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: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
David Herrmann 2014-01-29 10:18:02 +01:00
parent 45e212d20f
commit f4aede2e32

View File

@ -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;