Merge branch 'mlxsw-identical-routes-handling'

Jiri Pirko says:

====================
mlxsw: Identical routes handling

Ido says:

The kernel can store several FIB aliases that share the same prefix and
length. These aliases can differ in other parameters such as TOS and
metric, which are taken into account during lookup.

Offloading devices might not have the same flexibility, allowing only a
single route with the same prefix and length to be reflected. mlxsw is
one such device.

This patchset aims to correctly handle this situation in the mlxsw
driver. The first four patches introduce small changes in the IPv4 FIB
code, so that listeners of the FIB notification chain will be able to
correctly handle identical routes.

The last three patches build on top of previous work and introduce the
necessary changes in the mlxsw driver. The biggest change is the
introduction of a FIB node, where identical routes are chained, instead
of a primitive reference counting. This is explained in detail in the
fifth patch.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -109,7 +109,6 @@ mlxsw_sp_prefix_usage_clear(struct mlxsw_sp_prefix_usage *prefix_usage,
 }
 
 struct mlxsw_sp_fib_key {
-	struct net_device *dev;
 	unsigned char addr[sizeof(struct in6_addr)];
 	unsigned char prefix_len;
 };
@@ -122,94 +121,39 @@ enum mlxsw_sp_fib_entry_type {
 
 struct mlxsw_sp_nexthop_group;
 
-struct mlxsw_sp_fib_entry {
-	struct rhash_head ht_node;
+struct mlxsw_sp_fib_node {
+	struct list_head entry_list;
 	struct list_head list;
+	struct rhash_head ht_node;
+	struct mlxsw_sp_vr *vr;
 	struct mlxsw_sp_fib_key key;
+};
+
+struct mlxsw_sp_fib_entry_params {
+	u32 tb_id;
+	u32 prio;
+	u8 tos;
+	u8 type;
+};
+
+struct mlxsw_sp_fib_entry {
+	struct list_head list;
+	struct mlxsw_sp_fib_node *fib_node;
 	enum mlxsw_sp_fib_entry_type type;
-	unsigned int ref_count;
-	struct mlxsw_sp_vr *vr;
 	struct list_head nexthop_group_node;
 	struct mlxsw_sp_nexthop_group *nh_group;
+	struct mlxsw_sp_fib_entry_params params;
 	bool offloaded;
 };
 
 struct mlxsw_sp_fib {
 	struct rhashtable ht;
-	struct list_head entry_list;
+	struct list_head node_list;
 	unsigned long prefix_ref_count[MLXSW_SP_PREFIX_COUNT];
 	struct mlxsw_sp_prefix_usage prefix_usage;
 };
 
-static const struct rhashtable_params mlxsw_sp_fib_ht_params = {
-	.key_offset = offsetof(struct mlxsw_sp_fib_entry, key),
-	.head_offset = offsetof(struct mlxsw_sp_fib_entry, ht_node),
-	.key_len = sizeof(struct mlxsw_sp_fib_key),
-	.automatic_shrinking = true,
-};
-
-static int mlxsw_sp_fib_entry_insert(struct mlxsw_sp_fib *fib,
-				     struct mlxsw_sp_fib_entry *fib_entry)
-{
-	unsigned char prefix_len = fib_entry->key.prefix_len;
-	int err;
-
-	err = rhashtable_insert_fast(&fib->ht, &fib_entry->ht_node,
-				     mlxsw_sp_fib_ht_params);
-	if (err)
-		return err;
-	list_add_tail(&fib_entry->list, &fib->entry_list);
-	if (fib->prefix_ref_count[prefix_len]++ == 0)
-		mlxsw_sp_prefix_usage_set(&fib->prefix_usage, prefix_len);
-	return 0;
-}
-
-static void mlxsw_sp_fib_entry_remove(struct mlxsw_sp_fib *fib,
-				      struct mlxsw_sp_fib_entry *fib_entry)
-{
-	unsigned char prefix_len = fib_entry->key.prefix_len;
-
-	if (--fib->prefix_ref_count[prefix_len] == 0)
-		mlxsw_sp_prefix_usage_clear(&fib->prefix_usage, prefix_len);
-	list_del(&fib_entry->list);
-	rhashtable_remove_fast(&fib->ht, &fib_entry->ht_node,
-			       mlxsw_sp_fib_ht_params);
-}
-
-static struct mlxsw_sp_fib_entry *
-mlxsw_sp_fib_entry_create(struct mlxsw_sp_fib *fib, const void *addr,
-			  size_t addr_len, unsigned char prefix_len,
-			  struct net_device *dev)
-{
-	struct mlxsw_sp_fib_entry *fib_entry;
-
-	fib_entry = kzalloc(sizeof(*fib_entry), GFP_KERNEL);
-	if (!fib_entry)
-		return NULL;
-	fib_entry->key.dev = dev;
-	memcpy(fib_entry->key.addr, addr, addr_len);
-	fib_entry->key.prefix_len = prefix_len;
-	return fib_entry;
-}
-
-static void mlxsw_sp_fib_entry_destroy(struct mlxsw_sp_fib_entry *fib_entry)
-{
-	kfree(fib_entry);
-}
-
-static struct mlxsw_sp_fib_entry *
-mlxsw_sp_fib_entry_lookup(struct mlxsw_sp_fib *fib, const void *addr,
-			  size_t addr_len, unsigned char prefix_len,
-			  struct net_device *dev)
-{
-	struct mlxsw_sp_fib_key key;
-
-	memset(&key, 0, sizeof(key));
-	key.dev = dev;
-	memcpy(key.addr, addr, addr_len);
-	key.prefix_len = prefix_len;
-	return rhashtable_lookup_fast(&fib->ht, &key, mlxsw_sp_fib_ht_params);
-}
+static const struct rhashtable_params mlxsw_sp_fib_ht_params;
 
