On Tue, Jun 14, 2016 at 08:51:02PM +0200, Daniel Vetter wrote:
> Another place gone where modern drivers could have hit
> dev->struct_mutex.
>
> To avoid too deeply nesting control flow rework it a bit.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
> ---
> drivers/gpu/drm/drm_auth.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
> index e015a7edb154..a58b2eb0d004 100644
> --- a/drivers/gpu/drm/drm_auth.c
> +++ b/drivers/gpu/drm/drm_auth.c
> @@ -246,11 +246,14 @@ int drm_master_open(struct drm_file *file_priv)
> void drm_master_release(struct drm_file *file_priv)
> {
> struct drm_device *dev = file_priv->minor->dev;
> + struct drm_master *master = file_priv->master;
> +
Spare newline.
> mutex_lock(&dev->master_mutex);
> - if (file_priv->is_master) {
> - struct drm_master *master = file_priv->master;
> + if (!file_priv->is_master)
> + goto out_unlock;
>
> + if (!drm_core_check_feature(dev, DRIVER_MODESET)) {
> /*
> * Since the master is disappearing, so is the
> * possibility to lock.
> @@ -264,19 +267,20 @@ void drm_master_release(struct drm_file *file_priv)
> wake_up_interruptible_all(&master->lock.lock_queue);
> }
> mutex_unlock(&dev->struct_mutex);
> + }
>
> - if (file_priv->minor->master == file_priv->master) {
> - /* drop the reference held my the minor */
> - if (dev->driver->master_drop)
> - dev->driver->master_drop(dev, file_priv, true);
> - drm_master_put(&file_priv->minor->master);
> - }
> + if (file_priv->minor->master == file_priv->master) {
> + /* drop the reference held my the minor */
> + if (dev->driver->master_drop)
> + dev->driver->master_drop(dev, file_priv, true);
> + drm_master_put(&file_priv->minor->master);
> }
>
> /* drop the master reference held by the file priv */
> if (file_priv->master)
> drm_master_put(&file_priv->master);
> file_priv->is_master = 0;
> +out_unlock:
This changes the reference counting, and from my quick scan we can have
a reference on file_priv->master but file_priv->is_master == 0.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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