From: akepner@sgi.com
To: Grant Grundler <grundler@parisc-linux.org>
Cc: linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz,
gregkh@suse.de,
James Bottomley <James.Bottomley@HansenPartnership.com>,
Jesse Barnes <jbarnes@virtuousgeek.org>,
Jes Sorensen <jes@sgi.com>,
Randy Dunlap <randy.dunlap@oracle.com>,
David Miller <davem@davemloft.net>
Subject: Re: [PATCH 0/3] pci: let devices flush DMA to host memory
Date: Mon, 27 Aug 2007 15:20:27 -0700 [thread overview]
Message-ID: <20070827222027.GD29161@sgi.com> (raw)
In-Reply-To: <20070827220548.GB22484@colo.lackof.org>
On Mon, Aug 27, 2007 at 04:05:48PM -0600, Grant Grundler wrote:
> .....
> After reading the thread, my take is we need a more elegant way for a
> device driver to handle registration of DMA regions allocated by user
> space. The API would "make this page/region act like dma_alloc_coherent()".
> That implies strong ordering between CPU and DMA to/from the device.
> Maybe the code is the right thing and I want a name that makes
> sense in the context of current DMA API.
Need to think about this...
>
> On IRC, willy suggested an mmap() flag and that sounds reasonable too
> though I don't know if it's feasible.
>
Yeah, we're doing something like this now as a band-aid solution.
Not a flag to mmap(), but a magic offset value. But it wasn't
acceptable to the maintainer of the mthca IB driver (Roland
Dreier), hence the new proposal....
--
Arthur
prev parent reply other threads:[~2007-08-27 22:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-24 18:02 [PATCH 0/3] pci: let devices flush DMA to host memory akepner
2007-08-27 22:05 ` Grant Grundler
2007-08-27 22:20 ` akepner [this message]
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