> There are three ways out of this. You could have your own cache > (I haven't looked at your headers so I don't know whether that > makes sense), have no cache at all, or add a new field that gets > added to hard_header_len for the purposes of calculating head > room. I tried the last option, patch below, didn't quite work out yet, but I got: [ 256.241496] KERNEL: assertion (!atomic_read(&sk->sk_wmem_alloc)) failed at net/packet/af_packet.c (225) any ideas about that? johannes --- include/linux/netdevice.h | 10 ++++++++-- net/core/netpoll.c | 2 +- net/econet/af_econet.c | 2 +- net/ipv4/arp.c | 2 +- net/ipv4/igmp.c | 4 ++-- net/ipv4/ip_forward.c | 4 +++- net/ipv4/ipconfig.c | 6 +++--- net/ipv4/ipip.c | 1 + net/ipv4/ipmr.c | 1 + net/ipv4/ipvs/ip_vs_xmit.c | 1 + net/ipv4/raw.c | 10 ++++------ net/ipv6/ip6_output.c | 3 ++- net/ipv6/mcast.c | 4 ++-- net/ipv6/ndisc.c | 4 ++-- net/ipv6/raw.c | 10 ++++------ net/ipv6/sit.c | 2 ++ net/packet/af_packet.c | 2 +- net/xfrm/xfrm_output.c | 11 ++++++----- 18 files changed, 45 insertions(+), 34 deletions(-) --- everything.orig/include/linux/netdevice.h 2008-05-04 14:48:47.000000000 +0200 +++ everything/include/linux/netdevice.h 2008-05-04 15:34:04.000000000 +0200 @@ -254,11 +254,16 @@ struct hh_cache * * We could use other alignment values, but we must maintain the * relationship HH alignment <= LL alignment. + * + * LL_ALLOCATED_SPACE also takes into account the tailroom the device + * may need. */ #define LL_RESERVED_SPACE(dev) \ - (((dev)->hard_header_len&~(HH_DATA_MOD - 1)) + HH_DATA_MOD) + ((((dev)->hard_header_len+(dev)->needed_headroom)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD) #define LL_RESERVED_SPACE_EXTRA(dev,extra) \ - ((((dev)->hard_header_len+extra)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD) + ((((dev)->hard_header_len+(dev)->needed_headroom+(extra))&~(HH_DATA_MOD - 1)) + HH_DATA_MOD) +#define LL_ALLOCATED_SPACE(dev) \ + ((((dev)->hard_header_len+(dev)->needed_headroom+(dev)->needed_tailroom)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD) struct header_ops { int (*create) (struct sk_buff *skb, struct net_device *dev, @@ -576,6 +581,7 @@ struct net_device unsigned mtu; /* interface MTU value */ unsigned short type; /* interface hardware type */ unsigned short hard_header_len; /* hardware hdr length */ + unsigned short needed_headroom, needed_tailroom; struct net_device *master; /* Pointer to master device of a group, * which this device is member of. --- everything.orig/net/core/netpoll.c 2008-05-04 14:53:54.000000000 +0200 +++ everything/net/core/netpoll.c 2008-05-04 15:02:53.000000000 +0200 @@ -421,7 +421,7 @@ static void arp_reply(struct sk_buff *sk return; size = sizeof(struct arphdr) + 2 * (skb->dev->addr_len + 4); - send_skb = find_skb(np, size + LL_RESERVED_SPACE(np->dev), + send_skb = find_skb(np, size + LL_ALLOCATED_SPACE(np->dev), LL_RESERVED_SPACE(np->dev)); if (!send_skb) --- everything.orig/net/econet/af_econet.c 2008-05-04 14:53:53.000000000 +0200 +++ everything/net/econet/af_econet.c 2008-05-04 14:56:53.000000000 +0200 @@ -340,7 +340,7 @@ static int econet_sendmsg(struct kiocb * dev_hold(dev); - skb = sock_alloc_send_skb(sk, len+LL_RESERVED_SPACE(dev), + skb = sock_alloc_send_skb(sk, len+LL_ALLOCATED_SPACE(dev), msg->msg_flags & MSG_DONTWAIT, &err); if (skb==NULL) goto out_unlock; --- everything.orig/net/ipv4/arp.c 2008-05-04 14:53:54.000000000 +0200 +++ everything/net/ipv4/arp.c 2008-05-04 15:04:18.000000000 +0200 @@ -571,7 +571,7 @@ struct sk_buff *arp_create(int type, int */ skb = alloc_skb(sizeof(struct arphdr)+ 2*(dev->addr_len+4) - + LL_RESERVED_SPACE(dev), GFP_ATOMIC); + + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC); if (skb == NULL) return NULL; --- everything.orig/net/ipv4/igmp.c 2008-05-04 14:53:55.000000000 +0200 +++ everything/net/ipv4/igmp.c 2008-05-04 15:06:59.000000000 +0200 @@ -292,7 +292,7 @@ static struct sk_buff *igmpv3_newpack(st struct iphdr *pip; struct igmpv3_report *pig; - skb = alloc_skb(size + LL_RESERVED_SPACE(dev), GFP_ATOMIC); + skb = alloc_skb(size + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC); if (skb == NULL) return NULL; @@ -653,7 +653,7 @@ static int igmp_send_report(struct in_de return -1; } - skb=alloc_skb(IGMP_SIZE+LL_RESERVED_SPACE(dev), GFP_ATOMIC); + skb=alloc_skb(IGMP_SIZE+LL_ALLOCATED_SPACE(dev), GFP_ATOMIC); if (skb == NULL) { ip_rt_put(rt); return -1; --- everything.orig/net/ipv4/ip_forward.c 2008-05-04 14:53:54.000000000 +0200 +++ everything/net/ipv4/ip_forward.c 2008-05-04 15:05:43.000000000 +0200 @@ -93,7 +93,9 @@ int ip_forward(struct sk_buff *skb) goto drop; } - /* We are about to mangle packet. Copy it! */ + /* We are about to mangle packet. Copy it! + * FIXME: account for needed tail length? + */ if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+rt->u.dst.header_len)) goto drop; iph = ip_hdr(skb); --- everything.orig/net/ipv4/ipconfig.c 2008-05-04 14:53:54.000000000 +0200 +++ everything/net/ipv4/ipconfig.c 2008-05-04 15:06:16.000000000 +0200 @@ -713,14 +713,14 @@ static void __init ic_bootp_send_if(stru struct net_device *dev = d->dev; struct sk_buff *skb; struct bootp_pkt *b; - int hh_len = LL_RESERVED_SPACE(dev); struct iphdr *h; /* Allocate packet */ - skb = alloc_skb(sizeof(struct bootp_pkt) + hh_len + 15, GFP_KERNEL); + skb = alloc_skb(sizeof(struct bootp_pkt) + + LL_ALLOCATED_SPACE(dev) + 15, GFP_KERNEL); if (!skb) return; - skb_reserve(skb, hh_len); + skb_reserve(skb, LL_RESERVED_SPACE(dev)); b = (struct bootp_pkt *) skb_put(skb, sizeof(struct bootp_pkt)); memset(b, 0, sizeof(struct bootp_pkt)); --- everything.orig/net/ipv4/ipip.c 2008-05-04 14:53:55.000000000 +0200 +++ everything/net/ipv4/ipip.c 2008-05-04 15:07:10.000000000 +0200 @@ -587,6 +587,7 @@ static int ipip_tunnel_xmit(struct sk_bu /* * Okay, now see if we can stuff it in the buffer as-is. + * FIXME: tail room? */ max_headroom = (LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr)); --- everything.orig/net/ipv4/ipmr.c 2008-05-04 14:53:54.000000000 +0200 +++ everything/net/ipv4/ipmr.c 2008-05-04 15:06:32.000000000 +0200 @@ -1211,6 +1211,7 @@ static void