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 kraxel@redhat.com Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Thomas Hellstrom thellstrom@vmware.com Cc: Qian Cai cai@lca.pw Cc: "Ursulin, Tvrtko" tvrtko.ursulin@intel.com Suggested-by: Christoph Hellwig hch@lst.de Signed-off-by: Jason Gunthorpe jgg@nvidia.com --- drivers/gpu/drm/drm_prime.c | 4 ++-- drivers/gpu/drm/i915/i915_scatterlist.h | 2 +- drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 3 +-- include/linux/scatterlist.h | 6 ------ tools/testing/scatterlist/main.c | 2 +- 5 files changed, 5 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index d6808f678db541..c3693e5e8b74b0 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -816,8 +816,8 @@ 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 b7b59328cb76ab..883dd8d09d6bf2 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 31e3e5c9f36223..c1817f1a3006e0 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.c @@ -792,8 +792,7 @@ 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 36c47e7e66a203..6f70572b2938be 100644 --- a/include/linux/scatterlist.h +++ b/include/linux/scatterlist.h @@ -18,12 +18,6 @@ struct scatterlist { #endif };
-/* - * 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. diff --git a/tools/testing/scatterlist/main.c b/tools/testing/scatterlist/main.c index b2c7e9f7b8d3dc..d264bf853034bd 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 },