8 files changed, 35 insertions, 21 deletions

diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index bc8edbeca3fd..bb8f58012189 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c
@@ -109,7 +109,7 @@ drm_clflush_sg(struct sg_table *st)
 
                 mb();
                 for_each_sg_page(st->sgl, &sg_iter, st->nents, 0)
-                        drm_clflush_page(sg_iter.page);
+                        drm_clflush_page(sg_page_iter_page(&sg_iter));
                 mb();
 
                 return;
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1d091ea12fad..f69538508d8c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1543,7 +1543,7 @@ static inline struct page *i915_gem_object_get_page(struct drm_i915_gem_object *
         struct sg_page_iter sg_iter;
 
         for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, n)
-                return sg_iter.page;
+                return sg_page_iter_page(&sg_iter);
 
         return NULL;
 }
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a1123a32dc27..911bd40ef513 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -442,7 +442,7 @@ i915_gem_shmem_pread(struct drm_device *dev,
 
         for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents,
                          offset >> PAGE_SHIFT) {
-                struct page *page = sg_iter.page;
+                struct page *page = sg_page_iter_page(&sg_iter);
 
                 if (remain <= 0)
                         break;
@@ -765,7 +765,7 @@ i915_gem_shmem_pwrite(struct drm_device *dev,
 
         for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents,
                          offset >> PAGE_SHIFT) {
-                struct page *page = sg_iter.page;
+                struct page *page = sg_page_iter_page(&sg_iter);
                 int partial_cacheline_write;
 
                 if (remain <= 0)
@@ -1647,7 +1647,7 @@ i915_gem_object_put_pages_gtt(struct drm_i915_gem_object *obj)
                 obj->dirty = 0;
 
         for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) {
-                struct page *page = sg_iter.page;
+                struct page *page = sg_page_iter_page(&sg_iter);
 
                 if (obj->dirty)
                         set_page_dirty(page);
@@ -1827,7 +1827,7 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
 err_pages:
         sg_mark_end(sg);
         for_each_sg_page(st->sgl, &sg_iter, st->nents, 0)
-                page_cache_release(sg_iter.page);
+                page_cache_release(sg_page_iter_page(&sg_iter));
         sg_free_table(st);
         kfree(st);
         return PTR_ERR(page);
diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
index 898615d2d5e2..c6dfc1466e3a 100644
--- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c
@@ -130,7 +130,7 @@ static void *i915_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 
         i = 0;
         for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0);
-                pages[i++] = sg_iter.page;
+                pages[i++] = sg_page_iter_page(&sg_iter);
 
         obj->dma_buf_vmapping = vmap(pages, i, 0, PAGE_KERNEL);
         drm_free_large(pages);
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 4cbae7bbb833..24a23b31b55f 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -123,8 +123,7 @@ static void gen6_ppgtt_insert_entries(struct i915_hw_ppgtt *ppgtt,
         for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
                 dma_addr_t page_addr;
 
-                page_addr = sg_dma_address(sg_iter.sg) +
-                                (sg_iter.sg_pgoffset << PAGE_SHIFT);
+                page_addr = sg_page_iter_dma_address(&sg_iter);
                 pt_vaddr[act_pte] = gen6_pte_encode(ppgtt->dev, page_addr,
                                                     cache_level);
                 if (++act_pte == I915_PPGTT_PT_ENTRIES) {
@@ -424,8 +423,7 @@ static void gen6_ggtt_insert_entries(struct drm_device *dev,
         dma_addr_t addr;
 
         for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) {
-                addr = sg_dma_address(sg_iter.sg) +
-                        (sg_iter.sg_pgoffset << PAGE_SHIFT);
+                addr = sg_page_iter_dma_address(&sg_iter);
                 iowrite32(gen6_pte_encode(dev, addr, level), &gtt_entries[i]);
                 i++;
         }
diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
index f799708bcb85..c807eb93755b 100644
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -481,7 +481,7 @@ i915_gem_object_do_bit_17_swizzle(struct drm_i915_gem_object *obj)
 