 static struct mlxsw_sp_fib *mlxsw_sp_fib_create(void)
 {
@@ -222,7 +166,7 @@ static struct mlxsw_sp_fib *mlxsw_sp_fib_create(void)
 	err = rhashtable_init(&fib->ht, &mlxsw_sp_fib_ht_params);
 	if (err)
 		goto err_rhashtable_init;
-	INIT_LIST_HEAD(&fib->entry_list);
+	INIT_LIST_HEAD(&fib->node_list);
 	return fib;
 
 err_rhashtable_init:
@@ -232,6 +176,7 @@ static struct mlxsw_sp_fib *mlxsw_sp_fib_create(void)
 
 static void mlxsw_sp_fib_destroy(struct mlxsw_sp_fib *fib)
 {
+	WARN_ON(!list_empty(&fib->node_list));
 	rhashtable_destroy(&fib->ht);
 	kfree(fib);
 }
@@ -1239,9 +1184,9 @@ static int mlxsw_sp_adj_index_mass_update(struct mlxsw_sp *mlxsw_sp,
 	int err;
 
 	list_for_each_entry(fib_entry, &nh_grp->fib_list, nexthop_group_node) {
-		if (vr == fib_entry->vr)
+		if (vr == fib_entry->fib_node->vr)
 			continue;
-		vr = fib_entry->vr;
+		vr = fib_entry->fib_node->vr;
 		err = mlxsw_sp_adj_index_mass_update_vr(mlxsw_sp, vr,
 							old_adj_index,
 							old_ecmp_size,
@@ -1727,6 +1672,9 @@ mlxsw_sp_fib_entry_should_offload(const struct mlxsw_sp_fib_entry *fib_entry)
 {
 	struct mlxsw_sp_nexthop_group *nh_group = fib_entry->nh_group;
 
+	if (fib_entry->params.tos)
+		return false;
+
 	switch (fib_entry->type) {
 	case MLXSW_SP_FIB_ENTRY_TYPE_REMOTE:
 		return !!nh_group->adj_index_valid;
@@ -1741,7 +1689,7 @@ static void mlxsw_sp_fib_entry_offload_set(struct mlxsw_sp_fib_entry *fib_entry)
 {
 	fib_entry->offloaded = true;
 
-	switch (fib_entry->vr->proto) {
+	switch (fib_entry->fib_node->vr->proto) {
 	case MLXSW_SP_L3_PROTO_IPV4:
 		fib_info_offload_inc(fib_entry->nh_group->key.fi);
 		break;
@@ -1753,7 +1701,7 @@ static void mlxsw_sp_fib_entry_offload_set(struct mlxsw_sp_fib_entry *fib_entry)
 static void
 mlxsw_sp_fib_entry_offload_unset(struct mlxsw_sp_fib_entry *fib_entry)
 {
-	switch (fib_entry->vr->proto) {
+	switch (fib_entry->fib_node->vr->proto) {
 	case MLXSW_SP_L3_PROTO_IPV4:
 		fib_info_offload_dec(fib_entry->nh_group->key.fi);
 		break;
@@ -1793,8 +1741,8 @@ static int mlxsw_sp_fib_entry_op4_remote(struct mlxsw_sp *mlxsw_sp,
 					 enum mlxsw_reg_ralue_op op)
 {
 	char ralue_pl[MLXSW_REG_RALUE_LEN];
-	u32 *p_dip = (u32 *) fib_entry->key.addr;
-	struct mlxsw_sp_vr *vr = fib_entry->vr;
+	u32 *p_dip = (u32 *) fib_entry->fib_node->key.addr;
+	struct mlxsw_sp_vr *vr = fib_entry->fib_node->vr;
 	enum mlxsw_reg_ralue_trap_action trap_action;
 	u16 trap_id = 0;
 	u32 adjacency_index = 0;
@@ -1815,7 +1763,8 @@ static int mlxsw_sp_fib_entry_op4_remote(struct mlxsw_sp *mlxsw_sp,
 
 	mlxsw_reg_ralue_pack4(ralue_pl,
 			      (enum mlxsw_reg_ralxx_protocol) vr->proto, op,
-			      vr->id, fib_entry->key.prefix_len, *p_dip);
+			      vr->id, fib_entry->fib_node->key.prefix_len,
+			      *p_dip);
 	mlxsw_reg_ralue_act_remote_pack(ralue_pl, trap_action, trap_id,
 					adjacency_index, ecmp_size);
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralue), ralue_pl);
@@ -1828,8 +1777,8 @@ static int mlxsw_sp_fib_entry_op4_local(struct mlxsw_sp *mlxsw_sp,
 	struct mlxsw_sp_rif *r = fib_entry->nh_group->nh_rif;
 	enum mlxsw_reg_ralue_trap_action trap_action;
 	char ralue_pl[MLXSW_REG_RALUE_LEN];
-	u32 *p_dip = (u32 *) fib_entry->key.addr;
-	struct mlxsw_sp_vr *vr = fib_entry->vr;
+	u32 *p_dip = (u32 *) fib_entry->fib_node->key.addr;
+	struct mlxsw_sp_vr *vr = fib_entry->fib_node->vr;
 	u16 trap_id = 0;
 	u16 rif = 0;
 
@@ -1843,7 +1792,8 @@ static int mlxsw_sp_fib_entry_op4_local(struct mlxsw_sp *mlxsw_sp,
 
 	mlxsw_reg_ralue_pack4(ralue_pl,
 			      (enum mlxsw_reg_ralxx_protocol) vr->proto, op,
-			      vr->id, fib_entry->key.prefix_len, *p_dip);
+			      vr->id, fib_entry->fib_node->key.prefix_len,
+			      *p_dip);
 	mlxsw_reg_ralue_act_local_pack(ralue_pl, trap_action, trap_id, rif);
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralue), ralue_pl);
 }
@@ -1853,12 +1803,13 @@ static int mlxsw_sp_fib_entry_op4_trap(struct mlxsw_sp *mlxsw_sp,
 				       enum mlxsw_reg_ralue_op op)
 {
 	char ralue_pl[MLXSW_REG_RALUE_LEN];
-	u32 *p_dip = (u32 *) fib_entry->key.addr;
-	struct mlxsw_sp_vr *vr = fib_entry->vr;
+	u32 *p_dip = (u32 *) fib_entry->fib_node->key.addr;
+	struct mlxsw_sp_vr *vr = fib_entry->fib_node->vr;
 
