[PATCH v4 03/15] drm/i915: Fix i915_sg_page_sizes to record dma segments rather than physical pages

[Thomas Hellström]

All users of this function actually want the dma segment sizes, but that's
not what's calculated. Fix that and rename the function to
i915_sg_dma_sizes to reflect what's calculated.

Signed-off-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c  |  2 +-
 drivers/gpu/drm/i915/gem/i915_gem_phys.c    |  2 +-
 drivers/gpu/drm/i915/gem/i915_gem_userptr.c |  2 +-
 drivers/gpu/drm/i915/i915_scatterlist.h     | 16 ++++++++++++----
 4 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index ccede73c6465..616c3a2f1baf 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -209,7 +209,7 @@ static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
 	if (IS_ERR(pages))
 		return PTR_ERR(pages);
 
-	sg_page_sizes = i915_sg_page_sizes(pages->sgl);
+	sg_page_sizes = i915_sg_dma_sizes(pages->sgl);
 
 	__i915_gem_object_set_pages(obj, pages, sg_page_sizes);
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_phys.c b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
index 51a05e62875d..be72ad0634ba 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_phys.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_phys.c
@@ -207,7 +207,7 @@ static int i915_gem_object_shmem_to_phys(struct drm_i915_gem_object *obj)
 
 err_xfer:
 	if (!IS_ERR_OR_NULL(pages)) {
-		unsigned int sg_page_sizes = i915_sg_page_sizes(pages->sgl);
+		unsigned int sg_page_sizes = i915_sg_dma_sizes(pages->sgl);
 
 		__i915_gem_object_set_pages(obj, pages, sg_page_sizes);
 	}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
index a657b99ec760..602f0ed983ec 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
@@ -173,7 +173,7 @@ static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 		goto err;
 	}
 
-	sg_page_sizes = i915_sg_page_sizes(st->sgl);
+	sg_page_sizes = i915_sg_dma_sizes(st->sgl);
 
 	__i915_gem_object_set_pages(obj, st, sg_page_sizes);
 
diff --git a/drivers/gpu/drm/i915/i915_scatterlist.h b/drivers/gpu/drm/i915/i915_scatterlist.h
index 9cb26a224034..b96baad66a3a 100644
--- a/drivers/gpu/drm/i915/i915_scatterlist.h
+++ b/drivers/gpu/drm/i915/i915_scatterlist.h
@@ -101,15 +101,23 @@ static inline struct scatterlist *__sg_next(struct scatterlist *sg)
 	     (((__iter).curr += PAGE_SIZE) >= (__iter).max) ?		\
 	     (__iter) = __sgt_iter(__sg_next((__iter).sgp), false), 0 : 0)
 
-static inline unsigned int i915_sg_page_sizes(struct scatterlist *sg)
+/**
+ * i915_sg_dma_sizes - Record the dma segment sizes of a scatterlist
+ * @sg: The scatterlist
+ *
+ * Return: An unsigned int with segment sizes logically or'ed together.
+ * A caller can use this information to determine what hardware page table
+ * entry sizes can be used to map the memory represented by the scatterlist.
+ */
+static inline unsigned int i915_sg_dma_sizes(struct scatterlist *sg)
 {
 	unsigned int page_sizes;
 
 	page_sizes = 0;
-	while (sg) {
+	while (sg && sg_dma_len(sg)) {
 		GEM_BUG_ON(sg->offset);
-		GEM_BUG_ON(!IS_ALIGNED(sg->length, PAGE_SIZE));
-		page_sizes |= sg->length;
+		GEM_BUG_ON(!IS_ALIGNED(sg_dma_len(sg), PAGE_SIZE));
+		page_sizes |= sg_dma_len(sg);
 		sg = __sg_next(sg);
 	}
 
-- 
2.31.1