ipmr, ip6mr: Make mfc_cache a common structure

mfc_cache and mfc6_cache are almost identical - the main difference is
in the origin/group addresses and comparison-key. Make a common
structure encapsulating most of the multicast routing logic  - mr_mfc
and convert both ipmr and ip6mr into using it.

For easy conversion [casting, in this case] mr_mfc has to be the first
field inside every multicast routing abstraction utilizing it.
Signed-off-by: Yuval Mintz <yuvalm@mellanox.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -126,8 +126,8 @@ mlxsw_sp_mr_route_ivif_in_evifs(const struct mlxsw_sp_mr_route *mr_route)
 
 	switch (mr_route->mr_table->proto) {
 	case MLXSW_SP_L3_PROTO_IPV4:
-		ivif = mr_route->mfc4->mfc_parent;
-		return mr_route->mfc4->mfc_un.res.ttls[ivif] != 255;
+		ivif = mr_route->mfc4->_c.mfc_parent;
+		return mr_route->mfc4->_c.mfc_un.res.ttls[ivif] != 255;
 	case MLXSW_SP_L3_PROTO_IPV6:
 		/* fall through */
 	default:
@@ -364,7 +364,7 @@ mlxsw_sp_mr_route4_create(struct mlxsw_sp_mr_table *mr_table,
 	mr_route->mfc4 = mfc;
 	mr_route->mr_table = mr_table;
 	for (i = 0; i < MAXVIFS; i++) {
-		if (mfc->mfc_un.res.ttls[i] != 255) {
+		if (mfc->_c.mfc_un.res.ttls[i] != 255) {
 			err = mlxsw_sp_mr_route_evif_link(mr_route,
 							  &mr_table->vifs[i]);
 			if (err)
@@ -374,7 +374,8 @@ mlxsw_sp_mr_route4_create(struct mlxsw_sp_mr_table *mr_table,
 				mr_route->min_mtu = mr_table->vifs[i].dev->mtu;
 		}
 	}
-	mlxsw_sp_mr_route_ivif_link(mr_route, &mr_table->vifs[mfc->mfc_parent]);
+	mlxsw_sp_mr_route_ivif_link(mr_route,
+				    &mr_table->vifs[mfc->_c.mfc_parent]);
 
 	mr_route->route_action = mlxsw_sp_mr_route_action(mr_route);
 	return mr_route;
@@ -418,9 +419,9 @@ static void mlxsw_sp_mr_mfc_offload_set(struct mlxsw_sp_mr_route *mr_route,
 	switch (mr_route->mr_table->proto) {
 	case MLXSW_SP_L3_PROTO_IPV4:
 		if (offload)
-			mr_route->mfc4->mfc_flags |= MFC_OFFLOAD;
+			mr_route->mfc4->_c.mfc_flags |= MFC_OFFLOAD;
 		else
-			mr_route->mfc4->mfc_flags &= ~MFC_OFFLOAD;
+			mr_route->mfc4->_c.mfc_flags &= ~MFC_OFFLOAD;
 		break;
 	case MLXSW_SP_L3_PROTO_IPV6:
 		/* fall through */
@@ -943,10 +944,10 @@ static void mlxsw_sp_mr_route_stats_update(struct mlxsw_sp *mlxsw_sp,
 
 	switch (mr_route->mr_table->proto) {
 	case MLXSW_SP_L3_PROTO_IPV4:
-		if (mr_route->mfc4->mfc_un.res.pkt != packets)
-			mr_route->mfc4->mfc_un.res.lastuse = jiffies;
-		mr_route->mfc4->mfc_un.res.pkt = packets;
-		mr_route->mfc4->mfc_un.res.bytes = bytes;
+		if (mr_route->mfc4->_c.mfc_un.res.pkt != packets)
+			mr_route->mfc4->_c.mfc_un.res.lastuse = jiffies;
+		mr_route->mfc4->_c.mfc_un.res.pkt = packets;
+		mr_route->mfc4->_c.mfc_un.res.bytes = bytes;
 		break;
 	case MLXSW_SP_L3_PROTO_IPV6:
 		/* fall through */