 	mlxsw_reg_ralue_pack4(ralue_pl,
 			      (enum mlxsw_reg_ralxx_protocol) vr->proto, op,
-			      vr->id, fib_entry->key.prefix_len, *p_dip);
+			      vr->id, fib_entry->fib_node->key.prefix_len,
+			      *p_dip);
 	mlxsw_reg_ralue_act_ip2me_pack(ralue_pl);
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralue), ralue_pl);
 }
@@ -1884,7 +1835,7 @@ static int mlxsw_sp_fib_entry_op(struct mlxsw_sp *mlxsw_sp,
 {
 	int err = -EINVAL;
 
-	switch (fib_entry->vr->proto) {
+	switch (fib_entry->fib_node->vr->proto) {
 	case MLXSW_SP_L3_PROTO_IPV4:
 		err = mlxsw_sp_fib_entry_op4(mlxsw_sp, fib_entry, op);
 		break;
@@ -1930,130 +1881,429 @@ mlxsw_sp_fib4_entry_type_set(struct mlxsw_sp *mlxsw_sp,
 }
 
 static struct mlxsw_sp_fib_entry *
-mlxsw_sp_fib_entry_get(struct mlxsw_sp *mlxsw_sp,
+mlxsw_sp_fib4_entry_create(struct mlxsw_sp *mlxsw_sp,
+			   struct mlxsw_sp_fib_node *fib_node,
 			   const struct fib_entry_notifier_info *fen_info)
 {
 	struct mlxsw_sp_fib_entry *fib_entry;
-	struct fib_info *fi = fen_info->fi;
-	struct mlxsw_sp_vr *vr;
 	int err;
 
-	vr = mlxsw_sp_vr_get(mlxsw_sp, fen_info->dst_len, fen_info->tb_id,
-			     MLXSW_SP_L3_PROTO_IPV4);
-	if (IS_ERR(vr))
-		return ERR_CAST(vr);
-
-	fib_entry = mlxsw_sp_fib_entry_lookup(vr->fib, &fen_info->dst,
-					      sizeof(fen_info->dst),
-					      fen_info->dst_len, fi->fib_dev);
-	if (fib_entry) {
-		/* Already exists, just take a reference */
-		fib_entry->ref_count++;
-		return fib_entry;
-	}
-	fib_entry = mlxsw_sp_fib_entry_create(vr->fib, &fen_info->dst,
-					      sizeof(fen_info->dst),
-					      fen_info->dst_len, fi->fib_dev);
+	fib_entry = kzalloc(sizeof(*fib_entry), GFP_KERNEL);
 	if (!fib_entry) {
 		err = -ENOMEM;
-		goto err_fib_entry_create;
+		goto err_fib_entry_alloc;
 	}
-	fib_entry->vr = vr;
-	fib_entry->ref_count = 1;
 
 	err = mlxsw_sp_fib4_entry_type_set(mlxsw_sp, fen_info, fib_entry);
 	if (err)
 		goto err_fib4_entry_type_set;
 
-	err = mlxsw_sp_nexthop_group_get(mlxsw_sp, fib_entry, fi);
+	err = mlxsw_sp_nexthop_group_get(mlxsw_sp, fib_entry, fen_info->fi);
 	if (err)
 		goto err_nexthop_group_get;
 
+	fib_entry->params.prio = fen_info->fi->fib_priority;
+	fib_entry->params.tb_id = fen_info->tb_id;
+	fib_entry->params.type = fen_info->type;
+	fib_entry->params.tos = fen_info->tos;
+
+	fib_entry->fib_node = fib_node;
+
 	return fib_entry;
 
 err_nexthop_group_get:
 err_fib4_entry_type_set:
-	mlxsw_sp_fib_entry_destroy(fib_entry);
-err_fib_entry_create:
-	mlxsw_sp_vr_put(mlxsw_sp, vr);
-
+	kfree(fib_entry);
+err_fib_entry_alloc:
 	return ERR_PTR(err);
 }
 
