > - ret = uvc_status_start(stream->dev, GFP_KERNEL); > - if (ret < 0) { > - mutex_unlock(&stream->dev->lock); > - usb_autopm_put_interface(stream->dev->intf); > - kfree(handle); > - return ret; > - } > + ret = uvc_status_get(stream->dev); > + if (ret) { > + usb_autopm_put_interface(stream->dev->intf); > + kfree(handle); > + return ret; > } > > - stream->dev->users++; > - mutex_unlock(&stream->dev->lock); > - > v4l2_fh_init(&handle->vfh, &stream->vdev); > v4l2_fh_add(&handle->vfh); > handle->chain = stream->chain; > @@ -670,10 +663,7 @@ static int uvc_v4l2_release(struct file *file) > kfree(handle); > file->private_data = NULL; > > - mutex_lock(&stream->dev->lock); > - if (--stream->dev->users == 0) > - uvc_status_stop(stream->dev); > - mutex_unlock(&stream->dev->lock); > + uvc_status_put(stream->dev); > > usb_autopm_put_interface(stream->dev->intf); > return 0; > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > index 6fb0a78b1b00..00b600eb058c 100644 > --- a/drivers/media/usb/uvc/uvcvideo.h > +++ b/drivers/media/usb/uvc/uvcvideo.h > @@ -555,8 +555,6 @@ struct uvc_device { > > const struct uvc_device_info *info; > > - struct mutex lock; /* Protects users */ > - unsigned int users; > atomic_t nmappings; > > /* Video control interface */ > @@ -578,6 +576,8 @@ struct uvc_device { > struct usb_host_endpoint *int_ep; > struct urb *int_urb; > struct uvc_status *status; > + struct mutex status_lock; /* Protects status_users */ > + unsigned int status_users; > bool flush_status; > > struct input_dev *input; > @@ -744,8 +744,10 @@ int uvc_register_video_device(struct uvc_device *dev, > int uvc_status_init(struct uvc_device *dev); > void uvc_status_unregister(struct uvc_device *dev); > void uvc_status_cleanup(struct uvc_device *dev); > -int uvc_status_start(struct uvc_device *dev, gfp_t flags); > -void uvc_status_stop(struct uvc_device *dev); > +int uvc_status_resume(struct uvc_device *dev); > +void uvc_status_suspend(struct uvc_device *dev); > +int uvc_status_get(struct uvc_device *dev); > +void uvc_status_put(struct uvc_device *dev); > > /* Controls */ > extern const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited;
On Wed, Sep 25, 2024 at 10:15:39PM +0300, Laurent Pinchart wrote: > Hi Ricardo, > > Thank you for the patch. > > On Fri, Jun 14, 2024 at 12:41:28PM +0000, Ricardo Ribalda wrote: > > There are two different use-cases of uvc_status(): > > I'd add a blank line here, and remove the leading tabs from the next two > lines. > > > - adding/removing a user when the camera is open/closed > > - stopping/starting when the camera is suspended/resumed > > > > Make the API reflect these two use-cases and move all the refcounting > > and locking logic to the uvc_status.c file. > > If my understanding is correct, this doesn't introduce any functional > change, and is not a dependency of further patches in the series. I > don't have a strong opinion on the refactoring itself, so I'm fine with > it, but I'd like a mention in the commit message that no functional > change is introduced. > > > Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> > > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org> > > --- > > drivers/media/usb/uvc/uvc_driver.c | 13 ++------- > > drivers/media/usb/uvc/uvc_status.c | 55 ++++++++++++++++++++++++++++++++++++-- > > drivers/media/usb/uvc/uvc_v4l2.c | 22 +++++---------- > > drivers/media/usb/uvc/uvcvideo.h | 10 ++++--- > > 4 files changed, 67 insertions(+), 33 