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| author | Jason Gunthorpe <jgg@nvidia.com> | 2020-10-28 16:15:26 -0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2020-11-02 14:42:57 +0100 |
| commit | 7a60c2dd0f575ab14a457e99582af0ca1e072a74 (patch) | |
| tree | e243aaf15c18c1a8e45528884ffcc7caf398f6f1 | |
| parent | 95d7a1a6f867f5e6acf62e07a463e0bea1d47b68 (diff) | |
| download | lwn-7a60c2dd0f575ab14a457e99582af0ca1e072a74.tar.gz lwn-7a60c2dd0f575ab14a457e99582af0ca1e072a74.zip | |
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 <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>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/0-v1-44733fccd781+13d-rm_scatterlist_max_jgg@nvidia.com
| -rw-r--r-- | drivers/gpu/drm/drm_prime.c | 4 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_scatterlist.h | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/vmwgfx/vmwgfx_drv.c | 3 | ||||
| -rw-r--r-- | include/linux/scatterlist.h | 6 | ||||
| -rw-r--r-- | 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 187b55ede62e..a7b61c2d9190 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 b7b59328cb76..883dd8d09d6b 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 b3a60959b5d5..0c42d2c05f43 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 36c47e7e66a2..6f70572b2938 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 b2c7e9f7b8d3..d264bf853034 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 }, |