ipmr_queue_xmit(struct sk_bu goto out_free; } + /* FIXME: what about needed tailroom? */ encap += LL_RESERVED_SPACE(dev) + rt->u.dst.header_len; if (skb_cow(skb, encap)) { --- everything.orig/net/ipv4/ipvs/ip_vs_xmit.c 2008-05-04 14:53:54.000000000 +0200 +++ everything/net/ipv4/ipvs/ip_vs_xmit.c 2008-05-04 15:04:34.000000000 +0200 @@ -363,6 +363,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, s /* * Okay, now see if we can stuff it in the buffer as-is. + * FIXME: account for needed tailroom? */ max_headroom = LL_RESERVED_SPACE(tdev) + sizeof(struct iphdr); --- everything.orig/net/ipv4/raw.c 2008-05-04 14:53:54.000000000 +0200 +++ everything/net/ipv4/raw.c 2008-05-04 15:30:46.000000000 +0200 @@ -329,7 +329,6 @@ static int raw_send_hdrinc(struct sock * unsigned int flags) { struct inet_sock *inet = inet_sk(sk); - int hh_len; struct iphdr *iph; struct sk_buff *skb; unsigned int iphlen; @@ -343,13 +342,12 @@ static int raw_send_hdrinc(struct sock * if (flags&MSG_PROBE) goto out; - hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); - - skb = sock_alloc_send_skb(sk, length+hh_len+15, - flags&MSG_DONTWAIT, &err); + skb = sock_alloc_send_skb( + sk, length + LL_ALLOCATED_SPACE(rt->u.dst.dev) + 15, + flags & MSG_DONTWAIT, &err); if (skb == NULL) goto error; - skb_reserve(skb, hh_len); + skb_reserve(skb, LL_RESERVED_SPACE(rt->u.dst.dev)); skb->priority = sk->sk_priority; skb->mark = sk->sk_mark; --- everything.orig/net/ipv6/ip6_output.c 2008-05-04 14:53:53.000000000 +0200 +++ everything/net/ipv6/ip6_output.c 2008-05-04 15:02:05.000000000 +0200 @@ -201,6 +201,7 @@ int ip6_xmit(struct sock *sk, struct sk_ /* First: exthdrs may take lots of space (~8K for now) MAX_HEADER is not enough. + FIXME: LL_ALLOCATED_SPACE? */ head_room = opt->opt_nflen + opt->opt_flen; seg_len += head_room; @@ -780,7 +781,7 @@ slow_path: * Allocate buffer. */ - if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_RESERVED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) { + if ((frag = alloc_skb(len+hlen+sizeof(struct frag_hdr)+LL_ALLOCATED_SPACE(rt->u.dst.dev), GFP_ATOMIC)) == NULL) { NETDEBUG(KERN_INFO "IPv6: frag: no memory for new fragment!\n"); IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS); --- everything.orig/net/ipv6/mcast.c 2008-05-04 14:53:53.000000000 +0200 +++ everything/net/ipv6/mcast.c 2008-05-04 15:01:21.000000000 +0200 @@ -1403,7 +1403,7 @@ static struct sk_buff *mld_newpack(struc IPV6_TLV_PADN, 0 }; /* we assume size > sizeof(ra) here */ - skb = sock_alloc_send_skb(sk, size + LL_RESERVED_SPACE(dev), 1, &err); + skb = sock_alloc_send_skb(sk, size + LL_ALLOCATED_SPACE(dev), 1, &err); if (!skb) return NULL; @@ -1776,7 +1776,7 @@ static void igmp6_send(struct in6_addr * payload_len = len + sizeof(ra); full_len = sizeof(struct ipv6hdr) + payload_len; - skb = sock_alloc_send_skb(sk, LL_RESERVED_SPACE(dev) + full_len, 1, &err); + skb = sock_alloc_send_skb(sk, LL_ALLOCATED_SPACE(dev) + full_len, 1, &err); if (skb == NULL) { rcu_read_lock(); --- everything.orig/net/ipv6/ndisc.c 2008-05-04 14:53:53.000000000 +0200 +++ everything/net/ipv6/ndisc.c 2008-05-04 15:01:37.000000000 +0200 @@ -494,7 +494,7 @@ static void __ndisc_send(struct net_devi skb = sock_alloc_send_skb(sk, (MAX_HEADER + sizeof(struct ipv6hdr) + - len + LL_RESERVED_SPACE(dev)), + len + LL_ALLOCATED_SPACE(dev)), 1, &err); if (!skb) { ND_PRINTK0(KERN_ERR @@ -1494,7 +1494,7 @@ void ndisc_send_redirect(struct sk_buff buff = sock_alloc_send_skb(sk, (MAX_HEADER + sizeof(struct ipv6hdr) + - len + LL_RESERVED_SPACE(dev)), + len + LL_ALLOCATED_SPACE(dev)), 1, &err); if (buff == NULL) { ND_PRINTK0(KERN_ERR --- everything.orig/net/ipv6/raw.c 2008-05-04 14:53:53.000000000 +0200 +++ everything/net/ipv6/raw.c 2008-05-04 14:57:58.000000000 +0200 @@ -624,7 +624,6 @@ static int rawv6_send_hdrinc(struct sock struct ipv6_pinfo *np = inet6_sk(sk); struct ipv6hdr *iph; struct sk_buff *skb; - unsigned int hh_len; int err; if (length > rt->u.dst.dev->mtu) { @@ -634,13 +633,12 @@ static int rawv6_send_hdrinc(struct sock if (flags&MSG_PROBE) goto out; - hh_len = LL_RESERVED_SPACE(rt->u.dst.dev); - - skb = sock_alloc_send_skb(sk, length+hh_len+15, - flags&MSG_DONTWAIT, &err); + skb = sock_alloc_send_skb( + sk, length + LL_ALLOCATED_SPACE(rt->u.dst.dev) + 15, + flags & MSG_DONTWAIT, &err); if (skb == NULL) goto error; - skb_reserve(skb, hh_len); + skb_reserve(skb, LL_RESERVED_SPACE(rt->u.dst.dev)); skb->priority = sk->sk_priority; skb->mark = sk->sk_mark; --- everything.orig/net/ipv6/sit.c 2008-05-04 14:53:53.000000000 +0200 +++ everything/net/ipv6/sit.c 2008-05-04 15:00:55.000000000 +0200 @@ -603,6 +603,8 @@ static int ipip6_tunnel_xmit(struct sk_b /* * Okay, now see if we can stuff it in the buffer as-is. + * + * XXX: tailroom? LL_ALLOCATED_SPACE? */ max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr); --- everything.orig/net/packet/af_packet.c 2008-05-04 14:53:53.000000000 +0200 +++ everything/net/packet/af_packet.c 2008-05-04 15:02:33.000000000 +0200 @@ -743,7 +743,7 @@ static int packet_sendmsg(struct kiocb * if (len > dev->mtu+reserve) goto out_unlock; - skb = sock_alloc_send_skb(sk, len + LL_RESERVED_SPACE(dev), + skb = sock_alloc_send_skb(sk, len + LL_ALLOCATED_SPACE(dev), msg->msg_flags & MSG_DONTWAIT, &err); if (skb==NULL) goto out_unlock; --- everything.orig/net/xfrm/xfrm_output.c 2008-05-04 14:53:52.000000000 +0200 +++ everything/net/xfrm/xfrm_output.c 2008-05-04 15:46:11.000000000 +0200 @@ -23,13 +23,14 @@ static int xfrm_output2(struct sk_buff * static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb) { struct dst_entry *dst = skb->dst; - int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev) - - skb_headroom(skb); + int nhead = max_t(int, 0, dst->header_len + LL_RESERVED_SPACE(dst->dev) + - skb_headroom(skb)); + int ntail = max_t(int, 0, dst->dev->needed_tailroom + - skb_tailroom(skb)); - if (nhead > 0) - return pskb_expand_head(skb, nhead, 0, GFP_ATOMIC); + if (nhead || ntail) + return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC); - /* Check tail too... */ return 0; } -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html