From: Alexander Duyck <alexander.h.duyck@intel.com>
To: linux-mm@kvack.org, akpm@linux-foundation.org
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
linux-kernel@vger.kernel.org, Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [mm PATCH v2 18/26] arch/powerpc: Add option to skip DMA sync as a part of mapping
Date: Wed, 02 Nov 2016 07:15:18 -0400 [thread overview]
Message-ID: <20161102111513.79519.65315.stgit@ahduyck-blue-test.jf.intel.com> (raw)
In-Reply-To: <20161102111031.79519.14741.stgit@ahduyck-blue-test.jf.intel.com>
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: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
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);
}
next parent reply other threads:[~2016-11-02 17:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20161102111031.79519.14741.stgit@ahduyck-blue-test.jf.intel.com>
2016-11-02 11:15 ` Alexander Duyck [this message]
2016-11-04 3:16 ` [mm PATCH v2 18/26] arch/powerpc: Add option to skip DMA sync as a part of mapping Michael Ellerman
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