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Commit 9c19fb10 authored by Jason Ekstrand's avatar Jason Ekstrand Committed by Dave Airlie
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drm/syncobj: Add a callback mechanism for replace_fence (v3) 



It is useful in certain circumstances to know when the fence is replaced
in a syncobj.  Specifically, it may be useful to know when the fence
goes from NULL to something valid.  This does make syncobj_replace_fence
a little more expensive because it has to take a lock but, in the common
case where there is no callback list, it spends a very short amount of
time inside the lock.

v2:
 - Don't lock in drm_syncobj_fence_get.  We only really need to lock
   around fence_replace to make the callback work.
v3:
 - Fix the cb_list comment to make kbuild happy

Signed-off-by: default avatarJason Ekstrand <jason@jlekstrand.net>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 5e60a10e

drivers/gpu/drm/drm_syncobj.c

+58 −2
Original line number Original line Diff line number Diff line
@@ -80,6 +80,46 @@ struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private, 
}

}

EXPORT_SYMBOL(drm_syncobj_find);

EXPORT_SYMBOL(drm_syncobj_find);





static void drm_syncobj_add_callback_locked(struct drm_syncobj *syncobj,

					    struct drm_syncobj_cb *cb,

					    drm_syncobj_func_t func)

{

	cb->func = func;

	list_add_tail(&cb->node, &syncobj->cb_list);

}



/**

 * drm_syncobj_add_callback - adds a callback to syncobj::cb_list

 * @syncobj: Sync object to which to add the callback

 * @cb: Callback to add

 * @func: Func to use when initializing the drm_syncobj_cb struct

 *

 * This adds a callback to be called next time the fence is replaced

 */

void drm_syncobj_add_callback(struct drm_syncobj *syncobj,

			      struct drm_syncobj_cb *cb,

			      drm_syncobj_func_t func)

{

	spin_lock(&syncobj->lock);

	drm_syncobj_add_callback_locked(syncobj, cb, func);

	spin_unlock(&syncobj->lock);

}

EXPORT_SYMBOL(drm_syncobj_add_callback);



/**

 * drm_syncobj_add_callback - removes a callback to syncobj::cb_list

 * @syncobj: Sync object from which to remove the callback

 * @cb: Callback to remove

 */

void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,

				 struct drm_syncobj_cb *cb)

{

	spin_lock(&syncobj->lock);

	list_del_init(&cb->node);

	spin_unlock(&syncobj->lock);

}

EXPORT_SYMBOL(drm_syncobj_remove_callback);



/**

/**

 * drm_syncobj_replace_fence - replace fence in a sync object.

 * drm_syncobj_replace_fence - replace fence in a sync object.

 * @syncobj: Sync object to replace fence in

 * @syncobj: Sync object to replace fence in
@@ -91,10 +131,24 @@ void drm_syncobj_replace_fence(struct drm_syncobj *syncobj, 
			       struct dma_fence *fence)

			       struct dma_fence *fence)

{

{

	struct dma_fence *old_fence;

	struct dma_fence *old_fence;

	struct drm_syncobj_cb *cur, *tmp;





	if (fence)

	if (fence)

		dma_fence_get(fence);

		dma_fence_get(fence);

	old_fence = xchg(&syncobj->fence, fence);



	spin_lock(&syncobj->lock);



	old_fence = syncobj->fence;

	syncobj->fence = fence;



	if (fence != old_fence) {

		list_for_each_entry_safe(cur, tmp, &syncobj->cb_list, node) {

			list_del_init(&cur->node);

			cur->func(syncobj, cur);

		}

	}



	spin_unlock(&syncobj->lock);





	dma_fence_put(old_fence);

	dma_fence_put(old_fence);

