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From: Greg KH <gregkh@suse.de>
To: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Cc: Roland Dreier <rolandd@cisco.com>,
	"Michael S. Tsirkin" <mst@mellanox.co.il>,
	linux-pci@atrey.karlin.mff.cuni.cz, openib-general@openib.org,
	linux-kernel@vger.kernel.org, mj@ucw.cz, ian.pratt@cl.cam.ac.uk
Subject: Re: [openib-general] Re: [PATCH] arch/xx/pci: remap_pfn_range -> io_remap_pfn_range
Date: Thu, 28 Jul 2005 09:17:20 -0700	[thread overview]
Message-ID: <20050728161720.GA23507@suse.de> (raw)
In-Reply-To: <A95E2296287EAD4EB592B5DEEFCE0E9D282808@liverpoolst.ad.cl.cam.ac.uk>

On Thu, Jul 28, 2005 at 12:57:51PM +0100, Ian Pratt wrote:
> > >     Greg> Hm, you do realize that io_remap_pfn_range() is the same
> > >     Greg> thing as remap_pfn_range() on i386, right?
> > > 
> > >     Greg> So, why would this patch change anything?
> > > 
> > > It's not the same thing under Xen.  I think this patch 
> > fixes userspace 
> > > access to PCI memory for XenLinux.
> > 
> > But Xen is a separate arch, and hence, will get different pci 
> > arch specific functions, right?
> > 
> > In short, what is this patch trying to fix?  What is the 
> > problem anyone is seeing with the existing code?
> 
> As I understand it, remap_pfn_range should be used for mapping pages
> that are backed by memory, and io_remap_pfn_range should be used for
> mapping MMIO regions.
> There's a distinciton between the two for architectures like Sparc and
> xen/x86. 

I agree, but not for i386, which is what the patch was trying to change.

If this is a fix for xen, fine, then say so in the changelog information
for the patch, as it is, no such information was given.

thanks,

greg k-h

  parent reply	other threads:[~2005-07-28 16:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-07-28 11:57 [openib-general] Re: [PATCH] arch/xx/pci: remap_pfn_range -> io_remap_pfn_range Ian Pratt
2005-07-28 14:18 ` Randy.Dunlap
2005-07-28 16:17 ` Greg KH [this message]
2005-07-31  8:51   ` Michael S. Tsirkin
  -- strict thread matches above, loose matches on Subject: below --
2005-07-28 14:40 [openib-general] " Ian Pratt
2005-07-25 22:32 Michael S. Tsirkin
2005-07-28  4:26 ` Greg KH
2005-07-28  4:30   ` [openib-general] " Roland Dreier
2005-07-28  4:50     ` Greg KH

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