Merge branch 'mlxsw-Add-support-for-nexthop-group-consolidation-for-IPv6'

Jiri Pirko says:

====================
mlxsw: Add support for nexthop group consolidation for IPv6

Arkadi says:

Due to limited ASIC resources the maximum number of routes is limited by
the nexthop resource. In order to improve the routing scale nexthop
consolidation should be performed.

In case of IPv4, the kernel does the consolidation of nexthops in the form
of the fib_info struct. In that case, the driver uses the fib_info's
address as a key for the internal nexthop group representative struct
lookup. In case of IPv6, the kernel doesn't do consolidation, thus the
driver should implement it by itself.

The hash value is calculated based on the nexthop set, by performing
bitwise xor on the ifindexs of the nexthops, in a similar way to IPV4's
kernel implementation. In case of collision a full match is performed
between the sets which include address and ifindex comparison.

In order to use the same hash table in both cases (IPv4/6), the rhashtable
is changed to operate on variable length key.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1509,6 +1509,7 @@ struct mlxsw_sp_nexthop {
 	struct rhash_head ht_node;
 	struct mlxsw_sp_nexthop_key key;
 	unsigned char gw_addr[sizeof(struct in6_addr)];
+	int ifindex;
 	struct mlxsw_sp_rif *rif;
 	u8 should_offload:1, /* set indicates this neigh is connected and
 			      * should be put to KVD linear area of this group.
@@ -1522,15 +1523,11 @@ struct mlxsw_sp_nexthop {
 	struct mlxsw_sp_neigh_entry *neigh_entry;
 };
 
-struct mlxsw_sp_nexthop_group_key {
-	struct fib_info *fi;
-};
-
 struct mlxsw_sp_nexthop_group {
+	void *priv;
 	struct rhash_head ht_node;
 	struct list_head fib_list; /* list of fib entries that use this group */
 	struct neigh_table *neigh_tbl;
-	struct mlxsw_sp_nexthop_group_key key;
 	u8 adj_index_valid:1,
 	   gateway:1; /* routes using the group use a gateway */
 	u32 adj_index;
@@ -1540,15 +1537,154 @@ struct mlxsw_sp_nexthop_group {
 #define nh_rif	nexthops[0].rif
 };
 
