Date: Mon, 7 Feb 2011 09:07:47 -0800
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Felix Fietkau <nbd@openwrt.org>
Cc: linux-wireless@vger.kernel.org, linville@tuxdriver.com,
	johannes@sipsolutions.net
Subject: Re: [PATCH 2.6.38] mac80211: fix the skb cloned check in the tx path
Message-ID: <20110207170747.GA31901@core.coreip.homeip.net>
References: <1297076700-76871-1-git-send-email-nbd@openwrt.org>
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In-Reply-To: <1297076700-76871-1-git-send-email-nbd@openwrt.org>
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On Mon, Feb 07, 2011 at 12:05:00PM +0100, Felix Fietkau wrote:
> Using skb_header_cloned to check if it's safe to write to the skb is not
> enough - mac80211 also touches the tailroom of the skb.
> Initially this check was only used to increase a counter, however this
> commit changed the code to also skip skb data reallocation if no extra
> head/tailroom was needed:
> 
> commit 4cd06a344db752f513437138953af191cbe9a691
> mac80211: skip unnecessary pskb_expand_head calls
> 
> It added a regression at least with iwl3945, which is fixed by this patch.
> 
> Reported-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Make it

	Tested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

as well since it cures my issue with sshfs getting stuck under load.

Would be nice if the patch made it in .38.

Thanks!


> Signed-off-by: Felix Fietkau <nbd@openwrt.org>
> ---
>  net/mac80211/tx.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index 2915168..fc1d728 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -1549,7 +1549,7 @@ static int ieee80211_skb_resize(struct ieee80211_local *local,
>  		skb_orphan(skb);
>  	}
>  
> -	if (skb_header_cloned(skb))
> +	if (skb_cloned(skb))
>  		I802_DEBUG_INC(local->tx_expand_skb_head_cloned);
>  	else if (head_need || tail_need)
>  		I802_DEBUG_INC(local->tx_expand_skb_head);
> -- 
> 1.7.3.2
> 

-- 
Dmitry