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authorAlexander Duyck <alexander.h.duyck@intel.com>2016-12-14 15:04:29 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-14 16:04:07 -0800
commit8a3385d2d47cd912f28d23bd2225ee37de518d86 (patch)
tree20bcdbfd49f6004cccf2cbddb8ebb2fe206b803c /arch/arc
parent7560ef39dc0bfebba8f43766d8bb4c1ec5eb66fc (diff)
arch/arc: add option to skip sync on DMA mapping
Patch series "Add support for DMA writable pages being writable by the network stack", v3. The first 19 patches in the set add support for the DMA attribute DMA_ATTR_SKIP_CPU_SYNC on multiple platforms/architectures. This is needed so that we can flag the calls to dma_map/unmap_page so that we do not invalidate cache lines that do not currently belong to the device. Instead we have to take care of this in the driver via a call to sync_single_range_for_cpu prior to freeing the Rx page. Patch 20 adds support for dma_map_page_attrs and dma_unmap_page_attrs so that we can unmap and map a page using the DMA_ATTR_SKIP_CPU_SYNC attribute. Patch 21 adds support for freeing a page that has multiple references being held by a single caller. This way we can free page fragments that were allocated by a given driver. The last 2 patches use these updates in the igb driver, and lay the groundwork to allow for us to reimplement the use of build_skb. This patch (of 23): This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to avoid invoking cache line invalidation if the driver will just handle it later via a sync_for_cpu or sync_for_device call. Link: http://lkml.kernel.org/r/20161110113419.76501.38491.stgit@ahduyck-blue-test.jf.intel.com Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arc')
-rw-r--r--arch/arc/mm/dma.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index cd8aad8226dd..08450a1a5b5f 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -158,7 +158,10 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
unsigned long attrs)
{
phys_addr_t paddr = page_to_phys(page) + offset;
- _dma_cache_sync(paddr, size, dir);
+
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ _dma_cache_sync(paddr, size, dir);
+
return plat_phys_to_dma(dev, paddr);
}