From: Christoph Hellwig <hch@infradead.org>
To: Ramkrishna Vepa <Ramkrishna.Vepa@neterion.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Jeff Garzik <jgarzik@pobox.com>,
Linus Torvalds <torvalds@osdl.org>,
netdev@vger.kernel.org, rolandd@cisco.com
Subject: Re: [PATCH] s2io ppc64 fix for readq/writeq
Date: Mon, 6 Nov 2006 20:46:43 +0000 [thread overview]
Message-ID: <20061106204643.GA11788@infradead.org> (raw)
In-Reply-To: <78C9135A3D2ECE4B8162EBDCE82CAD77E29496@nekter>
On Mon, Nov 06, 2006 at 03:33:19PM -0500, Ramkrishna Vepa wrote:
> The 64 bit io operation on the IA64 platform is a 64 bit transaction on
> the pci bus and is optimal to leave it as such. I prefer Jeff's
> suggestion -
>
> guaranteeing that a "good enough for drivers" readq() and writeq() exist
> on all platforms even 32-bit platforms where the operation isn't
> inherently atomic.
For consistencies sake we really want to have readq() and writeq() available
on all platforms. I remember that some IB cards require it to actually
be a 64bit transactions, otherwise they have to do funny workarounds.
I think the best solution is to define ARCH_HAS_ATOMIC_READQ_WRITEQ
and let drivers do their workarounds based on that.
I've Cc'ed Roland because he should be able to explain the IB issue in
details.
next prev parent reply other threads:[~2006-11-06 20:47 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-06 20:33 [PATCH] s2io ppc64 fix for readq/writeq Ramkrishna Vepa
2006-11-06 20:46 ` Christoph Hellwig [this message]
2006-11-06 20:54 ` Roland Dreier
-- strict thread matches above, loose matches on Subject: below --
2006-11-07 2:57 Ramkrishna Vepa
2006-11-06 2:28 Benjamin Herrenschmidt
2006-11-06 7:50 ` Jeff Garzik
2006-11-06 8:04 ` Benjamin Herrenschmidt
2006-11-06 8:21 ` Jeff Garzik
2006-11-06 8:52 ` Benjamin Herrenschmidt
2006-11-06 9:34 ` Jeff Garzik
2006-11-07 0:17 ` Benjamin Herrenschmidt
2006-11-06 9:37 ` Linus Torvalds
2006-11-06 9:42 ` Benjamin Herrenschmidt
2006-11-06 9:50 ` Linus Torvalds
2006-11-06 9:51 ` Benjamin Herrenschmidt
2006-11-06 9:55 ` Jeff Garzik
2006-11-06 9:57 ` Benjamin Herrenschmidt
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