Re: [Intel-gfx] [RFC 06/17] drm: i915: fix sg_table nents vs. orig_nents misuse
Hi On 28.04.2020 16:27, Tvrtko Ursulin wrote: > > On 28/04/2020 14:19, Marek Szyprowski wrote: >> 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 >> --- >> 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
Re: [Intel-gfx] [RFC 06/17] drm: i915: fix sg_table nents vs. orig_nents misuse
On 28/04/2020 14:19, Marek Szyprowski wrote: 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 --- 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++) {
[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 --- 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