Merge branch 'mlxsw-Align-multipath-hash-parameters-with-kernels'

Jiri Pirko says:

====================
mlxsw: Align multipath hash parameters with kernel's

Ido says:

This set makes sure the device is using the same parameters as the
kernel when it computes the multipath hash during IP forwarding.

First patch adds a new netevent to let interested listeners know that
the multipath hash policy has changed.

Next two patches do small and non-functional changes in the mlxsw
driver.

Last patches configure the multipath hash policy upon driver
initialization and as a response to netevents.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 270 insertions, 25 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/reg.h b/drivers/net/ethernet/mellanox/mlxsw/reg.h
index db6cd263dd61..5066553dd0b6 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/reg.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/reg.h
@@ -5844,6 +5844,137 @@ static inline void mlxsw_reg_rigr2_erif_entry_pack(char *payload, int index,
 	mlxsw_reg_rigr2_erif_entry_erif_set(payload, index, erif);
 }
 
+/* RECR-V2 - Router ECMP Configuration Version 2 Register
+ * ------------------------------------------------------
+ */
+#define MLXSW_REG_RECR2_ID 0x8025
+#define MLXSW_REG_RECR2_LEN 0x38
+
+MLXSW_REG_DEFINE(recr2, MLXSW_REG_RECR2_ID, MLXSW_REG_RECR2_LEN);
+
+/* reg_recr2_pp
+ * Per-port configuration
+ * Access: Index
+ */
+MLXSW_ITEM32(reg, recr2, pp, 0x00, 24, 1);
+
+/* reg_recr2_sh
+ * Symmetric hash
+ * Access: RW
+ */
+MLXSW_ITEM32(reg, recr2, sh, 0x00, 8, 1);
+
+/* reg_recr2_seed
+ * Seed
+ * Access: RW
+ */
+MLXSW_ITEM32(reg, recr2, seed, 0x08, 0, 32);
+
+enum {
+	/* Enable IPv4 fields if packet is not TCP and not UDP */
+	MLXSW_REG_RECR2_IPV4_EN_NOT_TCP_NOT_UDP	= 3,
+	/* Enable IPv4 fields if packet is TCP or UDP */
+	MLXSW_REG_RECR2_IPV4_EN_TCP_UDP		= 4,
+	/* Enable IPv6 fields if packet is not TCP and not UDP */
+	MLXSW_REG_RECR2_IPV6_EN_NOT_TCP_NOT_UDP	= 5,
+	/* Enable IPv6 fields if packet is TCP or UDP */
+	MLXSW_REG_RECR2_IPV6_EN_TCP_UDP		= 6,
+	/* Enable TCP/UDP header fields if packet is IPv4 */
+	MLXSW_REG_RECR2_TCP_UDP_EN_IPV4		= 7,
+	/* Enable TCP/UDP header fields if packet is IPv6 */
+	MLXSW_REG_RECR2_TCP_UDP_EN_IPV6		= 8,
+};
+
+/* reg_recr2_outer_header_enables
+ * Bit mask where each bit enables a specific layer to be included in
+ * the hash calculation.
+ * Access: RW
+ */
+MLXSW_ITEM_BIT_ARRAY(reg, recr2, outer_header_enables, 0x10, 0x04, 1);
+
+enum {
+	/* IPv4 Source IP */
+	MLXSW_REG_RECR2_IPV4_SIP0			= 9,
+	MLXSW_REG_RECR2_IPV4_SIP3			= 12,
+	/* IPv4 Destination IP */
+	MLXSW_REG_RECR2_IPV4_DIP0			= 13,
+	MLXSW_REG_RECR2_IPV4_DIP3			= 16,
+	/* IP Protocol */
+	MLXSW_REG_RECR2_IPV4_PROTOCOL			= 17,
+	/* IPv6 Source IP */
+	MLXSW_REG_RECR2_IPV6_SIP0_7			= 21,