+static struct fib_info *
+mlxsw_sp_nexthop4_group_fi(const struct mlxsw_sp_nexthop_group *nh_grp)
+{
+	return nh_grp->priv;
+}
+
+struct mlxsw_sp_nexthop_group_cmp_arg {
+	enum mlxsw_sp_l3proto proto;
+	union {
+		struct fib_info *fi;
+		struct mlxsw_sp_fib6_entry *fib6_entry;
+	};
+};
+
+static bool
+mlxsw_sp_nexthop6_group_has_nexthop(const struct mlxsw_sp_nexthop_group *nh_grp,
+				    const struct in6_addr *gw, int ifindex)
+{
+	int i;
+
+	for (i = 0; i < nh_grp->count; i++) {
+		const struct mlxsw_sp_nexthop *nh;
+
+		nh = &nh_grp->nexthops[i];
+		if (nh->ifindex == ifindex &&
+		    ipv6_addr_equal(gw, (struct in6_addr *) nh->gw_addr))
+			return true;
+	}
+
+	return false;
+}
+
+static bool
+mlxsw_sp_nexthop6_group_cmp(const struct mlxsw_sp_nexthop_group *nh_grp,
+			    const struct mlxsw_sp_fib6_entry *fib6_entry)
+{
+	struct mlxsw_sp_rt6 *mlxsw_sp_rt6;
+
+	if (nh_grp->count != fib6_entry->nrt6)
+		return false;
+
+	list_for_each_entry(mlxsw_sp_rt6, &fib6_entry->rt6_list, list) {
+		struct in6_addr *gw;
+		int ifindex;
+
+		ifindex = mlxsw_sp_rt6->rt->dst.dev->ifindex;
+		gw = &mlxsw_sp_rt6->rt->rt6i_gateway;
+		if (!mlxsw_sp_nexthop6_group_has_nexthop(nh_grp, gw, ifindex))
+			return false;
+	}
+
+	return true;
+}
+
+static int
+mlxsw_sp_nexthop_group_cmp(struct rhashtable_compare_arg *arg, const void *ptr)
+{
+	const struct mlxsw_sp_nexthop_group_cmp_arg *cmp_arg = arg->key;
+	const struct mlxsw_sp_nexthop_group *nh_grp = ptr;
+
+	switch (cmp_arg->proto) {
+	case MLXSW_SP_L3_PROTO_IPV4:
+		return cmp_arg->fi != mlxsw_sp_nexthop4_group_fi(nh_grp);
+	case MLXSW_SP_L3_PROTO_IPV6:
+		return !mlxsw_sp_nexthop6_group_cmp(nh_grp,
+						    cmp_arg->fib6_entry);
+	default:
+		WARN_ON(1);
+		return 1;
+	}
+}
+
+static int
+mlxsw_sp_nexthop_group_type(const struct mlxsw_sp_nexthop_group *nh_grp)
+{
+	return nh_grp->neigh_tbl->family;
+}
+
+static u32 mlxsw_sp_nexthop_group_hash_obj(const void *data, u32 len, u32 seed)
+{
+	const struct mlxsw_sp_nexthop_group *nh_grp = data;
+	const struct mlxsw_sp_nexthop *nh;
+	struct fib_info *fi;
+	unsigned int val;
+	int i;
+
+	switch (mlxsw_sp_nexthop_group_type(nh_grp)) {
+	case AF_INET:
+		fi = mlxsw_sp_nexthop4_group_fi(nh_grp);
+		return jhash(&fi, sizeof(fi), seed);
+	case AF_INET6:
+		val = nh_grp->count;
+		for (i = 0; i < nh_grp->count; i++) {
+			nh = &nh_grp->nexthops[i];
+			val ^= nh->ifindex;
+		}
+		return jhash(&val, sizeof(val), seed);
+	default:
+		WARN_ON(1);
+		return 0;
+	}
+}
+
+static u32
+mlxsw_sp_nexthop6_group_hash(struct mlxsw_sp_fib6_entry *fib6_entry, u32 seed)
+{
+	unsigned int val = fib6_entry->nrt6;
+	struct mlxsw_sp_rt6 *mlxsw_sp_rt6;
+	struct net_device *dev;
+
+	list_for_each_entry(mlxsw_sp_rt6, &fib6_entry->rt6_list, list) {
+		dev = mlxsw_sp_rt6->rt->dst.dev;
+		val ^= dev->ifindex;
+	}
+
+	return jhash(&val, sizeof(val), seed);
+}
+
+static u32
+mlxsw_sp_nexthop_group_hash(const void *data, u32 len, u32 seed)
+{
+	const struct mlxsw_sp_nexthop_group_cmp_arg *cmp_arg = data;
+
+	switch (cmp_arg->proto) {
+	case MLXSW_SP_L3_PROTO_IPV4:
+		return jhash(&cmp_arg->fi, sizeof(cmp_arg->fi), seed);
+	case MLXSW_SP_L3_PROTO_IPV6:
+		return mlxsw_sp_nexthop6_group_hash(cmp_arg->fib6_entry, seed);
+	default:
+		WARN_ON(1);
+		return 0;
+	}
+}
+
 static const struct rhashtable_params mlxsw_sp_nexthop_group_ht_params = {
-	.key_offset = offsetof(struct mlxsw_sp_nexthop_group, key),
 	.head_offset = offsetof(struct mlxsw_sp_nexthop_group, ht_node),
-	.key_len = sizeof(struct mlxsw_sp_nexthop_group_key),
+	.hashfn	     = mlxsw_sp_nexthop_group_hash,
+	.obj_hashfn  = mlxsw_sp_nexthop_group_hash_obj,
+	.obj_cmpfn   = mlxsw_sp_nexthop_group_cmp,
 };
 
