Reviewed-by: Thomas Hellstrom <thellstrom at vmware.com>
On 10/29/2012 06:35 PM, Ilija Hadzic wrote:
> Some drivers (specifically vmwgfx) look at dev_mapping
> in their open hook, so we have to set dev->dev_mapping
> earlier in the process.
>
> Reference:
> http://lists.freedesktop.org/archives/dri-devel/2012-October/029420.html
>
> Signed-off-by: Ilija Hadzic <ihadzic at research.bell-labs.com>
> Reported-by: Thomas Hellstrom <thellstrom at vmware.com>
> Cc: stable at vger.kernel.org
> ---
> drivers/gpu/drm/drm_fops.c | 47
> +++++++++++++++++++++++++++++-----------------
> 1 file changed, 30 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
> index af68eca..133b413 100644
> --- a/drivers/gpu/drm/drm_fops.c
> +++ b/drivers/gpu/drm/drm_fops.c
> @@ -121,6 +121,8 @@ int drm_open(struct inode *inode, struct file *filp)
> int minor_id = iminor(inode);
> struct drm_minor *minor;
> int retcode = 0;
> + int need_setup = 0;
> + struct address_space *old_mapping;
>
> minor = idr_find(&drm_minors_idr, minor_id);
> if (!minor)
> @@ -132,26 +134,37 @@ int drm_open(struct inode *inode, struct file *filp)
> if (drm_device_is_unplugged(dev))
> return -ENODEV;
>
> + if (!dev->open_count++)
> + need_setup = 1;
> + mutex_lock(&dev->struct_mutex);
> + old_mapping = dev->dev_mapping;
> + if (old_mapping == NULL)
> + dev->dev_mapping = &inode->i_data;
> + /* ihold ensures nobody can remove inode with our i_data */
> + ihold(container_of(dev->dev_mapping, struct inode, i_data));
> + inode->i_mapping = dev->dev_mapping;
> + filp->f_mapping = dev->dev_mapping;
> + mutex_unlock(&dev->struct_mutex);
> +
> retcode = drm_open_helper(inode, filp, dev);
> - if (!retcode) {
> - atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
> - if (!dev->open_count++) {
> - retcode = drm_setup(dev);
> - if (retcode)
> - dev->open_count--;
> - }
> - }
> - if (!retcode) {
> - mutex_lock(&dev->struct_mutex);
> - if (dev->dev_mapping == NULL)
> - dev->dev_mapping = &inode->i_data;
> - /* ihold ensures nobody can remove inode with our i_data */
> - ihold(container_of(dev->dev_mapping, struct inode, i_data));
> - inode->i_mapping = dev->dev_mapping;
> - filp->f_mapping = dev->dev_mapping;
> - mutex_unlock(&dev->struct_mutex);
> + if (retcode)
> + goto err_undo;
> + atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
> + if (need_setup) {
> + retcode = drm_setup(dev);
> + if (retcode)
> + goto err_undo;
> }
> + return 0;
>
> +err_undo:
> + mutex_lock(&dev->struct_mutex);
> + filp->f_mapping = old_mapping;
> + inode->i_mapping = old_mapping;
> + iput(container_of(dev->dev_mapping, struct inode, i_data));
> + dev->dev_mapping = old_mapping;
> + mutex_unlock(&dev->struct_mutex);
> + dev->open_count--;
> return retcode;
> }
> EXPORT_SYMBOL(drm_open);
