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From: Stephen Hemminger <shemminger@vyatta•com>
To: Arvid Brodin <arvid.brodin@enea•com>
Cc: "David S. Miller" <davem@davemloft•net>, <netdev@vger•kernel.org>,
	Bruno Ferreira <balferreira@googlemail•com>
Subject: Re: [RFC] net/hsr: Add support for IEC 62439-3 High-availability Seamless Redundancy
Date: Tue, 3 Apr 2012 11:37:51 -0700	[thread overview]
Message-ID: <20120403113751.21fd0b17@s6510.linuxnetplumber.net> (raw)
In-Reply-To: <4F71BEAD.5080605@enea.com>

On Tue, 27 Mar 2012 15:20:45 +0200
Arvid Brodin <arvid.brodin@enea•com> wrote:

> +config NONSTANDARD_HSR
> +	bool "HSR: Use efficient tag (breaks HSR standard, read help!)"
> +	depends on HSR
> +	---help---
> +	  The HSR standard specifies a 6-byte HSR tag to be inserted into the
> +	  transmitted network frames. This breaks the 32-bit alignment that the
> +	  Linux network stack relies on, and would cause kernel panics on
> +	  certain architectures. To avoid this, the whole frame payload is
> +	  memmoved 2 bytes on reception on these architectures - which is very
> +	  inefficient!

This option won't fly. Don't do it.
If you need to copy/realign packets on some architecture the stack
should be changed to handle it.

  reply	other threads:[~2012-04-03 18:37 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-27 13:20 [RFC] net/hsr: Add support for IEC 62439-3 High-availability Seamless Redundancy Arvid Brodin
2012-04-03 18:37 ` Stephen Hemminger [this message]
2012-04-04 23:09   ` Arvid Brodin
2012-04-04 23:55     ` Stephen Hemminger
2012-04-05  0:21       ` David Miller
2012-04-06 15:51         ` Arvid Brodin
2012-04-06 16:43           ` David Miller
2012-04-06 17:08             ` Arvid Brodin
2012-04-06 17:06           ` Ben Hutchings
2012-04-06 18:19             ` Stephen Hemminger
2012-04-11  0:00               ` Arvid Brodin
2012-04-11  1:28                 ` Stephen Hemminger
2012-04-11 14:39                   ` Arvid Brodin
2012-04-05  0:17     ` David Miller
2012-04-05 19:21       ` Ben Hutchings
2012-04-05 22:31         ` David Miller
2012-05-14 18:11 ` Arvid Brodin
2012-05-14 18:28   ` Stephen Hemminger
2012-05-24 17:09     ` Arvid Brodin
2012-05-24 17:16       ` Stephen Hemminger

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