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Groups > linux.kernel > #1519201

[mm PATCH v3 08/23] arch/m68k: Add option to skip DMA sync as a part of mapping

From Alexander Duyck <alexander.h.duyck@intel.com>
Newsgroups linux.kernel
Subject [mm PATCH v3 08/23] arch/m68k: Add option to skip DMA sync as a part of mapping
Date 2016-11-10 18:40 +0100
Message-ID <sC1ur-MX-63@gated-at.bofh.it> (permalink)
References <sC1up-MX-9@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/m68k/kernel/dma.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/m68k/kernel/dma.c b/arch/m68k/kernel/dma.c
index 8cf97cb..0707006 100644
--- a/arch/m68k/kernel/dma.c
+++ b/arch/m68k/kernel/dma.c
@@ -134,7 +134,9 @@ static dma_addr_t m68k_dma_map_page(struct device *dev, struct page *page,
 {
 	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 *dev, struct scatterlist *sglist,
 
 	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);
 	}

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Thread

[mm PATCH v3 00/23] Add support for DMA writable pages being  writable by the network stack Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
  [mm PATCH v3 19/23] arch/xtensa: Add option to skip DMA sync as a  part of mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
  [mm PATCH v3 08/23] arch/m68k: Add option to skip DMA sync as a  part of mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
  [mm PATCH v3 17/23] arch/sparc: Add option to skip DMA sync as a  part of map and unmap Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
  [mm PATCH v3 23/23] igb: Update code to better handle incrementing  page count Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
  [mm PATCH v3 03/23] arch/avr32: Add option to skip sync on DMA map Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
  [mm PATCH v3 15/23] arch/powerpc: Add option to skip DMA sync as a  part of mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
  [mm PATCH v3 12/23] arch/nios2: Add option to skip DMA sync as a  part of map and unmap Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
    Re: [mm PATCH v3 12/23] arch/nios2: Add option to skip DMA sync as a  part of map and unmap Tobias Klauser <tklauser@distanz.ch> - 2016-11-11 12:00 +0100
  [mm PATCH v3 10/23] arch/microblaze: Add option to skip DMA sync as  a part of map and unmap Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:40 +0100
  [mm PATCH v3 04/23] arch/blackfin: Add option to skip sync on DMA  map Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:50 +0100
  [mm PATCH v3 16/23] arch/sh: Add option to skip DMA sync as a part  of mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:50 +0100
  [mm PATCH v3 05/23] arch/c6x: Add option to skip sync on DMA map  and unmap Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:50 +0100
  [mm PATCH v3 13/23] arch/openrisc: Add option to skip DMA sync as a  part of mapping Alexander Duyck <alexander.h.duyck@intel.com> - 2016-11-10 18:50 +0100

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