lib/scatterlist: Provide a dedicated function to support table append

RDMA is the only in-kernel user that uses __sg_alloc_table_from_pages to
append pages dynamically. In the next patch. That mode will be extended
and that function will get more parameters. So separate it into a unique
function to make such change more clear.

Link: https://lore.kernel.org/r/20210824142531.3877007-2-maorg@nvidia.com
Signed-off-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

3 files changed, 15 insertions, 23 deletions

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 2a54f86856af..cf3278041f9c 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -807,8 +807,8 @@ struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
 				       struct page **pages, unsigned int nr_pages)
 {
 	struct sg_table *sg;
-	struct scatterlist *sge;
 	size_t max_segment = 0;
+	int err;
 
 	sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL);
 	if (!sg)
@@ -818,13 +818,12 @@ struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev,
 		max_segment = dma_max_mapping_size(dev->dev);
 	if (max_segment == 0)
 		max_segment = UINT_MAX;
-	sge = __sg_alloc_table_from_pages(sg, pages, nr_pages, 0,
-					  nr_pages << PAGE_SHIFT,
-					  max_segment,
-					  NULL, 0, GFP_KERNEL);
-	if (IS_ERR(sge)) {
+	err = sg_alloc_table_from_pages_segment(sg, pages, nr_pages, 0,
+						nr_pages << PAGE_SHIFT,
+						max_segment, GFP_KERNEL);
+	if (err) {
 		kfree(sg);
-		sg = ERR_CAST(sge);
+		sg = ERR_PTR(err);
 	}
 	return sg;
 }
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index 7487bab11f0b..458f797a9e1e 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -133,7 +133,6 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 	unsigned int max_segment = i915_sg_segment_size();
 	struct sg_table *st;
 	unsigned int sg_page_sizes;
-	struct scatterlist *sg;
 	struct page **pvec;
 	int ret;
 
@@ -153,13 +152,11 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 	spin_unlock(&i915->mm.notifier_lock);
 
 alloc_table:
-	sg = __sg_alloc_table_from_pages(st, pvec, num_pages, 0,
-					 num_pages << PAGE_SHIFT, max_segment,
-					 NULL, 0, GFP_KERNEL);
-	if (IS_ERR(sg)) {
-		ret = PTR_ERR(sg);
+	ret = sg_alloc_table_from_pages_segment(st, pvec, num_pages, 0,
+						num_pages << PAGE_SHIFT,
+						max_segment, GFP_KERNEL);
+	if (ret)
 		goto err;
-	}
 
 	ret = i915_gem_gtt_prepare_pages(obj, st);
 	if (ret) {
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
index 0488042fb287..fc372d2e52a1 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
@@ -363,7 +363,6 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt)
 	int ret = 0;
 	static size_t sgl_size;
 	static size_t sgt_size;
-	struct scatterlist *sg;
 
 	if (vmw_tt->mapped)
 		return 0;
@@ -386,15 +385,12 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt)
 		if (unlikely(ret != 0))
 			return ret;
 
-		sg = __sg_alloc_table_from_pages(&vmw_tt->sgt, vsgt->pages,
-				vsgt->num_pages, 0,
-				(unsigned long) vsgt->num_pages << PAGE_SHIFT,
-				dma_get_max_seg_size(dev_priv->drm.dev),
-				NULL, 0, GFP_KERNEL);
-		if (IS_ERR(sg)) {
-			ret = PTR_ERR(sg);
+		ret = sg_alloc_table_from_pages_segment(
+			&vmw_tt->sgt, vsgt->pages, vsgt->num_pages, 0,
+			(unsigned long)vsgt->num_pages << PAGE_SHIFT,
+			dma_get_max_seg_size(dev_priv->drm.dev), GFP_KERNEL);
+		if (ret)
 			goto out_sg_alloc_fail;
-		}
 
 		if (vsgt->num_pages > vmw_tt->sgt.orig_nents) {
 			uint64_t over_alloc =