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[mm PATCH v3 00/23] Add support for DMA writable pages being writable by the network stack

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  [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
      Re: [mm PATCH v3 17/23] arch/sparc: Add option to skip DMA sync as  a part of map and unmap David Miller <davem@davemloft.net> - 2016-11-13 18:30 +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
    Re: [mm PATCH v3 00/23] Add support for DMA writable pages being  writable by the network stack Alexander Duyck <alexander.duyck@gmail.com> - 2016-11-18 17:20 +0100

#1519196 — [mm PATCH v3 00/23] Add support for DMA writable pages being writable by the network stack

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.

v1: Minor fixes based on issues found by kernel build bot
    Few minor changes for issues found on code review
    Added Acked-by for patches that were acked and not changed

v2: Added a few more Acked-by
    Submitting patches to mm instead of net-next

v3: Added Acked-by for PowerPC architecture
    Dropped first 3 patches which were accepted into swiotlb tree
    Dropped comments describing swiotlb changes.

---

Alexander Duyck (23):
      arch/arc: Add option to skip sync on DMA mapping
      arch/arm: Add option to skip sync on DMA map and unmap
      arch/avr32: Add option to skip sync on DMA map
      arch/blackfin: Add option to skip sync on DMA map
      arch/c6x: Add option to skip sync on DMA map and unmap
      arch/frv: Add option to skip sync on DMA map
      arch/hexagon: Add option to skip DMA sync as a part of mapping
      arch/m68k: Add option to skip DMA sync as a part of mapping
      arch/metag: Add option to skip DMA sync as a part of map and unmap
      arch/microblaze: Add option to skip DMA sync as a part of map and unmap
      arch/mips: Add option to skip DMA sync as a part of map and unmap
      arch/nios2: Add option to skip DMA sync as a part of map and unmap
      arch/openrisc: Add option to skip DMA sync as a part of mapping
      arch/parisc: Add option to skip DMA sync as a part of map and unmap
      arch/powerpc: Add option to skip DMA sync as a part of mapping
      arch/sh: Add option to skip DMA sync as a part of mapping
      arch/sparc: Add option to skip DMA sync as a part of map and unmap
      arch/tile: Add option to skip DMA sync as a part of map and unmap
      arch/xtensa: Add option to skip DMA sync as a part of mapping
      dma: Add calls for dma_map_page_attrs and dma_unmap_page_attrs
      mm: Add support for releasing multiple instances of a page
      igb: Update driver to make use of DMA_ATTR_SKIP_CPU_SYNC
      igb: Update code to better handle incrementing page count


 arch/arc/mm/dma.c                         |    5 ++
 arch/arm/common/dmabounce.c               |   16 ++++--
 arch/avr32/mm/dma-coherent.c              |    7 ++-
 arch/blackfin/kernel/dma-mapping.c        |    8 +++
 arch/c6x/kernel/dma.c                     |   14 ++++-
 arch/frv/mb93090-mb00/pci-dma-nommu.c     |   14 ++++-
 arch/frv/mb93090-mb00/pci-dma.c           |    9 +++
 arch/hexagon/kernel/dma.c                 |    6 ++
 arch/m68k/kernel/dma.c                    |    8 +++
 arch/metag/kernel/dma.c                   |   16 +++++-
 arch/microblaze/kernel/dma.c              |   10 +++-
 arch/mips/loongson64/common/dma-swiotlb.c |    2 -
 arch/mips/mm/dma-default.c                |    8 ++-
 arch/nios2/mm/dma-mapping.c               |   26 +++++++---
 arch/openrisc/kernel/dma.c                |    3 +
 arch/parisc/kernel/pci-dma.c              |   20 ++++++--
 arch/powerpc/kernel/dma.c                 |    9 +++
 arch/sh/kernel/dma-nommu.c                |    7 ++-
 arch/sparc/kernel/iommu.c                 |    4 +-
 arch/sparc/kernel/ioport.c                |    4 +-
 arch/tile/kernel/pci-dma.c                |   12 ++++-
 arch/xtensa/kernel/pci-dma.c              |    7 ++-
 drivers/net/ethernet/intel/igb/igb.h      |    7 ++-
 drivers/net/ethernet/intel/igb/igb_main.c |   77 +++++++++++++++++++----------
 include/linux/dma-mapping.h               |   20 +++++---
 include/linux/gfp.h                       |    2 +
 mm/page_alloc.c                           |   14 +++++
 27 files changed, 246 insertions(+), 89 deletions(-)

--

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#1519199 — [mm PATCH v3 19/23] arch/xtensa: 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
via a sync_for_cpu or sync_for_device call.

Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/xtensa/kernel/pci-dma.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index 1e68806..6a16dec 100644
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -189,7 +189,9 @@ static dma_addr_t xtensa_map_page(struct device *dev, struct page *page,
 {
 	dma_addr_t dma_handle = page_to_phys(page) + offset;
 
-	xtensa_sync_single_for_device(dev, dma_handle, size, dir);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		xtensa_sync_single_for_device(dev, dma_handle, size, dir);
+
 	return dma_handle;
 }
 
@@ -197,7 +199,8 @@ static void xtensa_unmap_page(struct device *dev, dma_addr_t dma_handle,
 			      size_t size, enum dma_data_direction dir,
 			      unsigned long attrs)
 {
-	xtensa_sync_single_for_cpu(dev, dma_handle, size, dir);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		xtensa_sync_single_for_cpu(dev, dma_handle, size, dir);
 }
 
 static int xtensa_map_sg(struct device *dev, struct scatterlist *sg,

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#1519201 — [mm PATCH v3 08/23] 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.

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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#1519206 — [mm PATCH v3 17/23] arch/sparc: Add option to skip DMA sync as a part of map and unmap

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
via a sync_for_cpu or sync_for_device call.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/sparc/kernel/iommu.c  |    4 ++--
 arch/sparc/kernel/ioport.c |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
index 5c615ab..8fda4e4 100644
--- a/arch/sparc/kernel/iommu.c
+++ b/arch/sparc/kernel/iommu.c
@@ -415,7 +415,7 @@ static void dma_4u_unmap_page(struct device *dev, dma_addr_t bus_addr,
 		ctx = (iopte_val(*base) & IOPTE_CONTEXT) >> 47UL;
 
 	/* Step 1: Kick data out of streaming buffers if necessary. */
-	if (strbuf->strbuf_enabled)
+	if (strbuf->strbuf_enabled && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		strbuf_flush(strbuf, iommu, bus_addr, ctx,
 			     npages, direction);
 
@@ -640,7 +640,7 @@ static void dma_4u_unmap_sg(struct device *dev, struct scatterlist *sglist,
 		base = iommu->page_table + entry;
 
 		dma_handle &= IO_PAGE_MASK;
-		if (strbuf->strbuf_enabled)
+		if (strbuf->strbuf_enabled && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 			strbuf_flush(strbuf, iommu, dma_handle, ctx,
 				     npages, direction);
 
diff --git a/arch/sparc/kernel/ioport.c b/arch/sparc/kernel/ioport.c
index 2344103..6ffaec4 100644
--- a/arch/sparc/kernel/ioport.c
+++ b/arch/sparc/kernel/ioport.c
@@ -527,7 +527,7 @@ static dma_addr_t pci32_map_page(struct device *dev, struct page *page,
 static void pci32_unmap_page(struct device *dev, dma_addr_t ba, size_t size,
 			     enum dma_data_direction dir, unsigned long attrs)
 {
-	if (dir != PCI_DMA_TODEVICE)
+	if (dir != PCI_DMA_TODEVICE && !(attrs & DMA_ATTR_SKIP_CPU_SYNC))
 		dma_make_coherent(ba, PAGE_ALIGN(size));
 }
 
@@ -572,7 +572,7 @@ static void pci32_unmap_sg(struct device *dev, struct scatterlist *sgl,
 	struct scatterlist *sg;
 	int n;
 
-	if (dir != PCI_DMA_TODEVICE) {
+	if (dir != PCI_DMA_TODEVICE && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
 		for_each_sg(sgl, sg, nents, n) {
 			dma_make_coherent(sg_phys(sg), PAGE_ALIGN(sg->length));
 		}

