Subject: Re: [PATCH 10 of 20] ipath - support for userspace apps using core
	driver
From: "Bryan O'Sullivan" <bos@pathscale.com>
To: Roland Dreier <rdreier@cisco.com>
Cc: Andrew Morton <akpm@osdl.org>, Hugh@veritas.com, torvalds@osdl.org,
       hch@infradead.org, linux-kernel@vger.kernel.org
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Date: Thu, 16 Mar 2006 07:12:23 -0800
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On Wed, 2006-03-15 at 21:54 -0800, Roland Dreier wrote:

> How about the case where one wants to map pages from
> dma_alloc_coherent() into userspace?

This is precisely our case, btw.  The pages in question are allocated
during fops->open (some during dev->probe).  mmap and nopage never
allocate anything.

>   It seems one should do
> get_page() in .nopage, and then the driver can do dma_free_coherent()
> when the vma is released.

If that were the case, I'm unclear on how I would do this.  Add a
vmops->close method along with the existing vmops->nopage handler?

	<b

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