linux-stable/net/dsa/switch.c
Vladimir Oltean 338a3a4745 net: dsa: introduce locking for the address lists on CPU and DSA ports
Now that the rtnl_mutex is going away for dsa_port_{host_,}fdb_{add,del},
no one is serializing access to the address lists that DSA keeps for the
purpose of reference counting on shared ports (CPU and cascade ports).

It can happen for one dsa_switch_do_fdb_del to do list_del on a dp->fdbs
element while another dsa_switch_do_fdb_{add,del} is traversing dp->fdbs.
We need to avoid that.

Currently dp->mdbs is not at risk, because dsa_switch_do_mdb_{add,del}
still runs under the rtnl_mutex. But it would be nice if it would not
depend on that being the case. So let's introduce a mutex per port (the
address lists are per port too) and share it between dp->mdbs and
dp->fdbs.

The place where we put the locking is interesting. It could be tempting
to put a DSA-level lock which still serializes calls to
.port_fdb_{add,del}, but it would still not avoid concurrency with other
driver code paths that are currently under rtnl_mutex (.port_fdb_dump,
.port_fast_age). So it would add a very false sense of security (and
adding a global switch-wide lock in DSA to resynchronize with the
rtnl_lock is also counterproductive and hard).

So the locking is intentionally done only where the dp->fdbs and dp->mdbs
lists are traversed. That means, from a driver perspective, that
.port_fdb_add will be called with the dp->addr_lists_lock mutex held on
the CPU port, but not held on user ports. This is done so that driver
writers are not encouraged to rely on any guarantee offered by
dp->addr_lists_lock.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-25 12:59:42 +01:00

813 lines
19 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Handling of a single switch chip, part of a switch fabric
*
* Copyright (c) 2017 Savoir-faire Linux Inc.
* Vivien Didelot <vivien.didelot@savoirfairelinux.com>
*/
#include <linux/if_bridge.h>
#include <linux/netdevice.h>
#include <linux/notifier.h>
#include <linux/if_vlan.h>
#include <net/switchdev.h>
#include "dsa_priv.h"
static unsigned int dsa_switch_fastest_ageing_time(struct dsa_switch *ds,
unsigned int ageing_time)
{
struct dsa_port *dp;
dsa_switch_for_each_port(dp, ds)
if (dp->ageing_time && dp->ageing_time < ageing_time)
ageing_time = dp->ageing_time;
return ageing_time;
}
static int dsa_switch_ageing_time(struct dsa_switch *ds,
struct dsa_notifier_ageing_time_info *info)
{
unsigned int ageing_time = info->ageing_time;
if (ds->ageing_time_min && ageing_time < ds->ageing_time_min)
return -ERANGE;
if (ds->ageing_time_max && ageing_time > ds->ageing_time_max)
return -ERANGE;
/* Program the fastest ageing time in case of multiple bridges */
ageing_time = dsa_switch_fastest_ageing_time(ds, ageing_time);
if (ds->ops->set_ageing_time)
return ds->ops->set_ageing_time(ds, ageing_time);
return 0;
}
static bool dsa_port_mtu_match(struct dsa_port *dp,
struct dsa_notifier_mtu_info *info)
{
if (dp->ds->index == info->sw_index && dp->index == info->port)
return true;
/* Do not propagate to other switches in the tree if the notifier was
* targeted for a single switch.
