[PATCH v2 16/21] drm: host1x: fix sg_table nents vs. orig_nents misuse
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2020-05-04 12:54:31
Also in:
dri-devel, linux-iommu, linux-tegra, lkml
Subsystem:
drm drivers, drm drivers for nvidia tegra, the rest · Maintainers:
David Airlie, Simona Vetter, Thierry Reding, Mikko Perttunen, 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/host1x/job.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/host1x/job.c b/drivers/gpu/host1x/job.c
index a10643a..3ea185e 100644
--- a/drivers/gpu/host1x/job.c
+++ b/drivers/gpu/host1x/job.c@@ -166,8 +166,9 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job) goto unpin; } - err = dma_map_sg(dev, sgt->sgl, sgt->nents, dir); - if (!err) { + sgt->nents = dma_map_sg(dev, sgt->sgl, sgt->orig_nents, + dir); + if (!sgt->nents) { err = -ENOMEM; goto unpin; }
@@ -217,7 +218,7 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job) } if (!IS_ENABLED(CONFIG_TEGRA_HOST1X_FIREWALL) && host->domain) { - for_each_sg(sgt->sgl, sg, sgt->nents, j) + for_each_sg(sgt->sgl, sg, sgt->orig_nents, j) gather_size += sg->length; gather_size = iova_align(&host->iova, gather_size);
@@ -231,7 +232,7 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job) err = iommu_map_sg(host->domain, iova_dma_addr(&host->iova, alloc), - sgt->sgl, sgt->nents, IOMMU_READ); + sgt->sgl, sgt->orig_nents, IOMMU_READ); if (err == 0) { __free_iova(&host->iova, alloc); err = -EINVAL;
@@ -241,9 +242,9 @@ static unsigned int pin_job(struct host1x *host, struct host1x_job *job) job->unpins[job->num_unpins].size = gather_size; phys_addr = iova_dma_addr(&host->iova, alloc); } else if (sgt) { - err = dma_map_sg(host->dev, sgt->sgl, sgt->nents, - DMA_TO_DEVICE); - if (!err) { + sgt->nents = dma_map_sg(host->dev, sgt->sgl, + sgt->orig_nents, DMA_TO_DEVICE); + if (!sgt->nents) { err = -ENOMEM; goto unpin; }
@@ -647,7 +648,7 @@ void host1x_job_unpin(struct host1x_job *job) } if (unpin->dev && sgt) - dma_unmap_sg(unpin->dev, sgt->sgl, sgt->nents, + dma_unmap_sg(unpin->dev, sgt->sgl, sgt->orig_nents, unpin->dir); host1x_bo_unpin(dev, unpin->bo, sgt);
--
1.9.1
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