include/linux/mroute.h

@@ -81,28 +81,13 @@ struct mfc_cache_cmp_arg {
 
 /**
  * struct mfc_cache - multicast routing entries
- * @mnode: rhashtable list
+ * @_c: Common multicast routing information; has to be first [for casting]
  * @mfc_mcastgrp: destination multicast group address
  * @mfc_origin: source address
  * @cmparg: used for rhashtable comparisons
- * @mfc_parent: source interface (iif)
- * @mfc_flags: entry flags
- * @expires: unresolved entry expire time
- * @unresolved: unresolved cached skbs
- * @last_assert: time of last assert
- * @minvif: minimum VIF id
- * @maxvif: maximum VIF id
- * @bytes: bytes that have passed for this entry
- * @pkt: packets that have passed for this entry
- * @wrong_if: number of wrong source interface hits
- * @lastuse: time of last use of the group (traffic or update)
- * @ttls: OIF TTL threshold array
- * @refcount: reference count for this entry
- * @list: global entry list
- * @rcu: used for entry destruction
  */
 struct mfc_cache {
-	struct rhlist_head mnode;
+	struct mr_mfc _c;
 	union {
 		struct {
 			__be32 mfc_mcastgrp;
@@ -110,28 +95,6 @@ struct mfc_cache {
 		};
 		struct mfc_cache_cmp_arg cmparg;
 	};
-	vifi_t mfc_parent;
-	int mfc_flags;
-
-	union {
-		struct {
-			unsigned long expires;
-			struct sk_buff_head unresolved;
-		} unres;
-		struct {
-			unsigned long last_assert;
-			int minvif;
-			int maxvif;
-			unsigned long bytes;
-			unsigned long pkt;
-			unsigned long wrong_if;
-			unsigned long lastuse;
-			unsigned char ttls[MAXVIFS];
-			refcount_t refcount;
-		} res;
-	} mfc_un;
-	struct list_head list;
-	struct rcu_head	rcu;
 };
 
 struct mfc_entry_notifier_info {
@@ -155,12 +118,12 @@ static inline void ipmr_cache_free(struct mfc_cache *mfc_cache)
 
 static inline void ipmr_cache_put(struct mfc_cache *c)
 {
-	if (refcount_dec_and_test(&c->mfc_un.res.refcount))
+	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->mfc_un.res.refcount);
+	refcount_inc(&c->_c.mfc_un.res.refcount);
 }
 
 #endif

include/linux/mroute6.h

@@ -71,7 +71,7 @@ struct mfc6_cache_cmp_arg {
 };
 
 struct mfc6_cache {
-	struct rhlist_head mnode;
+	struct mr_mfc _c;
 	union {
 		struct {
 			struct in6_addr mf6c_mcastgrp;
@@ -79,27 +79,6 @@ struct mfc6_cache {
 		};
 		struct mfc6_cache_cmp_arg cmparg;
 	};
-	mifi_t mf6c_parent;			/* Source interface		*/
-	int mfc_flags;				/* Flags on line		*/
-
-	union {
-		struct {
-			unsigned long expires;
-			struct sk_buff_head unresolved;	/* Unresolved buffers		*/
-		} unres;
-		struct {
-			unsigned long last_assert;
-			int minvif;
-			int maxvif;
-			unsigned long bytes;
-			unsigned long pkt;
-			unsigned long wrong_if;
-			unsigned long lastuse;
-			unsigned char ttls[MAXMIFS];	/* TTL thresholds		*/
-		} res;
-	} mfc_un;
-	struct list_head list;
-	struct rcu_head rcu;
 };
 
 #define MFC_STATIC		1

include/linux/mroute_base.h

@@ -44,6 +44,51 @@ struct vif_device {
 
 #define VIF_EXISTS(_mrt, _idx) (!!((_mrt)->vif_table[_idx].dev))
 
+/**
+ * struct mr_mfc - common multicast routing entries
+ * @mnode: rhashtable list
+ * @mfc_parent: source interface (iif)
+ * @mfc_flags: entry flags
+ * @expires: unresolved entry expire time
+ * @unresolved: unresolved cached skbs
+ * @last_assert: time of last assert
+ * @minvif: minimum VIF id
+ * @maxvif: maximum VIF id
+ * @bytes: bytes that have passed for this entry
+ * @pkt: packets that have passed for this entry
+ * @wrong_if: number of wrong source interface hits
+ * @lastuse: time of last use of the group (traffic or update)
+ * @ttls: OIF TTL threshold array
+ * @refcount: reference count for this entry
+ * @list: global entry list
+ * @rcu: used for entry destruction
+ */
+struct mr_mfc {
+	struct rhlist_head mnode;
+	unsigned short mfc_parent;
+	int mfc_flags;
+
+	union {
+		struct {
+			unsigned long expires;
+			struct sk_buff_head unresolved;
+		} unres;
+		struct {
+			unsigned long last_assert;
+			int minvif;
+			int maxvif;
+			unsigned long bytes;
+			unsigned long pkt;
+			unsigned long wrong_if;
+			unsigned long lastuse;
+			unsigned char ttls[MAXVIFS];
+			refcount_t refcount;
+		} res;
+	} mfc_un;
+	struct list_head list;
+	struct rcu_head	rcu;
+};
+
 /**
  * struct mr_table - a multicast routing table
  * @list: entry within a list of multicast routing tables