deletions(-) > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > index 55132688e363..c8c0352af1e5 100644 > > --- a/drivers/media/usb/uvc/uvc_driver.c > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > @@ -2135,7 +2135,6 @@ static int uvc_probe(struct usb_interface *intf, > > INIT_LIST_HEAD(&dev->streams); > > kref_init(&dev->ref); > > atomic_set(&dev->nmappings, 0); > > - mutex_init(&dev->lock); > > > > dev->udev = usb_get_dev(udev); > > dev->intf = usb_get_intf(intf); > > @@ -2301,10 +2300,7 @@ static int uvc_suspend(struct usb_interface *intf, pm_message_t message) > > /* Controls are cached on the fly so they don't need to be saved. */ > > if (intf->cur_altsetting->desc.bInterfaceSubClass == > > UVC_SC_VIDEOCONTROL) { > > - mutex_lock(&dev->lock); > > - if (dev->users) > > - uvc_status_stop(dev); > > - mutex_unlock(&dev->lock); > > + uvc_status_suspend(dev); > > return 0; > > } > > > > @@ -2335,12 +2331,7 @@ static int __uvc_resume(struct usb_interface *intf, int reset) > > return ret; > > } > > > > - mutex_lock(&dev->lock); > > - if (dev->users) > > - ret = uvc_status_start(dev, GFP_NOIO); > > - mutex_unlock(&dev->lock); > > - > > - return ret; > > + return uvc_status_resume(dev); > > } > > > > list_for_each_entry(stream, &dev->streams, list) { > > diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c > > index a78a88c710e2..375a95dd3011 100644 > > --- a/drivers/media/usb/uvc/uvc_status.c > > +++ b/drivers/media/usb/uvc/uvc_status.c > > @@ -257,6 +257,8 @@ int uvc_status_init(struct uvc_device *dev) > > unsigned int pipe; > > int interval; > > > > + mutex_init(&dev->status_lock); > > + > > if (ep == NULL) > > return 0; > > > > @@ -302,18 +304,22 @@ void uvc_status_cleanup(struct uvc_device *dev) > > kfree(dev->status); > > } > > > > -int uvc_status_start(struct uvc_device *dev, gfp_t flags) > > +static int __uvc_status_start(struct uvc_device *dev, gfp_t flags) > > Do we need a double underscore prefix here and for the stop() function ? The uvc_status_start() function is also referenced in comments in this file. If you keep the double undescore prefix they need to be renamed. > > { > > + lockdep_assert_held(&dev->status_lock); > > + > > if (dev->int_urb == NULL) > > return 0; > > > > return usb_submit_urb(dev->int_urb, flags); > > } > > > > -void uvc_status_stop(struct uvc_device *dev) > > +static void __uvc_status_stop(struct uvc_device *dev) > > { > > struct uvc_ctrl_work *w = &dev->async_ctrl; > > > > + lockdep_assert_held(&dev->status_lock); > > + > > /* > > * Prevent the asynchronous control handler from requeing the URB. The > > * barrier is needed so the flush_status change is visible to other > > @@ -350,3 +356,48 @@ void uvc_status_stop(struct uvc_device *dev) > > */ > > smp_store_release(&dev->flush_status, false); > > } > > + > > +int uvc_status_resume(struct uvc_device *dev) > > +{ > > + int ret = 0; > > + > > + mutex_lock(&dev->status_lock); > > + if (dev->status_users) > > + ret = __uvc_status_start(dev, GFP_NOIO); > > + mutex_unlock(&dev->status_lock); > > + > > + return ret; > > Now that we have scoped guards, this can be written as > > guard(mutex)(&dev->status_lock); > > if (!dev->status_users) > return 0; > > return __uvc_status_start(dev, GFP_NOIO); > > > +} > > + > > +void uvc_status_suspend(struct uvc_device *dev) > > +{ > > + mutex_lock(&dev->status_lock); > > + if (dev->status_users) > > + __uvc_status_stop(dev); > > + mutex_unlock(&dev->status_lock); > > guard(mutex)(&dev->status_lock); > > if (dev->status_users) > __uvc_status_stop(dev); > > Same below. > > > +} > > + > > +int uvc_status_get(struct uvc_device *dev) > > +{ > > + int ret = 0; > > + > > + mutex_lock(&dev->status_lock); > > + if (!dev->status_users) > > + ret = __uvc_status_start(dev, GFP_KERNEL); > > + if (!ret) > > + dev->status_users++; > > + mutex_unlock(&dev->status_lock); > > + > > + return ret; > > +} > > + > > +void uvc_status_put(struct uvc_device *dev) > > +{ > > + mutex_lock(&dev->status_lock); > > + if (dev->status_users == 1) > > + __uvc_status_stop(dev); > > + WARN_ON(!dev->status_users); > > Is this needed, or could we keep the original code ? > > if (--dev->status_users == 0) > __uvc_status_stop(dev); > > All those comments are quite minor, the next version will have my R-b. > > > + if (dev->status_users) > > + dev->status_users--; > > + mutex_unlock(&dev->status_lock); > > +} > > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c > > index f4988f03640a..97c5407f6603 100644 > > --- a/drivers/media/usb/uvc/uvc_v4l2.c > > +++ b/drivers/media/usb/uvc/uvc_v4l2.c > > @@ -628,20 +628,13 @@ static int uvc_v4l2_open(struct file *file) > > return -ENOMEM; > > } > > > > - mutex_lock(&stream->dev->lock); > > - if (stream->dev->users == 0) { > > - ret = uvc_status_start(stream->dev, GFP_KERNEL); > > - if (ret < 0) { > > - mutex_unlock(&stream->dev->lock); > > - usb_autopm_put_interface(stream->dev->intf); > > - kfree(handle); > > - return ret; > > - } > > + ret = uvc_status_get(stream->dev); > > + if (ret) { > > + usb_autopm_put_interface(stream->dev->intf); > > + kfree(handle); > > + return ret; > > } > > > > - stream->dev->users++; > > - mutex_unlock(&stream->dev->lock); > > - > > v4l2_fh_init(&handle->vfh, &stream->vdev); > > v4l2_fh_add(&handle->vfh); > > handle->chain = stream->chain; > > @@ -670,10 +663,7 @@ static int uvc_v4l2_release(struct file *file) > > kfree(handle); > > file->private_data = NULL; > > > > - mutex_lock(&stream->dev->lock); > > - if (--stream->dev->users == 0) > > - uvc_status_stop(stream->dev); > > - mutex_unlock(&stream->dev->lock); > > + uvc_status_put(stream->dev); > > > > usb_autopm_put_interface(stream->dev->intf); > > return 0; > > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > > index 6fb0a78b1b00..00b600eb058c 100644 > > --- a/drivers/media/usb/uvc/uvcvideo.h > > +++ b/drivers/media/usb/uvc/uvcvideo.h > > @@ -555,8 +555,6 @@ struct uvc_device { > > > > const struct uvc_device_info *info; > > > > - struct mutex lock; /* Protects users */ > > - unsigned int users; > > atomic_t nmappings; > > > > /* Video control interface */ > > @@ -578,6 +576,8 @@ struct uvc_device { > > struct usb_host_endpoint *int_ep; > > struct urb *int_urb; > > struct uvc_status *status; > > + struct mutex status_lock; /* Protects status_users */ > > + unsigned int status_users; > > bool flush_status; > > > > struct input_dev *input; > > @@ -744,8 +744,10 @@ int uvc_register_video_device(struct uvc_device *dev, > > int uvc_status_init(struct uvc_device *dev); > > void uvc_status_unregister(struct uvc_device *dev); > > void uvc_status_cleanup(struct uvc_device *dev); > > -int uvc_status_start(struct uvc_device *dev, gfp_t flags); > > -void uvc_status_stop(struct uvc_device *dev); > > +int uvc_status_resume(struct uvc_device *dev); > > +void uvc_status_suspend(struct uvc_device *dev); > > +int uvc_status_get(struct uvc_device *dev); > > +void uvc_status_put(struct uvc_device *dev); > > > > /* Controls */ > > extern const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited;