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#1520626 — Re: [mm PATCH v3 17/23] arch/sparc: Add option to skip DMA sync as a part of map and unmap

From: Alexander Duyck <alexander.h.duyck@intel.com>
Date: Thu, 10 Nov 2016 06:35:45 -0500

> 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
> via a sync_for_cpu or sync_for_device call.
> 
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>

Acked-by: David S. Miller <davem@davemloft.net>

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#1519207 — [mm PATCH v3 23/23] igb: Update code to better handle incrementing page count

This patch updates the driver code so that we do bulk updates of the page
reference count instead of just incrementing it by one reference at a time.
The advantage to doing this is that we cut down on atomic operations and
this in turn should give us a slight improvement in cycles per packet.  In
addition if we eventually move this over to using build_skb the gains will
be more noticeable.

Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 drivers/net/ethernet/intel/igb/igb.h      |    7 ++++++-
 drivers/net/ethernet/intel/igb/igb_main.c |   24 +++++++++++++++++-------
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
index 5387b3a..786de01 100644
--- a/drivers/net/ethernet/intel/igb/igb.h
+++ b/drivers/net/ethernet/intel/igb/igb.h
@@ -210,7 +210,12 @@ struct igb_tx_buffer {
 struct igb_rx_buffer {
 	dma_addr_t dma;
 	struct page *page;
-	unsigned int page_offset;
+#if (BITS_PER_LONG > 32) || (PAGE_SIZE >= 65536)
+	__u32 page_offset;
+#else
+	__u16 page_offset;
+#endif
+	__u16 pagecnt_bias;
 };
 
 struct igb_tx_queue_stats {
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index ba97392..f5a9fd6 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -3937,7 +3937,8 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring)
 				     PAGE_SIZE,
 				     DMA_FROM_DEVICE,
 				     DMA_ATTR_SKIP_CPU_SYNC);
-		__free_page(buffer_info->page);
+		__page_frag_drain(buffer_info->page, 0,
+				  buffer_info->pagecnt_bias);
 
 		buffer_info->page = NULL;
 	}
@@ -6813,13 +6814,15 @@ static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer,
 				  struct page *page,
 				  unsigned int truesize)
 {
+	unsigned int pagecnt_bias = rx_buffer->pagecnt_bias--;
+
 	/* avoid re-using remote pages */
 	if (unlikely(igb_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
 	/* if we are only owner of page we can reuse it */
-	if (unlikely(page_count(page) != 1))
+	if (unlikely(page_ref_count(page) != pagecnt_bias))
 		return false;
 
 	/* flip page offset to other buffer */
@@ -6832,10 +6835,14 @@ static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer,
 		return false;
 #endif
 
-	/* Even if we own the page, we are not allowed to use atomic_set()
-	 * This would break get_page_unless_zero() users.
+	/* If we have drained the page fragment pool we need to update
+	 * the pagecnt_bias and page count so that we fully restock the
+	 * number of references the driver holds.
 	 */
-	page_ref_inc(page);
+	if (unlikely(pagecnt_bias == 1)) {
+		page_ref_add(page, USHRT_MAX);
+		rx_buffer->pagecnt_bias = USHRT_MAX;
+	}
 
 	return true;
 }
@@ -6887,7 +6894,6 @@ static bool igb_add_rx_frag(struct igb_ring *rx_ring,
 			return true;
 
 		/* this page cannot be reused so discard it */
-		__free_page(page);
 		return false;
 	}
 
@@ -6958,10 +6964,13 @@ static struct sk_buff *igb_fetch_rx_buffer(struct igb_ring *rx_ring,
 		/* hand second half of page back to the ring */
 		igb_reuse_rx_page(rx_ring, rx_buffer);
 	} else {
-		/* we are not reusing the buffer so unmap it */
+		/* We are not reusing the buffer so unmap it and free
+		 * any references we are holding to it
+		 */
 		dma_unmap_page_attrs(rx_ring->dev, rx_buffer->dma,
 				     PAGE_SIZE, DMA_FROM_DEVICE,
 				     DMA_ATTR_SKIP_CPU_SYNC);
+		__page_frag_drain(page, 0, rx_buffer->pagecnt_bias);
 	}
 
