net: skb->dst accessors

Define three accessors to get/set dst attached to a skb

struct dst_entry *skb_dst(const struct sk_buff *skb)

void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)

void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;

Delete skb->dst field

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

drivers/infiniband/ulp/ipoib/ipoib_cm.c

@@ -1394,8 +1394,8 @@ void ipoib_cm_skb_too_long(struct net_device *dev, struct sk_buff *skb,
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 	int e = skb_queue_empty(&priv->cm.skb_queue);
 
-	if (skb->dst)
-		skb->dst->ops->update_pmtu(skb->dst, mtu);
+	if (skb_dst(skb))
+		skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 
 	skb_queue_tail(&priv->cm.skb_queue, skb);
 	if (e)

drivers/infiniband/ulp/ipoib/ipoib_main.c

@@ -561,7 +561,7 @@ static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
 	struct ipoib_neigh *neigh;
 	unsigned long flags;
 
-	neigh = ipoib_neigh_alloc(skb->dst->neighbour, skb->dev);
+	neigh = ipoib_neigh_alloc(skb_dst(skb)->neighbour, skb->dev);
 	if (!neigh) {
 		++dev->stats.tx_dropped;
 		dev_kfree_skb_any(skb);
@@ -570,9 +570,9 @@ static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
 
 	spin_lock_irqsave(&priv->lock, flags);
 
-	path = __path_find(dev, skb->dst->neighbour->ha + 4);
+	path = __path_find(dev, skb_dst(skb)->neighbour->ha + 4);
 	if (!path) {
-		path = path_rec_create(dev, skb->dst->neighbour->ha + 4);
+		path = path_rec_create(dev, skb_dst(skb)->neighbour->ha + 4);
 		if (!path)
 			goto err_path;
 
@@ -605,7 +605,7 @@ static void neigh_add_path(struct sk_buff *skb, struct net_device *dev)
 				goto err_drop;
 			}
 		} else
-			ipoib_send(dev, skb, path->ah, IPOIB_QPN(skb->dst->neighbour->ha));
+			ipoib_send(dev, skb, path->ah, IPOIB_QPN(skb_dst(skb)->neighbour->ha));
 	} else {
 		neigh->ah  = NULL;
 
@@ -635,15 +635,15 @@ static void ipoib_path_lookup(struct sk_buff *skb, struct net_device *dev)
 	struct ipoib_dev_priv *priv = netdev_priv(skb->dev);
 
 	/* Look up path record for unicasts */
-	if (skb->dst->neighbour->ha[4] != 0xff) {
+	if (skb_dst(skb)->neighbour->ha[4] != 0xff) {
 		neigh_add_path(skb, dev);
 		return;
 	}
 
 	/* Add in the P_Key for multicasts */
-	skb->dst->neighbour->ha[8] = (priv->pkey >> 8) & 0xff;
-	skb->dst->neighbour->ha[9] = priv->pkey & 0xff;
-	ipoib_mcast_send(dev, skb->dst->neighbour->ha + 4, skb);
+	skb_dst(skb)->neighbour->ha[8] = (priv->pkey >> 8) & 0xff;
+	skb_dst(skb)->neighbour->ha[9] = priv->pkey & 0xff;
+	ipoib_mcast_send(dev, skb_dst(skb)->neighbour->ha + 4, skb);
 }
 
 static void unicast_arp_send(struct sk_buff *skb, struct net_device *dev,
@@ -708,16 +708,16 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct ipoib_neigh *neigh;
 	unsigned long flags;
 
-	if (likely(skb->dst && skb->dst->neighbour)) {
-		if (unlikely(!*to_ipoib_neigh(skb->dst->neighbour))) {
+	if (likely(skb_dst(skb) && skb_dst(skb)->neighbour)) {
+		if (unlikely(!*to_ipoib_neigh(skb_dst(skb)->neighbour))) {
 			ipoib_path_lookup(skb, dev);
 			return NETDEV_TX_OK;
 		}
 
-		neigh = *to_ipoib_neigh(skb->dst->neighbour);
+		neigh = *to_ipoib_neigh(skb_dst(skb)->neighbour);
 
 		if (unlikely((memcmp(&neigh->dgid.raw,
-				     skb->dst->neighbour->ha + 4,
+				     skb_dst(skb)->neighbour->ha + 4,
 				     sizeof(union ib_gid))) ||
 			     (neigh->dev != dev))) {
 			spin_lock_irqsave(&priv->lock, flags);
@@ -743,7 +743,7 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
 				return NETDEV_TX_OK;
 			}
 		} else if (neigh->ah) {
-			ipoib_send(dev, skb, neigh->ah, IPOIB_QPN(skb->dst->neighbour->ha));
+			ipoib_send(dev, skb, neigh->ah, IPOIB_QPN(skb_dst(skb)->neighbour->ha));
 			return NETDEV_TX_OK;
 		}
 
