From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Mon, 23 Jan 2017 17:39:58 +0000 Subject: [PATCH v2 2/2] iommu/dma: Implement PCI allocation optimisation In-Reply-To: References: Message-ID: <20170123173957.GD28914@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jan 16, 2017 at 01:24:55PM +0000, Robin Murphy wrote: > Whilst PCI devices may have 64-bit DMA masks, they still benefit from > using 32-bit addresses wherever possible in order to avoid DAC (PCI) or > longer address packets (PCIe), which may incur a performance overhead. > Implement the same optimisation as other allocators by trying to get a > 32-bit address first, only falling back to the full mask if that fails. > > Signed-off-by: Robin Murphy > --- > drivers/iommu/dma-iommu.c | 21 +++++++++++++++------ > 1 file changed, 15 insertions(+), 6 deletions(-) Looks good to me, and has the added benefit of getting PCI ethernet working on Juno when using the SMMU. Unintended side-effect, but: Acked-by: Will Deacon Will