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Commit 95c081c1 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm: Move master pointer from drm_minor to drm_device 



There can only be one current master, and it's for the overall device.
Render/control minors don't support master-based auth at all.

This simplifies the master logic a lot, at least in my eyes: All these
additional pointer chases are just confusing.

While doing the conversion I spotted some locking fail:
- drm_lock/drm_auth check dev->master without holding the
  master_mutex. This is fallout from

  commit c996fd0b
  Author: Thomas Hellstrom <thellstrom@vmware.com>
  Date:   Tue Feb 25 19:57:44 2014 +0100

      drm: Protect the master management with a drm_device::master_mutex v3

  but I honestly don't care one bit about those old legacy drivers
  using this.

- debugfs name info should just grab master_mutex.

- And the fbdev helper looked at it to figure out whether someone is
  using KMS. We just need a consistent value, so READ_ONCE. Aside: We
  should probably check if anyone has opened a control node too, but I
  guess current userspace doesn't really do that yet.

v2: Balance locking, reported by Julia.

v3: Rebase on top of Chris' oops fixes.

Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v2)
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> (v2)
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466499262-18717-1-git-send-email-daniel.vetter@ffwll.ch
parent 84601dbd

drivers/gpu/drm/drm_auth.c

+13 −13
Original line number Diff line number Diff line
@@ -128,13 +128,13 @@ static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv) 
	lockdep_assert_held_once(&dev->master_mutex);



	/* create a new master */

	fpriv->minor->master = drm_master_create(fpriv->minor->dev);

	if (!fpriv->minor->master)

	dev->master = drm_master_create(dev);

	if (!dev->master)

		return -ENOMEM;



	/* take another reference for the copy in the local file priv */

	old_master = fpriv->master;

	fpriv->master = drm_master_get(fpriv->minor->master);

	fpriv->master = drm_master_get(dev->master);



	if (dev->driver->master_create) {

		ret = dev->driver->master_create(dev, fpriv->master);
@@ -157,7 +157,7 @@ static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv) 


out_err:

	/* drop both references and restore old master on failure */

	drm_master_put(&fpriv->minor->master);

	drm_master_put(&dev->master);

	drm_master_put(&fpriv->master);

	fpriv->master = old_master;
@@ -173,7 +173,7 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data, 
	if (file_priv->is_master)

		goto out_unlock;



	if (file_priv->minor->master) {

	if (dev->master) {

		ret = -EINVAL;

		goto out_unlock;

	}
@@ -188,13 +188,13 @@ int drm_setmaster_ioctl(struct drm_device *dev, void *data, 
		goto out_unlock;

	}



	file_priv->minor->master = drm_master_get(file_priv->master);

	dev->master = drm_master_get(file_priv->master);

	file_priv->is_master = 1;

	if (dev->driver->master_set) {

		ret = dev->driver->master_set(dev, file_priv, false);

		if (unlikely(ret != 0)) {

			file_priv->is_master = 0;

			drm_master_put(&file_priv->minor->master);

			drm_master_put(&dev->master);

		}

	}
@@ -212,13 +212,13 @@ int drm_dropmaster_ioctl(struct drm_device *dev, void *data, 
	if (!file_priv->is_master)

		goto out_unlock;



	if (!file_priv->minor->master)

	if (!dev->master)

		goto out_unlock;



	ret = 0;

	if (dev->driver->master_drop)

		dev->driver->master_drop(dev, file_priv, false);

	drm_master_put(&file_priv->minor->master);

	drm_master_put(&dev->master);

	file_priv->is_master = 0;



out_unlock:
@@ -234,10 +234,10 @@ int drm_master_open(struct drm_file *file_priv) 
	/* if there is no current master make this fd it, but do not create

	 * any master object for render clients */

	mutex_lock(&dev->master_mutex);

	if (!file_priv->minor->master)

	if (!dev->master)

		ret = drm_new_set_master(dev, file_priv);

	else

		file_priv->master = drm_master_get(file_priv->minor->master);

		file_priv->master = drm_master_get(dev->master);

	mutex_unlock(&dev->master_mutex);



	return ret;
@@ -271,11 +271,11 @@ void drm_master_release(struct drm_file *file_priv) 
		mutex_unlock(&dev->struct_mutex);

	}



	if (file_priv->minor->master == file_priv->master) {

	if (dev->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);

		drm_master_put(&dev->master);

	}

out:

	/* drop the master reference held by the file priv */

drivers/gpu/drm/drm_bufs.c

+4 −4
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ static struct drm_map_list *drm_find_matching_map(struct drm_device *dev, 
		 */

		if (!entry->map ||

		    map->type != entry->map->type ||

		    entry->master != dev->primary->master)

		    entry->master != dev->master)

			continue;

		switch (map->type) {

		case _DRM_SHM:
@@ -245,12 +245,12 @@ static int drm_addmap_core(struct drm_device * dev, resource_size_t offset, 
		map->offset = (unsigned long)map->handle;

		if (map->flags & _DRM_CONTAINS_LOCK) {

			/* Prevent a 2nd X Server from creating a 2nd lock */

			if (dev->primary->master->lock.hw_lock != NULL) {

			if (dev->master->lock.hw_lock != NULL) {

				vfree(map->handle);

				kfree(map);

				return -EBUSY;

			}

			dev->sigdata.lock = dev->primary->master->lock.hw_lock = map->handle;	/* Pointer to lock */

			dev->sigdata.lock = dev->master->lock.hw_lock = map->handle;	/* Pointer to lock */

		}

		break;

	case _DRM_AGP: {
@@ -356,7 +356,7 @@ static int drm_addmap_core(struct drm_device * dev, resource_size_t offset, 
	mutex_unlock(&dev->struct_mutex);



	if (!(map->flags & _DRM_DRIVER))

		list->master = dev->primary->master;

		list->master = dev->master;

	*maplist = list;

	return 0;

}

drivers/gpu/drm/drm_fb_helper.c

+1 −1
Original line number Diff line number Diff line
@@ -464,7 +464,7 @@ static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper) 


	/* Sometimes user space wants everything disabled, so don't steal the

	 * display if there's a master. */

	if (dev->primary->master)

	if (READ_ONCE(dev->master))

		return false;



	drm_for_each_crtc(crtc, dev) {

drivers/gpu/drm/drm_info.c

+8 −1
Original line number Diff line number Diff line
@@ -50,7 +50,12 @@ int drm_name_info(struct seq_file *m, void *data) 
	struct drm_info_node *node = (struct drm_info_node *) m->private;

	struct drm_minor *minor = node->minor;

	struct drm_device *dev = minor->dev;

	struct drm_master *master = minor->master;

	struct drm_master *master;



	mutex_lock(&dev->master_mutex);

	master = dev->master;

	if (!master)

		goto out_unlock;



	seq_printf(m, "%s", dev->driver->name);

	if (dev->dev)
@@ -60,6 +65,8 @@ int drm_name_info(struct seq_file *m, void *data) 
	if (dev->unique)

		seq_printf(m, " unique=%s", dev->unique);

	seq_printf(m, "\n");

out_unlock:

	mutex_unlock(&dev->master_mutex);



	return 0;

}

drivers/gpu/drm/drm_lock.c

+1 −1
Original line number Diff line number Diff line
@@ -334,7 +334,7 @@ void drm_legacy_lock_release(struct drm_device *dev, struct file *filp) 
	struct drm_file *file_priv = filp->private_data;



	/* if the master has gone away we can't do anything with the lock */

	if (!file_priv->minor->master)

	if (!dev->master)

		return;



	if (drm_legacy_i_have_hw_lock(dev, file_priv)) {