+static void mlxsw_sp_fib4_entry_destroy(struct mlxsw_sp *mlxsw_sp,
+					struct mlxsw_sp_fib_entry *fib_entry)
+{
+	mlxsw_sp_nexthop_group_put(mlxsw_sp, fib_entry);
+	kfree(fib_entry);
+}
+
+static struct mlxsw_sp_fib_node *
+mlxsw_sp_fib4_node_get(struct mlxsw_sp *mlxsw_sp,
+		       const struct fib_entry_notifier_info *fen_info);
+
 static struct mlxsw_sp_fib_entry *
-mlxsw_sp_fib_entry_find(struct mlxsw_sp *mlxsw_sp,
+mlxsw_sp_fib4_entry_lookup(struct mlxsw_sp *mlxsw_sp,
 			   const struct fib_entry_notifier_info *fen_info)
 {
+	struct mlxsw_sp_fib_entry *fib_entry;
+	struct mlxsw_sp_fib_node *fib_node;
+
+	fib_node = mlxsw_sp_fib4_node_get(mlxsw_sp, fen_info);
+	if (IS_ERR(fib_node))
+		return NULL;
+
+	list_for_each_entry(fib_entry, &fib_node->entry_list, list) {
+		if (fib_entry->params.tb_id == fen_info->tb_id &&
+		    fib_entry->params.tos == fen_info->tos &&
+		    fib_entry->params.type == fen_info->type &&
+		    fib_entry->nh_group->key.fi == fen_info->fi) {
+			return fib_entry;
+		}
+	}
+
+	return NULL;
+}
+
+static const struct rhashtable_params mlxsw_sp_fib_ht_params = {
+	.key_offset = offsetof(struct mlxsw_sp_fib_node, key),
+	.head_offset = offsetof(struct mlxsw_sp_fib_node, ht_node),
+	.key_len = sizeof(struct mlxsw_sp_fib_key),
+	.automatic_shrinking = true,
+};
+
+static int mlxsw_sp_fib_node_insert(struct mlxsw_sp_fib *fib,
+				    struct mlxsw_sp_fib_node *fib_node)
+{
+	return rhashtable_insert_fast(&fib->ht, &fib_node->ht_node,
+				      mlxsw_sp_fib_ht_params);
+}
+
+static void mlxsw_sp_fib_node_remove(struct mlxsw_sp_fib *fib,
+				     struct mlxsw_sp_fib_node *fib_node)
+{
+	rhashtable_remove_fast(&fib->ht, &fib_node->ht_node,
+			       mlxsw_sp_fib_ht_params);
+}
+
+static struct mlxsw_sp_fib_node *
+mlxsw_sp_fib_node_lookup(struct mlxsw_sp_fib *fib, const void *addr,
+			 size_t addr_len, unsigned char prefix_len)
+{
+	struct mlxsw_sp_fib_key key;
+
+	memset(&key, 0, sizeof(key));
+	memcpy(key.addr, addr, addr_len);
+	key.prefix_len = prefix_len;
+	return rhashtable_lookup_fast(&fib->ht, &key, mlxsw_sp_fib_ht_params);
+}
+
+static struct mlxsw_sp_fib_node *
+mlxsw_sp_fib_node_create(struct mlxsw_sp_vr *vr, const void *addr,
+			 size_t addr_len, unsigned char prefix_len)
+{
+	struct mlxsw_sp_fib_node *fib_node;
+
+	fib_node = kzalloc(sizeof(*fib_node), GFP_KERNEL);
+	if (!fib_node)
+		return NULL;
+
+	INIT_LIST_HEAD(&fib_node->entry_list);
+	list_add(&fib_node->list, &vr->fib->node_list);
+	memcpy(fib_node->key.addr, addr, addr_len);
+	fib_node->key.prefix_len = prefix_len;
+	mlxsw_sp_fib_node_insert(vr->fib, fib_node);
+	fib_node->vr = vr;
+
+	return fib_node;
+}
+
+static void mlxsw_sp_fib_node_destroy(struct mlxsw_sp_fib_node *fib_node)
+{
+	mlxsw_sp_fib_node_remove(fib_node->vr->fib, fib_node);
+	list_del(&fib_node->list);
+	WARN_ON(!list_empty(&fib_node->entry_list));
+	kfree(fib_node);
+}
+
+static bool
+mlxsw_sp_fib_node_entry_is_first(const struct mlxsw_sp_fib_node *fib_node,
+				 const struct mlxsw_sp_fib_entry *fib_entry)
+{
+	return list_first_entry(&fib_node->entry_list,
+				struct mlxsw_sp_fib_entry, list) == fib_entry;
+}
+
+static void mlxsw_sp_fib_node_prefix_inc(struct mlxsw_sp_fib_node *fib_node)
+{
+	unsigned char prefix_len = fib_node->key.prefix_len;
+	struct mlxsw_sp_fib *fib = fib_node->vr->fib;
+
+	if (fib->prefix_ref_count[prefix_len]++ == 0)
+		mlxsw_sp_prefix_usage_set(&fib->prefix_usage, prefix_len);
+}
+
+static void mlxsw_sp_fib_node_prefix_dec(struct mlxsw_sp_fib_node *fib_node)
+{
+	unsigned char prefix_len = fib_node->key.prefix_len;
+	struct mlxsw_sp_fib *fib = fib_node->vr->fib;
+
+	if (--fib->prefix_ref_count[prefix_len] == 0)
+		mlxsw_sp_prefix_usage_clear(&fib->prefix_usage, prefix_len);
+}
+
+static struct mlxsw_sp_fib_node *
+mlxsw_sp_fib4_node_get(struct mlxsw_sp *mlxsw_sp,
+		       const struct fib_entry_notifier_info *fen_info)
+{
+	struct mlxsw_sp_fib_node *fib_node;
 	struct mlxsw_sp_vr *vr;
+	int err;
 
-	vr = mlxsw_sp_vr_find(mlxsw_sp, fen_info->tb_id,
+	vr = mlxsw_sp_vr_get(mlxsw_sp, fen_info->dst_len, fen_info->tb_id,
 			     MLXSW_SP_L3_PROTO_IPV4);
-	if (!vr)
-		return NULL;
+	if (IS_ERR(vr))
+		return ERR_CAST(vr);
 
-	return mlxsw_sp_fib_entry_lookup(vr->fib, &fen_info->dst,
+	fib_node = mlxsw_sp_fib_node_lookup(vr->fib, &fen_info->dst,
 					    sizeof(fen_info->dst),
-					 fen_info->dst_len,
-					 fen_info->fi->fib_dev);
+					    fen_info->dst_len);
+	if (fib_node)
+		return fib_node;
+
+	fib_node = mlxsw_sp_fib_node_create(vr, &fen_info->dst,
+					    sizeof(fen_info->dst),
+					    fen_info->dst_len);
+	if (!fib_node) {
+		err = -ENOMEM;
+		goto err_fib_node_create;
+	}
+
+	return fib_node;
+
+err_fib_node_create:
+	mlxsw_sp_vr_put(mlxsw_sp, vr);
+	return ERR_PTR(err);
+}
+
+static void mlxsw_sp_fib4_node_put(struct mlxsw_sp *mlxsw_sp,
+				   struct mlxsw_sp_fib_node *fib_node)
+{
+	struct mlxsw_sp_vr *vr = fib_node->vr;
+
+	if (!list_empty(&fib_node->entry_list))
+		return;
+	mlxsw_sp_fib_node_destroy(fib_node);
+	mlxsw_sp_vr_put(mlxsw_sp, vr);
+}
+
+static struct mlxsw_sp_fib_entry *
+mlxsw_sp_fib4_node_entry_find(const struct mlxsw_sp_fib_node *fib_node,
+			      const struct mlxsw_sp_fib_entry_params *params)
+{
+	struct mlxsw_sp_fib_entry *fib_entry;
+
+	list_for_each_entry(fib_entry, &fib_node->entry_list, list) {
+		if (fib_entry->params.tb_id > params->tb_id)
+			continue;
+		if (fib_entry->params.tb_id != params->tb_id)
+			break;
+		if (fib_entry->params.tos > params->tos)
+			continue;
+		if (fib_entry->params.prio >= params->prio ||
+		    fib_entry->params.tos < params->tos)
+			return fib_entry;
+	}
+
+	return NULL;
+}
+
+static int mlxsw_sp_fib4_node_list_append(struct mlxsw_sp_fib_entry *fib_entry,
+					  struct mlxsw_sp_fib_entry *new_entry)
+{
+	struct mlxsw_sp_fib_node *fib_node;
+
+	if (WARN_ON(!fib_entry))
+		return -EINVAL;
+
+	fib_node = fib_entry->fib_node;
+	list_for_each_entry_from(fib_entry, &fib_node->entry_list, list) {
+		if (fib_entry->params.tb_id != new_entry->params.tb_id ||
+		    fib_entry->params.tos != new_entry->params.tos ||
+		    fib_entry->params.prio != new_entry->params.prio)
+			break;
+	}
+
+	list_add_tail(&new_entry->list, &fib_entry->list);
+	return 0;
 }
 