@@ -772,7 +772,7 @@ static int ipoib_start_xmit(struct sk_buff *skb, struct net_device *dev)
 			if ((be16_to_cpup((__be16 *) skb->data) != ETH_P_ARP) &&
 			    (be16_to_cpup((__be16 *) skb->data) != ETH_P_RARP)) {
 				ipoib_warn(priv, "Unicast, no %s: type %04x, QPN %06x %pI6\n",
-					   skb->dst ? "neigh" : "dst",
+					   skb_dst(skb) ? "neigh" : "dst",
 					   be16_to_cpup((__be16 *) skb->data),
 					   IPOIB_QPN(phdr->hwaddr),
 					   phdr->hwaddr + 4);
@@ -817,7 +817,7 @@ static int ipoib_hard_header(struct sk_buff *skb,
 	 * destination address onto the front of the skb so we can
 	 * figure out where to send the packet later.
 	 */
-	if ((!skb->dst || !skb->dst->neighbour) && daddr) {
+	if ((!skb_dst(skb) || !skb_dst(skb)->neighbour) && daddr) {
 		struct ipoib_pseudoheader *phdr =
 			(struct ipoib_pseudoheader *) skb_push(skb, sizeof *phdr);
 		memcpy(phdr->hwaddr, daddr, INFINIBAND_ALEN);

drivers/infiniband/ulp/ipoib/ipoib_multicast.c

@@ -261,7 +261,7 @@ static int ipoib_mcast_join_finish(struct ipoib_mcast *mcast,
 
 		skb->dev = dev;
 
-		if (!skb->dst || !skb->dst->neighbour) {
+		if (!skb_dst(skb) || !skb_dst(skb)->neighbour) {
 			/* put pseudoheader back on for next time */
 			skb_push(skb, sizeof (struct ipoib_pseudoheader));
 		}
@@ -707,10 +707,10 @@ void ipoib_mcast_send(struct net_device *dev, void *mgid, struct sk_buff *skb)
 
 out:
 	if (mcast && mcast->ah) {
-		if (skb->dst		&&
-		    skb->dst->neighbour &&
-		    !*to_ipoib_neigh(skb->dst->neighbour)) {
-			struct ipoib_neigh *neigh = ipoib_neigh_alloc(skb->dst->neighbour,
+		if (skb_dst(skb)		&&
+		    skb_dst(skb)->neighbour &&
+		    !*to_ipoib_neigh(skb_dst(skb)->neighbour)) {
+			struct ipoib_neigh *neigh = ipoib_neigh_alloc(skb_dst(skb)->neighbour,
 									skb->dev);
 
 			if (neigh) {

drivers/net/pppol2tp.c

@@ -433,8 +433,7 @@ static void pppol2tp_recv_dequeue_skb(struct pppol2tp_session *session, struct s
 		 *   to the inner packet either
 		 */
 		secpath_reset(skb);
-		dst_release(skb->dst);
-		skb->dst = NULL;
+		skb_dst_drop(skb);
 		nf_reset(skb);
 
 		po = pppox_sk(session_sock);
@@ -976,7 +975,7 @@ static int pppol2tp_sendmsg(struct kiocb *iocb, struct socket *sock, struct msgh
 	/* Calculate UDP checksum if configured to do so */
 	if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
 		skb->ip_summed = CHECKSUM_NONE;
-	else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
+	else if (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
 		skb->ip_summed = CHECKSUM_COMPLETE;
 		csum = skb_checksum(skb, 0, udp_len, 0);
 		uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,
@@ -1172,14 +1171,14 @@ static int pppol2tp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
 	nf_reset(skb);
 
 	/* Get routing info from the tunnel socket */
-	dst_release(skb->dst);
-	skb->dst = dst_clone(__sk_dst_get(sk_tun));
+	skb_dst_drop(skb);
+	skb_dst_set(skb, dst_clone(__sk_dst_get(sk_tun)));
 	pppol2tp_skb_set_owner_w(skb, sk_tun);
 
 	/* Calculate UDP checksum if configured to do so */
 	if (sk_tun->sk_no_check == UDP_CSUM_NOXMIT)
 		skb->ip_summed = CHECKSUM_NONE;
-	else if (!(skb->dst->dev->features & NETIF_F_V4_CSUM)) {
+	else if (!(skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
 		skb->ip_summed = CHECKSUM_COMPLETE;
 		csum = skb_checksum(skb, 0, udp_len, 0);
 		uh->check = csum_tcpudp_magic(inet->saddr, inet->daddr,

drivers/s390/net/qeth_core_main.c

@@ -2937,8 +2937,8 @@ int qeth_get_cast_type(struct qeth_card *card, struct sk_buff *skb)
 	if (card->info.type == QETH_CARD_TYPE_OSN)
 		return cast_type;
 