+	MLXSW_REG_RECR2_IPV6_SIP8			= 29,
+	MLXSW_REG_RECR2_IPV6_SIP15			= 36,
+	/* IPv6 Destination IP */
+	MLXSW_REG_RECR2_IPV6_DIP0_7			= 37,
+	MLXSW_REG_RECR2_IPV6_DIP8			= 45,
+	MLXSW_REG_RECR2_IPV6_DIP15			= 52,
+	/* IPv6 Next Header */
+	MLXSW_REG_RECR2_IPV6_NEXT_HEADER		= 53,
+	/* IPv6 Flow Label */
+	MLXSW_REG_RECR2_IPV6_FLOW_LABEL			= 57,
+	/* TCP/UDP Source Port */
+	MLXSW_REG_RECR2_TCP_UDP_SPORT			= 74,
+	/* TCP/UDP Destination Port */
+	MLXSW_REG_RECR2_TCP_UDP_DPORT			= 75,
+};
+
+/* reg_recr2_outer_header_fields_enable
+ * Packet fields to enable for ECMP hash subject to outer_header_enable.
+ * Access: RW
+ */
+MLXSW_ITEM_BIT_ARRAY(reg, recr2, outer_header_fields_enable, 0x14, 0x14, 1);
+
+static inline void mlxsw_reg_recr2_ipv4_sip_enable(char *payload)
+{
+	int i;
+
+	for (i = MLXSW_REG_RECR2_IPV4_SIP0; i <= MLXSW_REG_RECR2_IPV4_SIP3; i++)
+		mlxsw_reg_recr2_outer_header_fields_enable_set(payload, i,
+							       true);
+}
+
+static inline void mlxsw_reg_recr2_ipv4_dip_enable(char *payload)
+{
+	int i;
+
+	for (i = MLXSW_REG_RECR2_IPV4_DIP0; i <= MLXSW_REG_RECR2_IPV4_DIP3; i++)
+		mlxsw_reg_recr2_outer_header_fields_enable_set(payload, i,
+							       true);
+}
+
+static inline void mlxsw_reg_recr2_ipv6_sip_enable(char *payload)
+{
+	int i = MLXSW_REG_RECR2_IPV6_SIP0_7;
+
+	mlxsw_reg_recr2_outer_header_fields_enable_set(payload, i, true);
+
+	i = MLXSW_REG_RECR2_IPV6_SIP8;
+	for (; i <= MLXSW_REG_RECR2_IPV6_SIP15; i++)
+		mlxsw_reg_recr2_outer_header_fields_enable_set(payload, i,
+							       true);
+}
+
+static inline void mlxsw_reg_recr2_ipv6_dip_enable(char *payload)
+{
+	int i = MLXSW_REG_RECR2_IPV6_DIP0_7;
+
+	mlxsw_reg_recr2_outer_header_fields_enable_set(payload, i, true);
+
+	i = MLXSW_REG_RECR2_IPV6_DIP8;
+	for (; i <= MLXSW_REG_RECR2_IPV6_DIP15; i++)
+		mlxsw_reg_recr2_outer_header_fields_enable_set(payload, i,
+							       true);
+}
+
+static inline void mlxsw_reg_recr2_pack(char *payload, u32 seed)
+{
+	MLXSW_REG_ZERO(recr2, payload);
+	mlxsw_reg_recr2_pp_set(payload, false);
+	mlxsw_reg_recr2_sh_set(payload, true);
+	mlxsw_reg_recr2_seed_set(payload, seed);
+}
+
 /* RMFT-V2 - Router Multicast Forwarding Table Version 2 Register
  * --------------------------------------------------------------
  * The RMFT_V2 register is used to configure and query the multicast table.
@@ -7313,6 +7444,7 @@ static const struct mlxsw_reg_info *mlxsw_reg_infos[] = {
 	MLXSW_REG(raleu),
 	MLXSW_REG(rauhtd),
 	MLXSW_REG(rigr2),
+	MLXSW_REG(recr2),
 	MLXSW_REG(rmft2),
 	MLXSW_REG(mfcr),
 	MLXSW_REG(mfsc),
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 3f4be9556e56..52f38b480669 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -4574,10 +4574,6 @@ static struct notifier_block mlxsw_sp_inet6addr_nb __read_mostly = {
 	.notifier_call = mlxsw_sp_inet6addr_event,
 };
 
