Commit 96601e8a authored by Christian König's avatar Christian König
Browse files

dma-buf: use new iterator in dma_resv_copy_fences 



This makes the function much simpler since the complex
retry logic is now handled else where.

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20211005113742.1101-5-christian.koenig@amd.com
parent c921ff37

drivers/dma-buf/dma-resv.c

+32 −52
Original line number Diff line number Diff line
@@ -432,74 +432,54 @@ EXPORT_SYMBOL(dma_resv_iter_next_unlocked); 
 */

int dma_resv_copy_fences(struct dma_resv *dst, struct dma_resv *src)

{

	struct dma_resv_list *src_list, *dst_list;

	struct dma_fence *old, *new;

	unsigned int i;

	struct dma_resv_iter cursor;

	struct dma_resv_list *list;

	struct dma_fence *f, *excl;



	dma_resv_assert_held(dst);



	rcu_read_lock();

	src_list = dma_resv_shared_list(src);

	list = NULL;

	excl = NULL;



retry:

	if (src_list) {

		unsigned int shared_count = src_list->shared_count;

	dma_resv_iter_begin(&cursor, src, true);

	dma_resv_for_each_fence_unlocked(&cursor, f) {



		rcu_read_unlock();

		if (dma_resv_iter_is_restarted(&cursor)) {

			dma_resv_list_free(list);

			dma_fence_put(excl);



		dst_list = dma_resv_list_alloc(shared_count);

		if (!dst_list)

			return -ENOMEM;

			if (cursor.fences) {

				unsigned int cnt = cursor.fences->shared_count;



		rcu_read_lock();

		src_list = dma_resv_shared_list(src);

		if (!src_list || src_list->shared_count > shared_count) {

			kfree(dst_list);

			goto retry;

				list = dma_resv_list_alloc(cnt);

				if (!list) {

					dma_resv_iter_end(&cursor);

					return -ENOMEM;

				}



		dst_list->shared_count = 0;

		for (i = 0; i < src_list->shared_count; ++i) {

			struct dma_fence __rcu **dst;

			struct dma_fence *fence;

				list->shared_count = 0;



			fence = rcu_dereference(src_list->shared[i]);

			if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT,

				     &fence->flags))

				continue;



			if (!dma_fence_get_rcu(fence)) {

				dma_resv_list_free(dst_list);

				src_list = dma_resv_shared_list(src);

				goto retry;

			} else {

				list = NULL;

			}



			if (dma_fence_is_signaled(fence)) {

				dma_fence_put(fence);

				continue;

			excl = NULL;

		}



			dst = &dst_list->shared[dst_list->shared_count++];

			rcu_assign_pointer(*dst, fence);

		}

	} else {

		dst_list = NULL;

		dma_fence_get(f);

		if (dma_resv_iter_is_exclusive(&cursor))

			excl = f;

		else

			RCU_INIT_POINTER(list->shared[list->shared_count++], f);

	}



	new = dma_fence_get_rcu_safe(&src->fence_excl);

	rcu_read_unlock();



	src_list = dma_resv_shared_list(dst);

	old = dma_resv_excl_fence(dst);

	dma_resv_iter_end(&cursor);



	write_seqcount_begin(&dst->seq);

	/* write_seqcount_begin provides the necessary memory barrier */

	RCU_INIT_POINTER(dst->fence_excl, new);

	RCU_INIT_POINTER(dst->fence, dst_list);

	excl = rcu_replace_pointer(dst->fence_excl, excl, dma_resv_held(dst));

	list = rcu_replace_pointer(dst->fence, list, dma_resv_held(dst));

	write_seqcount_end(&dst->seq);



	dma_resv_list_free(src_list);

	dma_fence_put(old);

	dma_resv_list_free(list);

	dma_fence_put(excl);



	return 0;

}