-	if (skb->dst && skb->dst->neighbour) {
-		cast_type = skb->dst->neighbour->type;
+	if (skb_dst(skb) && skb_dst(skb)->neighbour) {
+		cast_type = skb_dst(skb)->neighbour->type;
 		if ((cast_type == RTN_BROADCAST) ||
 		    (cast_type == RTN_MULTICAST) ||
 		    (cast_type == RTN_ANYCAST))

drivers/s390/net/qeth_l3_main.c

@@ -2549,9 +2549,9 @@ static void qeth_l3_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
 		/* IPv4 */
 		hdr->hdr.l3.flags = qeth_l3_get_qeth_hdr_flags4(cast_type);
 		memset(hdr->hdr.l3.dest_addr, 0, 12);
-		if ((skb->dst) && (skb->dst->neighbour)) {
+		if ((skb_dst(skb)) && (skb_dst(skb)->neighbour)) {
 			*((u32 *) (&hdr->hdr.l3.dest_addr[12])) =
-			    *((u32 *) skb->dst->neighbour->primary_key);
+			    *((u32 *) skb_dst(skb)->neighbour->primary_key);
 		} else {
 			/* fill in destination address used in ip header */
 			*((u32 *) (&hdr->hdr.l3.dest_addr[12])) =
@@ -2562,9 +2562,9 @@ static void qeth_l3_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
 		hdr->hdr.l3.flags = qeth_l3_get_qeth_hdr_flags6(cast_type);
 		if (card->info.type == QETH_CARD_TYPE_IQD)
 			hdr->hdr.l3.flags &= ~QETH_HDR_PASSTHRU;
-		if ((skb->dst) && (skb->dst->neighbour)) {
+		if ((skb_dst(skb)) && (skb_dst(skb)->neighbour)) {
 			memcpy(hdr->hdr.l3.dest_addr,
-			       skb->dst->neighbour->primary_key, 16);
+			       skb_dst(skb)->neighbour->primary_key, 16);
 		} else {
 			/* fill in destination address used in ip header */
 			memcpy(hdr->hdr.l3.dest_addr,

include/linux/skbuff.h

@@ -323,7 +323,6 @@ struct sk_buff {
 	struct net_device	*dev;
 
 	union {
-		struct  dst_entry	*dst;
 		unsigned long		_skb_dst;
 	};
 #ifdef CONFIG_XFRM
@@ -426,9 +425,19 @@ extern void skb_dma_unmap(struct device *dev, struct sk_buff *skb,
 			  enum dma_data_direction dir);
 #endif
 
+static inline struct dst_entry *skb_dst(const struct sk_buff *skb)
+{
+	return (struct dst_entry *)skb->_skb_dst;
+}
+
+static inline void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)
+{
+	skb->_skb_dst = (unsigned long)dst;
+}
+
 static inline struct rtable *skb_rtable(const struct sk_buff *skb)
 {
-	return (struct rtable *)skb->_skb_dst;
+	return (struct rtable *)skb_dst(skb);
 }
 
 extern void kfree_skb(struct sk_buff *skb);

include/net/dst.h

@@ -195,6 +195,12 @@ struct dst_entry * dst_clone(struct dst_entry * dst)
 }
 
 extern void dst_release(struct dst_entry *dst);
+static inline void skb_dst_drop(struct sk_buff *skb)
+{
+	if (skb->_skb_dst)
+		dst_release(skb_dst(skb));
+	skb->_skb_dst = 0UL;
+}
 
 /* Children define the path of the packet through the
  * Linux networking.  Thus, destinations are stackable.
@@ -246,7 +252,7 @@ static inline void dst_negative_advice(struct dst_entry **dst_p)
 
 static inline void dst_link_failure(struct sk_buff *skb)
 {
-	struct dst_entry * dst = skb->dst;
+	struct dst_entry *dst = skb_dst(skb);
 	if (dst && dst->ops && dst->ops->link_failure)
 		dst->ops->link_failure(skb);
 }
@@ -265,13 +271,13 @@ static inline void dst_set_expires(struct dst_entry *dst, int timeout)
 /* Output packet to network from transport.  */
 static inline int dst_output(struct sk_buff *skb)
 {
-	return skb->dst->output(skb);
+	return skb_dst(skb)->output(skb);
 }
 
 /* Input packet from network to transport.  */
 static inline int dst_input(struct sk_buff *skb)
 {
-	return skb->dst->input(skb);
+	return skb_dst(skb)->input(skb);
 }
 
