Message-ID: <50355021.7000408@lwfinger.net> (sfid-20120822_233342_750120_DC810200)
Date: Wed, 22 Aug 2012 16:33:21 -0500
From: Larry Finger <Larry.Finger@lwfinger.net>
MIME-Version: 1.0
To: Eric Dumazet <eric.dumazet@gmail.com>
CC: Neal Cardwell <ncardwell@google.com>,
	"David S. Miller" <davem@davemloft.net>,
	John W Linville <linville@tuxdriver.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Regression associated with commit c8628155ece3 - "tcp: reduce
 out_of_order memory use"
References: <50345B12.1050600@lwfinger.net> <1345612503.5158.566.camel@edumazet-glaptop>
In-Reply-To: <1345612503.5158.566.camel@edumazet-glaptop>
Content-Type: text/plain; charset=UTF-8; format=flowed
Sender: linux-wireless-owner@vger.kernel.org

On 08/22/2012 12:15 AM, Eric Dumazet wrote:
>
> This particular commit is the start of a patches batch that ended in the
> generic TCP coalescing mechanism.
>
> It is known to have problem on drivers doing skb_clone() in their rx
> path.
>
> Current kernels should be ok, because coalescing doesnt happen if the
> destination skb is cloned (skb_cloned(to) in skb_try_coalesce())

The skb_clone() call is not the source of the problem for r8712u, as it is only 
used when a memory allocation fails, which is not happening. The suggestion did 
lead to another patch that I had been preparing. The initial allocation of RX 
buffers used a size of 30720 bytes, while 9100 is sufficient to allow 
aggregation. Upon reducing the buffer size, the driver now works for me. I am 
now awaiting tests by the OP on the Red Hat bugzilla before sending the patch 
upstream.

So far, no ideas for the problem in connecting to WPA1 networks.

Larry