-static void mlxsw_sp_fib_entry_put(struct mlxsw_sp *mlxsw_sp,
+static int
+mlxsw_sp_fib4_node_list_insert(struct mlxsw_sp_fib_node *fib_node,
+			       struct mlxsw_sp_fib_entry *new_entry,
+			       bool replace, bool append)
+{
+	struct mlxsw_sp_fib_entry *fib_entry;
+
+	fib_entry = mlxsw_sp_fib4_node_entry_find(fib_node, &new_entry->params);
+
+	if (append)
+		return mlxsw_sp_fib4_node_list_append(fib_entry, new_entry);
+	if (replace && WARN_ON(!fib_entry))
+		return -EINVAL;
+
+	/* Insert new entry before replaced one, so that we can later
+	 * remove the second.
+	 */
+	if (fib_entry) {
+		list_add_tail(&new_entry->list, &fib_entry->list);
+	} else {
+		struct mlxsw_sp_fib_entry *last;
+
+		list_for_each_entry(last, &fib_node->entry_list, list) {
+			if (new_entry->params.tb_id > last->params.tb_id)
+				break;
+			fib_entry = last;
+		}
+
+		if (fib_entry)
+			list_add(&new_entry->list, &fib_entry->list);
+		else
+			list_add(&new_entry->list, &fib_node->entry_list);
+	}
+
+	return 0;
+}
+
+static void
+mlxsw_sp_fib4_node_list_remove(struct mlxsw_sp_fib_entry *fib_entry)
+{
+	list_del(&fib_entry->list);
+}
+
+static int
+mlxsw_sp_fib4_node_entry_add(struct mlxsw_sp *mlxsw_sp,
+			     const struct mlxsw_sp_fib_node *fib_node,
 			     struct mlxsw_sp_fib_entry *fib_entry)
 {
-	struct mlxsw_sp_vr *vr = fib_entry->vr;
+	if (!mlxsw_sp_fib_node_entry_is_first(fib_node, fib_entry))
+		return 0;
 
-	if (--fib_entry->ref_count == 0) {
-		mlxsw_sp_nexthop_group_put(mlxsw_sp, fib_entry);
-		mlxsw_sp_fib_entry_destroy(fib_entry);
+	/* To prevent packet loss, overwrite the previously offloaded
+	 * entry.
+	 */
+	if (!list_is_singular(&fib_node->entry_list)) {
+		enum mlxsw_reg_ralue_op op = MLXSW_REG_RALUE_OP_WRITE_DELETE;
+		struct mlxsw_sp_fib_entry *n = list_next_entry(fib_entry, list);
+
+		mlxsw_sp_fib_entry_offload_refresh(n, op, 0);
 	}
-	mlxsw_sp_vr_put(mlxsw_sp, vr);
+
+	return mlxsw_sp_fib_entry_update(mlxsw_sp, fib_entry);
 }
 
-static void mlxsw_sp_fib_entry_put_all(struct mlxsw_sp *mlxsw_sp,
+static void
+mlxsw_sp_fib4_node_entry_del(struct mlxsw_sp *mlxsw_sp,
+			     const struct mlxsw_sp_fib_node *fib_node,
 			     struct mlxsw_sp_fib_entry *fib_entry)
 {
-	unsigned int last_ref_count;
+	if (!mlxsw_sp_fib_node_entry_is_first(fib_node, fib_entry))
+		return;
 
-	do {
-		last_ref_count = fib_entry->ref_count;
-		mlxsw_sp_fib_entry_put(mlxsw_sp, fib_entry);
-	} while (last_ref_count != 1);
+	/* Promote the next entry by overwriting the deleted entry */
+	if (!list_is_singular(&fib_node->entry_list)) {
+		struct mlxsw_sp_fib_entry *n = list_next_entry(fib_entry, list);
+		enum mlxsw_reg_ralue_op op = MLXSW_REG_RALUE_OP_WRITE_DELETE;
+
+		mlxsw_sp_fib_entry_update(mlxsw_sp, n);
+		mlxsw_sp_fib_entry_offload_refresh(fib_entry, op, 0);
+		return;
+	}
+
+	mlxsw_sp_fib_entry_del(mlxsw_sp, fib_entry);
 }
 
