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Subject[net-next PATCH 21/27] arch/tile: Add option to skip DMA sync as a part of map and unmap
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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
via a sync_for_cpu or sync_for_device call.

Cc: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
arch/tile/kernel/pci-dma.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/tile/kernel/pci-dma.c b/arch/tile/kernel/pci-dma.c
index 09bb774..24e0f8c 100644
--- a/arch/tile/kernel/pci-dma.c
+++ b/arch/tile/kernel/pci-dma.c
@@ -213,10 +213,12 @@ static int tile_dma_map_sg(struct device *dev, struct scatterlist *sglist,

for_each_sg(sglist, sg, nents, i) {
sg->dma_address = sg_phys(sg);
- __dma_prep_pa_range(sg->dma_address, sg->length, direction);
#ifdef CONFIG_NEED_SG_DMA_LENGTH
sg->dma_length = sg->length;
#endif
+ if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+ continue;
+ __dma_prep_pa_range(sg->dma_address, sg->length, direction);
}

return nents;
@@ -232,6 +234,8 @@ static void tile_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
BUG_ON(!valid_dma_direction(direction));
for_each_sg(sglist, sg, nents, i) {
sg->dma_address = sg_phys(sg);
+ if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+ continue;
__dma_complete_pa_range(sg->dma_address, sg->length,
direction);
}
@@ -245,7 +249,8 @@ static dma_addr_t tile_dma_map_page(struct device *dev, struct page *page,
BUG_ON(!valid_dma_direction(direction));

BUG_ON(offset + size > PAGE_SIZE);
- __dma_prep_page(page, offset, size, direction);
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ __dma_prep_page(page, offset, size, direction);

return page_to_pa(page) + offset;
}
@@ -256,6 +261,9 @@ static void tile_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
{
BUG_ON(!valid_dma_direction(direction));

+ if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
+ return;
+
__dma_complete_page(pfn_to_page(PFN_DOWN(dma_address)),
dma_address & (PAGE_SIZE - 1), size, direction);
}
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