From: Alexander Duyck <alexander.h.duyck@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.com>,
David Miller <davem@davemloft.net>
Cc: romieu@fr.zoreil.com, netdev@vger.kernel.org, nix@esperi.org.uk,
rl@hellgate.ch, gurligebis@gentoo.org
Subject: Re: [PATCH net-next 1/4] via-rhine: commit receive buffer address before descriptor status update.
Date: Tue, 07 Apr 2015 15:12:28 -0700 [thread overview]
Message-ID: <5524564C.9090809@redhat.com> (raw)
In-Reply-To: <1428443685.25985.212.camel@edumazet-glaptop2.roam.corp.google.com>
On 04/07/2015 02:54 PM, Eric Dumazet wrote:
> On Tue, 2015-04-07 at 17:27 -0400, David Miller wrote:
>
>> That's exactly dma_wmb().
>>
>> It barriers cpu writes so that the device sees things in a certain
>> order.
>>
>> It's what all the most common ethernet chip drivers use in their
>> descriptor handling routines now.
> To be fair, only 2 drivers currently use dma_wmb()
Hey, I got at least 4.. :-) I only got around to patching 3 Intel
drivers and one RealTek since that is what I had to test with. I was
honestly hoping there would be more interest from other developers to
pick this up and update their drivers to avoid unnecessary barriers but
it doesn't look like I have had much luck on that front.
Maybe what I can do is submit a set of patches over the next couple of
weeks to try and update all the spots that either need to have a barrier
added, such as what is being addressed here, or can have a barrier
weakened as I have already done for a few other drivers.
- Alex
next prev parent reply other threads:[~2015-04-07 22:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-06 18:01 [PATCH RFT net-next 0/4] via-rhine receive buffers rework Francois Romieu
2015-04-06 18:01 ` [PATCH net-next 1/4] via-rhine: commit receive buffer address before descriptor status update Francois Romieu
2015-04-07 19:52 ` David Miller
2015-04-07 21:02 ` Francois Romieu
2015-04-07 21:19 ` Alexander Duyck
2015-04-07 21:27 ` David Miller
2015-04-07 21:54 ` Eric Dumazet
2015-04-07 22:12 ` Alexander Duyck [this message]
2015-04-07 22:22 ` Eric Dumazet
2015-04-07 23:20 ` Alexander Duyck
2015-04-08 11:40 ` David Laight
2015-04-07 19:54 ` Alexander Duyck
2015-04-06 18:01 ` [PATCH net-next 2/4] via-rhine: add allocation helpers Francois Romieu
2015-04-06 18:01 ` [PATCH net-next 3/4] via-rhine: gotoize rhine_open error path Francois Romieu
2015-04-06 18:01 ` [PATCH net-next 4/4] via-rhine: forbid holes in the receive descriptor ring Francois Romieu
2015-04-06 21:46 ` [PATCH RFT net-next 0/4] via-rhine receive buffers rework Nix
2015-04-07 10:46 ` Nix
2015-04-07 19:31 ` Francois Romieu
2015-04-07 19:41 ` Nix
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