Commit f091a3d4 authored by Francisco Jerez's avatar Francisco Jerez Committed by Ben Skeggs
Browse files

drm/nouveau: Implement weak channel references. 



nouveau_channel_ref() takes a "weak" channel reference that doesn't
prevent the hardware channel resources from being released, it just
keeps the channel data structure alive.

Signed-off-by: default avatarFrancisco Jerez <currojerez@riseup.net>
Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
parent 36c952e8

drivers/gpu/drm/nouveau/nouveau_channel.c

+40 −15
Original line number Diff line number Diff line
@@ -125,7 +125,8 @@ nouveau_channel_alloc(struct drm_device *dev, struct nouveau_channel **chan_ret, 
	chan->vram_handle = vram_handle;

	chan->gart_handle = gart_handle;



	atomic_set(&chan->refcount, 1);

	kref_init(&chan->ref);

	atomic_set(&chan->users, 1);

	mutex_init(&chan->mutex);

	mutex_lock(&chan->mutex);
@@ -133,7 +134,7 @@ nouveau_channel_alloc(struct drm_device *dev, struct nouveau_channel **chan_ret, 
	spin_lock_irqsave(&dev_priv->channels.lock, flags);

	for (chan->id = 0; chan->id < pfifo->channels; chan->id++) {

		if (!dev_priv->channels.ptr[chan->id]) {

			dev_priv->channels.ptr[chan->id] = chan;

			nouveau_channel_ref(chan, &dev_priv->channels.ptr[chan->id]);

			break;

		}

	}
@@ -240,10 +241,12 @@ nouveau_channel_alloc(struct drm_device *dev, struct nouveau_channel **chan_ret, 
struct nouveau_channel *

nouveau_channel_get_unlocked(struct nouveau_channel *ref)

{

	if (likely(ref && atomic_inc_not_zero(&ref->refcount)))

		return ref;

	struct nouveau_channel *chan = NULL;



	return NULL;

	if (likely(ref && atomic_inc_not_zero(&ref->users)))

		nouveau_channel_ref(ref, &chan);



	return chan;

}



struct nouveau_channel *
@@ -281,15 +284,14 @@ nouveau_channel_put_unlocked(struct nouveau_channel **pchan) 
	int ret;



	/* decrement the refcount, and we're done if there's still refs */

	if (likely(!atomic_dec_and_test(&chan->refcount))) {

		*pchan = NULL;

	if (likely(!atomic_dec_and_test(&chan->users))) {

		nouveau_channel_ref(NULL, pchan);

		return;

	}



	/* noone wants the channel anymore */

	NV_DEBUG(dev, "freeing channel %d\n", chan->id);

	nouveau_debugfs_channel_fini(chan);

	*pchan = NULL;



	/* give it chance to idle */

	nouveau_fence_update(chan);
@@ -333,7 +335,7 @@ nouveau_channel_put_unlocked(struct nouveau_channel **pchan) 
	 * remove it from the channel list

	 */

	spin_lock_irqsave(&dev_priv->channels.lock, flags);

	dev_priv->channels.ptr[chan->id] = NULL;

	nouveau_channel_ref(NULL, &dev_priv->channels.ptr[chan->id]);

	spin_unlock_irqrestore(&dev_priv->channels.lock, flags);



	/* destroy any resources the channel owned */
@@ -345,10 +347,8 @@ nouveau_channel_put_unlocked(struct nouveau_channel **pchan) 
	}

	nouveau_gpuobj_channel_takedown(chan);

	nouveau_notifier_takedown_channel(chan);

	if (chan->user)

		iounmap(chan->user);



	kfree(chan);

	nouveau_channel_ref(NULL, pchan);

}



void
@@ -358,6 +358,31 @@ nouveau_channel_put(struct nouveau_channel **pchan) 
	nouveau_channel_put_unlocked(pchan);

}



static void

nouveau_channel_del(struct kref *ref)

{

	struct nouveau_channel *chan =

		container_of(ref, struct nouveau_channel, ref);



	if (chan->user)

		iounmap(chan->user);



	kfree(chan);

}



void

nouveau_channel_ref(struct nouveau_channel *chan,

		    struct nouveau_channel **pchan)

{

	if (chan)

		kref_get(&chan->ref);



	if (*pchan)

		kref_put(&(*pchan)->ref, nouveau_channel_del);



	*pchan = chan;

}



/* cleans up all the fifos from file_priv */

void

nouveau_channel_cleanup(struct drm_device *dev, struct drm_file *file_priv)
@@ -373,7 +398,7 @@ nouveau_channel_cleanup(struct drm_device *dev, struct drm_file *file_priv) 
		if (IS_ERR(chan))

			continue;



		atomic_dec(&chan->refcount);

		atomic_dec(&chan->users);

		nouveau_channel_put(&chan);

	}

}
@@ -427,7 +452,7 @@ nouveau_ioctl_fifo_alloc(struct drm_device *dev, void *data, 
				    &init->notifier_handle);



	if (ret == 0)

		atomic_inc(&chan->refcount); /* userspace reference */

		atomic_inc(&chan->users); /* userspace reference */

	nouveau_channel_put(&chan);

	return ret;

}
@@ -443,7 +468,7 @@ nouveau_ioctl_fifo_free(struct drm_device *dev, void *data, 
	if (IS_ERR(chan))

		return PTR_ERR(chan);



	atomic_dec(&chan->refcount);

	atomic_dec(&chan->users);

	nouveau_channel_put(&chan);

	return 0;

}

drivers/gpu/drm/nouveau/nouveau_drv.h

+7 −1
Original line number Diff line number Diff line
@@ -165,7 +165,11 @@ struct nouveau_channel { 
	struct drm_device *dev;

	int id;



	atomic_t refcount;

	/* references to the channel data structure */

	struct kref ref;

	/* users of the hardware channel resources, the hardware

	 * context will be kicked off when it reaches zero. */

	atomic_t users;

	struct mutex mutex;



	/* owner of this fifo */
@@ -808,6 +812,8 @@ extern struct nouveau_channel * 
nouveau_channel_get(struct drm_device *, struct drm_file *, int id);

extern void nouveau_channel_put_unlocked(struct nouveau_channel **);

extern void nouveau_channel_put(struct nouveau_channel **);

extern void nouveau_channel_ref(struct nouveau_channel *chan,

				struct nouveau_channel **pchan);



/* nouveau_object.c */

extern int  nouveau_gpuobj_early_init(struct drm_device *);