From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH 2.6.19] AT91RM9200 Ethernet update 3 Date: Mon, 4 Dec 2006 10:08:31 -0800 Message-ID: <20061204100831.0af6790f@freekitty> References: <1165236624.4606.111.camel@fuzzie.sanpeople.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, jgarzik@pobox.com Return-path: Received: from smtp.osdl.org ([65.172.181.25]:47021 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936673AbWLDSIn (ORCPT ); Mon, 4 Dec 2006 13:08:43 -0500 To: Andrew Victor In-Reply-To: <1165236624.4606.111.camel@fuzzie.sanpeople.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 04 Dec 2006 14:50:24 +0200 Andrew Victor wrote: > A minor fix to the Atmel AT91RM9200 Ethernet driver. > > 1. Use dev_alloc_skb() instead of alloc_skb(). > 2. It is not necessary to adjust skb->len manually. > > > Signed-off-by: Andrew Victor > > > diff -urN linux-2.6.19-final.orig/drivers/net/arm/at91_ether.c linux-2.6.19-final/drivers/net/arm/at91_ether.c > --- linux-2.6.19-final.orig/drivers/net/arm/at91_ether.c Mon Dec 4 14:42:05 2006 > +++ linux-2.6.19-final/drivers/net/arm/at91_ether.c Mon Dec 4 14:43:57 2006 > @@ -855,14 +855,13 @@ > while (dlist->descriptors[lp->rxBuffIndex].addr & EMAC_DESC_DONE) { > p_recv = dlist->recv_buf[lp->rxBuffIndex]; > pktlen = dlist->descriptors[lp->rxBuffIndex].size & 0x7ff; /* Length of frame including FCS */ > - skb = alloc_skb(pktlen + 2, GFP_ATOMIC); > + skb = dev_alloc_skb(pktlen + 2); > if (skb != NULL) { > skb_reserve(skb, 2); > memcpy(skb_put(skb, pktlen), p_recv, pktlen); > > skb->dev = dev; > skb->protocol = eth_type_trans(skb, dev); > - skb->len = pktlen; > dev->last_rx = jiffies; > lp->stats.rx_bytes += pktlen; > netif_rx(skb); > Use netdev_alloc_skb instead. It sets skb->dev so you don't have to. Setting skb->len is redundant since that is what skb_put() does. It would be best if you didn't have to copy data at all and could receive directly into the skb. If you have to copy received data, it is better to implement NAPI since that allows you to copy data in soft irq. The existing code will cause poor realtime performance since the driver is copying received data with IRQ's disabled. -- Stephen Hemminger