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Commit 4154f051 authored by Maarten Lankhorst's avatar Maarten Lankhorst Committed by Dave Airlie
Browse files

drm/ttm: change fence_lock to inner lock 



This requires changing the order in ttm_bo_cleanup_refs_or_queue to
take the reservation first, as there is otherwise no race free way to
take lru lock before fence_lock.

Signed-off-by: default avatarMaarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: default avatarThomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 1a1494de

drivers/gpu/drm/ttm/ttm_bo.c

+11 −20
Original line number Diff line number Diff line
@@ -500,27 +500,17 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo) 
{

	struct ttm_bo_device *bdev = bo->bdev;

	struct ttm_bo_global *glob = bo->glob;

	struct ttm_bo_driver *driver;

	struct ttm_bo_driver *driver = bdev->driver;

	void *sync_obj = NULL;

	int put_count;

	int ret;



	spin_lock(&bdev->fence_lock);

	(void) ttm_bo_wait(bo, false, false, true);

	if (!bo->sync_obj) {



	spin_lock(&glob->lru_lock);



		/**

		 * Lock inversion between bo:reserve and bdev::fence_lock here,

		 * but that's OK, since we're only trylocking.

		 */



	ret = ttm_bo_reserve_locked(bo, false, true, false, 0);



		if (unlikely(ret == -EBUSY))

			goto queue;



	spin_lock(&bdev->fence_lock);

	(void) ttm_bo_wait(bo, false, false, true);

	if (!ret && !bo->sync_obj) {

		spin_unlock(&bdev->fence_lock);

		put_count = ttm_bo_del_from_lru(bo);
@@ -530,18 +520,19 @@ static void ttm_bo_cleanup_refs_or_queue(struct ttm_buffer_object *bo) 
		ttm_bo_list_ref_sub(bo, put_count, true);



		return;

	} else {

		spin_lock(&glob->lru_lock);

	}

queue:

	driver = bdev->driver;

	if (bo->sync_obj)

		sync_obj = driver->sync_obj_ref(bo->sync_obj);

	spin_unlock(&bdev->fence_lock);



	if (!ret) {

		atomic_set(&bo->reserved, 0);

		wake_up_all(&bo->event_queue);

	}



	kref_get(&bo->list_kref);

	list_add_tail(&bo->ddestroy, &bdev->ddestroy);

	spin_unlock(&glob->lru_lock);

	spin_unlock(&bdev->fence_lock);



	if (sync_obj) {

		driver->sync_obj_flush(sync_obj);

drivers/gpu/drm/ttm/ttm_execbuf_util.c

+2 −2
Original line number Diff line number Diff line
@@ -213,8 +213,8 @@ void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj) 
	driver = bdev->driver;

	glob = bo->glob;



	spin_lock(&bdev->fence_lock);

	spin_lock(&glob->lru_lock);

	spin_lock(&bdev->fence_lock);



	list_for_each_entry(entry, list, head) {

		bo = entry->bo;
@@ -223,8 +223,8 @@ void ttm_eu_fence_buffer_objects(struct list_head *list, void *sync_obj) 
		ttm_bo_unreserve_locked(bo);

		entry->reserved = false;

	}

	spin_unlock(&glob->lru_lock);

	spin_unlock(&bdev->fence_lock);

	spin_unlock(&glob->lru_lock);



	list_for_each_entry(entry, list, head) {

		if (entry->old_sync_obj)