From: Robin Murphy <robin.murphy@arm.com>
To: Christoph Hellwig <hch@lst.de>, Nicolin Chen <nicoleotsuka@gmail.com>
Cc: 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 13:37:54 +0100 [thread overview]
Message-ID: <0e3e6d8b-de44-d23e-a039-8d11b578ec5c@arm.com> (raw)
In-Reply-To: <20190430105640.GA20021@lst.de>
On 30/04/2019 11:56, Christoph Hellwig wrote:
> So while I really, really like this cleanup it turns out it isn't
> actually safe for arm :( arm remaps the CMA allocation in place
> instead of using a new mapping, which can be done because they don't
> share PMDs with the kernel.
>
> So we'll probably need a __dma_alloc_from_contiguous version with
> an additional bool fallback argument - everyone but arms uses
> dma_alloc_from_contiguous as in your patch, just arm will get the
> non-fallback one.
Or we even just implement dma_{alloc,free}_contiguous() as a wrapper
around the existing APIs so that users can be thoroughly checked and
converted one-by-one.
Robin.
WARNING: multiple messages have this Message-ID (diff)
From: Robin Murphy <robin.murphy@arm.com>
To: Christoph Hellwig <hch@lst.de>, Nicolin Chen <nicoleotsuka@gmail.com>
Cc: chris@zankel.net, linux-xtensa@linux-xtensa.org,
keescook@chromium.org, sfr@canb.auug.org.au, tony@atomide.com,
catalin.marinas@arm.com, will.deacon@arm.com,
linux@armlinux.org.uk, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, jcmvbkbc@gmail.com,
wsa+renesas@sang-engineering.com, akpm@linux-foundation.org,
treding@nvidia.com, dwmw2@infradead.org, iamjoonsoo.kim@lge.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC/RFT PATCH 1/2] dma-contiguous: Simplify dma_*_from_contiguous() function calls
Date: Tue, 30 Apr 2019 13:37:54 +0100 [thread overview]
Message-ID: <0e3e6d8b-de44-d23e-a039-8d11b578ec5c@arm.com> (raw)
Message-ID: <20190430123754.w-33XAk30DUsJjyv4xMN9gPKb1aihyEYxTlYOi6Buus@z> (raw)
In-Reply-To: <20190430105640.GA20021@lst.de>
On 30/04/2019 11:56, Christoph Hellwig wrote:
> So while I really, really like this cleanup it turns out it isn't
> actually safe for arm :( arm remaps the CMA allocation in place
> instead of using a new mapping, which can be done because they don't
> share PMDs with the kernel.
>
> So we'll probably need a __dma_alloc_from_contiguous version with
> an additional bool fallback argument - everyone but arms uses
> dma_alloc_from_contiguous as in your patch, just arm will get the
> non-fallback one.
Or we even just implement dma_{alloc,free}_contiguous() as a wrapper
around the existing APIs so that users can be thoroughly checked and
converted one-by-one.
Robin.
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-04-30 12:37 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 [this message]
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
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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