ip6mr: Add refcounting to mfc

Since ipmr and ip6mr are using the same mr_mfc struct at their core, we
can now refactor the ipmr_cache_{hold,put} logic and apply refcounting
to both ipmr and ip6mr.
Signed-off-by: NYuval Mintz <yuvalm@mellanox.com>
Signed-off-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c

@@ -360,7 +360,7 @@ mlxsw_sp_mr_route4_create(struct mlxsw_sp_mr_table *mr_table,
 
 	/* Find min_mtu and link iVIF and eVIFs */
 	mr_route->min_mtu = ETH_MAX_MTU;
-	ipmr_cache_hold(mfc);
+	mr_cache_hold(&mfc->_c);
 	mr_route->mfc4 = mfc;
 	mr_route->mr_table = mr_table;
 	for (i = 0; i < MAXVIFS; i++) {
@@ -380,7 +380,7 @@ mlxsw_sp_mr_route4_create(struct mlxsw_sp_mr_table *mr_table,
 	mr_route->route_action = mlxsw_sp_mr_route_action(mr_route);
 	return mr_route;
 err:
-	ipmr_cache_put(mfc);
+	mr_cache_put(&mfc->_c);
 	list_for_each_entry_safe(rve, tmp, &mr_route->evif_list, route_node)
 		mlxsw_sp_mr_route_evif_unlink(rve);
 	kfree(mr_route);
@@ -393,7 +393,7 @@ static void mlxsw_sp_mr_route4_destroy(struct mlxsw_sp_mr_table *mr_table,
 	struct mlxsw_sp_mr_route_vif_entry *rve, *tmp;
 
 	mlxsw_sp_mr_route_ivif_unlink(mr_route);
-	ipmr_cache_put(mr_route->mfc4);
+	mr_cache_put((struct mr_mfc *)mr_route->mfc4);
 	list_for_each_entry_safe(rve, tmp, &mr_route->evif_list, route_node)
 		mlxsw_sp_mr_route_evif_unlink(rve);
 	kfree(mr_route);

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -5685,11 +5685,11 @@ static void mlxsw_sp_router_fibmr_event_work(struct work_struct *work)
 						replace);
 		if (err)
 			mlxsw_sp_router_fib_abort(mlxsw_sp);
-		ipmr_cache_put((struct mfc_cache *) fib_work->men_info.mfc);
+		mr_cache_put(fib_work->men_info.mfc);
 		break;
 	case FIB_EVENT_ENTRY_DEL:
 		mlxsw_sp_router_fibmr_del(mlxsw_sp, &fib_work->men_info);
-		ipmr_cache_put((struct mfc_cache *) fib_work->men_info.mfc);
+		mr_cache_put(fib_work->men_info.mfc);
 		break;
 	case FIB_EVENT_VIF_ADD:
 		err = mlxsw_sp_router_fibmr_vif_add(mlxsw_sp,
@@ -5769,7 +5769,7 @@ mlxsw_sp_router_fibmr_event(struct mlxsw_sp_fib_event_work *fib_work,
 	case FIB_EVENT_ENTRY_ADD: /* fall through */
 	case FIB_EVENT_ENTRY_DEL:
 		memcpy(&fib_work->men_info, info, sizeof(fib_work->men_info));
-		ipmr_cache_hold((struct mfc_cache *) fib_work->men_info.mfc);
+		mr_cache_hold(fib_work->men_info.mfc);
 		break;
 	case FIB_EVENT_VIF_ADD: /* fall through */
 	case FIB_EVENT_VIF_DEL:

include/linux/mroute.h

@@ -84,23 +84,4 @@ struct rtmsg;
 int ipmr_get_route(struct net *net, struct sk_buff *skb,
 		   __be32 saddr, __be32 daddr,
 		   struct rtmsg *rtm, u32 portid);
-
-#ifdef CONFIG_IP_MROUTE
-void ipmr_cache_free(struct mfc_cache *mfc_cache);
-#else
-static inline void ipmr_cache_free(struct mfc_cache *mfc_cache)
-{
-}
-#endif
-
-static inline void ipmr_cache_put(struct mfc_cache *c)
-{
-	if (refcount_dec_and_test(&c->_c.mfc_un.res.refcount))
-		ipmr_cache_free(c);
-}
-static inline void ipmr_cache_hold(struct mfc_cache *c)
-{
-	refcount_inc(&c->_c.mfc_un.res.refcount);
-}
-
 #endif

include/linux/mroute_base.h

@@ -125,6 +125,7 @@ enum {
  * @refcount: reference count for this entry
  * @list: global entry list
  * @rcu: used for entry destruction
+ * @free: Operation used for freeing an entry under RCU
  */
 struct mr_mfc {
 	struct rhlist_head mnode;
@@ -150,8 +151,20 @@ struct mr_mfc {
 	} mfc_un;
 	struct list_head list;
 	struct rcu_head	rcu;
+	void (*free)(struct rcu_head *head);
 };
 