Hi Laurent On Wed, 25 Sept 2024 at 21:15, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > > Hi Ricardo, > > Thank you for the patch. > > On Fri, Jun 14, 2024 at 12:41:28PM +0000, Ricardo Ribalda wrote: > > There are two different use-cases of uvc_status(): > > I'd add a blank line here, and remove the leading tabs from the next two > lines. > > > - adding/removing a user when the camera is open/closed > > - stopping/starting when the camera is suspended/resumed > > > > Make the API reflect these two use-cases and move all the refcounting > > and locking logic to the uvc_status.c file. > > If my understanding is correct, this doesn't introduce any functional > change, and is not a dependency of further patches in the series. I > don't have a strong opinion on the refactoring itself, so I'm fine with > it, but I'd like a mention in the commit message that no functional > change is introduced. > > > Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> > > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org> > > --- > > drivers/media/usb/uvc/uvc_driver.c | 13 ++------- > > drivers/media/usb/uvc/uvc_status.c | 55 ++++++++++++++++++++++++++++++++++++-- > > drivers/media/usb/uvc/uvc_v4l2.c | 22 +++++---------- > > drivers/media/usb/uvc/uvcvideo.h | 10 ++++--- > > 4 files changed, 67 insertions(+), 33 deletions(-) > > > > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c > > index 55132688e363..c8c0352af1e5 100644 > > --- a/drivers/media/usb/uvc/uvc_driver.c > > +++ b/drivers/media/usb/uvc/uvc_driver.c > > @@ -2135,7 +2135,6 @@ static int uvc_probe(struct usb_interface *intf, > > INIT_LIST_HEAD(&dev->streams); > > kref_init(&dev->ref); > > atomic_set(&dev->nmappings, 0); > > - mutex_init(&dev->lock); > > > > dev->udev = usb_get_dev(udev); > > dev->intf = usb_get_intf(intf); > > @@ -2301,10 +2300,7 @@ static int uvc_suspend(struct usb_interface *intf, pm_message_t message) > > /* Controls are cached on the fly so they don't need to be saved. */ > > if (intf->cur_altsetting->desc.bInterfaceSubClass == > > UVC_SC_VIDEOCONTROL) { > > - mutex_lock(&dev->lock); > > - if (dev->users) > > - uvc_status_stop(dev); > > - mutex_unlock(&dev->lock); > > + uvc_status_suspend(dev); > > return 0; > > } > > > > @@ -2335,12 +2331,7 @@ static int __uvc_resume(struct usb_interface *intf, int reset) > > return ret; > > } > > > > - mutex_lock(&dev->lock); > > - if (dev->users) > > - ret = uvc_status_start(dev, GFP_NOIO); > > - mutex_unlock(&dev->lock); > > - > > - return ret; > > + return uvc_status_resume(dev); > > } > > > > list_for_each_entry(stream, &dev->streams, list) { > > diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c > > index a78a88c710e2..375a95dd3011 100644 > > --- a/drivers/media/usb/uvc/uvc_status.c > > +++ b/drivers/media/usb/uvc/uvc_status.c > > @@ -257,6 +257,8 @@ int uvc_status_init(struct uvc_device *dev) > > unsigned int pipe; > > int interval; > > > > + mutex_init(&dev->status_lock); > > + > > if (ep == NULL) > > return 0; > > > > @@ -302,18 +304,22 @@ void uvc_status_cleanup(struct uvc_device *dev) > > kfree(dev->status); > > } > > > > -int uvc_status_start(struct uvc_device *dev, gfp_t flags) > > +static int __uvc_status_start(struct uvc_device *dev, gfp_t flags) > > Do we need a double underscore prefix here and for the stop() function ? > > > { > > + lockdep_assert_held(&dev->status_lock); > > + > > if (dev->int_urb == NULL) > > return 0; > > > > return usb_submit_urb(dev->int_urb, flags); > > } > > > > -void