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>

3 files changed, 19 insertions, 13 deletions

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index b4a13178fb40..e0009c17d809 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -251,8 +251,7 @@ resume:
         nf_reset(skb);
 
         if (decaps) {
-                dst_release(skb->dst);
-                skb->dst = NULL;
+                skb_dst_drop(skb);
                 netif_rx(skb);
                 return 0;
         } else {
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c
index c235597ba8dd..b9fe13138c07 100644
--- a/net/xfrm/xfrm_output.c
+++ b/net/xfrm/xfrm_output.c
@@ -22,7 +22,7 @@ static int xfrm_output2(struct sk_buff *skb);
 
 static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
 {
-        struct dst_entry *dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
                 - skb_headroom(skb);
         int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
@@ -39,7 +39,7 @@ static int xfrm_state_check_space(struct xfrm_state *x, struct sk_buff *skb)
 
 static int xfrm_output_one(struct sk_buff *skb, int err)
 {
-        struct dst_entry *dst = skb->dst;
+        struct dst_entry *dst = skb_dst(skb);
         struct xfrm_state *x = dst->xfrm;
         struct net *net = xs_net(x);
 
@@ -94,12 +94,13 @@ resume:
                         goto error_nolock;
                 }
 
-                if (!(skb->dst = dst_pop(dst))) {
+                dst = dst_pop(dst);
+                if (!dst) {
                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
                         err = -EHOSTUNREACH;
                         goto error_nolock;
                 }
-                dst = skb->dst;
+                skb_dst_set(skb, dst);
                 x = dst->xfrm;
         } while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));
 
@@ -119,16 +120,16 @@ int xfrm_output_resume(struct sk_buff *skb, int err)
         while (likely((err = xfrm_output_one(skb, err)) == 0)) {
                 nf_reset(skb);
 
-                err = skb->dst->ops->local_out(skb);
+                err = skb_dst(skb)->ops->local_out(skb);
                 if (unlikely(err != 1))
                         goto out;
 
-                if (!skb->dst->xfrm)
+                if (!skb_dst(skb)->xfrm)
                         return dst_output(skb);
 
-                err = nf_hook(skb->dst->ops->family,
+                err = nf_hook(skb_dst(skb)->ops->family,
                               NF_INET_POST_ROUTING, skb,
-                              NULL, skb->dst->dev, xfrm_output2);
+                              NULL, skb_dst(skb)->dev, xfrm_output2);
                 if (unlikely(err != 1))
                         goto out;
         }
@@ -179,7 +180,7 @@ static int xfrm_output_gso(struct sk_buff *skb)
 
 int xfrm_output(struct sk_buff *skb)
 {
-        struct net *net = dev_net(skb->dst->dev);
+        struct net *net = dev_net(skb_dst(skb)->dev);
         int err;
 
         if (skb_is_gso(skb))
@@ -202,7 +203,7 @@ int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
         struct xfrm_mode *inner_mode;
         if (x->sel.family == AF_UNSPEC)
                 inner_mode = xfrm_ip2inner_mode(x,
-                                xfrm_af2proto(skb->dst->ops->family));
+                                xfrm_af2proto(skb_dst(skb)->ops->family));
         else
                 inner_mode = x->inner_mode;
 
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 9c068ab3a834..cb81ca35b0d6 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2027,6 +2027,8 @@ int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
 {
         struct net *net = dev_net(skb->dev);
         struct flowi fl;
+        struct dst_entry *dst;
+        int res;
 
         if (xfrm_decode_session(skb, &fl, family) < 0) {
                 /* XXX: we should have something like FWDHDRERROR here. */
@@ -2034,7 +2036,11 @@ int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
                 return 0;
         }
 
-        return xfrm_lookup(net, &skb->dst, &fl, NULL, 0) == 0;
+        dst = skb_dst(skb);
+
+        res = xfrm_lookup(net, &dst, &fl, NULL, 0) == 0;
+        skb_dst_set(skb, dst);
+        return res;
 }
 EXPORT_SYMBOL(__xfrm_route_forward);