 	/* clear contents of rx_buffer */
@@ -7235,6 +7244,7 @@ static bool igb_alloc_mapped_page(struct igb_ring *rx_ring,
 	bi->dma = dma;
 	bi->page = page;
 	bi->page_offset = 0;
+	bi->pagecnt_bias = 1;
 
 	return true;
 }

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#1519208 — [mm PATCH v3 03/23] arch/avr32: Add option to skip sync on DMA map

The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the DMA
APIs in the arch/arm folder.  This change is meant to correct that so that
we get consistent behavior.

Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/avr32/mm/dma-coherent.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/avr32/mm/dma-coherent.c b/arch/avr32/mm/dma-coherent.c
index 58610d0..54534e5 100644
--- a/arch/avr32/mm/dma-coherent.c
+++ b/arch/avr32/mm/dma-coherent.c
@@ -146,7 +146,8 @@ static dma_addr_t avr32_dma_map_page(struct device *dev, struct page *page,
 {
 	void *cpu_addr = page_address(page) + offset;
 
-	dma_cache_sync(dev, cpu_addr, size, direction);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_cache_sync(dev, cpu_addr, size, direction);
 	return virt_to_bus(cpu_addr);
 }
 
@@ -162,6 +163,10 @@ static int avr32_dma_map_sg(struct device *dev, struct scatterlist *sglist,
 
 		sg->dma_address = page_to_bus(sg_page(sg)) + sg->offset;
 		virt = sg_virt(sg);
+
+		if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+			continue;
+
 		dma_cache_sync(dev, virt, sg->length, direction);
 	}
 

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#1519212 — [mm PATCH v3 15/23] arch/powerpc: 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
via a sync_for_cpu or sync_for_device call.

Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/powerpc/kernel/dma.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index e64a601..6877e3f 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -203,6 +203,10 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
 	for_each_sg(sgl, sg, nents, i) {
 		sg->dma_address = sg_phys(sg) + get_dma_offset(dev);
 		sg->dma_length = sg->length;
+
+		if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+			continue;
+
 		__dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
 	}
 
@@ -235,7 +239,10 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev,
 					     unsigned long attrs)
 {
 	BUG_ON(dir == DMA_NONE);
-	__dma_sync_page(page, offset, size, dir);
+
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		__dma_sync_page(page, offset, size, dir);
+
 	return page_to_phys(page) + offset + get_dma_offset(dev);
 }
 

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#1519213 — [mm PATCH v3 12/23] arch/nios2: Add option to skip DMA sync as a part of map and unmap

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
via a sync_for_cpu or sync_for_device call.

Cc: Ley Foon Tan <lftan@altera.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/nios2/mm/dma-mapping.c |   26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/arch/nios2/mm/dma-mapping.c b/arch/nios2/mm/dma-mapping.c
index d800fad..f6a5dcf 100644
--- a/arch/nios2/mm/dma-mapping.c
+++ b/arch/nios2/mm/dma-mapping.c
@@ -98,13 +98,17 @@ static int nios2_dma_map_sg(struct device *dev, struct scatterlist *sg,
 	int i;
 
 	for_each_sg(sg, sg, nents, i) {
-		void *addr;
+		void *addr = sg_virt(sg);
 
-		addr = sg_virt(sg);
-		if (addr) {
-			__dma_sync_for_device(addr, sg->length, direction);
-			sg->dma_address = sg_phys(sg);
-		}
+		if (!addr)
+			continue;
+
+		sg->dma_address = sg_phys(sg);
+
+		if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+			continue;
+
+		__dma_sync_for_device(addr, sg->length, direction);
 	}
 
 	return nents;
@@ -117,7 +121,9 @@ static dma_addr_t nios2_dma_map_page(struct device *dev, struct page *page,
 {
 	void *addr = page_address(page) + offset;
 
