[Intel-gfx] [RFC 4/7] drm/i915: Use i915_sg_create for rotated pages view

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

As for the partial view, just simplifies the loop and
enables entry coalescing.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 42 +++++++++++++------------------------
 1 file changed, 14 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index f0c70e7c8daa..655c31182c68 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3464,11 +3464,10 @@ i915_gem_obj_lookup_or_create_vma(struct drm_i915_gem_object *obj,
 	return vma;
 }
 
-static struct scatterlist *
+static void
 rotate_pages(const dma_addr_t *in, unsigned int offset,
-	     unsigned int width, unsigned int height,
-	     unsigned int stride,
-	     struct sg_table *st, struct scatterlist *sg)
+	     unsigned int width, unsigned int height, unsigned int stride,
+	     struct i915_sg_create_state *state)
 {
 	unsigned int column, row;
 	unsigned int src_idx;
@@ -3476,34 +3475,27 @@ rotate_pages(const dma_addr_t *in, unsigned int offset,
 	for (column = 0; column < width; column++) {
 		src_idx = stride * (height - 1) + column;
 		for (row = 0; row < height; row++) {
-			st->nents++;
 			/* We don't need the pages, but need to initialize
 			 * the entries so the sg list can be happily traversed.
 			 * The only thing we need are DMA addresses.
 			 */
-			sg_set_page(sg, NULL, PAGE_SIZE, 0);
-			sg_dma_address(sg) = in[offset + src_idx];
-			sg_dma_len(sg) = PAGE_SIZE;
-			sg = sg_next(sg);
+			i915_sg_add_dma(state, in[offset + src_idx]);
 			src_idx -= stride;
 		}
 	}
-
-	return sg;
 }
 
 static struct sg_table *
 intel_rotate_fb_obj_pages(const struct intel_rotation_info *rot_info,
 			  struct drm_i915_gem_object *obj)
 {
+	struct i915_sg_create_state *state;
 	const size_t n_pages = obj->base.size / PAGE_SIZE;
 	unsigned int size = intel_rotation_info_size(rot_info);
 	struct sgt_iter sgt_iter;
 	dma_addr_t dma_addr;
 	unsigned long i;
 	dma_addr_t *page_addr_list;
-	struct sg_table *st;
-	struct scatterlist *sg;
 	int ret = -ENOMEM;
 
 	/* Allocate a temporary list of source pages for random access. */
@@ -3513,14 +3505,12 @@ intel_rotate_fb_obj_pages(const struct intel_rotation_info *rot_info,
 	if (!page_addr_list)
 		return ERR_PTR(ret);
 
-	/* Allocate target SG list. */
-	st = kmalloc(sizeof(*st), GFP_KERNEL);
-	if (!st)
+	/* Begin creation of the target SG list. */
+	state = i915_sg_create(size);
+	if (IS_ERR(state)) {
+		ret = PTR_ERR(state);
 		goto err_st_alloc;
-
-	ret = sg_alloc_table(st, size, GFP_KERNEL);
-	if (ret)
-		goto err_sg_alloc;
+	}
 
 	/* Populate source page list from the object. */
 	i = 0;
@@ -3528,13 +3518,11 @@ intel_rotate_fb_obj_pages(const struct intel_rotation_info *rot_info,
 		page_addr_list[i++] = dma_addr;
 
 	GEM_BUG_ON(i != n_pages);
-	st->nents = 0;
-	sg = st->sgl;
 
 	for (i = 0 ; i < ARRAY_SIZE(rot_info->plane); i++) {
-		sg = rotate_pages(page_addr_list, rot_info->plane[i].offset,
-				  rot_info->plane[i].width, rot_info->plane[i].height,
-				  rot_info->plane[i].stride, st, sg);
+		rotate_pages(page_addr_list, rot_info->plane[i].offset,
+			     rot_info->plane[i].width, rot_info->plane[i].height,
+			     rot_info->plane[i].stride, state);
 	}
 
 	DRM_DEBUG_KMS("Created rotated page mapping for object size %zu (%ux%u tiles, %u pages)\n",
@@ -3542,10 +3530,8 @@ intel_rotate_fb_obj_pages(const struct intel_rotation_info *rot_info,
 
 	drm_free_large(page_addr_list);
 
-	return st;
+	return i915_sg_complete(state);
 
-err_sg_alloc:
-	kfree(st);
 err_st_alloc:
 	drm_free_large(page_addr_list);
 
-- 
2.7.4