-static int mlxsw_sp_router_fib4_add(struct mlxsw_sp *mlxsw_sp,
-				    struct fib_entry_notifier_info *fen_info)
+static int mlxsw_sp_fib4_node_entry_link(struct mlxsw_sp *mlxsw_sp,
+					 struct mlxsw_sp_fib_entry *fib_entry,
+					 bool replace, bool append)
+{
+	struct mlxsw_sp_fib_node *fib_node = fib_entry->fib_node;
+	int err;
+
+	err = mlxsw_sp_fib4_node_list_insert(fib_node, fib_entry, replace,
+					     append);
+	if (err)
+		return err;
+
+	err = mlxsw_sp_fib4_node_entry_add(mlxsw_sp, fib_node, fib_entry);
+	if (err)
+		goto err_fib4_node_entry_add;
+
+	mlxsw_sp_fib_node_prefix_inc(fib_node);
+
+	return 0;
+
+err_fib4_node_entry_add:
+	mlxsw_sp_fib4_node_list_remove(fib_entry);
+	return err;
+}
+
+static void
+mlxsw_sp_fib4_node_entry_unlink(struct mlxsw_sp *mlxsw_sp,
+				struct mlxsw_sp_fib_entry *fib_entry)
+{
+	struct mlxsw_sp_fib_node *fib_node = fib_entry->fib_node;
+
+	mlxsw_sp_fib_node_prefix_dec(fib_node);
+	mlxsw_sp_fib4_node_entry_del(mlxsw_sp, fib_node, fib_entry);
+	mlxsw_sp_fib4_node_list_remove(fib_entry);
+}
+
+static void mlxsw_sp_fib4_entry_replace(struct mlxsw_sp *mlxsw_sp,
+					struct mlxsw_sp_fib_entry *fib_entry,
+					bool replace)
+{
+	struct mlxsw_sp_fib_node *fib_node = fib_entry->fib_node;
+	struct mlxsw_sp_fib_entry *replaced;
+
+	if (!replace)
+		return;
+
+	/* We inserted the new entry before replaced one */
+	replaced = list_next_entry(fib_entry, list);
+
+	mlxsw_sp_fib4_node_entry_unlink(mlxsw_sp, replaced);
+	mlxsw_sp_fib4_entry_destroy(mlxsw_sp, replaced);
+	mlxsw_sp_fib4_node_put(mlxsw_sp, fib_node);
+}
+
+static int
+mlxsw_sp_router_fib4_add(struct mlxsw_sp *mlxsw_sp,
+			 const struct fib_entry_notifier_info *fen_info,
+			 bool replace, bool append)
 {
 	struct mlxsw_sp_fib_entry *fib_entry;
-	struct mlxsw_sp_vr *vr;
+	struct mlxsw_sp_fib_node *fib_node;
 	int err;
 
 	if (mlxsw_sp->router.aborted)
 		return 0;
 
-	fib_entry = mlxsw_sp_fib_entry_get(mlxsw_sp, fen_info);
-	if (IS_ERR(fib_entry)) {
-		dev_warn(mlxsw_sp->bus_info->dev, "Failed to get FIB4 entry being added.\n");
-		return PTR_ERR(fib_entry);
+	fib_node = mlxsw_sp_fib4_node_get(mlxsw_sp, fen_info);
+	if (IS_ERR(fib_node)) {
+		dev_warn(mlxsw_sp->bus_info->dev, "Failed to get FIB node\n");
+		return PTR_ERR(fib_node);
 	}
 
-	if (fib_entry->ref_count != 1)
-		return 0;
+	fib_entry = mlxsw_sp_fib4_entry_create(mlxsw_sp, fib_node, fen_info);
+	if (IS_ERR(fib_entry)) {
+		dev_warn(mlxsw_sp->bus_info->dev, "Failed to create FIB entry\n");
+		err = PTR_ERR(fib_entry);
+		goto err_fib4_entry_create;
+	}
 
-	vr = fib_entry->vr;
-	err = mlxsw_sp_fib_entry_insert(vr->fib, fib_entry);
+	err = mlxsw_sp_fib4_node_entry_link(mlxsw_sp, fib_entry, replace,
+					    append);
 	if (err) {
-		dev_warn(mlxsw_sp->bus_info->dev, "Failed to insert FIB4 entry being added.\n");
-		goto err_fib_entry_insert;
+		dev_warn(mlxsw_sp->bus_info->dev, "Failed to link FIB entry to node\n");
+		goto err_fib4_node_entry_link;
 	}
-	err = mlxsw_sp_fib_entry_update(mlxsw_sp, fib_entry);
-	if (err)
-		goto err_fib_entry_add;
+
+	mlxsw_sp_fib4_entry_replace(mlxsw_sp, fib_entry, replace);
+
 	return 0;
 
-err_fib_entry_add:
-	mlxsw_sp_fib_entry_remove(vr->fib, fib_entry);
-err_fib_entry_insert:
-	mlxsw_sp_fib_entry_put(mlxsw_sp, fib_entry);
+err_fib4_node_entry_link:
+	mlxsw_sp_fib4_entry_destroy(mlxsw_sp, fib_entry);
+err_fib4_entry_create:
+	mlxsw_sp_fib4_node_put(mlxsw_sp, fib_node);
 	return err;
 }
 
@@ -2061,20 +2311,19 @@ static void mlxsw_sp_router_fib4_del(struct mlxsw_sp *mlxsw_sp,
 				     struct fib_entry_notifier_info *fen_info)
 {
 	struct mlxsw_sp_fib_entry *fib_entry;
+	struct mlxsw_sp_fib_node *fib_node;
 
 	if (mlxsw_sp->router.aborted)
 		return;
 
-	fib_entry = mlxsw_sp_fib_entry_find(mlxsw_sp, fen_info);
-	if (!fib_entry)
+	fib_entry = mlxsw_sp_fib4_entry_lookup(mlxsw_sp, fen_info);
+	if (WARN_ON(!fib_entry))
 		return;
+	fib_node = fib_entry->fib_node;
 
