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 <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 24 insertions, 21 deletions

diff --git a/net/decnet/af_decnet.c b/net/decnet/af_decnet.c
index bccb3887773e..a5e3a593e472 100644
--- a/net/decnet/af_decnet.c
+++ b/net/decnet/af_decnet.c
@@ -1075,6 +1075,7 @@ static int dn_accept(struct socket *sock, struct socket *newsock, int flags)
         int err = 0;
         unsigned char type;
         long timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
+        struct dst_entry *dst;
 
         lock_sock(sk);
 
@@ -1102,8 +1103,9 @@ static int dn_accept(struct socket *sock, struct socket *newsock, int flags)
         }
         release_sock(sk);
 
-        dst_release(xchg(&newsk->sk_dst_cache, skb->dst));
-        skb->dst = NULL;
+        dst = skb_dst(skb);
+        dst_release(xchg(&newsk->sk_dst_cache, dst));
+        skb_dst_set(skb, NULL);
 
         DN_SK(newsk)->state        = DN_CR;
         DN_SK(newsk)->addrrem      = cb->src_port;
diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index 05b5aa05e50e..923786bd6d01 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -204,7 +204,7 @@ static void dn_short_error_report(struct neighbour *neigh, struct sk_buff *skb)
 
 static int dn_neigh_output_packet(struct sk_buff *skb)
 {
-        struct dst_entry *dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         struct dn_route *rt = (struct dn_route *)dst;
         struct neighbour *neigh = dst->neighbour;
         struct net_device *dev = neigh->dev;
@@ -224,7 +224,7 @@ static int dn_neigh_output_packet(struct sk_buff *skb)
 
 static int dn_long_output(struct sk_buff *skb)
 {
-        struct dst_entry *dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         struct neighbour *neigh = dst->neighbour;
         struct net_device *dev = neigh->dev;
         int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
@@ -270,7 +270,7 @@ static int dn_long_output(struct sk_buff *skb)
 
 static int dn_short_output(struct sk_buff *skb)
 {
-        struct dst_entry *dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         struct neighbour *neigh = dst->neighbour;
         struct net_device *dev = neigh->dev;
         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
@@ -313,7 +313,7 @@ static int dn_short_output(struct sk_buff *skb)
  */
 static int dn_phase3_output(struct sk_buff *skb)
 {
-        struct dst_entry *dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         struct neighbour *neigh = dst->neighbour;
         struct net_device *dev = neigh->dev;
         int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
diff --git a/net/decnet/dn_nsp_out.c b/net/decnet/dn_nsp_out.c
index da04f459337e..a65e929ce76c 100644
--- a/net/decnet/dn_nsp_out.c
+++ b/net/decnet/dn_nsp_out.c
@@ -85,7 +85,7 @@ static void dn_nsp_send(struct sk_buff *skb)
         dst = sk_dst_check(sk, 0);
         if (dst) {
 try_again:
-                skb->dst = dst;
+                skb_dst_set(skb, dst);
                 dst_output(skb);
                 return;
         }
@@ -582,7 +582,7 @@ static __inline__ void dn_nsp_do_disc(struct sock *sk, unsigned char msgflg,
          * to be able to send disc packets out which have no socket
          * associations.
          */
-        skb->dst = dst_clone(dst);
+        skb_dst_set(skb, dst_clone(dst));
         dst_output(skb);
 }
 
@@ -611,7 +611,7 @@ void dn_nsp_return_disc(struct sk_buff *skb, unsigned char msgflg,
         int ddl = 0;
         gfp_t gfp = GFP_ATOMIC;
 
-        dn_nsp_do_disc(NULL, msgflg, reason, gfp, skb->dst, ddl,
+        dn_nsp_do_disc(NULL, msgflg, reason, gfp, skb_dst(skb), ddl,
                         NULL, cb->src_port, cb->dst_port);
 }
 