*/
if (info->targeted_match)
return false;
if (dsa_port_is_dsa(dp) || dsa_port_is_cpu(dp))
return true;
return false;
}
static int dsa_switch_mtu(struct dsa_switch *ds,
struct dsa_notifier_mtu_info *info)
{
struct dsa_port *dp;
int ret;
if (!ds->ops->port_change_mtu)
return -EOPNOTSUPP;
dsa_switch_for_each_port(dp, ds) {
if (dsa_port_mtu_match(dp, info)) {
ret = ds->ops->port_change_mtu(ds, dp->index,
info->mtu);
if (ret)
return ret;
}
}
return 0;
}
static int dsa_switch_bridge_join(struct dsa_switch *ds,
struct dsa_notifier_bridge_info *info)
{
struct dsa_switch_tree *dst = ds->dst;
int err;
if (dst->index == info->tree_index && ds->index == info->sw_index) {
if (!ds->ops->port_bridge_join)
return -EOPNOTSUPP;
err = ds->ops->port_bridge_join(ds, info->port, info->br);
if (err)
return err;
}
if ((dst->index != info->tree_index || ds->index != info->sw_index) &&
ds->ops->crosschip_bridge_join) {
err = ds->ops->crosschip_bridge_join(ds, info->tree_index,
info->sw_index,
info->port, info->br);
if (err)
return err;
}
return dsa_tag_8021q_bridge_join(ds, info);
}
static int dsa_switch_bridge_leave(struct dsa_switch *ds,
struct dsa_notifier_bridge_info *info)
{
struct dsa_switch_tree *dst = ds->dst;
struct netlink_ext_ack extack = {0};
bool change_vlan_filtering = false;
bool vlan_filtering;
struct dsa_port *dp;
int err;
if (dst->index == info->tree_index && ds->index == info->sw_index &&
ds->ops->port_bridge_leave)
ds->ops->port_bridge_leave(ds, info->port, info->br);
if ((dst->index != info->tree_index || ds->index != info->sw_index) &&
ds->ops->crosschip_bridge_leave)
ds->ops->crosschip_bridge_leave(ds, info->tree_index,
info->sw_index, info->port,
info->br);
if (ds->needs_standalone_vlan_filtering && !br_vlan_enabled(info->br)) {
change_vlan_filtering = true;
vlan_filtering = true;
} else if (!ds->needs_standalone_vlan_filtering &&
br_vlan_enabled(info->br)) {
change_vlan_filtering = true;
vlan_filtering = false;
}
/* If the bridge was vlan_filtering, the bridge core doesn't trigger an
* event for changing vlan_filtering setting upon slave ports leaving
* it. That is a good thing, because that lets us handle it and also
* handle the case where the switch's vlan_filtering setting is global
* (not per port). When that happens, the correct moment to trigger the
* vlan_filtering callback is only when the last port leaves the last
* VLAN-aware bridge.
*/
if (change_vlan_filtering && ds->vlan_filtering_is_global) {
dsa_switch_for_each_port(dp, ds) {
struct net_device *bridge_dev;
bridge_dev = dp->bridge_dev;
if (bridge_dev && br_vlan_enabled(bridge_dev)) {
change_vlan_filtering = false;
break;
}
}
}
if (change_vlan_filtering) {
err = dsa_port_vlan_filtering(dsa_to_port(ds, info->port),
vlan_filtering, &extack);
if (extack._msg)
dev_err(ds->dev, "port %d: %s\n", info->port,
extack._msg);
if (err && err != -EOPNOTSUPP)
return err;
}
return dsa_tag_8021q_bridge_leave(ds, info);
}
/* Matches for all upstream-facing ports (the CPU port and all upstream-facing
* DSA links) that sit between the targeted port on which the notifier was
* emitted and its dedicated CPU port.
