From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [net-next PATCH] xen-netback: switch to use skb_partial_csum_set() Date: Thu, 11 Apr 2013 15:58:32 +0800 Message-ID: <51666D28.7090500@redhat.com> References: <1365662129-38031-1-git-send-email-jasowang@redhat.com> <1365666364.27868.114.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "davem@davemloft.net" To: Ian Campbell Return-path: In-Reply-To: <1365666364.27868.114.camel@zakaz.uk.xensource.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 04/11/2013 03:46 PM, Ian Campbell wrote: > On Thu, 2013-04-11 at 07:35 +0100, Jason Wang wrote: >> Switch to use skb_partial_csum_set() to simplify the codes. > This is incremental on top of your previous patch, right? It's an independent patch, since the previous patch has been applied. >> Cc: Ian Campbell >> Signed-off-by: Jason Wang >> --- >> Note: >> - Compile test only. >> --- >> drivers/net/xen-netback/netback.c | 22 ++++++++-------------- >> 1 files changed, 8 insertions(+), 14 deletions(-) >> >> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c >> index 83905a9..70631f0 100644 >> --- a/drivers/net/xen-netback/netback.c >> +++ b/drivers/net/xen-netback/netback.c >> @@ -1156,7 +1156,6 @@ static int netbk_set_skb_gso(struct xenvif *vif, >> static int checksum_setup(struct xenvif *vif, struct sk_buff *skb) >> { >> struct iphdr *iph; >> - unsigned char *th; >> int err = -EPROTO; >> int recalculate_partial_csum = 0; >> >> @@ -1180,28 +1179,26 @@ static int checksum_setup(struct xenvif *vif, struct sk_buff *skb) >> goto out; >> >> iph = (void *)skb->data; >> - th = skb->data + 4 * iph->ihl; >> - if (th >= skb_tail_pointer(skb)) >> - goto out; >> - >> - skb_set_transport_header(skb, 4 * iph->ihl); > Is removing this line really correct? After commit e5d5deca (net: core: let skb_partial_csum_set() set transport header), this work was done by skb_partial_csum_set(). > >> - skb->csum_start = th - skb->head; >> switch (iph->protocol) { >> case IPPROTO_TCP: >> - skb->csum_offset = offsetof(struct tcphdr, check); >> + if (!skb_partial_csum_set(skb, 4 * iph->ihl, >> + offsetof(struct tcphdr, check))) >> + goto out; >> >> if (recalculate_partial_csum) { >> - struct tcphdr *tcph = (struct tcphdr *)th; >> + struct tcphdr *tcph = tcp_hdr(skb); >> tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, >> skb->len - iph->ihl*4, >> IPPROTO_TCP, 0); >> } >> break; >> case IPPROTO_UDP: >> - skb->csum_offset = offsetof(struct udphdr, check); >> + if (!skb_partial_csum_set(skb, 4 * iph->ihl, >> + offsetof(struct udphdr, check))) >> + goto out; >> >> if (recalculate_partial_csum) { >> - struct udphdr *udph = (struct udphdr *)th; >> + struct udphdr *udph = udp_hdr(skb); >> udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, >> skb->len - iph->ihl*4, >> IPPROTO_UDP, 0); >> @@ -1215,9 +1212,6 @@ static int checksum_setup(struct xenvif *vif, struct sk_buff *skb) >> goto out; >> } >> >> - if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb)) >> - goto out; >> - >> err = 0; >> >> out: >