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 0cc4394117df..1d6ca8a98dc6 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -678,7 +678,7 @@ out:
 
 static int dn_output(struct sk_buff *skb)
 {
-        struct dst_entry *dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         struct dn_route *rt = (struct dn_route *)dst;
         struct net_device *dev = dst->dev;
         struct dn_skb_cb *cb = DN_SKB_CB(skb);
@@ -717,7 +717,7 @@ error:
 static int dn_forward(struct sk_buff *skb)
 {
         struct dn_skb_cb *cb = DN_SKB_CB(skb);
-        struct dst_entry *dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         struct dn_dev *dn_db = dst->dev->dn_ptr;
         struct dn_route *rt;
         struct neighbour *neigh = dst->neighbour;
@@ -730,7 +730,7 @@ static int dn_forward(struct sk_buff *skb)
                 goto drop;
 
         /* Ensure that we have enough space for headers */
-        rt = (struct dn_route *)skb->dst;
+        rt = (struct dn_route *)skb_dst(skb);
         header_len = dn_db->use_long ? 21 : 6;
         if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+header_len))
                 goto drop;
@@ -1392,7 +1392,8 @@ make_route:
                 goto e_neighbour;
 
         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
-        dn_insert_route(rt, hash, (struct dn_route **)&skb->dst);
+        dn_insert_route(rt, hash, &rt);
+        skb_dst_set(skb, &rt->u.dst);
 
 done:
         if (neigh)
@@ -1424,7 +1425,7 @@ static int dn_route_input(struct sk_buff *skb)
         struct dn_skb_cb *cb = DN_SKB_CB(skb);
         unsigned hash = dn_hash(cb->src, cb->dst);
 
-        if (skb->dst)
+        if (skb_dst(skb))
                 return 0;
 
         rcu_read_lock();
@@ -1437,7 +1438,7 @@ static int dn_route_input(struct sk_buff *skb)
                     (rt->fl.iif == cb->iif)) {
                         dst_use(&rt->u.dst, jiffies);
                         rcu_read_unlock();
-                        skb->dst = (struct dst_entry *)rt;
+                        skb_dst_set(skb, (struct dst_entry *)rt);
                         return 0;
                 }
         }
@@ -1449,7 +1450,7 @@ static int dn_route_input(struct sk_buff *skb)
 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
                            int event, int nowait, unsigned int flags)
 {
-        struct dn_route *rt = (struct dn_route *)skb->dst;
+        struct dn_route *rt = (struct dn_route *)skb_dst(skb);
         struct rtmsg *r;
         struct nlmsghdr *nlh;
         unsigned char *b = skb_tail_pointer(skb);
@@ -1554,7 +1555,7 @@ static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void
                 err = dn_route_input(skb);
                 local_bh_enable();
                 memset(cb, 0, sizeof(struct dn_skb_cb));
-                rt = (struct dn_route *)skb->dst;
+                rt = (struct dn_route *)skb_dst(skb);
                 if (!err && -rt->u.dst.error)
                         err = rt->u.dst.error;
         } else {
@@ -1570,7 +1571,7 @@ static int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void
         skb->dev = NULL;
         if (err)
                 goto out_free;
-        skb->dst = &rt->u.dst;
+        skb_dst_set(skb, &rt->u.dst);
         if (rtm->rtm_flags & RTM_F_NOTIFY)
                 rt->rt_flags |= RTCF_NOTIFY;
 
@@ -1622,15 +1623,15 @@ int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
                         rt = rcu_dereference(rt->u.dst.dn_next), idx++) {
                         if (idx < s_idx)
                                 continue;
-                        skb->dst = dst_clone(&rt->u.dst);
+                        skb_dst_set(skb, dst_clone(&rt->u.dst));
                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
                                         1, NLM_F_MULTI) <= 0) {
-                                dst_release(xchg(&skb->dst, NULL));
+                                skb_dst_drop(skb);
                                 rcu_read_unlock_bh();
                                 goto done;
                         }
-                        dst_release(xchg(&skb->dst, NULL));
+                        skb_dst_drop(skb);
                 }
                 rcu_read_unlock_bh();
         }