+static inline void mr_cache_put(struct mr_mfc *c)
+{
+	if (refcount_dec_and_test(&c->mfc_un.res.refcount))
+		call_rcu(&c->rcu, c->free);
+}
+
+static inline void mr_cache_hold(struct mr_mfc *c)
+{
+	refcount_inc(&c->mfc_un.res.refcount);
+}
+
 struct mfc_entry_notifier_info {
 	struct fib_notifier_info info;
 	struct mr_mfc *mfc;

net/ipv4/ipmr.c

@@ -732,11 +732,10 @@ static void ipmr_cache_free_rcu(struct rcu_head *head)
 	kmem_cache_free(mrt_cachep, (struct mfc_cache *)c);
 }
 
-void ipmr_cache_free(struct mfc_cache *c)
+static void ipmr_cache_free(struct mfc_cache *c)
 {
 	call_rcu(&c->_c.rcu, ipmr_cache_free_rcu);
 }
-EXPORT_SYMBOL(ipmr_cache_free);
 
 /* Destroy an unresolved cache entry, killing queued skbs
  * and reporting error to netlink readers.
@@ -987,6 +986,7 @@ static struct mfc_cache *ipmr_cache_alloc(void)
 	if (c) {
 		c->_c.mfc_un.res.last_assert = jiffies - MFC_ASSERT_THRESH - 1;
 		c->_c.mfc_un.res.minvif = MAXVIFS;
+		c->_c.free = ipmr_cache_free_rcu;
 		refcount_set(&c->_c.mfc_un.res.refcount, 1);
 	}
 	return c;
@@ -1206,7 +1206,7 @@ static int ipmr_mfc_delete(struct mr_table *mrt, struct mfcctl *mfc, int parent)
 	list_del_rcu(&c->_c.list);
 	call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, c, mrt->id);
 	mroute_netlink_event(mrt, c, RTM_DELROUTE);
-	ipmr_cache_put(c);
+	mr_cache_put(&c->_c);
 
 	return 0;
 }
@@ -1318,7 +1318,7 @@ static void mroute_clean_tables(struct mr_table *mrt, bool all)
 		call_ipmr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, cache,
 					      mrt->id);
 		mroute_netlink_event(mrt, cache, RTM_DELROUTE);
-		ipmr_cache_put(cache);
+		mr_cache_put(c);
 	}
 
 	if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {

net/ipv6/ip6mr.c

@@ -989,6 +989,8 @@ static struct mfc6_cache *ip6mr_cache_alloc(void)
 		return NULL;
 	c->_c.mfc_un.res.last_assert = jiffies - MFC_ASSERT_THRESH - 1;
 	c->_c.mfc_un.res.minvif = MAXMIFS;
+	c->_c.free = ip6mr_cache_free_rcu;
+	refcount_set(&c->_c.mfc_un.res.refcount, 1);
 	return c;
 }
 
@@ -1227,7 +1229,7 @@ static int ip6mr_mfc_delete(struct mr_table *mrt, struct mf6cctl *mfc,
 	call_ip6mr_mfc_entry_notifiers(read_pnet(&mrt->net),
 				       FIB_EVENT_ENTRY_DEL, c, mrt->id);
 	mr6_netlink_event(mrt, c, RTM_DELROUTE);
-	ip6mr_cache_free(c);
+	mr_cache_put(&c->_c);
 	return 0;
 }
 
@@ -1516,7 +1518,7 @@ static void mroute_clean_tables(struct mr_table *mrt, bool all)
 		rhltable_remove(&mrt->mfc_hash, &c->mnode, ip6mr_rht_params);
 		list_del_rcu(&c->list);
 		mr6_netlink_event(mrt, (struct mfc6_cache *)c, RTM_DELROUTE);
-		ip6mr_cache_free((struct mfc6_cache *)c);
+		mr_cache_put(c);
 	}
 
 	if (atomic_read(&mrt->cache_resolve_queue_len) != 0) {