 static int mlxsw_sp_nexthop_group_insert(struct mlxsw_sp *mlxsw_sp,
 					 struct mlxsw_sp_nexthop_group *nh_grp)
 {
+	if (mlxsw_sp_nexthop_group_type(nh_grp) == AF_INET6 &&
+	    !nh_grp->gateway)
+		return 0;
+
 	return rhashtable_insert_fast(&mlxsw_sp->router->nexthop_group_ht,
 				      &nh_grp->ht_node,
 				      mlxsw_sp_nexthop_group_ht_params);
@@ -1557,16 +1693,38 @@ static int mlxsw_sp_nexthop_group_insert(struct mlxsw_sp *mlxsw_sp,
 static void mlxsw_sp_nexthop_group_remove(struct mlxsw_sp *mlxsw_sp,
 					  struct mlxsw_sp_nexthop_group *nh_grp)
 {
+	if (mlxsw_sp_nexthop_group_type(nh_grp) == AF_INET6 &&
+	    !nh_grp->gateway)
+		return;
+
 	rhashtable_remove_fast(&mlxsw_sp->router->nexthop_group_ht,
 			       &nh_grp->ht_node,
 			       mlxsw_sp_nexthop_group_ht_params);
 }
 
 static struct mlxsw_sp_nexthop_group *
-mlxsw_sp_nexthop_group_lookup(struct mlxsw_sp *mlxsw_sp,
-			      struct mlxsw_sp_nexthop_group_key key)
+mlxsw_sp_nexthop4_group_lookup(struct mlxsw_sp *mlxsw_sp,
+			       struct fib_info *fi)
+{
+	struct mlxsw_sp_nexthop_group_cmp_arg cmp_arg;
+
+	cmp_arg.proto = MLXSW_SP_L3_PROTO_IPV4;
+	cmp_arg.fi = fi;
+	return rhashtable_lookup_fast(&mlxsw_sp->router->nexthop_group_ht,
+				      &cmp_arg,
+				      mlxsw_sp_nexthop_group_ht_params);
+}
+
+static struct mlxsw_sp_nexthop_group *
+mlxsw_sp_nexthop6_group_lookup(struct mlxsw_sp *mlxsw_sp,
+			       struct mlxsw_sp_fib6_entry *fib6_entry)
 {
-	return rhashtable_lookup_fast(&mlxsw_sp->router->nexthop_group_ht, &key,
+	struct mlxsw_sp_nexthop_group_cmp_arg cmp_arg;
+
+	cmp_arg.proto = MLXSW_SP_L3_PROTO_IPV6;
+	cmp_arg.fib6_entry = fib6_entry;
+	return rhashtable_lookup_fast(&mlxsw_sp->router->nexthop_group_ht,
+				      &cmp_arg,
 				      mlxsw_sp_nexthop_group_ht_params);
 }
 
@@ -2063,12 +2221,12 @@ mlxsw_sp_nexthop4_group_create(struct mlxsw_sp *mlxsw_sp, struct fib_info *fi)
 	nh_grp = kzalloc(alloc_size, GFP_KERNEL);
 	if (!nh_grp)
 		return ERR_PTR(-ENOMEM);
+	nh_grp->priv = fi;
 	INIT_LIST_HEAD(&nh_grp->fib_list);
 	nh_grp->neigh_tbl = &arp_tbl;
 
 	nh_grp->gateway = fi->fib_nh->nh_scope == RT_SCOPE_LINK;
 	nh_grp->count = fi->fib_nhs;
-	nh_grp->key.fi = fi;
 	fib_info_hold(fi);
 	for (i = 0; i < nh_grp->count; i++) {
 		nh = &nh_grp->nexthops[i];
@@ -2089,7 +2247,7 @@ mlxsw_sp_nexthop4_group_create(struct mlxsw_sp *mlxsw_sp, struct fib_info *fi)
 		nh = &nh_grp->nexthops[i];
 		mlxsw_sp_nexthop4_fini(mlxsw_sp, nh);
 	}
-	fib_info_put(nh_grp->key.fi);
+	fib_info_put(fi);
 	kfree(nh_grp);
 	return ERR_PTR(err);
 }
@@ -2108,7 +2266,7 @@ mlxsw_sp_nexthop4_group_destroy(struct mlxsw_sp *mlxsw_sp,
 	}
 	mlxsw_sp_nexthop_group_refresh(mlxsw_sp, nh_grp);
 	WARN_ON_ONCE(nh_grp->adj_index_valid);
-	fib_info_put(nh_grp->key.fi);
+	fib_info_put(mlxsw_sp_nexthop4_group_fi(nh_grp));
 	kfree(nh_grp);
 }
 
