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Message-Id: <20080512.205032.14370318.davem@davemloft.net>
Date: Mon, 12 May 2008 20:50:32 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: johannes@...solutions.net
Cc: herbert@...dor.apana.org.au, netdev@...r.kernel.org,
linux-wireless@...r.kernel.org
Subject: Re: [RFC] allow netdevices to specify needed head/tailroom
From: Johannes Berg <johannes@...solutions.net>
Date: Mon, 05 May 2008 15:01:26 +0200
> Forgot again to post this this morning, sorry.
No worries.
I made some minor cleanups and removed the comment "FIXME" blobs
you added the for skb_cow()/skb_realloc_headroom() code paths.
I promise we'll investigate and inspect those :-)
Here is the final patch I applied.
net: Allow netdevices to specify needed head/tailroom
This patch adds needed_headroom/needed_tailroom members to struct
net_device and updates many places that allocate sbks to use them. Not
all of them can be converted though, and I'm sure I missed some (I
mostly grepped for LL_RESERVED_SPACE)
Signed-off-by: Johannes Berg <johannes@...solutions.net>
Signed-off-by: David S. Miller <davem@...emloft.net>
---
include/linux/netdevice.h | 16 ++++++++++++++--
net/core/netpoll.c | 2 +-
net/econet/af_econet.c | 2 +-
net/ipv4/arp.c | 2 +-
net/ipv4/igmp.c | 4 ++--
net/ipv4/ipconfig.c | 6 +++---
net/ipv4/raw.c | 10 ++++------
net/ipv6/ip6_output.c | 2 +-
net/ipv6/mcast.c | 4 ++--
net/ipv6/ndisc.c | 4 ++--
net/ipv6/raw.c | 10 ++++------
net/packet/af_packet.c | 2 +-
net/xfrm/xfrm_output.c | 6 +++---
13 files changed, 39 insertions(+), 31 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a3fb57f..b11e6e1 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -246,11 +246,16 @@ 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,
@@ -569,6 +574,13 @@ struct net_device
unsigned short type; /* interface hardware type */
unsigned short hard_header_len; /* hardware hdr length */
+ /* extra head- and tailroom the hardware may need, but not in all cases
+ * can this be guaranteed, especially tailroom. Some cases also use
+ * LL_MAX_HEADER instead to allocate the skb.
+ */
+ unsigned short needed_headroom;
+ unsigned short needed_tailroom;
+
struct net_device *master; /* Pointer to master device of a group,
* which this device is member of.
*/
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index b04d643..8fb134d 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -419,7 +419,7 @@ static void arp_reply(struct sk_buff *skb)
return;
size = arp_hdr_len(skb->dev);
- 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)
diff --git a/net/econet/af_econet.c b/net/econet/af_econet.c
index 68d1544..7c9bb13 100644
--- a/net/econet/af_econet.c
+++ b/net/econet/af_econet.c
@@ -340,7 +340,7 @@ static int econet_sendmsg(struct kiocb *iocb, struct socket *sock,
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;
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 68b72a7..418862f 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -570,7 +570,7 @@ struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
* Allocate a buffer
*/
- skb = alloc_skb(arp_hdr_len(dev) + LL_RESERVED_SPACE(dev), GFP_ATOMIC);
+ skb = alloc_skb(arp_hdr_len(dev) + LL_ALLOCATED_SPACE(dev), GFP_ATOMIC);
if (skb == NULL)
return NULL;
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 6250f42..2769dc4 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -292,7 +292,7 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
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_device *in_dev, struct ip_mc_list *pmc,
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;
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 89dee43..ed45037 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -710,14 +710,14 @@ static void __init ic_bootp_send_if(struct ic_device *d, unsigned long jiffies_d
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));
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 11d7f75..fead049 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -322,7 +322,6 @@ static int raw_send_hdrinc(struct sock *sk, void *from, size_t length,
unsigned int flags)
{
struct inet_sock *inet = inet_sk(sk);
- int hh_len;
struct iphdr *iph;
struct sk_buff *skb;
unsigned int iphlen;
@@ -336,13 +335,12 @@ static int raw_send_hdrinc(struct sock *sk, void *from, size_t length,
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;
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 0af2e05..48cdce9 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -780,7 +780,7 @@ 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);
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 54f91ef..fd632dd 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1411,7 +1411,7 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size)
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;
@@ -1790,7 +1790,7 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
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();
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 2c74885..a55fc05 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -479,7 +479,7 @@ static void __ndisc_send(struct net_device *dev,
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
@@ -1521,7 +1521,7 @@ void ndisc_send_redirect(struct sk_buff *skb, struct neighbour *neigh,
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
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 396f0ea..232e0dc 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -609,7 +609,6 @@ static int rawv6_send_hdrinc(struct sock *sk, void *from, int length,
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) {
@@ -619,13 +618,12 @@ static int rawv6_send_hdrinc(struct sock *sk, void *from, int length,
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;
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 2507024..2cee87d 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -743,7 +743,7 @@ static int packet_sendmsg(struct kiocb *iocb, struct socket *sock,
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;
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index 09cd9c0..3f964db 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -25,11 +25,11 @@ 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 ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
- if (nhead > 0)
- return pskb_expand_head(skb, nhead, 0, GFP_ATOMIC);
+ if (nhead > 0 || ntail > 0)
+ return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
- /* Check tail too... */
return 0;
}
--
1.5.5.1.57.g5909c
--
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