| Message ID | 20200513133245.6408-30-m.szyprowski@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v5,01/38] dma-mapping: add generic helpers for mapping sgtable objects | expand |
> diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c > index acb26c6..89e293b 100644 > --- a/drivers/dma-buf/udmabuf.c > +++ b/drivers/dma-buf/udmabuf.c > @@ -63,10 +63,9 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, > GFP_KERNEL); > if (ret < 0) > goto err; > - if (!dma_map_sg(dev, sg->sgl, sg->nents, direction)) { > - ret = -EINVAL; > + ret = dma_map_sgtable(dev, sg, direction, 0); > + if (ret < 0) > goto err; > - } > return sg; > > err: > @@ -78,7 +77,7 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, > static void put_sg_table(struct device *dev, struct sg_table *sg, > enum dma_data_direction direction) > { > - dma_unmap_sg(dev, sg->sgl, sg->nents, direction); > + dma_unmap_sgtable(dev, sg, direction, 0); > sg_free_table(sg); > kfree(sg); > } Easy straightforward conversation. Acked-by: Gerd Hoffmann <kraxel@redhat.com> take care, Gerd
diff --git a/drivers/dma-buf/heaps/heap-helpers.c b/drivers/dma-buf/heaps/heap-helpers.c index 9f964ca..d0696cf 100644 --- a/drivers/dma-buf/heaps/heap-helpers.c +++ b/drivers/dma-buf/heaps/heap-helpers.c @@ -140,13 +140,12 @@ struct sg_table *dma_heap_map_dma_buf(struct dma_buf_attachment *attachment, enum dma_data_direction direction) { struct dma_heaps_attachment *a = attachment->priv; - struct sg_table *table; - - table = &a->table; + struct sg_table *table = &a->table; + int ret; - if (!dma_map_sg(attachment->dev, table->sgl, table->nents, - direction)) - table = ERR_PTR(-ENOMEM); + ret = dma_map_sgtable(attachment->dev, table, direction, 0); + if (ret) + table = ERR_PTR(ret); return table; } @@ -154,7 +153,7 @@ static void dma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, struct sg_table *table, enum dma_data_direction direction) { - dma_unmap_sg(attachment->dev, table->sgl, table->nents, direction); + dma_unmap_sgtable(attachment->dev, table, direction, 0); } static vm_fault_t dma_heap_vm_fault(struct vm_fault *vmf) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index acb26c6..89e293b 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -63,10 +63,9 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, GFP_KERNEL); if (ret < 0) goto err; - if (!dma_map_sg(dev, sg->sgl, sg->nents, direction)) { - ret = -EINVAL; + ret = dma_map_sgtable(dev, sg, direction, 0); + if (ret < 0) goto err; - } return sg; err: @@ -78,7 +77,7 @@ static struct sg_table *get_sg_table(struct device *dev, struct dma_buf *buf, static void put_sg_table(struct device *dev, struct sg_table *sg, enum dma_data_direction direction) { - dma_unmap_sg(dev, sg->sgl, sg->nents, direction); + dma_unmap_sgtable(dev, sg, direction, 0); sg_free_table(sg); kfree(sg); }
The Documentation/DMA-API-HOWTO.txt states that the dma_map_sg() function returns the number of the created entries in the DMA address space. However the subsequent calls to the dma_sync_sg_for_{device,cpu}() and dma_unmap_sg must be called with the original number of the entries passed to the dma_map_sg(). struct sg_table is a common structure used for describing a non-contiguous memory buffer, used commonly in the DRM and graphics subsystems. It consists of a scatterlist with memory pages and DMA addresses (sgl entry), as well as the number of scatterlist entries: CPU pages (orig_nents entry) and DMA mapped pages (nents entry). It turned out that it was a common mistake to misuse nents and orig_nents entries, calling DMA-mapping functions with a wrong number of entries or ignoring the number of mapped entries returned by the dma_map_sg() function. To avoid such issues, lets use a common dma-mapping wrappers operating directly on the struct sg_table objects and use scatterlist page iterators where possible. This, almost always, hides references to the nents and orig_nents entries, making the code robust, easier to follow and copy/paste safe. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> --- For more information, see '[PATCH v5 00/38] DRM: fix struct sg_table nents vs. orig_nents misuse' thread: https://lore.kernel.org/linux-iommu/20200513132114.6046-1-m.szyprowski@samsung.com/T/ --- drivers/dma-buf/heaps/heap-helpers.c | 13 ++++++------- drivers/dma-buf/udmabuf.c | 7 +++---- 2 files changed, 9 insertions(+), 11 deletions(-)