From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] mv643xx_eth: Fix a possible deadlock upon ifdown
Date: Fri, 04 Jan 2013 15:20:31 -0800 (PST)
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From: Lubomir Rintel <lkundrak@v3.sk>
Date: Fri,  4 Jan 2013 15:17:43 +0100

> @@ -943,7 +943,7 @@ static int txq_reclaim(struct tx_queue *txq, int budget, int force)
>  	struct netdev_queue *nq = netdev_get_tx_queue(mp->dev, txq->index);
>  	int reclaimed;
>  
> -	__netif_tx_lock(nq, smp_processor_id());
> +	__netif_tx_lock_bh(nq);

I still don't understand why this change is necessary.

The TX reclaim function is invoked in software interrupt context in
all of the places where this lockdep warning might matter.