From: akepner@sgi.com
To: Michael Ellerman <michael@ellerman.id.au>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>,
Grant Grundler <grundler@parisc-linux.org>,
Tony Luck <tony.luck@intel.com>,
Jesse Barnes <jbarnes@virtuousgeek.org>,
Jes Sorensen <jes@sgi.com>,
Randy Dunlap <randy.dunlap@oracle.com>,
Roland Dreier <rdreier@cisco.com>,
David Miller <davem@davemloft.net>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
linux-kernel@vger.kernel.org, Mark Nelson <mdnelson@au1.ibm.com>
Subject: Re: [PATCH 1/3 v3] dma: document dma_{un}map_{single|sg}_attrs() interface
Date: Wed, 19 Mar 2008 17:32:58 -0700 [thread overview]
Message-ID: <20080320003258.GM1843@sgi.com> (raw)
In-Reply-To: <1205469029.7414.18.camel@concordia.ozlabs.ibm.com>
On Fri, Mar 14, 2008 at 03:30:29PM +1100, Michael Ellerman wrote:
>
> I like this better, sorry to keep nitpicking, but just a few comments
> below ..
Comments are appreciated.
> ...
> You say a "DMA to a memory region with the DMA_ATTR_BARRIER attribute
> forces all pending DMA writes to complete". Does it force _all_ DMA
> writes to complete, or just writes to the region, or just writes coming
> from devices? What if something is writing to a device?
>
Yes, forces all writes to complete (as others have already said).
> Does DMA_ATTR_BARRIER have any effect on reads?
>
No, changed the name to DMA_ATTR_WRITE_BARRIER to emphasize this.
--
Arthur
next prev parent reply other threads:[~2008-03-20 0:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-28 3:24 [PATCH 1/3 v3] dma: document dma_{un}map_{single|sg}_attrs() interface akepner
2008-02-29 2:45 ` Michael Ellerman
2008-02-29 18:25 ` Grant Grundler
2008-02-29 18:37 ` James Bottomley
2008-03-01 2:56 ` Benjamin Herrenschmidt
2008-03-01 3:11 ` Jesse Barnes
2008-03-01 7:18 ` Grant Grundler
2008-03-05 18:13 ` akepner
2008-03-05 19:02 ` Jesse Barnes
2008-03-06 6:01 ` Michael Ellerman
2008-03-12 1:19 ` akepner
2008-03-14 4:13 ` Grant Grundler
2008-03-14 4:30 ` Michael Ellerman
2008-03-14 5:21 ` Grant Grundler
2008-03-14 16:40 ` Jesse Barnes
2008-03-18 1:08 ` Michael Ellerman
2008-03-20 0:32 ` akepner [this message]
2008-02-29 21:23 ` akepner
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