-static struct notifier_block mlxsw_sp_router_netevent_nb __read_mostly = {
-	.notifier_call = mlxsw_sp_router_netevent_event,
-};
-
 static const struct pci_device_id mlxsw_sp_pci_id_table[] = {
 	{PCI_VDEVICE(MELLANOX, PCI_DEVICE_ID_MELLANOX_SPECTRUM), 0},
 	{0, },
@@ -4596,7 +4592,6 @@ static int __init mlxsw_sp_module_init(void)
 	register_inetaddr_notifier(&mlxsw_sp_inetaddr_nb);
 	register_inet6addr_validator_notifier(&mlxsw_sp_inet6addr_valid_nb);
 	register_inet6addr_notifier(&mlxsw_sp_inet6addr_nb);
-	register_netevent_notifier(&mlxsw_sp_router_netevent_nb);
 
 	err = mlxsw_core_driver_register(&mlxsw_sp_driver);
 	if (err)
@@ -4611,7 +4606,6 @@ static int __init mlxsw_sp_module_init(void)
 err_pci_driver_register:
 	mlxsw_core_driver_unregister(&mlxsw_sp_driver);
 err_core_driver_register:
-	unregister_netevent_notifier(&mlxsw_sp_router_netevent_nb);
 	unregister_inet6addr_notifier(&mlxsw_sp_inet6addr_nb);
 	unregister_inet6addr_validator_notifier(&mlxsw_sp_inet6addr_valid_nb);
 	unregister_inetaddr_notifier(&mlxsw_sp_inetaddr_nb);
@@ -4623,7 +4617,6 @@ static void __exit mlxsw_sp_module_exit(void)
 {
 	mlxsw_pci_driver_unregister(&mlxsw_sp_pci_driver);
 	mlxsw_core_driver_unregister(&mlxsw_sp_driver);
-	unregister_netevent_notifier(&mlxsw_sp_router_netevent_nb);
 	unregister_inet6addr_notifier(&mlxsw_sp_inet6addr_nb);
 	unregister_inet6addr_validator_notifier(&mlxsw_sp_inet6addr_valid_nb);
 	unregister_inetaddr_notifier(&mlxsw_sp_inetaddr_nb);
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.h b/drivers/net/ethernet/mellanox/mlxsw/spectrum.h
index aa0cefb25e18..b2393bb8cef9 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.h
@@ -385,8 +385,6 @@ static inline void mlxsw_sp_port_dcb_fini(struct mlxsw_sp_port *mlxsw_sp_port)
 /* spectrum_router.c */
 int mlxsw_sp_router_init(struct mlxsw_sp *mlxsw_sp);
 void mlxsw_sp_router_fini(struct mlxsw_sp *mlxsw_sp);
-int mlxsw_sp_router_netevent_event(struct notifier_block *unused,
-				   unsigned long event, void *ptr);
 int mlxsw_sp_netdevice_router_port_event(struct net_device *dev);
 int mlxsw_sp_inetaddr_event(struct notifier_block *unused,
 			    unsigned long event, void *ptr);
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 9fe4cdb23189..d657f01f2d79 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -47,6 +47,7 @@
 #include <linux/socket.h>
 #include <linux/route.h>
 #include <linux/gcd.h>
+#include <linux/random.h>
 #include <net/netevent.h>
 #include <net/neighbour.h>
 #include <net/arp.h>
@@ -96,6 +97,7 @@ struct mlxsw_sp_router {
 	struct list_head ipip_list;
 	bool aborted;
 	struct notifier_block fib_nb;
+	struct notifier_block netevent_nb;
 	const struct mlxsw_sp_rif_ops **rif_ops_arr;
 	const struct mlxsw_sp_ipip_ops **ipip_ops_arr;
 };
@@ -2025,7 +2027,7 @@ mlxsw_sp_neigh_entry_counter_update(struct mlxsw_sp *mlxsw_sp,
 	mlxsw_sp_neigh_entry_update(mlxsw_sp, neigh_entry, true);
 }
 
