Subject: Re: [PATCH] bonding: bond_select_queue off by one

From: Ben Hutchings <[email-masked]>
Date: Fri, 18 Feb 2011 03:46:31 +0000

On Thu, 2011-02-17 at 18:07 -0800, Phil Oester wrote:
> The bonding driver's bond_select_queue function simply returns
> skb->queue_mapping.  However queue_mapping could be == 16
> for queue #16.  This causes the following message to be flooded
> to syslog:
> 
> kernel: bondx selects TX queue 16, but real number of TX queues is 16
> 
> ndo_select_queue wants a zero-based number, so bonding driver needs
> to subtract one to return the proper queue number.  Also fix grammar in
> a comment while in the vicinity.
> 
> Phil Oester
> 
> Signed-off-by: Phil Oester <[email-masked]>

> --- linux-2.6/drivers/net/bonding/bond_main.c.orig      2011-01-30 09:15:09.813843817 -0800
> +++ linux-2.6/drivers/net/bonding/bond_main.c   2011-02-17 18:02:46.919050909 -0800
> @@ -4537,11 +4537,11 @@
>  {
>         /*
>          * This helper function exists to help dev_pick_tx get the correct
> -        * destination queue.  Using a helper function skips the a call to
> +        * destination queue.  Using a helper function skips a call to
>          * skb_tx_hash and will put the skbs in the queue we expect on their
>          * way down to the bonding driver.
>          */
> -       return skb->queue_mapping;
> +       return skb->queue_mapping ? skb->queue_mapping - 1 : 0;
>  }
>  
>  static netdev_tx_t bond_start_xmit(struct sk_buff *skb, struct net_device *dev) 

This looks basically correct, but it should use the proper functions:

	skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : 0;

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
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