[Linaro-mm-sig] [RFC 06/17] drm: i915: fix sg_table nents vs. orig_nents misuse

The Documentation/DMA-API-HOWTO.txt states that dma_map_sg returns the numer of the created entries in the DMA address space. However the subsequent calls to dma_sync_sg_for_{device,cpu} and dma_unmap_sg must be called with the original number of entries passed to dma_map_sg. The sg_table->nents in turn holds the result of the dma_map_sg call as stated in include/linux/scatterlist.h. Adapt the code to obey those rules.

Signed-off-by: Marek Szyprowski m.szyprowski@samsung.com --- drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 13 +++++++------ drivers/gpu/drm/i915/gem/i915_gem_internal.c | 4 ++-- drivers/gpu/drm/i915/gem/i915_gem_region.c | 4 ++-- drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 5 +++-- drivers/gpu/drm/i915/gem/selftests/huge_pages.c | 10 +++++----- drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c | 5 +++-- drivers/gpu/drm/i915/gt/intel_ggtt.c | 12 ++++++------ drivers/gpu/drm/i915/i915_gem_gtt.c | 12 +++++++----- drivers/gpu/drm/i915/i915_scatterlist.c | 4 ++-- drivers/gpu/drm/i915/selftests/scatterlist.c | 8 ++++---- 10 files changed, 41 insertions(+), 36 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c index 7db5a79..d829852 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c @@ -36,21 +36,22 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme goto err_unpin_pages; }

- ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL); + ret = sg_alloc_table(st, obj->mm.pages->orig_nents, GFP_KERNEL); if (ret) goto err_free;

src = obj->mm.pages->sgl; dst = st->sgl; - for (i = 0; i < obj->mm.pages->nents; i++) { + for (i = 0; i < obj->mm.pages->orig_nents; i++) { sg_set_page(dst, sg_page(src), src->length, 0); dst = sg_next(dst); src = sg_next(src); }

- if (!dma_map_sg_attrs(attachment->dev, - st->sgl, st->nents, dir, - DMA_ATTR_SKIP_CPU_SYNC)) { + st->nents = dma_map_sg_attrs(attachment->dev, + st->sgl, st->orig_nents, dir, + DMA_ATTR_SKIP_CPU_SYNC); + if (!st->nents) { ret = -ENOMEM; goto err_free_sg; } @@ -74,7 +75,7 @@ static void i915_gem_unmap_dma_buf(struct dma_buf_attachment *attachment, struct drm_i915_gem_object *obj = dma_buf_to_obj(attachment->dmabuf);

dma_unmap_sg_attrs(attachment->dev, - sg->sgl, sg->nents, dir, + sg->sgl, sg->orig_nents, dir, DMA_ATTR_SKIP_CPU_SYNC); sg_free_table(sg); kfree(sg); diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c b/drivers/gpu/drm/i915/gem/i915_gem_internal.c index cbbff81..a8ebfdd 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c @@ -73,7 +73,7 @@ static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj) }

sg = st->sgl; - st->nents = 0; + st->nents = st->orig_nents = 0; sg_page_sizes = 0;

do { @@ -94,7 +94,7 @@ static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)

sg_set_page(sg, page, PAGE_SIZE << order, 0); sg_page_sizes |= PAGE_SIZE << order; - st->nents++; + st->nents = st->orig_nents = st->nents + 1;

npages -= 1 << order; if (!npages) { diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c index 1515384..58ca560 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_region.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c @@ -53,7 +53,7 @@ GEM_BUG_ON(list_empty(blocks));

sg = st->sgl; - st->nents = 0; + st->nents = st->orig_nents = 0; sg_page_sizes = 0; prev_end = (resource_size_t)-1;

@@ -78,7 +78,7 @@

sg->length = block_size;