uvc_status_stop(struct uvc_device *dev) > > +static void __uvc_status_stop(struct uvc_device *dev) > > { > > struct uvc_ctrl_work *w = &dev->async_ctrl; > > > > + lockdep_assert_held(&dev->status_lock); > > + > > /* > > * Prevent the asynchronous control handler from requeing the URB. The > > * barrier is needed so the flush_status change is visible to other > > @@ -350,3 +356,48 @@ void uvc_status_stop(struct uvc_device *dev) > > */ > > smp_store_release(&dev->flush_status, false); > > } > > + > > +int uvc_status_resume(struct uvc_device *dev) > > +{ > > + int ret = 0; > > + > > + mutex_lock(&dev->status_lock); > > + if (dev->status_users) > > + ret = __uvc_status_start(dev, GFP_NOIO); > > + mutex_unlock(&dev->status_lock); > > + > > + return ret; > > Now that we have scoped guards, this can be written as > > guard(mutex)(&dev->status_lock); > > if (!dev->status_users) > return 0; > > return __uvc_status_start(dev, GFP_NOIO); > > > +} > > + > > +void uvc_status_suspend(struct uvc_device *dev) > > +{ > > + mutex_lock(&dev->status_lock); > > + if (dev->status_users) > > + __uvc_status_stop(dev); > > + mutex_unlock(&dev->status_lock); > > guard(mutex)(&dev->status_lock); > > if (dev->status_users) > __uvc_status_stop(dev); > > Same below. > > > +} > > + > > +int uvc_status_get(struct uvc_device *dev) > > +{ > > + int ret = 0; > > + > > + mutex_lock(&dev->status_lock); > > + if (!dev->status_users) > > + ret = __uvc_status_start(dev, GFP_KERNEL); > > + if (!ret) > > + dev->status_users++; > > + mutex_unlock(&dev->status_lock); > > + > > + return ret; > > +} > > + > > +void uvc_status_put(struct uvc_device *dev) > > +{ > > + mutex_lock(&dev->status_lock); > > + if (dev->status_users == 1) > > + __uvc_status_stop(dev); > > + WARN_ON(!dev->status_users); > > Is this needed, or could we keep the original code ? > > if (--dev->status_users == 0) > __uvc_status_stop(dev); I'd prefer to keep the code. When I was playing with the granular PM it was very nice to display a WARN and make sure that status_users was never underflowed. > > All those comments are quite minor, the next version will have my R-b. > > > + if (dev->status_users) > > + dev->status_users--; > > + mutex_unlock(&dev->status_lock); > > +} > > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c > > index f4988f03640a..97c5407f6603 100644 > > --- a/drivers/media/usb/uvc/uvc_v4l2.c > > +++ b/drivers/media/usb/uvc/uvc_v4l2.c > > @@ -628,20 +628,13 @@ static int uvc_v4l2_open(struct file *file) > > return -ENOMEM; > > } > > > > - mutex_lock(&stream->dev->lock); > > - if (stream->dev->users == 0) { > > - ret = uvc_status_start(stream->dev, GFP_KERNEL); > > - if (ret < 0) { > > - mutex_unlock(&stream->dev->lock); > > - usb_autopm_put_interface(stream->dev->intf); > > - kfree(handle); > > - return ret; > > - } > > + ret = uvc_status_get(stream->dev); > > + if (ret) { > > + usb_autopm_put_interface(stream->dev->intf); > > + kfree(handle); > > + return ret; > > } > > > > - stream->dev->users++; > > - mutex_unlock(&stream->dev->lock); > > - > > v4l2_fh_init(&handle->vfh, &stream->vdev); > > v4l2_fh_add(&handle->vfh); > > handle->chain = stream->chain; > > @@ -670,10 +663,7 @@ static int uvc_v4l2_release(struct file *file) > > kfree(handle); > > file->private_data = NULL; > > > > - mutex_lock(&stream->dev->lock); > > - if (--stream->dev->users == 0) > > - uvc_status_stop(stream->dev); > > - mutex_unlock(&stream->dev->lock); > > + uvc_status_put(stream->dev); > > > > usb_autopm_put_interface(stream->dev->intf); > > return 0; > > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h > > index 6fb0a78b1b00..00b600eb058c 100644 > > --- a/drivers/media/usb/uvc/uvcvideo.h > > +++ b/drivers/media/usb/uvc/uvcvideo.h > > @@ -555,8 +555,6 @@ struct uvc_device { > > > > const struct uvc_device_info *info; > > > > - struct mutex lock; /* Protects users */ > > - unsigned int users; > > atomic_t nmappings; > > > > /* Video control interface */ > > @@ -578,6 +576,8 @@ struct uvc_device { > > struct usb_host_endpoint *int_ep; > > struct urb *int_urb; > > struct uvc_status *status; > > + struct mutex status_lock; /* Protects status_users */ > > + unsigned int status_users; > > bool flush_status; > > > > struct input_dev *input; > > @@ -744,8 +744,10 @@ int uvc_register_video_device(struct uvc_device *dev, > > int uvc_status_init(struct uvc_device *dev); > > void uvc_status_unregister(struct uvc_device *dev); > > void uvc_status_cleanup(struct uvc_device *dev); > > -int uvc_status_start(struct uvc_device *dev, gfp_t flags); > > -void uvc_status_stop(struct uvc_device *dev); > > +int uvc_status_resume(struct uvc_device *dev); > > +void uvc_status_suspend(struct uvc_device *dev); > > +int uvc_status_get(struct uvc_device *dev); > > +void uvc_status_put(struct uvc_device *dev); > > > > /* Controls */ > > extern const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited; > > -- > Regards, > > Laurent Pinchart
diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index 55132688e363..c8c0352af1e5 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -2135,7 +2135,6 @@ static int uvc_probe(struct usb_interface *intf, INIT_LIST_HEAD(&dev->streams); kref_init(&dev->ref); atomic_set(&dev->nmappings, 0); - mutex_init(&dev->lock); dev->udev = usb_get_dev(udev); dev->intf = usb_get_intf(intf); @@ -2301,10 +2300,7 @@ static int uvc_suspend(struct usb_interface *intf, pm_message_t message) /* Controls are cached on the fly so they don't need to be saved. */ if (intf->cur_altsetting->desc.bInterfaceSubClass == UVC_SC_VIDEOCONTROL) { - mutex_lock(&dev->lock); - if (dev->users) - uvc_status_stop(dev); - mutex_unlock(&dev->lock); + uvc_status_suspend(dev); return 0; } @@ -2335,12 +2331,7 @@ static int __uvc_resume(struct usb_interface *intf, int reset) return ret; } - mutex_lock(&dev->lock); - if (dev->users) - ret = uvc_status_start(dev, GFP_NOIO); - mutex_unlock(&dev->lock); - - return ret; + return uvc_status_resume(dev); } list_for_each_entry(stream, &dev->streams, list) { diff --git a/drivers/media/usb/uvc/uvc_status.c b/drivers/media/usb/uvc/uvc_status.c index a78a88c710e2..375a95dd3011 100644 --- a/drivers/media/usb/uvc/uvc_status.c +++ b/drivers/media/usb/uvc/uvc_status.c @@ -257,6 +257,8 @@ int uvc_status_init(struct uvc_device *dev) unsigned int pipe; int interval; + mutex_init(&dev->status_lock); + if (ep == NULL) return 0; @@ -302,18 +304,22 @@ void uvc_status_cleanup(struct uvc_device *dev) kfree(dev->status); } -int uvc_status_start(struct uvc_device *dev, gfp_t flags) +static int __uvc_status_start(struct uvc_device *dev, gfp_t flags) { + lockdep_assert_held(&dev->status_lock); + if (dev->int_urb == NULL) return 0; return usb_submit_urb(dev->int_urb, flags); } -void uvc_status_stop(struct uvc_device *dev) +static void __uvc_status_stop(struct uvc_device *dev) { struct uvc_ctrl_work *w = &dev->async_ctrl; + lockdep_assert_held(&dev->status_lock); + /* * Prevent the asynchronous control handler