-	if (fib_entry->ref_count == 1) {
-		mlxsw_sp_fib_entry_del(mlxsw_sp, fib_entry);
-		mlxsw_sp_fib_entry_remove(fib_entry->vr->fib, fib_entry);
-	}
-
-	mlxsw_sp_fib_entry_put(mlxsw_sp, fib_entry);
+	mlxsw_sp_fib4_node_entry_unlink(mlxsw_sp, fib_entry);
+	mlxsw_sp_fib4_entry_destroy(mlxsw_sp, fib_entry);
+	mlxsw_sp_fib4_node_put(mlxsw_sp, fib_node);
 }
 
 static int mlxsw_sp_router_set_abort_trap(struct mlxsw_sp *mlxsw_sp)
@@ -2108,10 +2357,42 @@ static int mlxsw_sp_router_set_abort_trap(struct mlxsw_sp *mlxsw_sp)
 	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(ralue), ralue_pl);
 }
 
+static void mlxsw_sp_fib4_node_flush(struct mlxsw_sp *mlxsw_sp,
+				     struct mlxsw_sp_fib_node *fib_node)
+{
+	struct mlxsw_sp_fib_entry *fib_entry, *tmp;
+
+	list_for_each_entry_safe(fib_entry, tmp, &fib_node->entry_list, list) {
+		bool do_break = &tmp->list == &fib_node->entry_list;
+
+		mlxsw_sp_fib4_node_entry_unlink(mlxsw_sp, fib_entry);
+		mlxsw_sp_fib4_entry_destroy(mlxsw_sp, fib_entry);
+		mlxsw_sp_fib4_node_put(mlxsw_sp, fib_node);
+		/* Break when entry list is empty and node was freed.
+		 * Otherwise, we'll access freed memory in the next
+		 * iteration.
+		 */
+		if (do_break)
+			break;
+	}
+}
+
+static void mlxsw_sp_fib_node_flush(struct mlxsw_sp *mlxsw_sp,
+				    struct mlxsw_sp_fib_node *fib_node)
+{
+	switch (fib_node->vr->proto) {
+	case MLXSW_SP_L3_PROTO_IPV4:
+		mlxsw_sp_fib4_node_flush(mlxsw_sp, fib_node);
+		break;
+	case MLXSW_SP_L3_PROTO_IPV6:
+		WARN_ON_ONCE(1);
+		break;
+	}
+}
+
 static void mlxsw_sp_router_fib_flush(struct mlxsw_sp *mlxsw_sp)
 {
-	struct mlxsw_sp_fib_entry *fib_entry;
-	struct mlxsw_sp_fib_entry *tmp;
+	struct mlxsw_sp_fib_node *fib_node, *tmp;
 	struct mlxsw_sp_vr *vr;
 	int i;
 
@@ -2121,14 +2402,11 @@ static void mlxsw_sp_router_fib_flush(struct mlxsw_sp *mlxsw_sp)
 		if (!vr->used)
 			continue;
 
-		list_for_each_entry_safe(fib_entry, tmp,
-					 &vr->fib->entry_list, list) {
-			bool do_break = &tmp->list == &vr->fib->entry_list;
+		list_for_each_entry_safe(fib_node, tmp, &vr->fib->node_list,
+					 list) {
+			bool do_break = &tmp->list == &vr->fib->node_list;
 
-			mlxsw_sp_fib_entry_del(mlxsw_sp, fib_entry);
-			mlxsw_sp_fib_entry_remove(fib_entry->vr->fib,
-						  fib_entry);
-			mlxsw_sp_fib_entry_put_all(mlxsw_sp, fib_entry);
+			mlxsw_sp_fib_node_flush(mlxsw_sp, fib_node);
 			if (do_break)
 				break;
 		}
@@ -2228,13 +2506,19 @@ static void mlxsw_sp_router_fib_event_work(struct work_struct *work)
 	struct mlxsw_sp_fib_event_work *fib_work =
 		container_of(work, struct mlxsw_sp_fib_event_work, work);
 	struct mlxsw_sp *mlxsw_sp = fib_work->mlxsw_sp;
+	bool replace, append;
 	int err;
 
 	/* Protect internal structures from changes */
 	rtnl_lock();
 	switch (fib_work->event) {
+	case FIB_EVENT_ENTRY_REPLACE: /* fall through */
+	case FIB_EVENT_ENTRY_APPEND: /* fall through */
 	case FIB_EVENT_ENTRY_ADD:
-		err = mlxsw_sp_router_fib4_add(mlxsw_sp, &fib_work->fen_info);
+		replace = fib_work->event == FIB_EVENT_ENTRY_REPLACE;
+		append = fib_work->event == FIB_EVENT_ENTRY_APPEND;
+		err = mlxsw_sp_router_fib4_add(mlxsw_sp, &fib_work->fen_info,
+					       replace, append);
 		if (err)
 			mlxsw_sp_router_fib4_abort(mlxsw_sp);
 		fib_info_put(fib_work->fen_info.fi);
@@ -2278,6 +2562,8 @@ static int mlxsw_sp_router_fib_event(struct notifier_block *nb,
 	fib_work->event = event;
 
 	switch (event) {
+	case FIB_EVENT_ENTRY_REPLACE: /* fall through */
+	case FIB_EVENT_ENTRY_APPEND: /* fall through */
 	case FIB_EVENT_ENTRY_ADD: /* fall through */
 	case FIB_EVENT_ENTRY_DEL:
 		memcpy(&fib_work->fen_info, ptr, sizeof(fib_work->fen_info));

include/net/ip_fib.h

@@ -211,7 +211,6 @@ struct fib_entry_notifier_info {
 	u8 tos;
 	u8 type;
 	u32 tb_id;
-	u32 nlflags;
 };
 
 struct fib_nh_notifier_info {
@@ -220,6 +219,8 @@ struct fib_nh_notifier_info {
 };
 
 enum fib_event_type {
+	FIB_EVENT_ENTRY_REPLACE,
+	FIB_EVENT_ENTRY_APPEND,
 	FIB_EVENT_ENTRY_ADD,
 	FIB_EVENT_ENTRY_DEL,
 	FIB_EVENT_RULE_ADD,

