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Message-Id: <20200428132005.21424-8-m.szyprowski@samsung.com>
Date: Tue, 28 Apr 2020 15:19:55 +0200
From: Marek Szyprowski <m.szyprowski@...sung.com>
To: dri-devel@...ts.freedesktop.org, iommu@...ts.linux-foundation.org,
linaro-mm-sig@...ts.linaro.org, linux-kernel@...r.kernel.org
Cc: Marek Szyprowski <m.szyprowski@...sung.com>,
Christoph Hellwig <hch@....de>,
Robin Murphy <robin.murphy@....com>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Sumit Semwal <sumit.semwal@...aro.org>,
Benjamin Gaignard <benjamin.gaignard@...aro.org>,
intel-gfx@...ts.freedesktop.org,
linux-arm-kernel@...ts.infradead.org,
amd-gfx@...ts.freedesktop.org, David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>
Subject: [RFC 07/17] drm: lima: 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@...sung.com>
---
drivers/gpu/drm/lima/lima_gem.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/lima/lima_gem.c b/drivers/gpu/drm/lima/lima_gem.c
index 5404e0d..3edd2ff 100644
--- a/drivers/gpu/drm/lima/lima_gem.c
+++ b/drivers/gpu/drm/lima/lima_gem.c
@@ -70,7 +70,7 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm)
if (bo->base.sgt) {
dma_unmap_sg(dev, bo->base.sgt->sgl,
- bo->base.sgt->nents, DMA_BIDIRECTIONAL);
+ bo->base.sgt->orig_nents, DMA_BIDIRECTIONAL);
sg_free_table(bo->base.sgt);
} else {
bo->base.sgt = kmalloc(sizeof(*bo->base.sgt), GFP_KERNEL);
@@ -80,7 +80,7 @@ int lima_heap_alloc(struct lima_bo *bo, struct lima_vm *vm)
}
}
- dma_map_sg(dev, sgt.sgl, sgt.nents, DMA_BIDIRECTIONAL);
+ sgt.nents = dma_map_sg(dev, sgt.sgl, sgt.orig_nents, DMA_BIDIRECTIONAL);
*bo->base.sgt = sgt;
--
1.9.1
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