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Commit d2a84a76 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Use radixtree to jump start intel_partial_pages() 



We can use the radixtree index of the obj->pages to find the start
position of the desired partial range.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-11-chris@chris-wilson.co.uk
parent 96d77634

drivers/gpu/drm/i915/i915_gem_gtt.c

+26 −14
Original line number Diff line number Diff line
@@ -3584,35 +3584,47 @@ intel_partial_pages(const struct i915_ggtt_view *view, 
		    struct drm_i915_gem_object *obj)

{

	struct sg_table *st;

	struct scatterlist *sg;

	struct sg_page_iter obj_sg_iter;

	struct scatterlist *sg, *iter;

	unsigned int count = view->params.partial.size;

	unsigned int offset;

	int ret = -ENOMEM;



	st = kmalloc(sizeof(*st), GFP_KERNEL);

	if (!st)

		goto err_st_alloc;



	ret = sg_alloc_table(st, view->params.partial.size, GFP_KERNEL);

	ret = sg_alloc_table(st, count, GFP_KERNEL);

	if (ret)

		goto err_sg_alloc;



	iter = i915_gem_object_get_sg(obj,

				      view->params.partial.offset,

				      &offset);

	GEM_BUG_ON(!iter);



	sg = st->sgl;

	st->nents = 0;

	for_each_sg_page(obj->pages->sgl, &obj_sg_iter, obj->pages->nents,

		view->params.partial.offset)

	{

		if (st->nents >= view->params.partial.size)

			break;

	do {

		unsigned int len;



		sg_set_page(sg, NULL, PAGE_SIZE, 0);

		sg_dma_address(sg) = sg_page_iter_dma_address(&obj_sg_iter);

		sg_dma_len(sg) = PAGE_SIZE;

		len = min(iter->length - (offset << PAGE_SHIFT),

			  count << PAGE_SHIFT);

		sg_set_page(sg, NULL, len, 0);

		sg_dma_address(sg) =

			sg_dma_address(iter) + (offset << PAGE_SHIFT);

		sg_dma_len(sg) = len;



		sg = sg_next(sg);

		st->nents++;

		count -= len >> PAGE_SHIFT;

		if (count == 0) {

			sg_mark_end(sg);

			return st;

		}



	return st;

		sg = __sg_next(sg);

		iter = __sg_next(iter);

		offset = 0;

	} while (1);



err_sg_alloc:

	kfree(st);