net/ipv4/fib_trie.c

@@ -124,7 +124,7 @@ static void fib_notify(struct net *net, struct notifier_block *nb,
 static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
 				   enum fib_event_type event_type, u32 dst,
 				   int dst_len, struct fib_info *fi,
-				   u8 tos, u8 type, u32 tb_id, u32 nlflags)
+				   u8 tos, u8 type, u32 tb_id)
 {
 	struct fib_entry_notifier_info info = {
 		.dst = dst,
@@ -133,7 +133,6 @@ static int call_fib_entry_notifier(struct notifier_block *nb, struct net *net,
 		.tos = tos,
 		.type = type,
 		.tb_id = tb_id,
-		.nlflags = nlflags,
 	};
 	return call_fib_notifier(nb, net, event_type, &info.info);
 }
@@ -197,7 +196,7 @@ int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
 static int call_fib_entry_notifiers(struct net *net,
 				    enum fib_event_type event_type, u32 dst,
 				    int dst_len, struct fib_info *fi,
-				    u8 tos, u8 type, u32 tb_id, u32 nlflags)
+				    u8 tos, u8 type, u32 tb_id)
 {
 	struct fib_entry_notifier_info info = {
 		.dst = dst,
@@ -206,7 +205,6 @@ static int call_fib_entry_notifiers(struct net *net,
 		.tos = tos,
 		.type = type,
 		.tb_id = tb_id,
-		.nlflags = nlflags,
 	};
 	return call_fib_notifiers(net, event_type, &info.info);
 }
@@ -1198,6 +1196,7 @@ static int fib_insert_alias(struct trie *t, struct key_vector *tp,
 int fib_table_insert(struct net *net, struct fib_table *tb,
 		     struct fib_config *cfg)
 {
+	enum fib_event_type event = FIB_EVENT_ENTRY_ADD;
 	struct trie *t = (struct trie *)tb->tb_data;
 	struct fib_alias *fa, *new_fa;
 	struct key_vector *l, *tp;
@@ -1295,6 +1294,13 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
 			new_fa->tb_id = tb->tb_id;
 			new_fa->fa_default = -1;
 
+			call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE,
+						 key, plen, fi,
+						 new_fa->fa_tos, cfg->fc_type,
+						 tb->tb_id);
+			rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
+				  tb->tb_id, &cfg->fc_nlinfo, nlflags);
+
 			hlist_replace_rcu(&fa->fa_list, &new_fa->fa_list);
 
 			alias_free_mem_rcu(fa);
@@ -1303,13 +1309,6 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
 			if (state & FA_S_ACCESSED)
 				rt_cache_flush(cfg->fc_nlinfo.nl_net);
 
-			call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_ADD,
-						 key, plen, fi,
-						 new_fa->fa_tos, cfg->fc_type,
-						 tb->tb_id, cfg->fc_nlflags);
-			rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen,
-				tb->tb_id, &cfg->fc_nlinfo, nlflags);
-
 			goto succeeded;
 		}
 		/* Error if we find a perfect match which
@@ -1319,11 +1318,13 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
 		if (fa_match)
 			goto out;
 
-		if (cfg->fc_nlflags & NLM_F_APPEND)
+		if (cfg->fc_nlflags & NLM_F_APPEND) {
+			event = FIB_EVENT_ENTRY_APPEND;
 			nlflags |= NLM_F_APPEND;
-		else
+		} else {
 			fa = fa_first;
 		}
+	}
 	err = -ENOENT;
 	if (!(cfg->fc_nlflags & NLM_F_CREATE))
 		goto out;
@@ -1351,8 +1352,8 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
 		tb->tb_num_default++;
 
 	rt_cache_flush(cfg->fc_nlinfo.nl_net);
-	call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_ADD, key, plen, fi, tos,
-				 cfg->fc_type, tb->tb_id, cfg->fc_nlflags);
+	call_fib_entry_notifiers(net, event, key, plen, fi, tos, cfg->fc_type,
+				 tb->tb_id);
 	rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, new_fa->tb_id,
 		  &cfg->fc_nlinfo, nlflags);
 succeeded:
@@ -1653,8 +1654,8 @@ int fib_table_delete(struct net *net, struct fib_table *tb,
 		return -ESRCH;
 
 	call_fib_entry_notifiers(net, FIB_EVENT_ENTRY_DEL, key, plen,
-				 fa_to_delete->fa_info, tos, cfg->fc_type,
-				 tb->tb_id, 0);
+				 fa_to_delete->fa_info, tos,
+				 fa_to_delete->fa_type, tb->tb_id);
 	rtmsg_fib(RTM_DELROUTE, htonl(key), fa_to_delete, plen, tb->tb_id,
 		  &cfg->fc_nlinfo, 0);
 
@@ -1963,7 +1964,8 @@ int fib_table_flush(struct net *net, struct fib_table *tb)
 		hlist_for_each_entry_safe(fa, tmp, &n->leaf, fa_list) {
 			struct fib_info *fi = fa->fa_info;
 
-			if (!fi || !(fi->fib_flags & RTNH_F_DEAD)) {
+			if (!fi || !(fi->fib_flags & RTNH_F_DEAD) ||
+			    tb->tb_id != fa->tb_id) {
 				slen = fa->fa_slen;
 				continue;
 			}
@@ -1972,7 +1974,7 @@ int fib_table_flush(struct net *net, struct fib_table *tb)
 						 n->key,
 						 KEYLENGTH - fa->fa_slen,
 						 fi, fa->fa_tos, fa->fa_type,
-						 tb->tb_id, 0);
+						 tb->tb_id);
 			hlist_del_rcu(&fa->fa_list);
 			fib_release_info(fa->fa_info);
 			alias_free_mem_rcu(fa);
@@ -2012,7 +2014,7 @@ static void fib_leaf_notify(struct net *net, struct key_vector *l,
 
 		call_fib_entry_notifier(nb, net, event_type, l->key,
 					KEYLENGTH - fa->fa_slen, fi, fa->fa_tos,
-					fa->fa_type, fa->tb_id, 0);
+					fa->fa_type, fa->tb_id);
 	}
 }