Date: Thu, 18 Oct 2007 10:10:05 -0700
From: Arjan van de Ven <arjan@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jens Axboe <jens.axboe@oracle.com>, David Miller <davem@davemloft.net>,
       fujita.tomonori@lab.ntt.co.jp, mingo@elte.hu,
       linux-kernel@vger.kernel.org, jgarzik@pobox.com,
       alan@lxorguk.ukuu.org.uk, tomof@acm.org
Subject: Re: [bug] ata subsystem related crash with latest -git
Message-ID: <20071018101005.5681a365@laptopd505.fenrus.org>
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On Thu, 18 Oct 2007 09:55:04 -0700 (PDT)
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> 
> 
> On Thu, 18 Oct 2007, Jens Axboe wrote:
> > -		unsigned long addr = page_to_phys(s->page) +
> > s->offset; 
> > +		unsigned long addr = page_to_phys(sg_page(s)) +
> > s->offset; 
> 
> Umm. May I suggest (I haven't read the whole thread yet, maybe
> somebody else already did) that
> 
> 	static inline unsigned long sg_phys(struct scatterlist *sg)
> 	{
> 		return 	page_to_phys(sg_page(sg)) + sg->offset;
> 	}
> 
> would be a good thing to have?
> 
> Very few drivers should care so much about the *page* itself (or the 
> offset). That's something that the generic allocation code etc cares 
> about, but the driver is almost bound to care mostly about the actual
> DMA address

.... but will that work for systems with IOMMU ? or is it fundamentally
the wrong interface
-
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