         i = 0;
         for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) {
-                struct page *page = sg_iter.page;
+                struct page *page = sg_page_iter_page(&sg_iter);
                 char new_bit_17 = page_to_phys(page) >> 17;
                 if ((new_bit_17 & 0x1) !=
                     (test_bit(i, obj->bit_17) != 0)) {
@@ -511,7 +511,7 @@ i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj)
 
         i = 0;
         for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) {
-                if (page_to_phys(sg_iter.page) & (1 << 17))
+                if (page_to_phys(sg_page_iter_page(&sg_iter)) & (1 << 17))
                         __set_bit(i, obj->bit_17);
                 else
                         __clear_bit(i, obj->bit_17);
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 2d8bdaef9611..e96b9546c4c6 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -235,13 +235,13 @@ size_t sg_copy_to_buffer(struct scatterlist *sgl, unsigned int nents,
  * sg page iterator
  *
  * Iterates over sg entries page-by-page.  On each successful iteration,
- * @piter->page points to the current page, @piter->sg to the sg holding this
- * page and @piter->sg_pgoffset to the page's page offset within the sg. The
- * iteration will stop either when a maximum number of sg entries was reached
- * or a terminating sg (sg_last(sg) == true) was reached.
+ * you can call sg_page_iter_page(@piter) and sg_page_iter_dma_address(@piter)
+ * to get the current page and its dma address. @piter->sg will point to the
+ * sg holding this page and @piter->sg_pgoffset to the page's page offset
+ * within the sg. The iteration will stop either when a maximum number of sg
+ * entries was reached or a terminating sg (sg_last(sg) == true) was reached.
  */
 struct sg_page_iter {
-        struct page             *page;          /* current page */
         struct scatterlist      *sg;            /* sg holding the page */
         unsigned int            sg_pgoffset;    /* page offset within the sg */
 
@@ -255,6 +255,24 @@ bool __sg_page_iter_next(struct sg_page_iter *piter);
 void __sg_page_iter_start(struct sg_page_iter *piter,
                           struct scatterlist *sglist, unsigned int nents,
                           unsigned long pgoffset);
+/**
+ * sg_page_iter_page - get the current page held by the page iterator
+ * @piter:      page iterator holding the page
+ */
+static inline struct page *sg_page_iter_page(struct sg_page_iter *piter)
+{
+        return nth_page(sg_page(piter->sg), piter->sg_pgoffset);
+}
+
+/**
+ * sg_page_iter_dma_address - get the dma address of the current page held by
+ * the page iterator.
+ * @piter:      page iterator holding the page
+ */
+static inline dma_addr_t sg_page_iter_dma_address(struct sg_page_iter *piter)
+{
+        return sg_dma_address(piter->sg) + (piter->sg_pgoffset << PAGE_SHIFT);
+}
 
 /**
  * for_each_sg_page - iterate over the pages of the given sg list
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index b83c144d731f..a1cf8cae60e7 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -401,7 +401,6 @@ void __sg_page_iter_start(struct sg_page_iter *piter,
         piter->__pg_advance = 0;
         piter->__nents = nents;
 
-        piter->page = NULL;
         piter->sg = sglist;
         piter->sg_pgoffset = pgoffset;
 }
@@ -426,7 +425,6 @@ bool __sg_page_iter_next(struct sg_page_iter *piter)
                 if (!--piter->__nents || !piter->sg)
                         return false;
         }
-        piter->page = nth_page(sg_page(piter->sg), piter->sg_pgoffset);
 
         return true;
 }
@@ -496,7 +494,7 @@ bool sg_miter_next(struct sg_mapping_iter *miter)
                 miter->__remaining = min_t(unsigned long, miter->__remaining,
                                            PAGE_SIZE - miter->__offset);
         }
-        miter->page = miter->piter.page;
+        miter->page = sg_page_iter_page(&miter->piter);
         miter->consumed = miter->length = miter->__remaining;
 
         if (miter->__flags & SG_MITER_ATOMIC)