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: Jason Ekstrand <jason@jlekstrand.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Jason Ekstrand
2017-08-28 07:39:25 -07:00
committed by Dave Airlie
parent 5e60a10eae
commit 9c19fb10a5
2 changed files with 97 additions and 2 deletions

View File

@@ -28,6 +28,8 @@
#include "linux/dma-fence.h"
struct drm_syncobj_cb;
/**
* struct drm_syncobj - sync object.
*
@@ -43,8 +45,21 @@ struct drm_syncobj {
/**
* @fence:
* 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;
/**
* @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:
* a file backing for this syncobj.
@@ -52,6 +67,25 @@ struct drm_syncobj {
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);
/**
@@ -91,6 +125,11 @@ drm_syncobj_fence_get(struct drm_syncobj *syncobj)
struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private,
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,
struct dma_fence *fence);
int drm_syncobj_find_fence(struct drm_file *file_private,