[IPSEC]: Store afinfo pointer in xfrm_mode

It is convenient to have a pointer from xfrm_state to address-specific
functions such as the output function for a family.  Currently the
address-specific policy code calls out to the xfrm state code to get
those pointers when we could get it in an easier way via the state
itself.

This patch adds an xfrm_state_afinfo to xfrm_mode (since they're
address-specific) and changes the policy code to use it.  I've also
added an owner field to do reference counting on the module providing
the afinfo even though it isn't strictly necessary today since IPv6
can't be unloaded yet.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 9 deletions

diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index dc438f2b9442..48b4a06b3d1a 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -57,6 +57,9 @@ static unsigned int xfrm_state_hashmax __read_mostly = 1 * 1024 * 1024;
 static unsigned int xfrm_state_num;
 static unsigned int xfrm_state_genid;
 
+static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family);
+static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo);
+
 static inline unsigned int xfrm_dst_hash(xfrm_address_t *daddr,
                                          xfrm_address_t *saddr,
                                          u32 reqid,
@@ -289,11 +292,18 @@ int xfrm_register_mode(struct xfrm_mode *mode, int family)
 
         err = -EEXIST;
         modemap = afinfo->mode_map;
-        if (likely(modemap[mode->encap] == NULL)) {
-                modemap[mode->encap] = mode;
-                err = 0;
-        }
+        if (modemap[mode->encap])
+                goto out;
 
+        err = -ENOENT;
+        if (!try_module_get(afinfo->owner))
+                goto out;
+
+        mode->afinfo = afinfo;
+        modemap[mode->encap] = mode;
+        err = 0;
+
+out:
         xfrm_state_unlock_afinfo(afinfo);
         return err;
 }
@@ -316,6 +326,7 @@ int xfrm_unregister_mode(struct xfrm_mode *mode, int family)
         modemap = afinfo->mode_map;
         if (likely(modemap[mode->encap] == mode)) {
                 modemap[mode->encap] = NULL;
+                module_put(mode->afinfo->owner);
                 err = 0;
         }
 
@@ -1869,7 +1880,7 @@ int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo)
 }
 EXPORT_SYMBOL(xfrm_state_unregister_afinfo);
 
-struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned short family)
+static struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned int family)
 {
         struct xfrm_state_afinfo *afinfo;
         if (unlikely(family >= NPROTO))
@@ -1881,14 +1892,11 @@ struct xfrm_state_afinfo *xfrm_state_get_afinfo(unsigned short family)
         return afinfo;
 }
 
-void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
+static void xfrm_state_put_afinfo(struct xfrm_state_afinfo *afinfo)
 {
         read_unlock(&xfrm_state_afinfo_lock);
 }
 
-EXPORT_SYMBOL(xfrm_state_get_afinfo);
-EXPORT_SYMBOL(xfrm_state_put_afinfo);
-
 /* Temporarily located here until net/xfrm/xfrm_tunnel.c is created */
 void xfrm_state_delete_tunnel(struct xfrm_state *x)
 {