[PATCH v2 01/21] drm: core: fix sg_table nents vs. orig_nents misuse
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2020-05-04 12:54:14
Also in:
dri-devel, linux-iommu, lkml
Subsystem:
drm drivers, drm drivers and misc gpu patches, the rest · Maintainers:
David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds
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/drm_cache.c | 2 +-
drivers/gpu/drm/drm_gem_shmem_helper.c | 7 ++++---
drivers/gpu/drm/drm_prime.c | 9 +++++----
3 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c
index 03e01b0..63bd497 100644
--- a/drivers/gpu/drm/drm_cache.c
+++ b/drivers/gpu/drm/drm_cache.c@@ -127,7 +127,7 @@ static void drm_cache_flush_clflush(struct page *pages[], struct sg_page_iter sg_iter; mb(); /*CLFLUSH is ordered only by using memory barriers*/ - for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) + for_each_sg_page(st->sgl, &sg_iter, st->orig_nents, 0) drm_clflush_page(sg_page_iter_page(&sg_iter)); mb(); /*Make sure that all cache line entry is flushed*/
diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
index df31e57..f47caa7 100644
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c
+++ b/drivers/gpu/drm/drm_gem_shmem_helper.c@@ -118,7 +118,7 @@ void drm_gem_shmem_free_object(struct drm_gem_object *obj) } else { if (shmem->sgt) { dma_unmap_sg(obj->dev->dev, shmem->sgt->sgl, - shmem->sgt->nents, DMA_BIDIRECTIONAL); + shmem->sgt->orig_nents, DMA_BIDIRECTIONAL); sg_free_table(shmem->sgt); kfree(shmem->sgt); }
@@ -396,7 +396,7 @@ void drm_gem_shmem_purge_locked(struct drm_gem_object *obj) WARN_ON(!drm_gem_shmem_is_purgeable(shmem)); dma_unmap_sg(obj->dev->dev, shmem->sgt->sgl, - shmem->sgt->nents, DMA_BIDIRECTIONAL); + shmem->sgt->orig_nents, DMA_BIDIRECTIONAL); sg_free_table(shmem->sgt); kfree(shmem->sgt); shmem->sgt = NULL;
@@ -623,7 +623,8 @@ struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_object *obj) goto err_put_pages; } /* Map the pages for use by the h/w. */ - dma_map_sg(obj->dev->dev, sgt->sgl, sgt->nents, DMA_BIDIRECTIONAL); + sgt->nents = dma_map_sg(obj->dev->dev, sgt->sgl, sgt->orig_nents, + DMA_BIDIRECTIONAL); shmem->sgt = sgt;
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 282774e..f3e2d2a 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c@@ -626,8 +626,9 @@ struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach, else sgt = obj->dev->driver->gem_prime_get_sg_table(obj); - if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir, - DMA_ATTR_SKIP_CPU_SYNC)) { + sgt->nents = dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->orig_nents, + dir, DMA_ATTR_SKIP_CPU_SYNC); + if (!sgt->nents) { sg_free_table(sgt); kfree(sgt); sgt = ERR_PTR(-ENOMEM);
@@ -652,7 +653,7 @@ void drm_gem_unmap_dma_buf(struct dma_buf_attachment *attach, if (!sgt) return; - dma_unmap_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir, + dma_unmap_sg_attrs(attach->dev, sgt->sgl, sgt->orig_nents, dir, DMA_ATTR_SKIP_CPU_SYNC); sg_free_table(sgt); kfree(sgt);
@@ -975,7 +976,7 @@ int drm_prime_sg_to_page_addr_arrays(struct sg_table *sgt, struct page **pages, */ page_index = 0; dma_index = 0; - for_each_sg(sgt->sgl, sg, sgt->nents, count) { + for_each_sg(sgt->sgl, sg, sgt->orig_nents, count) { page_len = sg->length; page = sg_page(sg); dma_len = sg_dma_len(sg);
--
1.9.1
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