linux-kernel - Re: bnx2 fails to compile on parisc because of missing get_dma

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Message-ID: <C27F8246C663564A84BB7AB3439772421B79CBCA1D@IRVEXCHCCR01.corp.ad.broadcom.com>
Date:	Wed, 16 Jun 2010 21:10:57 -0700
From:	"Michael Chan" <mchan@...adcom.com>
To:	"'Paul Mundt'" <lethal@...ux-sh.org>
cc:	"'Mike Frysinger'" <vapier@...too.org>,
	"James Bottomley" <JBottomley@...ell.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"linux-parisc@...r.kernel.org" <linux-parisc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"FUJITA Tomonori" <fujita.tomonori@....ntt.co.jp>
Subject: Re: bnx2 fails to compile on parisc because of missing
 get_dma_ops()

Paul Mundt wrote:

> On Wed, Jun 16, 2010 at 08:53:57PM -0700, Michael Chan wrote:
> > If sync_single is not defined, that means the CPU has a consistent
> > view of next_rx_buf and so it makes sense to prefetch it.
> >
> Except that's not a valid assertion, there are platforms that
> implement
> it for sanity checks yet still have consistent DMA. You are making
> inherently non-portable assumptions for a PCI driver, which is a good
> example of why drivers should never be side-stepping the API
> in the first
> place. If you want to have a micro-optimization for the consistent DMA
> case, you can check dma_is_consistent(), which is part of the API and
> will be variable on certain platform configurations (ie, some may be
> consistent with PCI but not on other busses, etc.)
>
>

Thanks for the tip.  I didn't know about the dma_is_consistent() API.
I'll use this to fix it then.

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