From: Christoph Hellwig <hch@lst.de>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Nicolin Chen <nicoleotsuka@gmail.com>,
hch@lst.de, m.szyprowski@samsung.com, vdumpa@nvidia.com,
linux@armlinux.org.uk, catalin.marinas@arm.com,
will.deacon@arm.com, chris@zankel.net, jcmvbkbc@gmail.com,
joro@8bytes.org, dwmw2@infradead.org, tony@atomide.com,
akpm@linux-foundation.org, sfr@canb.auug.org.au,
treding@nvidia.com, keescook@chromium.org,
iamjoonsoo.kim@lge.com, wsa+renesas@sang-engineering.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-xtensa@linux-xtensa.org,
iommu@lists.linux-foundation.org
Subject: Re: [RFC/RFT PATCH 1/2] dma-contiguous: Simplify dma_*_from_contiguous() function calls
Date: Tue, 30 Apr 2019 17:20:58 +0200 [thread overview]
Message-ID: <20190430152058.GC25447@lst.de> (raw)
In-Reply-To: <d43e1cfe-1d12-c0c6-d76b-81330918d9ab@arm.com>
On Tue, Apr 30, 2019 at 01:52:26PM +0100, Robin Murphy wrote:
> As Catalin pointed out before, many of the users above may still have
> implicit assumptions about the default CMA area, i.e. that this won't
> return something above the limit they originally passed to
> dma_contiguous_reserve(). I'm not sure how straightforward that is to
> resolve - at the very least we may have to monkey around with GFP_DMA{32}
> flags based on where dma_contiguous_default_area lies :(
Or just convert the callers one by one. The two most interesting ones
are dma-direct which always check addressability after the allocation,
and dma-iommu, which doesn't care. dma-iommu.c and intel-iommu.c also
don't care, but should use dma-iommu by next merge window anyway,
which leaves arm which is so complicated that we better don't touch
it for now, and xtensa, which I hope to switch to dma-direct in the
next merge window or two.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Robin Murphy <robin.murphy@arm.com>
Cc: tony@atomide.com, catalin.marinas@arm.com, will.deacon@arm.com,
jcmvbkbc@gmail.com, hch@lst.de, sfr@canb.auug.org.au,
linux@armlinux.org.uk, treding@nvidia.com,
linux-xtensa@linux-xtensa.org, keescook@chromium.org,
Nicolin Chen <nicoleotsuka@gmail.com>,
akpm@linux-foundation.org, linux-arm-kernel@lists.infradead.org,
chris@zankel.net, wsa+renesas@sang-engineering.com,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
iamjoonsoo.kim@lge.com, dwmw2@infradead.org
Subject: Re: [RFC/RFT PATCH 1/2] dma-contiguous: Simplify dma_*_from_contiguous() function calls
Date: Tue, 30 Apr 2019 17:20:58 +0200 [thread overview]
Message-ID: <20190430152058.GC25447@lst.de> (raw)
Message-ID: <20190430152058.4QwM2BzaanDM1V6hitCV8JXloxJHuufIzlAbHyIqpPk@z> (raw)
In-Reply-To: <d43e1cfe-1d12-c0c6-d76b-81330918d9ab@arm.com>
On Tue, Apr 30, 2019 at 01:52:26PM +0100, Robin Murphy wrote:
> As Catalin pointed out before, many of the users above may still have
> implicit assumptions about the default CMA area, i.e. that this won't
> return something above the limit they originally passed to
> dma_contiguous_reserve(). I'm not sure how straightforward that is to
> resolve - at the very least we may have to monkey around with GFP_DMA{32}
> flags based on where dma_contiguous_default_area lies :(
Or just convert the callers one by one. The two most interesting ones
are dma-direct which always check addressability after the allocation,
and dma-iommu, which doesn't care. dma-iommu.c and intel-iommu.c also
don't care, but should use dma-iommu by next merge window anyway,
which leaves arm which is so complicated that we better don't touch
it for now, and xtensa, which I hope to switch to dma-direct in the
next merge window or two.
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-04-30 15:20 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-30 1:55 [RFC/RFT PATCH 0/2] Optimize dma_*_from_contiguous calls Nicolin Chen
2019-04-30 1:55 ` Nicolin Chen
2019-04-30 1:55 ` [RFC/RFT PATCH 1/2] dma-contiguous: Simplify dma_*_from_contiguous() function calls Nicolin Chen
2019-04-30 1:55 ` Nicolin Chen
2019-04-30 10:56 ` Christoph Hellwig
2019-04-30 10:56 ` Christoph Hellwig
2019-04-30 12:37 ` Robin Murphy
2019-04-30 12:37 ` Robin Murphy
2019-04-30 15:18 ` Christoph Hellwig
2019-04-30 15:18 ` Christoph Hellwig
2019-04-30 19:46 ` Nicolin Chen
2019-04-30 19:46 ` Nicolin Chen
2019-04-30 12:52 ` Robin Murphy
2019-04-30 12:52 ` Robin Murphy
2019-04-30 15:20 ` Christoph Hellwig [this message]
2019-04-30 15:20 ` Christoph Hellwig
2019-04-30 1:55 ` [RFC/RFT PATCH 2/2] dma-contiguous: Use fallback alloc_pages for single pages Nicolin Chen
2019-04-30 1:55 ` Nicolin Chen
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