[patch 017/114] arch/m68k: add option to skip DMA sync as a part of mapping

[patch 017/114] arch/m68k: add option to skip DMA sync as a part of mapping

[akpm]

From: Alexander Duyck <alexander.h.duyck@intel.com>
Subject: arch/m68k: add option to skip DMA sync as a part of mapping

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/20161110113457.76501.77603.stgit@ahduyck-blue-test.jf.intel.com
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/m68k/kernel/dma.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff -puN arch/m68k/kernel/dma.c~arch-m68k-add-option-to-skip-dma-sync-as-a-part-of-mapping arch/m68k/kernel/dma.c
--- a/arch/m68k/kernel/dma.c~arch-m68k-add-option-to-skip-dma-sync-as-a-part-of-mapping
+++ a/arch/m68k/kernel/dma.c
@@ -134,7 +134,9 @@ static dma_addr_t m68k_dma_map_page(stru
 {
 	dma_addr_t handle = page_to_phys(page) + offset;
 
-	dma_sync_single_for_device(dev, handle, size, dir);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_sync_single_for_device(dev, handle, size, dir);
+
 	return handle;
 }
 
@@ -146,6 +148,10 @@ static int m68k_dma_map_sg(struct device
 
 	for_each_sg(sglist, sg, nents, i) {
 		sg->dma_address = sg_phys(sg);
+
+		if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+			continue;
+
 		dma_sync_single_for_device(dev, sg->dma_address, sg->length,
 					   dir);
 	}
_