Replace the current hand-crafted code for extracting pages and DMA addresses from the given scatterlist by the much more robust code based on the generic scatterlist iterators and recently introduced sg_table-based wrappers. The resulting code is simple and easy to understand, so the comment describing the old code is no longer needed.
Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com Reviewed-by: Andrzej Hajda a.hajda@samsung.com Reviewed-by: Robin Murphy robin.murphy@arm.com --- drivers/gpu/drm/drm_prime.c | 49 ++++++++++++------------------------- 1 file changed, 15 insertions(+), 34 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 4ed5ed1f078c..c5e796d4a489 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -990,45 +990,26 @@ EXPORT_SYMBOL(drm_gem_prime_import); int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages, dma_addr_t *addrs, int max_entries) { - unsigned count; - struct scatterlist *sg; - struct page *page; - u32 page_len, page_index; - dma_addr_t addr; - u32 dma_len, dma_index; - - /* - * Scatterlist elements contains both pages and DMA addresses, but - * one shoud not assume 1:1 relation between them. The sg->length is - * the size of the physical memory chunk described by the sg->page, - * while sg_dma_len(sg) is the size of the DMA (IO virtual) chunk - * described by the sg_dma_address(sg). - */ - page_index = 0; - dma_index = 0; - for_each_sg(sgt->sgl, sg, sgt->nents, count) { - page_len = sg->length; - page = sg_page(sg); - dma_len = sg_dma_len(sg); - addr = sg_dma_address(sg); - - while (pages && page_len > 0) { - if (WARN_ON(page_index >= max_entries)) + struct sg_dma_page_iter dma_iter; + struct sg_page_iter page_iter; + struct page **p = pages; + dma_addr_t *a = addrs; + + if (pages) { + for_each_sgtable_page(sgt, &page_iter, 0) { + if (WARN_ON(p - pages >= max_entries)) return -1; - pages[page_index] = page; - page++; - page_len -= PAGE_SIZE; - page_index++; + *p++ = sg_page_iter_page(&page_iter); } - while (addrs && dma_len > 0) { - if (WARN_ON(dma_index >= max_entries)) + } + if (addrs) { + for_each_sgtable_dma_page(sgt, &dma_iter, 0) { + if (WARN_ON(a - addrs >= max_entries)) return -1; - addrs[dma_index] = addr; - addr += PAGE_SIZE; - dma_len -= PAGE_SIZE; - dma_index++; + *a++ = sg_page_iter_dma_address(&dma_iter); } } + return 0; } EXPORT_SYMBOL(drm_prime_sg_to_page_addr_arrays);