linux-kernel - [swiotlb PATCH] swiotlb: Minor fix-ups for DMA_ATTR_SKIP_CPU

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:   Thu, 10 Nov 2016 07:05:31 -0500
From:   Alexander Duyck <alexander.h.duyck@...el.com>
To:     konrad.wilk@...cle.com
Cc:     linux-kernel@...r.kernel.org
Subject: [swiotlb PATCH] swiotlb: Minor fix-ups for DMA_ATTR_SKIP_CPU_SYNC
 support

I am updating the paths so that instead of trying to pass
"attr | DMA_ATTR_SKIP_CPU_SYNC" we instead just OR the value into attr and
then pass it since attr will not be used after we make the unmap call.

I realized there was one spot I had missed when I was applying the DMA
attribute to the DMA mapping exception handling.  This change corrects that.

Finally it looks like there is a stray blank line at the end of the
swiotlb_unmap_sg_attrs function that can be dropped.

Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
---
 drivers/xen/swiotlb-xen.c |    4 ++--
 lib/swiotlb.c             |    6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 3d048af..478fb91 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -420,8 +420,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 	if (dma_capable(dev, dev_addr, size))
 		return dev_addr;
 
-	swiotlb_tbl_unmap_single(dev, map, size, dir,
-				 attrs | DMA_ATTR_SKIP_CPU_SYNC);
+	attrs |= DMA_ATTR_SKIP_CPU_SYNC;
+	swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
 
 	return DMA_ERROR_CODE;
 }
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 8e883c7..cb1b54e 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -781,8 +781,8 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
 	if (dma_capable(dev, dev_addr, size))
 		return dev_addr;
 
-	swiotlb_tbl_unmap_single(dev, map, size, dir,
-				 attrs | DMA_ATTR_SKIP_CPU_SYNC);
+	attrs |= DMA_ATTR_SKIP_CPU_SYNC;
+	swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
 
 	return phys_to_dma(dev, io_tlb_overflow_buffer);
 }
@@ -912,6 +912,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
 				/* Don't panic here, we expect map_sg users
 				   to do proper error handling. */
 				swiotlb_full(hwdev, sg->length, dir, 0);
+				attrs |= DMA_ATTR_SKIP_CPU_SYNC;
 				swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
 						       attrs);
 				sg_dma_len(sgl) = 0;
@@ -943,7 +944,6 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 	for_each_sg(sgl, sg, nelems, i)
 		unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir,
 			     attrs);
-
 }
 EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);