*/
static bool dsa_port_host_address_match(struct dsa_port *dp,
int info_sw_index, int info_port)
{
struct dsa_port *targeted_dp, *cpu_dp;
struct dsa_switch *targeted_ds;
targeted_ds = dsa_switch_find(dp->ds->dst->index, info_sw_index);
targeted_dp = dsa_to_port(targeted_ds, info_port);
cpu_dp = targeted_dp->cpu_dp;
if (dsa_switch_is_upstream_of(dp->ds, targeted_ds))
return dp->index == dsa_towards_port(dp->ds, cpu_dp->ds->index,
cpu_dp->index);
return false;
}
static struct dsa_mac_addr *dsa_mac_addr_find(struct list_head *addr_list,
const unsigned char *addr,
u16 vid)
{
struct dsa_mac_addr *a;
list_for_each_entry(a, addr_list, list)
if (ether_addr_equal(a->addr, addr) && a->vid == vid)
return a;
return NULL;
}
static int dsa_port_do_mdb_add(struct dsa_port *dp,
const struct switchdev_obj_port_mdb *mdb)
{
struct dsa_switch *ds = dp->ds;
struct dsa_mac_addr *a;
int port = dp->index;
int err = 0;
/* No need to bother with refcounting for user ports */
if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
return ds->ops->port_mdb_add(ds, port, mdb);
mutex_lock(&dp->addr_lists_lock);
a = dsa_mac_addr_find(&dp->mdbs, mdb->addr, mdb->vid);
if (a) {
refcount_inc(&a->refcount);
goto out;
}
a = kzalloc(sizeof(*a), GFP_KERNEL);
if (!a) {
err = -ENOMEM;
goto out;
}
err = ds->ops->port_mdb_add(ds, port, mdb);
if (err) {
kfree(a);
goto out;
}
ether_addr_copy(a->addr, mdb->addr);
a->vid = mdb->vid;
refcount_set(&a->refcount, 1);
list_add_tail(&a->list, &dp->mdbs);
out:
mutex_unlock(&dp->addr_lists_lock);
return err;
}
static int dsa_port_do_mdb_del(struct dsa_port *dp,
const struct switchdev_obj_port_mdb *mdb)
{
struct dsa_switch *ds = dp->ds;
struct dsa_mac_addr *a;
int port = dp->index;
int err = 0;
/* No need to bother with refcounting for user ports */
if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
return ds->ops->port_mdb_del(ds, port, mdb);
mutex_lock(&dp->addr_lists_lock);
a = dsa_mac_addr_find(&dp->mdbs, mdb->addr, mdb->vid);
if (!a) {
err = -ENOENT;
goto out;
}
if (!refcount_dec_and_test(&a->refcount))
goto out;
err = ds->ops->port_mdb_del(ds, port, mdb);
if (err) {
refcount_set(&a->refcount, 1);
goto out;
}
list_del(&a->list);
kfree(a);
out:
mutex_unlock(&dp->addr_lists_lock);
return err;
}
static int dsa_port_do_fdb_add(struct dsa_port *dp, const unsigned char *addr,
u16 vid)
{
struct dsa_switch *ds = dp->ds;
struct dsa_mac_addr *a;
int port = dp->index;
int err = 0;
/* No need to bother with refcounting for user ports */
if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
return ds->ops->port_fdb_add(ds, port, addr, vid);
mutex_lock(&dp->addr_lists_lock);
a = dsa_mac_addr_find(&dp->fdbs, addr, vid);
if (a) {
refcount_inc(&a->refcount);
goto out;
}
a = kzalloc(sizeof(*a), GFP_KERNEL);
if (!a) {
err = -ENOMEM;
goto out;
}
err = ds->ops->port_fdb_add(ds, port, addr, vid);
if (err) {
kfree(a);
goto out;
}
ether_addr_copy(a->addr, addr);
a->vid = vid;
refcount_set(&a->refcount, 1);
list_add_tail(&a->list, &dp->fdbs);
out:
mutex_unlock(&dp->addr_lists_lock);
return err;
}
static int dsa_port_do_fdb_del(struct dsa_port *dp, const unsigned char *addr,
u16 vid)
{
struct dsa_switch *ds = dp->ds;
struct dsa_mac_addr *a;
int port = dp->index;
int err = 0;
/* No need to bother with refcounting for user ports */
if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
return ds->ops->port_fdb_del(ds, port, addr, vid);
mutex_lock(&dp->addr_lists_lock);
a = dsa_mac_addr_find(&dp->fdbs, addr, vid);
