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Message-ID: <9bff7460-e6fa-f765-dcb4-cc96eb86d92c@ozlabs.ru>
Date: Mon, 13 Jul 2020 14:59:39 +1000
From: Alexey Kardashevskiy <aik@...abs.ru>
To: Christoph Hellwig <hch@....de>, iommu@...ts.linux-foundation.org
Cc: linuxppc-dev@...ts.ozlabs.org, Lu Baolu <baolu.lu@...ux.intel.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Joerg Roedel <joro@...tes.org>,
Robin Murphy <robin.murphy@....com>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Björn Töpel <bjorn.topel@...il.com>,
Daniel Borkmann <daniel@...earbox.net>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/5] dma-mapping: add a dma_ops_bypass flag to struct
device
On 09/07/2020 01:24, Christoph Hellwig wrote:
> Several IOMMU drivers have a bypass mode where they can use a direct
> mapping if the devices DMA mask is large enough. Add generic support
> to the core dma-mapping code to do that to switch those drivers to
> a common solution.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> include/linux/device.h | 8 +++++
> kernel/dma/Kconfig | 8 +++++
> kernel/dma/mapping.c | 74 +++++++++++++++++++++++++++++-------------
> 3 files changed, 68 insertions(+), 22 deletions(-)
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 4c4af98321ebd6..1f71acf37f78d7 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -523,6 +523,11 @@ struct dev_links_info {
> * sync_state() callback.
> * @dma_coherent: this particular device is dma coherent, even if the
> * architecture supports non-coherent devices.
> + * @dma_ops_bypass: If set to %true then the dma_ops are bypassed for the
> + * streaming DMA operations (->map_* / ->unmap_* / ->sync_*),
> + * and optionall (if the coherent mask is large enough) also
s/optionall/optional/g
Otherwise the series looks good and works well on powernv and pseries.
Thanks,
--
Alexey
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