from requeing the URB. The * barrier is needed so the flush_status change is visible to other @@ -350,3 +356,48 @@ void uvc_status_stop(struct uvc_device *dev) */ smp_store_release(&dev->flush_status, false); } + +int uvc_status_resume(struct uvc_device *dev) +{ + int ret = 0; + + mutex_lock(&dev->status_lock); + if (dev->status_users) + ret = __uvc_status_start(dev, GFP_NOIO); + mutex_unlock(&dev->status_lock); + + return ret; +} + +void uvc_status_suspend(struct uvc_device *dev) +{ + mutex_lock(&dev->status_lock); + if (dev->status_users) + __uvc_status_stop(dev); + mutex_unlock(&dev->status_lock); +} + +int uvc_status_get(struct uvc_device *dev) +{ + int ret = 0; + + mutex_lock(&dev->status_lock); + if (!dev->status_users) + ret = __uvc_status_start(dev, GFP_KERNEL); + if (!ret) + dev->status_users++; + mutex_unlock(&dev->status_lock); + + return ret; +} + +void uvc_status_put(struct uvc_device *dev) +{ + mutex_lock(&dev->status_lock); + if (dev->status_users == 1) + __uvc_status_stop(dev); + WARN_ON(!dev->status_users); + if (dev->status_users) + dev->status_users--; + mutex_unlock(&dev->status_lock); +} diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c index f4988f03640a..97c5407f6603 100644 --- a/drivers/media/usb/uvc/uvc_v4l2.c +++ b/drivers/media/usb/uvc/uvc_v4l2.c @@ -628,20 +628,13 @@ static int uvc_v4l2_open(struct file *file) return -ENOMEM; } - mutex_lock(&stream->dev->lock); - if (stream->dev->users == 0) { - ret = uvc_status_start(stream->dev, GFP_KERNEL); - if (ret < 0) { - mutex_unlock(&stream->dev->lock); - usb_autopm_put_interface(stream->dev->intf); - kfree(handle); - return ret; - } + ret = uvc_status_get(stream->dev); + if (ret) { + usb_autopm_put_interface(stream->dev->intf); + kfree(handle); + return ret; } - stream->dev->users++; - mutex_unlock(&stream->dev->lock); - v4l2_fh_init(&handle->vfh, &stream->vdev); v4l2_fh_add(&handle->vfh); handle->chain = stream->chain; @@ -670,10 +663,7 @@ static int uvc_v4l2_release(struct file *file) kfree(handle); file->private_data = NULL; - mutex_lock(&stream->dev->lock); - if (--stream->dev->users == 0) - uvc_status_stop(stream->dev); - mutex_unlock(&stream->dev->lock); + uvc_status_put(stream->dev); usb_autopm_put_interface(stream->dev->intf); return 0; diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h index 6fb0a78b1b00..00b600eb058c 100644 --- a/drivers/media/usb/uvc/uvcvideo.h +++ b/drivers/media/usb/uvc/uvcvideo.h @@ -555,8 +555,6 @@ struct uvc_device { const struct uvc_device_info *info; - struct mutex lock; /* Protects users */ - unsigned int users; atomic_t nmappings; /* Video control interface */ @@ -578,6 +576,8 @@ struct uvc_device { struct usb_host_endpoint *int_ep; struct urb *int_urb; struct uvc_status *status; + struct mutex status_lock; /* Protects status_users */ + unsigned int status_users; bool flush_status; struct input_dev *input; @@ -744,8 +744,10 @@ int uvc_register_video_device(struct uvc_device *dev, int uvc_status_init(struct uvc_device *dev); void uvc_status_unregister(struct uvc_device *dev); void uvc_status_cleanup(struct uvc_device *dev); -int uvc_status_start(struct uvc_device *dev, gfp_t flags); -void uvc_status_stop(struct uvc_device *dev); +int uvc_status_resume(struct uvc_device *dev); +void uvc_status_suspend(struct uvc_device *dev); +int uvc_status_get(struct uvc_device *dev); +void uvc_status_put(struct uvc_device *dev); /* Controls */ extern const struct uvc_control_mapping uvc_ctrl_power_line_mapping_limited;