-	__dma_sync_for_device(addr, size, direction);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		__dma_sync_for_device(addr, size, direction);
+
 	return page_to_phys(page) + offset;
 }
 
@@ -125,7 +131,8 @@ static void nios2_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
 		size_t size, enum dma_data_direction direction,
 		unsigned long attrs)
 {
-	__dma_sync_for_cpu(phys_to_virt(dma_address), size, direction);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		__dma_sync_for_cpu(phys_to_virt(dma_address), size, direction);
 }
 
 static void nios2_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
@@ -138,6 +145,9 @@ static void nios2_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 	if (direction == DMA_TO_DEVICE)
 		return;
 
+	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+		return;
+
 	for_each_sg(sg, sg, nhwentries, i) {
 		addr = sg_virt(sg);
 		if (addr)

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#1519687 — Re: [mm PATCH v3 12/23] arch/nios2: Add option to skip DMA sync as a part of map and unmap

On 2016-11-10 at 12:35:18 +0100, Alexander Duyck <alexander.h.duyck@intel.com> wrote:
> 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
> via a sync_for_cpu or sync_for_device call.
> 
> Cc: Ley Foon Tan <lftan@altera.com>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>

Reviewed-by: Tobias Klauser <tklauser@distanz.ch>

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#1519219 — [mm PATCH v3 10/23] arch/microblaze: Add option to skip DMA sync as a part of map and unmap

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
via a sync_for_cpu or sync_for_device call.

Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/microblaze/kernel/dma.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/microblaze/kernel/dma.c b/arch/microblaze/kernel/dma.c
index ec04dc1..818daf2 100644
--- a/arch/microblaze/kernel/dma.c
+++ b/arch/microblaze/kernel/dma.c
@@ -61,6 +61,10 @@ static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
 	/* FIXME this part of code is untested */
 	for_each_sg(sgl, sg, nents, i) {
 		sg->dma_address = sg_phys(sg);
+
+		if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+			continue;
+
 		__dma_sync(page_to_phys(sg_page(sg)) + sg->offset,
 							sg->length, direction);
 	}
@@ -80,7 +84,8 @@ static inline dma_addr_t dma_direct_map_page(struct device *dev,
 					     enum dma_data_direction direction,
 					     unsigned long attrs)
 {
-	__dma_sync(page_to_phys(page) + offset, size, direction);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		__dma_sync(page_to_phys(page) + offset, size, direction);
 	return page_to_phys(page) + offset;
 }
 
@@ -95,7 +100,8 @@ static inline void dma_direct_unmap_page(struct device *dev,
  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
  * dma_address is physical address
  */
-	__dma_sync(dma_address, size, direction);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		__dma_sync(dma_address, size, direction);
 }
 
 static inline void

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#1519231 — [mm PATCH v3 04/23] arch/blackfin: Add option to skip sync on DMA map

The use of DMA_ATTR_SKIP_CPU_SYNC was not consistent across all of the DMA
APIs in the arch/arm folder.  This change is meant to correct that so that
we get consistent behavior.

Cc: Steven Miao <realmz6@gmail.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/blackfin/kernel/dma-mapping.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/blackfin/kernel/dma-mapping.c b/arch/blackfin/kernel/dma-mapping.c
index 53fbbb6..a27a74a 100644
--- a/arch/blackfin/kernel/dma-mapping.c
+++ b/arch/blackfin/kernel/dma-mapping.c
@@ -118,6 +118,10 @@ static int bfin_dma_map_sg(struct device *dev, struct scatterlist *sg_list,
 
 	for_each_sg(sg_list, sg, nents, i) {
 		sg->dma_address = (dma_addr_t) sg_virt(sg);
+
+		if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+			continue;
+
 		__dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
 	}
 
@@ -143,7 +147,9 @@ static dma_addr_t bfin_dma_map_page(struct device *dev, struct page *page,
 {
 	dma_addr_t handle = (dma_addr_t)(page_address(page) + offset);
 
-	_dma_sync(handle, size, dir);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		_dma_sync(handle, size, dir);
+
 	return handle;
 }
 

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#1519233 — [mm PATCH v3 16/23] arch/sh: 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
via a sync_for_cpu or sync_for_device call.

