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From: Vineet Gupta <>
To: Christoph Hellwig <>
Cc: "" <>,
	"" <>,,
	Alexander Duyck <>,
	Krzysztof Kozlowski <>,
	Andrew Morton <>,
	lkml <>,
	arcml <>
Subject: Re: semantics of dma_map_single()
Date: Mon, 17 Jul 2017 09:06:29 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Hi Christoph,

On 07/16/2017 11:42 PM, Christoph Hellwig wrote:
> I would expect that it would support any contiguous range in
> the kernel mapping (e.g. no vmalloc and friends).  But it's not
> documented anywhere, and if no in kernel users makes use of that
> fact at the moment it might be better to document a page size
> limitation and add asserts to enforce it.

My first thought was indeed to add a BUG_ON for @size > PAGE_SIZE (also accounting 
for offset etc), but I have a feeling this will cause too many breakages. So 
perhaps it would be better to add the fact to Documentation that it can handle any 
physically contiguous range.


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  reply	other threads:[~2017-07-17 16:06 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-16  1:24 semantics of dma_map_single() Vineet Gupta
2017-07-17  6:42 ` Christoph Hellwig
2017-07-17 16:06   ` Vineet Gupta [this message]
2017-07-17 16:46     ` James Bottomley

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