From: Stanislaw Gruszka <sgruszka@redhat.com>
To: linux-wireless@vger.kernel.org
Cc: users@rt2x00.serialmonkey.com,
Mark Asselstine <asselsm@gmail.com>,
"Antti S. Lankila" <alankila@bel.fi>
Subject: Re: [PATCH] rt2x00: do not align payload on modern H/W
Date: Tue, 11 Nov 2014 14:06:06 +0100 [thread overview]
Message-ID: <20141111130605.GA2892@redhat.com> (raw)
In-Reply-To: <20141102123846.GB9242@redhat.com>
On Sun, Nov 02, 2014 at 01:38:47PM +0100, Stanislaw Gruszka wrote:
> RT2800 and newer hardware require padding between header and payload if
> header length is not multiple of 4.
>
> For historical reasons we also align payload to to 4 bytes boundary, but
> such alignment is not needed on modern H/W.
>
> Patch improve performance on embedded CPUs and _possibly_ fixes
> skb_under_panic problems reported from time to time:
>
> https://bugzilla.kernel.org/show_bug.cgi?id=84911
> https://bugzilla.kernel.org/show_bug.cgi?id=72471
> http://marc.info/?l=linux-wireless&m=139108549530402&w=2
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1087591
>
> But we can not explain or otherwise confirm the patch fixes this panic
> issue for sure.
Antti on https://bugzilla.kernel.org/show_bug.cgi?id=72471 tested patch
and confirm it fixes the panic, he also provided traces showing that we
really eat headroom on each retransmission in some special case - no
payload and header length not being multiple of 4.
Taking that and since this patch was not yet applied I'll repost it with
updated changelog and direct to 3.18 stream and -stable.
Stanislaw
next prev parent reply other threads:[~2014-11-11 13:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-02 12:38 [PATCH] rt2x00: do not align payload on modern H/W Stanislaw Gruszka
2014-11-11 13:06 ` Stanislaw Gruszka [this message]
2014-11-11 13:28 ` [PATCH v2 3.18] " Stanislaw Gruszka
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