[PATCH 06/10] swiotlb: use swiotlb_map_page in swiotlb_map_sg_attrs

Christoph Hellwig
2018-10-08T08:03:27Z

No need to duplicate the code - map_sg is equivalent to map_page
for each page in the scatterlist.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
kernel/dma/swiotlb.c | 34 ++++++++++++----------------------
1 file changed, 12 insertions(+), 22 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 15335f3a1bf3..15755d7a5242 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -845,37 +845,27 @@ swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
* same here.
*/
int
-swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
+swiotlb_map_sg_attrs(struct device *dev, struct scatterlist *sgl, int nelems,
enum dma_data_direction dir, unsigned long attrs)
{
struct scatterlist *sg;
int i;

- BUG_ON(dir == DMA_NONE);
-
for_each_sg(sgl, sg, nelems, i) {
- phys_addr_t paddr = sg_phys(sg);
- dma_addr_t dev_addr = phys_to_dma(hwdev, paddr);
-
- if (swiotlb_force == SWIOTLB_FORCE ||
- !dma_capable(hwdev, dev_addr, sg->length)) {
- phys_addr_t map = map_single(hwdev, sg_phys(sg),
- sg->length, dir, attrs);
- if (map == SWIOTLB_MAP_ERROR) {
- /* Don't panic here, we expect map_sg users
- to do proper error handling. */
- attrs |= DMA_ATTR_SKIP_CPU_SYNC;
- swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
- attrs);
- sg_dma_len(sgl) = 0;
- return 0;
- }
- sg->dma_address = __phys_to_dma(hwdev, map);
- } else
- sg->dma_address = dev_addr;
+ sg->dma_address = swiotlb_map_page(dev, sg_page(sg), sg->offset,
+ sg->length, dir, attrs);
+ if (sg->dma_address == DIRECT_MAPPING_ERROR)
+ goto out_error;
sg_dma_len(sg) = sg->length;
}
+
return nelems;
+
+out_error:
+ swiotlb_unmap_sg_attrs(dev, sgl, i, dir,
+ attrs | DMA_ATTR_SKIP_CPU_SYNC);
+ sg_dma_len(sgl) = 0;
+ return 0;
}

/*
--
2.19.0