@@ -2116,11 +2274,9 @@ static int mlxsw_sp_nexthop4_group_get(struct mlxsw_sp *mlxsw_sp,
 				       struct mlxsw_sp_fib_entry *fib_entry,
 				       struct fib_info *fi)
 {
-	struct mlxsw_sp_nexthop_group_key key;
 	struct mlxsw_sp_nexthop_group *nh_grp;
 
-	key.fi = fi;
-	nh_grp = mlxsw_sp_nexthop_group_lookup(mlxsw_sp, key);
+	nh_grp = mlxsw_sp_nexthop4_group_lookup(mlxsw_sp, fi);
 	if (!nh_grp) {
 		nh_grp = mlxsw_sp_nexthop4_group_create(mlxsw_sp, fi);
 		if (IS_ERR(nh_grp))
@@ -2551,7 +2707,8 @@ mlxsw_sp_fib4_entry_lookup(struct mlxsw_sp *mlxsw_sp,
 		if (fib4_entry->tb_id == fen_info->tb_id &&
 		    fib4_entry->tos == fen_info->tos &&
 		    fib4_entry->type == fen_info->type &&
-		    fib4_entry->common.nh_group->key.fi == fen_info->fi) {
+		    mlxsw_sp_nexthop4_group_fi(fib4_entry->common.nh_group) ==
+		    fen_info->fi) {
 			return fib4_entry;
 		}
 	}
@@ -3162,6 +3319,7 @@ static int mlxsw_sp_nexthop6_init(struct mlxsw_sp *mlxsw_sp,
 
 	if (!dev)
 		return 0;
+	nh->ifindex = dev->ifindex;
 
 	rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, dev);
 	if (!rif)
@@ -3219,9 +3377,15 @@ mlxsw_sp_nexthop6_group_create(struct mlxsw_sp *mlxsw_sp,
 			goto err_nexthop6_init;
 		mlxsw_sp_rt6 = list_next_entry(mlxsw_sp_rt6, list);
 	}
+
+	err = mlxsw_sp_nexthop_group_insert(mlxsw_sp, nh_grp);
+	if (err)
+		goto err_nexthop_group_insert;
+
 	mlxsw_sp_nexthop_group_refresh(mlxsw_sp, nh_grp);
 	return nh_grp;
 
+err_nexthop_group_insert:
 err_nexthop6_init:
 	for (i--; i >= 0; i--) {
 		nh = &nh_grp->nexthops[i];
@@ -3238,6 +3402,7 @@ mlxsw_sp_nexthop6_group_destroy(struct mlxsw_sp *mlxsw_sp,
 	struct mlxsw_sp_nexthop *nh;
 	int i = nh_grp->count;
 
+	mlxsw_sp_nexthop_group_remove(mlxsw_sp, nh_grp);
 	for (i--; i >= 0; i--) {
 		nh = &nh_grp->nexthops[i];
 		mlxsw_sp_nexthop6_fini(mlxsw_sp, nh);
@@ -3252,10 +3417,12 @@ static int mlxsw_sp_nexthop6_group_get(struct mlxsw_sp *mlxsw_sp,
 {
 	struct mlxsw_sp_nexthop_group *nh_grp;
 
-	/* For now, don't consolidate nexthop groups */
+	nh_grp = mlxsw_sp_nexthop6_group_lookup(mlxsw_sp, fib6_entry);
+	if (!nh_grp) {
 		nh_grp = mlxsw_sp_nexthop6_group_create(mlxsw_sp, fib6_entry);
 		if (IS_ERR(nh_grp))
 			return PTR_ERR(nh_grp);
+	}
 
 	list_add_tail(&fib6_entry->common.nexthop_group_node,
 		      &nh_grp->fib_list);