From: Jason Gunthorpe Date: Wed, 28 Oct 2020 19:15:26 +0000 (-0300) Subject: drm: Remove SCATTERLIST_MAX_SEGMENT X-Git-Tag: v5.15~303^2~28^2~1533 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7a60c2dd0f575ab14a457e99582af0ca1e072a74;p=platform%2Fkernel%2Flinux-starfive.git drm: Remove SCATTERLIST_MAX_SEGMENT Since commit 9a40401cfa13 ("lib/scatterlist: Do not limit max_segment to PAGE_ALIGNED values") the max_segment input to sg_alloc_table_from_pages() does not have to be any special value. The new algorithm will always create something less than what the user provides. Thus eliminate this confusing constant. - vmwgfx should use the HW capability, not mix in the OS page size for calling dma_set_max_seg_size() - i915 uses i915_sg_segment_size() both for sg_alloc_table_from_pages and for some open coded sgl construction. This doesn't change the value since rounddown(size, UINT_MAX) == SCATTERLIST_MAX_SEGMENT - drm_prime_pages_to_sg uses it as a default if max_segment is zero, UINT_MAX is fine to use directly. Cc: Gerd Hoffmann Cc: Daniel Vetter Cc: Thomas Hellstrom Cc: Qian Cai Cc: "Ursulin, Tvrtko" Suggested-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/0-v1-44733fccd781+13d-rm_scatterlist_max_jgg@nvidia.com --- diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 187b55e..a7b61c2 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -820,8 +820,8 @@ struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev, if (dev) max_segment = dma_max_mapping_size(dev->dev); - if (max_segment == 0 || max_segment > SCATTERLIST_MAX_SEGMENT) - max_segment = SCATTERLIST_MAX_SEGMENT; + 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, diff --git a/drivers/gpu/drm/i915/i915_scatterlist.h b/drivers/gpu/drm/i915/i915_scatterlist.h index b7b5932..883dd8d 100644 --- a/drivers/gpu/drm/i915/i915_scatterlist.h +++ b/drivers/gpu/drm/i915/i915_scatterlist.h @@ -112,7 +112,7 @@ static inline unsigned int i915_sg_segment_size(void) unsigned int size = swiotlb_max_segment(); if (size == 0) - return SCATTERLIST_MAX_SEGMENT; + size = UINT_MAX; size = rounddown(size, PAGE_SIZE); /* swiotlb_max_segment_size can return 1 byte when it means one page. */ diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c index b3a6095..0c42d2c 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c @@ -794,8 +794,7 @@ static int vmw_driver_load(struct drm_device *dev, unsigned long chipset) if (unlikely(ret != 0)) goto out_err0; - dma_set_max_seg_size(dev->dev, min_t(unsigned int, U32_MAX & PAGE_MASK, - SCATTERLIST_MAX_SEGMENT)); + dma_set_max_seg_size(dev->dev, U32_MAX); if (dev_priv->capabilities & SVGA_CAP_GMR2) { DRM_INFO("Max GMR ids is %u\n", diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h index 36c47e7..6f70572 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -19,12 +19,6 @@ struct scatterlist { }; /* - * Since the above length field is an unsigned int, below we define the maximum - * length in bytes that can be stored in one scatterlist entry. - */ -#define SCATTERLIST_MAX_SEGMENT (UINT_MAX & PAGE_MASK) - -/* * These macros should be used after a dma_map_sg call has been done * to get bus addresses of each of the SG entries and their lengths. * You should only work with the number of sg entries dma_map_sg diff --git a/tools/testing/scatterlist/main.c b/tools/testing/scatterlist/main.c index b2c7e9f..d264bf8 100644 --- a/tools/testing/scatterlist/main.c +++ b/tools/testing/scatterlist/main.c @@ -50,7 +50,7 @@ static void fail(struct test *test, struct sg_table *st, const char *cond) int main(void) { - const unsigned int sgmax = SCATTERLIST_MAX_SEGMENT; + const unsigned int sgmax = UINT_MAX; struct test *test, tests[] = { { -EINVAL, 1, pfn(0), PAGE_SIZE, PAGE_SIZE + 1, 1 }, { -EINVAL, 1, pfn(0), PAGE_SIZE, 0, 1 },