From 9c19fb10a5893d6501df4d0fb93d954d5fc1d91b Mon Sep 17 00:00:00 2001 From: Jason Ekstrand Date: Mon, 28 Aug 2017 07:39:25 -0700 Subject: 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 Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_syncobj.c | 60 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 58 insertions(+), 2 deletions(-) (limited to 'drivers/gpu') diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c index 4e8563c36d6e..bade497b3f1d 100644 --- a/drivers/gpu/drm/drm_syncobj.c +++ b/drivers/gpu/drm/drm_syncobj.c @@ -80,6 +80,46 @@ struct drm_syncobj *drm_syncobj_find(struct drm_file *file_private, } 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. * @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 *old_fence; + struct drm_syncobj_cb *cur, *tmp; if (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); } @@ -130,7 +184,7 @@ void drm_syncobj_free(struct kref *kref) struct drm_syncobj *syncobj = container_of(kref, struct drm_syncobj, refcount); - dma_fence_put(syncobj->fence); + drm_syncobj_replace_fence(syncobj, NULL); kfree(syncobj); } EXPORT_SYMBOL(drm_syncobj_free); @@ -146,6 +200,8 @@ static int drm_syncobj_create(struct drm_file *file_private, return -ENOMEM; kref_init(&syncobj->refcount); + INIT_LIST_HEAD(&syncobj->cb_list); + spin_lock_init(&syncobj->lock); idr_preload(GFP_KERNEL); spin_lock(&file_private->syncobj_table_lock); -- cgit v1.2.3