 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)

include/net/inet6_hashtables.h

@@ -100,7 +100,7 @@ static inline struct sock *__inet6_lookup_skb(struct inet_hashinfo *hashinfo,
 
 	if (unlikely(sk = skb_steal_sock(skb)))
 		return sk;
-	else return __inet6_lookup(dev_net(skb->dst->dev), hashinfo,
+	else return __inet6_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
 				   &ipv6_hdr(skb)->saddr, sport,
 				   &ipv6_hdr(skb)->daddr, ntohs(dport),
 				   inet6_iif(skb));

include/net/inet_hashtables.h

@@ -385,7 +385,7 @@ static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
 	if (unlikely(sk = skb_steal_sock(skb)))
 		return sk;
 	else
-		return __inet_lookup(dev_net(skb->dst->dev), hashinfo,
+		return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
 				     iph->saddr, sport,
 				     iph->daddr, dport, inet_iif(skb));
 }

include/net/ip6_route.h

@@ -142,7 +142,7 @@ static inline void ip6_dst_store(struct sock *sk, struct dst_entry *dst,
 
 static inline int ipv6_unicast_destination(struct sk_buff *skb)
 {
-	struct rt6_info *rt = (struct rt6_info *) skb->dst;
+	struct rt6_info *rt = (struct rt6_info *) skb_dst(skb);
 
 	return rt->rt6i_flags & RTF_LOCAL;
 }

include/net/xfrm.h

@@ -994,7 +994,7 @@ static inline int __xfrm_policy_check2(struct sock *sk, int dir,
 		return __xfrm_policy_check(sk, ndir, skb, family);
 
 	return	(!net->xfrm.policy_count[dir] && !skb->sp) ||
-		(skb->dst->flags & DST_NOPOLICY) ||
+		(skb_dst(skb)->flags & DST_NOPOLICY) ||
 		__xfrm_policy_check(sk, ndir, skb, family);
 }
 
@@ -1048,7 +1048,7 @@ static inline int xfrm_route_forward(struct sk_buff *skb, unsigned short family)
 	struct net *net = dev_net(skb->dev);
 
 	return	!net->xfrm.policy_count[XFRM_POLICY_OUT] ||
-		(skb->dst->flags & DST_NOXFRM) ||
+		(skb_dst(skb)->flags & DST_NOXFRM) ||
 		__xfrm_route_forward(skb, family);
 }
 

net/atm/br2684.c

@@ -228,7 +228,7 @@ static int br2684_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	struct br2684_dev *brdev = BRPRIV(dev);
 	struct br2684_vcc *brvcc;
 
-	pr_debug("br2684_start_xmit, skb->dst=%p\n", skb->dst);
+	pr_debug("br2684_start_xmit, skb_dst(skb)=%p\n", skb_dst(skb));
 	read_lock(&devs_lock);
 	brvcc = pick_outgoing_vcc(skb, brdev);
 	if (brvcc == NULL) {

net/atm/clip.c

@@ -369,16 +369,16 @@ static int clip_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	unsigned long flags;
 
 	pr_debug("clip_start_xmit (skb %p)\n", skb);
-	if (!skb->dst) {
-		printk(KERN_ERR "clip_start_xmit: skb->dst == NULL\n");
+	if (!skb_dst(skb)) {
+		printk(KERN_ERR "clip_start_xmit: skb_dst(skb) == NULL\n");
 		dev_kfree_skb(skb);
 		dev->stats.tx_dropped++;
 		return 0;
 	}
-	if (!skb->dst->neighbour) {
+	if (!skb_dst(skb)->neighbour) {
 #if 0
-		skb->dst->neighbour = clip_find_neighbour(skb->dst, 1);
-		if (!skb->dst->neighbour) {
+		skb_dst(skb)->neighbour = clip_find_neighbour(skb_dst(skb), 1);
+		if (!skb_dst(skb)->neighbour) {
 			dev_kfree_skb(skb);	/* lost that one */
 			dev->stats.tx_dropped++;
 			return 0;
@@ -389,7 +389,7 @@ static int clip_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		dev->stats.tx_dropped++;
 		return 0;
 	}
-	entry = NEIGH2ENTRY(skb->dst->neighbour);
+	entry = NEIGH2ENTRY(skb_dst(skb)->neighbour);
 	if (!entry->vccs) {
 		if (time_after(jiffies, entry->expires)) {
 			/* should be resolved */
@@ -406,7 +406,7 @@ static int clip_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	}
 	pr_debug("neigh %p, vccs %p\n", entry, entry->vccs);
 	ATM_SKB(skb)->vcc = vcc = entry->vccs->vcc;
-	pr_debug("using neighbour %p, vcc %p\n", skb->dst->neighbour, vcc);
+	pr_debug("using neighbour %p, vcc %p\n", skb_dst(skb)->neighbour, vcc);
 	if (entry->vccs->encap) {
 		void *here;