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@xxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Thomas Hellstrom <thellstrom@xxxxxxxxxx>
Cc: Qian Cai <cai@xxxxxx>
Cc: "Ursulin, Tvrtko" <tvrtko.ursulin@xxxxxxxxx>
Suggested-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
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 },
--
2.28.0
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