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Commit f4aede2e authored by David Herrmann's avatar David Herrmann
Browse files

drm: skip redundant minor-lookup in open path 



The drm_open_helper() function is only used internally for drm_open() so
we can safely pass in the minor-object directly instead of the minor-id.
This way, we avoid the additional minor IDR lookup, which we already do
twice in drm_stub_open() and drm_open().

Signed-off-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 45e212d2

drivers/gpu/drm/drm_fops.c

+7 −12
Original line number Diff line number Diff line
@@ -44,7 +44,7 @@ DEFINE_MUTEX(drm_global_mutex); 
EXPORT_SYMBOL(drm_global_mutex);



static int drm_open_helper(struct inode *inode, struct file *filp,

			   struct drm_device * dev);

			   struct drm_minor *minor);



static int drm_setup(struct drm_device * dev)

{
@@ -110,7 +110,7 @@ int drm_open(struct inode *inode, struct file *filp) 
	filp->f_mapping = dev->dev_mapping;

	mutex_unlock(&dev->struct_mutex);



	retcode = drm_open_helper(inode, filp, dev);

	retcode = drm_open_helper(inode, filp, minor);

	if (retcode)

		goto err_undo;

	if (need_setup) {
@@ -196,16 +196,16 @@ static int drm_cpu_valid(void) 
 *

 * \param inode device inode.

 * \param filp file pointer.

 * \param dev device.

 * \param minor acquired minor-object.

 * \return zero on success or a negative number on failure.

 *

 * Creates and initializes a drm_file structure for the file private data in \p

 * filp and add it into the double linked list in \p dev.

 */

static int drm_open_helper(struct inode *inode, struct file *filp,

			   struct drm_device * dev)

			   struct drm_minor *minor)

{

	int minor_id = iminor(inode);

	struct drm_device *dev = minor->dev;

	struct drm_file *priv;

	int ret;
@@ -216,7 +216,7 @@ static int drm_open_helper(struct inode *inode, struct file *filp, 
	if (dev->switch_power_state != DRM_SWITCH_POWER_ON && dev->switch_power_state != DRM_SWITCH_POWER_DYNAMIC_OFF)

		return -EINVAL;



	DRM_DEBUG("pid = %d, minor = %d\n", task_pid_nr(current), minor_id);

	DRM_DEBUG("pid = %d, minor = %d\n", task_pid_nr(current), minor->index);



	priv = kzalloc(sizeof(*priv), GFP_KERNEL);

	if (!priv)
@@ -226,11 +226,7 @@ static int drm_open_helper(struct inode *inode, struct file *filp, 
	priv->filp = filp;

	priv->uid = current_euid();

	priv->pid = get_pid(task_pid(current));

	priv->minor = idr_find(&drm_minors_idr, minor_id);

	if (!priv->minor) {

		ret = -ENODEV;

		goto out_put_pid;

	}

	priv->minor = minor;



	/* for compatibility root is always authenticated */

	priv->always_authenticated = capable(CAP_SYS_ADMIN);
@@ -336,7 +332,6 @@ static int drm_open_helper(struct inode *inode, struct file *filp, 
		drm_prime_destroy_file_private(&priv->prime);

	if (dev->driver->driver_features & DRIVER_GEM)

		drm_gem_release(dev, priv);

out_put_pid:

	put_pid(priv->pid);

	kfree(priv);

	filp->private_data = NULL;