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/sh/kernel/dma-nommu.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/sh/kernel/dma-nommu.c b/arch/sh/kernel/dma-nommu.c
index eadb669..47fee3b 100644
--- a/arch/sh/kernel/dma-nommu.c
+++ b/arch/sh/kernel/dma-nommu.c
@@ -18,7 +18,9 @@ static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
 	dma_addr_t addr = page_to_phys(page) + offset;
 
 	WARN_ON(size == 0);
-	dma_cache_sync(dev, page_address(page) + offset, size, dir);
+
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		dma_cache_sync(dev, page_address(page) + offset, size, dir);
 
 	return addr;
 }
@@ -35,7 +37,8 @@ static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
 	for_each_sg(sg, s, nents, i) {
 		BUG_ON(!sg_page(s));
 
-		dma_cache_sync(dev, sg_virt(s), s->length, dir);
+		if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+			dma_cache_sync(dev, sg_virt(s), s->length, dir);
 
 		s->dma_address = sg_phys(s);
 		s->dma_length = s->length;

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#1519234 — [mm PATCH v3 05/23] arch/c6x: Add option to skip sync on DMA map and unmap

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.

Acked-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/c6x/kernel/dma.c |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/c6x/kernel/dma.c b/arch/c6x/kernel/dma.c
index db4a6a3..6752df3 100644
--- a/arch/c6x/kernel/dma.c
+++ b/arch/c6x/kernel/dma.c
@@ -42,14 +42,17 @@ static dma_addr_t c6x_dma_map_page(struct device *dev, struct page *page,
 {
 	dma_addr_t handle = virt_to_phys(page_address(page) + offset);
 
-	c6x_dma_sync(handle, size, dir);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		c6x_dma_sync(handle, size, dir);
+
 	return handle;
 }
 
 static void c6x_dma_unmap_page(struct device *dev, dma_addr_t handle,
 		size_t size, enum dma_data_direction dir, unsigned long attrs)
 {
-	c6x_dma_sync(handle, size, dir);
+	if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+		c6x_dma_sync(handle, size, dir);
 }
 
 static int c6x_dma_map_sg(struct device *dev, struct scatterlist *sglist,
@@ -60,7 +63,8 @@ static int c6x_dma_map_sg(struct device *dev, struct scatterlist *sglist,
 
 	for_each_sg(sglist, sg, nents, i) {
 		sg->dma_address = sg_phys(sg);
-		c6x_dma_sync(sg->dma_address, sg->length, dir);
+		if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+			c6x_dma_sync(sg->dma_address, sg->length, dir);
 	}
 
 	return nents;
@@ -72,9 +76,11 @@ static void c6x_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
 	struct scatterlist *sg;
 	int i;
 
+	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+		return;
+
 	for_each_sg(sglist, sg, nents, i)
 		c6x_dma_sync(sg_dma_address(sg), sg->length, dir);
-
 }
 
 static void c6x_dma_sync_single_for_cpu(struct device *dev, dma_addr_t handle,

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#1519243 — [mm PATCH v3 13/23] arch/openrisc: 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
via a sync_for_cpu or sync_for_device call.

Cc: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 arch/openrisc/kernel/dma.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
index 140c991..906998b 100644
--- a/arch/openrisc/kernel/dma.c
+++ b/arch/openrisc/kernel/dma.c
@@ -141,6 +141,9 @@ or1k_map_page(struct device *dev, struct page *page,
 	unsigned long cl;
 	dma_addr_t addr = page_to_phys(page) + offset;
 
+	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+		return addr;
+
 	switch (dir) {
 	case DMA_TO_DEVICE:
 		/* Flush the dcache for the requested range */