-struct mlxsw_sp_neigh_event_work {
+struct mlxsw_sp_netevent_work {
 	struct work_struct work;
 	struct mlxsw_sp *mlxsw_sp;
 	struct neighbour *n;
@@ -2033,11 +2035,11 @@ struct mlxsw_sp_neigh_event_work {
 
 static void mlxsw_sp_router_neigh_event_work(struct work_struct *work)
 {
-	struct mlxsw_sp_neigh_event_work *neigh_work =
-		container_of(work, struct mlxsw_sp_neigh_event_work, work);
-	struct mlxsw_sp *mlxsw_sp = neigh_work->mlxsw_sp;
+	struct mlxsw_sp_netevent_work *net_work =
+		container_of(work, struct mlxsw_sp_netevent_work, work);
+	struct mlxsw_sp *mlxsw_sp = net_work->mlxsw_sp;
 	struct mlxsw_sp_neigh_entry *neigh_entry;
-	struct neighbour *n = neigh_work->n;
+	struct neighbour *n = net_work->n;
 	unsigned char ha[ETH_ALEN];
 	bool entry_connected;
 	u8 nud_state, dead;
@@ -2073,18 +2075,32 @@ static void mlxsw_sp_router_neigh_event_work(struct work_struct *work)
 out:
 	rtnl_unlock();
 	neigh_release(n);
-	kfree(neigh_work);
+	kfree(net_work);
 }
 
-int mlxsw_sp_router_netevent_event(struct notifier_block *unused,
-				   unsigned long event, void *ptr)
+static int mlxsw_sp_mp_hash_init(struct mlxsw_sp *mlxsw_sp);
+
+static void mlxsw_sp_router_mp_hash_event_work(struct work_struct *work)
+{
+	struct mlxsw_sp_netevent_work *net_work =
+		container_of(work, struct mlxsw_sp_netevent_work, work);
+	struct mlxsw_sp *mlxsw_sp = net_work->mlxsw_sp;
+
+	mlxsw_sp_mp_hash_init(mlxsw_sp);
+	kfree(net_work);
+}
+
+static int mlxsw_sp_router_netevent_event(struct notifier_block *nb,
+					  unsigned long event, void *ptr)
 {
-	struct mlxsw_sp_neigh_event_work *neigh_work;
+	struct mlxsw_sp_netevent_work *net_work;
 	struct mlxsw_sp_port *mlxsw_sp_port;
+	struct mlxsw_sp_router *router;
 	struct mlxsw_sp *mlxsw_sp;
 	unsigned long interval;
 	struct neigh_parms *p;
 	struct neighbour *n;
+	struct net *net;
 
 	switch (event) {
 	case NETEVENT_DELAY_PROBE_TIME_UPDATE:
@@ -2118,24 +2134,39 @@ int mlxsw_sp_router_netevent_event(struct notifier_block *unused,
 		if (!mlxsw_sp_port)
 			return NOTIFY_DONE;
 
-		neigh_work = kzalloc(sizeof(*neigh_work), GFP_ATOMIC);
-		if (!neigh_work) {
+		net_work = kzalloc(sizeof(*net_work), GFP_ATOMIC);
+		if (!net_work) {
 			mlxsw_sp_port_dev_put(mlxsw_sp_port);
 			return NOTIFY_BAD;
 		}
 
-		INIT_WORK(&neigh_work->work, mlxsw_sp_router_neigh_event_work);
-		neigh_work->mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
-		neigh_work->n = n;
+		INIT_WORK(&net_work->work, mlxsw_sp_router_neigh_event_work);
+		net_work->mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+		net_work->n = n;
 