- st->nents++; + st->nents = st->orig_nents = st->nents + 1; } else { sg->length += block_size; sg_dma_len(sg) += block_size; diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c index 5d5d7ee..851a732 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c @@ -80,7 +80,7 @@ static int shmem_get_pages(struct drm_i915_gem_object *obj) noreclaim |= __GFP_NORETRY | __GFP_NOWARN;

sg = st->sgl; - st->nents = 0; + st->nents = st->orig_nents = 0; sg_page_sizes = 0; for (i = 0; i < page_count; i++) { const unsigned int shrink[] = { @@ -140,7 +140,8 @@ static int shmem_get_pages(struct drm_i915_gem_object *obj) sg_page_sizes |= sg->length; sg = sg_next(sg); } - st->nents++; + st->nents = st->orig_nents = st->nents + 1; + sg_set_page(sg, page, PAGE_SIZE, 0); } else { sg->length += PAGE_SIZE; diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c index c9988b6..bd141f9 100644 --- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c +++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c @@ -76,7 +76,7 @@ static int get_huge_pages(struct drm_i915_gem_object *obj)

rem = obj->base.size; sg = st->sgl; - st->nents = 0; + st->nents = st->orig_nents = 0; sg_page_sizes = 0;

/* @@ -99,7 +99,7 @@ static int get_huge_pages(struct drm_i915_gem_object *obj)

sg_set_page(sg, page, page_size, 0); sg_page_sizes |= page_size; - st->nents++; + st->nents = st->orig_nents = st->nents + 1;

rem -= page_size; if (!rem) { @@ -201,7 +201,7 @@ static int fake_get_huge_pages(struct drm_i915_gem_object *obj) /* Use optimal page sized chunks to fill in the sg table */ rem = obj->base.size; sg = st->sgl; - st->nents = 0; + st->nents = st->orig_nents = 0; sg_page_sizes = 0; do { unsigned int page_size = get_largest_page_size(i915, rem); @@ -217,7 +217,7 @@ static int fake_get_huge_pages(struct drm_i915_gem_object *obj)

sg_page_sizes |= len;

- st->nents++; + st->nents = st->orig_nents = st->nents + 1;

rem -= len; if (!rem) { @@ -252,7 +252,7 @@ static int fake_get_huge_pages_single(struct drm_i915_gem_object *obj) }

sg = st->sgl; - st->nents = 1; + st->nents = st->orig_nents = 1;

page_size = get_largest_page_size(i915, obj->base.size); GEM_BUG_ON(!page_size); diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c index debaf7b..5723525 100644 --- a/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/selftests/mock_dmabuf.c @@ -28,7 +28,8 @@ static struct sg_table *mock_map_dma_buf(struct dma_buf_attachment *attachment, sg = sg_next(sg); }

- if (!dma_map_sg(attachment->dev, st->sgl, st->nents, dir)) { + st->nents = dma_map_sg(attachment->dev, st->sgl, st->orig_nents, dir); + if (!st->nents) { err = -ENOMEM; goto err_st; } @@ -46,7 +47,7 @@ static void mock_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *st, enum dma_data_direction dir) { - dma_unmap_sg(attachment->dev, st->sgl, st->nents, dir); + dma_unmap_sg(attachment->dev, st->sgl, st->orig_nents, dir); sg_free_table(st); kfree(st); } diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c index 66165b1..9a298bf 100644 --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c @@ -1221,7 +1221,7 @@ void i915_ggtt_resume(struct i915_ggtt *ggtt) for (column = 0; column < width; column++) { src_idx = stride * (height - 1) + column + offset; for (row = 0; row < height; row++) { - st->nents++; + st->nents = st->orig_nents = st->nents + 1; /* * We don't need the pages, but need to initialize * the entries so the sg list can be happily traversed. @@ -1259,7 +1259,7 @@ void i915_ggtt_resume(struct i915_ggtt *ggtt) if (ret) goto err_sg_alloc;

- st->nents = 0; + st->nents = st->orig_nents = 0; sg = st->sgl;

for (i = 0 ; i < ARRAY_SIZE(rot_info->plane); i++) { @@ -1306,7 +1306,7 @@ void i915_ggtt_resume(struct i915_ggtt *ggtt)

length = min(left, length);

- st->nents++; + st->nents = st->orig_nents = st->nents + 1;

sg_set_page(sg, NULL, length, 0); sg_dma_address(sg) = addr; @@ -1343,7 +1343,7 @@ void i915_ggtt_resume(struct i915_ggtt *ggtt) if (ret) goto err_sg_alloc;

- st->nents = 0; + st->nents = st->orig_nents = 0; sg = st->sgl;

for (i = 0 ; i < ARRAY_SIZE(rem_info->plane); i++) { @@ -1389,7 +1389,7 @@ void i915_ggtt_resume(struct i915_ggtt *ggtt) GEM_BUG_ON(!iter);

sg = st->sgl; - st->nents = 0; + st->nents = st->orig_nents = 0; do { unsigned int len;

