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From: Christoph Hellwig <hch@lst.de>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>,
	iommu@lists.linux-foundation.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [RFC][DISCUSSION] dma-mapping: allocating noncoherent buffer without mapping
Date: Thu, 27 Jan 2022 11:08:48 +0100	[thread overview]
Message-ID: <20220127100848.GC15004@lst.de> (raw)
In-Reply-To: <bbf3b6d4-b2b5-64b3-6dec-f1cc45f96122@arm.com>

On Wed, Jan 26, 2022 at 01:08:04PM +0000, Robin Murphy wrote:
> This doesn't make sense to me. The point of dma_alloc_* is you get back a 
> dedicated DMA buffer which can then be used at any time. In the noncoherent 
> case you have to put in explicit dma_sync_*() calls around accesses when 
> the CPU or device is expected to have updated the buffer contents, but it's 
> still fundamentally the same paradigm.

Exactly.
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      reply	other threads:[~2022-01-27 10:08 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-26 11:54 [RFC][DISCUSSION] dma-mapping: allocating noncoherent buffer without mapping Hyeonggon Yoo
2022-01-26 13:08 ` Robin Murphy
2022-01-27 10:08   ` Christoph Hellwig [this message]

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