}

}
@@ -130,7 +184,7 @@ void drm_syncobj_free(struct kref *kref) 
	struct drm_syncobj *syncobj = container_of(kref,

	struct drm_syncobj *syncobj = container_of(kref,

						   struct drm_syncobj,

						   struct drm_syncobj,

						   refcount);

						   refcount);

	dma_fence_put(syncobj->fence);

	drm_syncobj_replace_fence(syncobj, NULL);

	kfree(syncobj);

	kfree(syncobj);

}

}

EXPORT_SYMBOL(drm_syncobj_free);

EXPORT_SYMBOL(drm_syncobj_free);
@@ -146,6 +200,8 @@ static int drm_syncobj_create(struct drm_file *file_private, 
		return -ENOMEM;

		return -ENOMEM;





	kref_init(&syncobj->refcount);

	kref_init(&syncobj->refcount);

	INIT_LIST_HEAD(&syncobj->cb_list);

	spin_lock_init(&syncobj->lock);





	idr_preload(GFP_KERNEL);

	idr_preload(GFP_KERNEL);

	spin_lock(&file_private->syncobj_table_lock);

	spin_lock(&file_private->syncobj_table_lock);

include/drm/drm_syncobj.h

+39 −0
Original line number Original line Diff line number Diff line
@@ -28,6 +28,8 @@ 




#include "linux/dma-fence.h"

#include "linux/dma-fence.h"





struct drm_syncobj_cb;



/**

/**

 * struct drm_syncobj - sync object.

 * struct drm_syncobj - sync object.

 *

 *
@@ -43,8 +45,21 @@ struct drm_syncobj { 
	/**

	/**

	 * @fence:

	 * @fence:

	 * NULL or a pointer to the fence bound to this object.

	 * NULL or a pointer to the fence bound to this object.

	 *

	 * This field should not be used directly.  Use drm_syncobj_fence_get

	 * and drm_syncobj_replace_fence instead.

	 */

	 */

	struct dma_fence *fence;

	struct dma_fence *fence;

	/**

	 * @cb_list:

	 * List of callbacks to call when the fence gets replaced

	 */

	struct list_head cb_list;

	/**

	 * @lock:

	 * locks cb_list and write-locks fence.

	 */

	spinlock_t lock;

	/**

	/**

	 * @file:

	 * @file:

	 * a file backing for this syncobj.

	 * a file backing for this syncobj.
@@ -52,6 +67,25 @@ struct drm_syncobj { 
	struct file *file;

	struct file *file;

};

};





typedef void (*drm_syncobj_func_t)(struct drm_syncobj *syncobj,

				   struct drm_syncobj_cb *cb);



/**

 * struct drm_syncobj_cb - callback for drm_syncobj_add_callback

 * @node: used by drm_syncob_add_callback to append this struct to

 *	  syncobj::cb_list

 * @func: drm_syncobj_func_t to call

 *

 * This struct will be initialized by drm_syncobj_add_callback, additional

 * data can be passed along by embedding drm_syncobj_cb in another struct.

 * The callback will get called the next time drm_syncobj_replace_fence is

 * called.

 */

struct drm_syncobj_cb {

	struct list_head node;

	drm_syncobj_func_t func;

};



void drm_syncobj_free(struct kref *kref);

void drm_syncobj_free(struct kref *kref);





/**

/**
@@ -91,6 +125,11 @@ drm_syncobj_fence_get(struct drm_syncobj *syncobj) 




struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,

struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,

				     u32 handle);

				     u32 handle);

void drm_syncobj_add_callback(struct drm_syncobj *syncobj,

			      struct drm_syncobj_cb *cb,

			      drm_syncobj_func_t func);

void drm_syncobj_remove_callback(struct drm_syncobj *syncobj,

				 struct drm_syncobj_cb *cb);

void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,

void drm_syncobj_replace_fence(struct drm_syncobj *syncobj,

			       struct dma_fence *fence);

			       struct dma_fence *fence);

int drm_syncobj_find_fence(struct drm_file *file_private,

int drm_syncobj_find_fence(struct drm_file *file_private,