[PATCH v2 11/21] drm: rockchip: fix sg_table nents vs. orig_nents misuse
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2020-05-04 12:55:09
Also in:
dri-devel, linux-iommu, lkml
Subsystem:
arm/rockchip soc support, drm drivers, drm drivers and misc gpu patches, drm drivers for rockchip, the rest · Maintainers:
Heiko Stuebner, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Sandy Huang, Heiko Stübner, Andy Yan, 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>
---
For more information, see '[PATCH v2 00/21] DRM: fix struct sg_table nents
vs. orig_nents misuse' thread: https://lkml.org/lkml/2020/5/4/373
---
drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index 0d18846..a024c71 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c@@ -37,7 +37,7 @@ static int rockchip_gem_iommu_map(struct rockchip_gem_object *rk_obj) rk_obj->dma_addr = rk_obj->mm.start; ret = iommu_map_sg(private->domain, rk_obj->dma_addr, rk_obj->sgt->sgl, - rk_obj->sgt->nents, prot); + rk_obj->sgt->orig_nents, prot); if (ret < rk_obj->base.size) { DRM_ERROR("failed to map buffer: size=%zd request_size=%zd\n", ret, rk_obj->base.size);
@@ -98,11 +98,11 @@ static int rockchip_gem_get_pages(struct rockchip_gem_object *rk_obj) * TODO: Replace this by drm_clflush_sg() once it can be implemented * without relying on symbols that are not exported. */ - for_each_sg(rk_obj->sgt->sgl, s, rk_obj->sgt->nents, i) + for_each_sg(rk_obj->sgt->sgl, s, rk_obj->sgt->orig_nents, i) sg_dma_address(s) = sg_phys(s); - dma_sync_sg_for_device(drm->dev, rk_obj->sgt->sgl, rk_obj->sgt->nents, - DMA_TO_DEVICE); + dma_sync_sg_for_device(drm->dev, rk_obj->sgt->sgl, + rk_obj->sgt->orig_nents, DMA_TO_DEVICE); return 0;
@@ -351,7 +351,8 @@ void rockchip_gem_free_object(struct drm_gem_object *obj) rockchip_gem_iommu_unmap(rk_obj); } else { dma_unmap_sg(drm->dev, rk_obj->sgt->sgl, - rk_obj->sgt->nents, DMA_BIDIRECTIONAL); + rk_obj->sgt->orig_nents, + DMA_BIDIRECTIONAL); } drm_prime_gem_destroy(obj, rk_obj->sgt); } else {
@@ -493,14 +494,14 @@ static unsigned long rockchip_sg_get_contiguous_size(struct sg_table *sgt, struct sg_table *sg, struct rockchip_gem_object *rk_obj) { - int count = dma_map_sg(drm->dev, sg->sgl, sg->nents, + int count = dma_map_sg(drm->dev, sg->sgl, sg->orig_nents, DMA_BIDIRECTIONAL); if (!count) return -EINVAL; if (rockchip_sg_get_contiguous_size(sg, count) < attach->dmabuf->size) { DRM_ERROR("failed to map sg_table to contiguous linear address.\n"); - dma_unmap_sg(drm->dev, sg->sgl, sg->nents, + dma_unmap_sg(drm->dev, sg->sgl, sg->orig_nents, DMA_BIDIRECTIONAL); return -EINVAL; }
--
1.9.1
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