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#1525485

On Thu, Nov 10, 2016 at 3:34 AM, Alexander Duyck
<alexander.h.duyck@intel.com> wrote:
> 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.
>
> v1: Minor fixes based on issues found by kernel build bot
>     Few minor changes for issues found on code review
>     Added Acked-by for patches that were acked and not changed
>
> v2: Added a few more Acked-by
>     Submitting patches to mm instead of net-next
>
> v3: Added Acked-by for PowerPC architecture
>     Dropped first 3 patches which were accepted into swiotlb tree
>     Dropped comments describing swiotlb changes.
>
> ---
>
> Alexander Duyck (23):
>       arch/arc: Add option to skip sync on DMA mapping
>       arch/arm: Add option to skip sync on DMA map and unmap
>       arch/avr32: Add option to skip sync on DMA map
>       arch/blackfin: Add option to skip sync on DMA map
>       arch/c6x: Add option to skip sync on DMA map and unmap
>       arch/frv: Add option to skip sync on DMA map
>       arch/hexagon: Add option to skip DMA sync as a part of mapping
>       arch/m68k: Add option to skip DMA sync as a part of mapping
>       arch/metag: Add option to skip DMA sync as a part of map and unmap
>       arch/microblaze: Add option to skip DMA sync as a part of map and unmap
>       arch/mips: Add option to skip DMA sync as a part of map and unmap
>       arch/nios2: Add option to skip DMA sync as a part of map and unmap
>       arch/openrisc: Add option to skip DMA sync as a part of mapping
>       arch/parisc: Add option to skip DMA sync as a part of map and unmap
>       arch/powerpc: Add option to skip DMA sync as a part of mapping
>       arch/sh: Add option to skip DMA sync as a part of mapping
>       arch/sparc: Add option to skip DMA sync as a part of map and unmap
>       arch/tile: Add option to skip DMA sync as a part of map and unmap
>       arch/xtensa: Add option to skip DMA sync as a part of mapping
>       dma: Add calls for dma_map_page_attrs and dma_unmap_page_attrs
>       mm: Add support for releasing multiple instances of a page
>       igb: Update driver to make use of DMA_ATTR_SKIP_CPU_SYNC
>       igb: Update code to better handle incrementing page count
>
>
>  arch/arc/mm/dma.c                         |    5 ++
>  arch/arm/common/dmabounce.c               |   16 ++++--
>  arch/avr32/mm/dma-coherent.c              |    7 ++-
>  arch/blackfin/kernel/dma-mapping.c        |    8 +++
>  arch/c6x/kernel/dma.c                     |   14 ++++-
>  arch/frv/mb93090-mb00/pci-dma-nommu.c     |   14 ++++-
>  arch/frv/mb93090-mb00/pci-dma.c           |    9 +++
>  arch/hexagon/kernel/dma.c                 |    6 ++
>  arch/m68k/kernel/dma.c                    |    8 +++
>  arch/metag/kernel/dma.c                   |   16 +++++-
>  arch/microblaze/kernel/dma.c              |   10 +++-
>  arch/mips/loongson64/common/dma-swiotlb.c |    2 -
>  arch/mips/mm/dma-default.c                |    8 ++-
>  arch/nios2/mm/dma-mapping.c               |   26 +++++++---
>  arch/openrisc/kernel/dma.c                |    3 +
>  arch/parisc/kernel/pci-dma.c              |   20 ++++++--
>  arch/powerpc/kernel/dma.c                 |    9 +++
>  arch/sh/kernel/dma-nommu.c                |    7 ++-
>  arch/sparc/kernel/iommu.c                 |    4 +-
>  arch/sparc/kernel/ioport.c                |    4 +-
>  arch/tile/kernel/pci-dma.c                |   12 ++++-
>  arch/xtensa/kernel/pci-dma.c              |    7 ++-
>  drivers/net/ethernet/intel/igb/igb.h      |    7 ++-
>  drivers/net/ethernet/intel/igb/igb_main.c |   77 +++++++++++++++++++----------
>  include/linux/dma-mapping.h               |   20 +++++---
>  include/linux/gfp.h                       |    2 +
>  mm/page_alloc.c                           |   14 +++++
>  27 files changed, 246 insertions(+), 89 deletions(-)
>

So I am just wondering if I need to resubmit this to pick up the new
"Acked-by"s or if I should just wait?

As I said in the description my hope is to get this into the -mm tree
and I am not familiar with what the process is for being accepted
there.

Thanks.

- Alex

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