 		/* Take a reference to ensure the neighbour won't be
 		 * destructed until we drop the reference in delayed
 		 * work.
 		 */
 		neigh_clone(n);
-		mlxsw_core_schedule_work(&neigh_work->work);
+		mlxsw_core_schedule_work(&net_work->work);
 		mlxsw_sp_port_dev_put(mlxsw_sp_port);
 		break;
+	case NETEVENT_MULTIPATH_HASH_UPDATE:
+		net = ptr;
+
+		if (!net_eq(net, &init_net))
+			return NOTIFY_DONE;
+
+		net_work = kzalloc(sizeof(*net_work), GFP_ATOMIC);
+		if (!net_work)
+			return NOTIFY_BAD;
+
+		router = container_of(nb, struct mlxsw_sp_router, netevent_nb);
+		INIT_WORK(&net_work->work, mlxsw_sp_router_mp_hash_event_work);
+		net_work->mlxsw_sp = router->mlxsw_sp;
+		mlxsw_core_schedule_work(&net_work->work);
+		break;
 	}
 
 	return NOTIFY_DONE;
@@ -6643,6 +6674,64 @@ static void mlxsw_sp_router_fib_dump_flush(struct notifier_block *nb)
 	mlxsw_sp_router_fib_flush(router->mlxsw_sp);
 }
 
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+static void mlxsw_sp_mp_hash_header_set(char *recr2_pl, int header)
+{
+	mlxsw_reg_recr2_outer_header_enables_set(recr2_pl, header, true);
+}
+
+static void mlxsw_sp_mp_hash_field_set(char *recr2_pl, int field)
+{
+	mlxsw_reg_recr2_outer_header_fields_enable_set(recr2_pl, field, true);
+}
+
+static void mlxsw_sp_mp4_hash_init(char *recr2_pl)
+{
+	bool only_l3 = !init_net.ipv4.sysctl_fib_multipath_hash_policy;
+
+	mlxsw_sp_mp_hash_header_set(recr2_pl,
+				    MLXSW_REG_RECR2_IPV4_EN_NOT_TCP_NOT_UDP);
+	mlxsw_sp_mp_hash_header_set(recr2_pl, MLXSW_REG_RECR2_IPV4_EN_TCP_UDP);
+	mlxsw_reg_recr2_ipv4_sip_enable(recr2_pl);
+	mlxsw_reg_recr2_ipv4_dip_enable(recr2_pl);
+	if (only_l3)
+		return;
+	mlxsw_sp_mp_hash_header_set(recr2_pl, MLXSW_REG_RECR2_TCP_UDP_EN_IPV4);
+	mlxsw_sp_mp_hash_field_set(recr2_pl, MLXSW_REG_RECR2_IPV4_PROTOCOL);
+	mlxsw_sp_mp_hash_field_set(recr2_pl, MLXSW_REG_RECR2_TCP_UDP_SPORT);
+	mlxsw_sp_mp_hash_field_set(recr2_pl, MLXSW_REG_RECR2_TCP_UDP_DPORT);
+}
+
+static void mlxsw_sp_mp6_hash_init(char *recr2_pl)
+{
+	mlxsw_sp_mp_hash_header_set(recr2_pl,
+				    MLXSW_REG_RECR2_IPV6_EN_NOT_TCP_NOT_UDP);
+	mlxsw_sp_mp_hash_header_set(recr2_pl, MLXSW_REG_RECR2_IPV6_EN_TCP_UDP);
+	mlxsw_reg_recr2_ipv6_sip_enable(recr2_pl);
+	mlxsw_reg_recr2_ipv6_dip_enable(recr2_pl);
+	mlxsw_sp_mp_hash_field_set(recr2_pl, MLXSW_REG_RECR2_IPV6_FLOW_LABEL);
+	mlxsw_sp_mp_hash_field_set(recr2_pl, MLXSW_REG_RECR2_IPV6_NEXT_HEADER);
+}
+
+static int mlxsw_sp_mp_hash_init(struct mlxsw_sp *mlxsw_sp)
+{
+	char recr2_pl[MLXSW_REG_RECR2_LEN];
+	u32 seed;
+
+	get_random_bytes(&seed, sizeof(seed));
+	mlxsw_reg_recr2_pack(recr2_pl, seed);
+	mlxsw_sp_mp4_hash_init(recr2_pl);
+	mlxsw_sp_mp6_hash_init(recr2_pl);
+
+	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(recr2), recr2_pl);
+}
+#else
+static int mlxsw_sp_mp_hash_init(struct mlxsw_sp *mlxsw_sp)
+{
+	return 0;
+}
+#endif
+
 static int __mlxsw_sp_router_init(struct mlxsw_sp *mlxsw_sp)
 {
 	char rgcr_pl[MLXSW_REG_RGCR_LEN];
@@ -6720,6 +6809,16 @@ int mlxsw_sp_router_init(struct mlxsw_sp *mlxsw_sp)
 	if (err)
 		goto err_neigh_init;
 
