From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: Re: [PATCH 1/3] [LLC]: skb allocation size for responses Date: Sat, 29 Mar 2008 09:02:23 -0300 Message-ID: <20080329120223.GZ14945@ghostprotocols.net> References: <1206691159-10872-1-git-send-email-joonwpark81@gmail.com> <20080328131202.GP14945@ghostprotocols.net> <20080329060655.GA15023@tp64> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, netdev@vger.kernel.org To: Joonwoo Park Return-path: Received: from mx1.redhat.com ([66.187.233.31]:43368 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750854AbYC2MCa (ORCPT ); Sat, 29 Mar 2008 08:02:30 -0400 Content-Disposition: inline In-Reply-To: <20080329060655.GA15023@tp64> Sender: netdev-owner@vger.kernel.org List-ID: Em Sat, Mar 29, 2008 at 03:06:55PM +0900, Joonwoo Park escreveu: > On Fri, Mar 28, 2008 at 10:12:02AM -0300, Arnaldo Carvalho de Melo wrote: > > > > > +static int llc_mac_header_len(unsigned short devtype) > > > +{ > > > + switch (devtype) { > > > + case ARPHRD_ETHER: > > > + case ARPHRD_LOOPBACK: > > > + return sizeof(struct ethhdr); > > > + } > > > + > > > + return __llc_tr_mac_header_len(devtype); > > > +} > > > > Nah, just drop __llc_tr_mac_header_len altogether and have another case > > entry for ARPHDR_IEEE802_TR. > > > > > /** > > > * llc_alloc_frame - allocates sk_buff for frame > > > * @dev: network device this skb will be sent over > > > + * @type: pdu type to allocate > > > + * @data_size: data size to allocate > > > * > > > * Allocates an sk_buff for frame and initializes sk_buff fields. > > > * Returns allocated skb or %NULL when out of memory. > > > */ > > > -struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev) > > > +struct sk_buff *llc_alloc_frame(struct sock *sk, struct net_device *dev, > > > + u8 type, u32 data_size) > > > { > > > - struct sk_buff *skb = alloc_skb(128, GFP_ATOMIC); > > > + int hlen = type == LLC_PDU_TYPE_U ? 3 : 4; > > > + struct sk_buff *skb; > > > + > > > + hlen += llc_mac_header_len(dev->type); > > > + skb = alloc_skb(hlen + data_size, GFP_ATOMIC); > > > > > > if (skb) { > > > skb_reset_mac_header(skb); > > > - skb_reserve(skb, 50); > > > + skb_reserve(skb, hlen); > > > > Well done, now it is better documented (LLC_PDU_TYPE_U passed) and uses > > less memory, no more magic numbers, good. > > > > - Arnaldo > > > I've respined the patch, thanks Arnaldo. > > --- > [LLC]: skb allocation size for responses > > Allocate the skb for llc responses with the received packet size by > using the size adjustable llc_frame_alloc. > Don't allocate useless extra payload. > Cleanup magic numbers. > > So, this fixes oops. > Reported by Jim Westfall: > kernel: skb_over_panic: text:c0541fc7 len:1000 put:997 head:c166ac00 data:c166ac2f tail:0xc166b017 end:0xc166ac80 dev:eth0 > kernel: ------------[ cut here ]------------ > kernel: kernel BUG at net/core/skbuff.c:95! Perfect, thanks a lot: Acked-by: Arnaldo Carvalho de Melo - Arnaldo