Re: [NET] Move local_bh_disable back in dev_queue_xmit

[Ingo Molnar <mingo@elte.hu>]

sure - perfectly fine to me.

	Ingo

* Herbert Xu <herbert@gondor.apana.org.au> wrote:

> Hi Ingo:
> 
> Your recent fix to dev_queue_xmit moved the local_bh_disable to
> include stuff like skb_linearize and skb_checksum_help.  These
> are potentially expensive operations.  Since they don't need to
> run with preempt off, we could simply move the local_bh_enable
> up instead.
> 
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
> 
> Cheers,
> -- 
> Visit Openswan at http://www.openswan.org/
> Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
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> ===== net/core/dev.c 1.171 vs edited =====
> --- 1.171/net/core/dev.c	2004-11-02 12:40:59 +11:00
> +++ edited/net/core/dev.c	2004-11-03 09:31:09 +11:00
> @@ -1261,11 +1261,6 @@
>  	struct Qdisc *q;
>  	int rc = -ENOMEM;
>  
> -	/* Disable soft irqs for various locks below. Also 
> -	 * stops preemption for RCU. 
> -	 */
> -	local_bh_disable(); 
> -
>  	if (skb_shinfo(skb)->frag_list &&
>  	    !(dev->features & NETIF_F_FRAGLIST) &&
>  	    __skb_linearize(skb, GFP_ATOMIC))
> @@ -1290,6 +1285,11 @@
>  	      	if (skb_checksum_help(skb, 0))
>  	      		goto out_kfree_skb;
>  
> +	/* Disable soft irqs for various locks below. Also 
> +	 * stops preemption for RCU. 
> +	 */
> +	local_bh_disable(); 
> +
>  	/* Updates of qdisc are serialized by queue_lock. 
>  	 * The struct Qdisc which is pointed to by qdisc is now a 
>  	 * rcu structure - it may be accessed without acquiring 
> @@ -1363,10 +1363,10 @@
>  	}
>  out_enetdown:
>  	rc = -ENETDOWN;
> -out_kfree_skb:
> -	kfree_skb(skb);
>  out:
>  	local_bh_enable();
> +out_kfree_skb:
> +	kfree_skb(skb);
>  	return rc;
>  }
>