+	mlxsw_sp->router->netevent_nb.notifier_call =
+		mlxsw_sp_router_netevent_event;
+	err = register_netevent_notifier(&mlxsw_sp->router->netevent_nb);
+	if (err)
+		goto err_register_netevent_notifier;
+
+	err = mlxsw_sp_mp_hash_init(mlxsw_sp);
+	if (err)
+		goto err_mp_hash_init;
+
 	mlxsw_sp->router->fib_nb.notifier_call = mlxsw_sp_router_fib_event;
 	err = register_fib_notifier(&mlxsw_sp->router->fib_nb,
 				    mlxsw_sp_router_fib_dump_flush);
@@ -6729,6 +6828,9 @@ int mlxsw_sp_router_init(struct mlxsw_sp *mlxsw_sp)
 	return 0;
 
 err_register_fib_notifier:
+err_mp_hash_init:
+	unregister_netevent_notifier(&mlxsw_sp->router->netevent_nb);
+err_register_netevent_notifier:
 	mlxsw_sp_neigh_fini(mlxsw_sp);
 err_neigh_init:
 	mlxsw_sp_vrs_fini(mlxsw_sp);
@@ -6754,6 +6856,7 @@ err_router_init:
 void mlxsw_sp_router_fini(struct mlxsw_sp *mlxsw_sp)
 {
 	unregister_fib_notifier(&mlxsw_sp->router->fib_nb);
+	unregister_netevent_notifier(&mlxsw_sp->router->netevent_nb);
 	mlxsw_sp_neigh_fini(mlxsw_sp);
 	mlxsw_sp_vrs_fini(mlxsw_sp);
 	mlxsw_sp_mr_fini(mlxsw_sp);
diff --git a/include/net/netevent.h b/include/net/netevent.h
index f440df172b56..e3f0e8f2f6e8 100644
--- a/include/net/netevent.h
+++ b/include/net/netevent.h
@@ -25,6 +25,7 @@ enum netevent_notif_type {
 	NETEVENT_NEIGH_UPDATE = 1, /* arg is struct neighbour ptr */
 	NETEVENT_REDIRECT,	   /* arg is struct netevent_redirect ptr */
 	NETEVENT_DELAY_PROBE_TIME_UPDATE, /* arg is struct neigh_parms ptr */
+	NETEVENT_MULTIPATH_HASH_UPDATE, /* arg is struct net ptr */
 };
 
 int register_netevent_notifier(struct notifier_block *nb);
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 4602af6d5358..8dcc2b185fcc 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -25,6 +25,7 @@
 #include <net/inet_frag.h>
 #include <net/ping.h>
 #include <net/protocol.h>
+#include <net/netevent.h>
 
 static int zero;
 static int one = 1;
@@ -385,6 +386,23 @@ static int proc_tcp_available_ulp(struct ctl_table *ctl,
 	return ret;
 }
 
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+static int proc_fib_multipath_hash_policy(struct ctl_table *table, int write,
+					  void __user *buffer, size_t *lenp,
+					  loff_t *ppos)
+{
+	struct net *net = container_of(table->data, struct net,
+	    ipv4.sysctl_fib_multipath_hash_policy);
+	int ret;
+
+	ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+	if (write && ret == 0)
+		call_netevent_notifiers(NETEVENT_MULTIPATH_HASH_UPDATE, net);
+
+	return ret;
+}
+#endif
+
 static struct ctl_table ipv4_table[] = {
 	{
 		.procname	= "tcp_max_orphans",
@@ -907,7 +925,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.data		= &init_net.ipv4.sysctl_fib_multipath_hash_policy,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
+		.proc_handler	= proc_fib_multipath_hash_policy,
 		.extra1		= &zero,
 		.extra2		= &one,
 	},