@@ -1400,7 +1400,7 @@ void i915_ggtt_resume(struct i915_ggtt *ggtt) sg_dma_address(iter) + (offset << PAGE_SHIFT); sg_dma_len(sg) = len;

- st->nents++; + st->nents = st->orig_nents = st->nents + 1; count -= len >> PAGE_SHIFT; if (count == 0) { sg_mark_end(sg); diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index cb43381..c4122cd3 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -28,10 +28,11 @@ int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj, struct sg_table *pages) { do { - if (dma_map_sg_attrs(&obj->base.dev->pdev->dev, - pages->sgl, pages->nents, - PCI_DMA_BIDIRECTIONAL, - DMA_ATTR_NO_WARN)) + pages->nents = dma_map_sg_attrs(&obj->base.dev->pdev->dev, + pages->sgl, pages->orig_nents, + PCI_DMA_BIDIRECTIONAL, + DMA_ATTR_NO_WARN); + if (page->nents) return 0;

/* @@ -68,7 +69,8 @@ void i915_gem_gtt_finish_pages(struct drm_i915_gem_object *obj, } }

- dma_unmap_sg(kdev, pages->sgl, pages->nents, PCI_DMA_BIDIRECTIONAL); + dma_unmap_sg(kdev, pages->sgl, pages->orig_nents, + PCI_DMA_BIDIRECTIONAL); }

/** diff --git a/drivers/gpu/drm/i915/i915_scatterlist.c b/drivers/gpu/drm/i915/i915_scatterlist.c index cc6b384..05bee13 100644 --- a/drivers/gpu/drm/i915/i915_scatterlist.c +++ b/drivers/gpu/drm/i915/i915_scatterlist.c @@ -15,11 +15,11 @@ bool i915_sg_trim(struct sg_table *orig_st) if (orig_st->nents == orig_st->orig_nents) return false;

- if (sg_alloc_table(&new_st, orig_st->nents, GFP_KERNEL | __GFP_NOWARN)) + if (sg_alloc_table(&new_st, orig_st->orig_nents, GFP_KERNEL | __GFP_NOWARN)) return false;

new_sg = new_st.sgl; - for_each_sg(orig_st->sgl, sg, orig_st->nents, i) { + for_each_sg(orig_st->sgl, sg, orig_st->orig_nents, i) { sg_set_page(new_sg, sg_page(sg), sg->length, 0); sg_dma_address(new_sg) = sg_dma_address(sg); sg_dma_len(new_sg) = sg_dma_len(sg); diff --git a/drivers/gpu/drm/i915/selftests/scatterlist.c b/drivers/gpu/drm/i915/selftests/scatterlist.c index d599186..4456fe5 100644 --- a/drivers/gpu/drm/i915/selftests/scatterlist.c +++ b/drivers/gpu/drm/i915/selftests/scatterlist.c @@ -48,9 +48,9 @@ static noinline int expect_pfn_sg(struct pfn_table *pt, unsigned long pfn, n;

pfn = pt->start; - for_each_sg(pt->st.sgl, sg, pt->st.nents, n) { + for_each_sg(pt->st.sgl, sg, pt->st.orig_nents, n) { struct page *page = sg_page(sg); - unsigned int npages = npages_fn(n, pt->st.nents, rnd); + unsigned int npages = npages_fn(n, pt->st.orig_nents, rnd);

if (page_to_pfn(page) != pfn) { pr_err("%s: %s left pages out of order, expected pfn %lu, found pfn %lu (using for_each_sg)\n", @@ -86,7 +86,7 @@ static noinline int expect_pfn_sg_page_iter(struct pfn_table *pt, unsigned long pfn;

pfn = pt->start; - for_each_sg_page(pt->st.sgl, &sgiter, pt->st.nents, 0) { + for_each_sg_page(pt->st.sgl, &sgiter, pt->st.orig_nents, 0) { struct page *page = sg_page_iter_page(&sgiter);

if (page != pfn_to_page(pfn)) { @@ -256,7 +256,7 @@ static int alloc_table(struct pfn_table *pt, pfn += npages; } sg_mark_end(sg); - pt->st.nents = n; + pt->st.nents = pt->st.orig_nents = n; pt->end = pfn;

return 0;