if (!a) {
err = -ENOENT;
goto out;
}
if (!refcount_dec_and_test(&a->refcount))
goto out;
err = ds->ops->port_fdb_del(ds, port, addr, vid);
if (err) {
refcount_set(&a->refcount, 1);
goto out;
}
list_del(&a->list);
kfree(a);
out:
mutex_unlock(&dp->addr_lists_lock);
return err;
}
static int dsa_switch_host_fdb_add(struct dsa_switch *ds,
struct dsa_notifier_fdb_info *info)
{
struct dsa_port *dp;
int err = 0;
if (!ds->ops->port_fdb_add)
return -EOPNOTSUPP;
dsa_switch_for_each_port(dp, ds) {
if (dsa_port_host_address_match(dp, info->sw_index,
info->port)) {
err = dsa_port_do_fdb_add(dp, info->addr, info->vid);
if (err)
break;
}
}
return err;
}
static int dsa_switch_host_fdb_del(struct dsa_switch *ds,
struct dsa_notifier_fdb_info *info)
{
struct dsa_port *dp;
int err = 0;
if (!ds->ops->port_fdb_del)
return -EOPNOTSUPP;
dsa_switch_for_each_port(dp, ds) {
if (dsa_port_host_address_match(dp, info->sw_index,
info->port)) {
err = dsa_port_do_fdb_del(dp, info->addr, info->vid);
if (err)
break;
}
}
return err;
}
static int dsa_switch_fdb_add(struct dsa_switch *ds,
struct dsa_notifier_fdb_info *info)
{
int port = dsa_towards_port(ds, info->sw_index, info->port);
struct dsa_port *dp = dsa_to_port(ds, port);
if (!ds->ops->port_fdb_add)
return -EOPNOTSUPP;
return dsa_port_do_fdb_add(dp, info->addr, info->vid);
}
static int dsa_switch_fdb_del(struct dsa_switch *ds,
struct dsa_notifier_fdb_info *info)
{
int port = dsa_towards_port(ds, info->sw_index, info->port);
struct dsa_port *dp = dsa_to_port(ds, port);
if (!ds->ops->port_fdb_del)
return -EOPNOTSUPP;
return dsa_port_do_fdb_del(dp, info->addr, info->vid);
}
static int dsa_switch_hsr_join(struct dsa_switch *ds,
struct dsa_notifier_hsr_info *info)
{
if (ds->index == info->sw_index && ds->ops->port_hsr_join)
return ds->ops->port_hsr_join(ds, info->port, info->hsr);
return -EOPNOTSUPP;
}
static int dsa_switch_hsr_leave(struct dsa_switch *ds,
struct dsa_notifier_hsr_info *info)
{
if (ds->index == info->sw_index && ds->ops->port_hsr_leave)
return ds->ops->port_hsr_leave(ds, info->port, info->hsr);
return -EOPNOTSUPP;
}
static int dsa_switch_lag_change(struct dsa_switch *ds,
struct dsa_notifier_lag_info *info)
{
if (ds->index == info->sw_index && ds->ops->port_lag_change)
return ds->ops->port_lag_change(ds, info->port);
if (ds->index != info->sw_index && ds->ops->crosschip_lag_change)
return ds->ops->crosschip_lag_change(ds, info->sw_index,
info->port);
return 0;
}
static int dsa_switch_lag_join(struct dsa_switch *ds,
struct dsa_notifier_lag_info *info)
{
if (ds->index == info->sw_index && ds->ops->port_lag_join)
return ds->ops->port_lag_join(ds, info->port, info->lag,
info->info);
if (ds->index != info->sw_index && ds->ops->crosschip_lag_join)
return ds->ops->crosschip_lag_join(ds, info->sw_index,
info->port, info->lag,
info->info);
return -EOPNOTSUPP;
}
static int dsa_switch_lag_leave(struct dsa_switch *ds,
struct dsa_notifier_lag_info *info)
{
if (ds->index == info->sw_index && ds->ops->port_lag_leave)
return ds->ops->port_lag_leave(ds, info->port, info->lag);
if (ds->index != info->sw_index && ds->ops->crosschip_lag_leave)
return ds->ops->crosschip_lag_leave(ds, info->sw_index,
info->port, info->lag);
return -EOPNOTSUPP;
}
static int dsa_switch_mdb_add(struct dsa_switch *ds,
struct dsa_notifier_mdb_info *info)
{
int port = dsa_towards_port(ds, info->sw_index, info->port);
struct dsa_port *dp = dsa_to_port(ds, port);
if (!ds->ops->port_mdb_add)
return -EOPNOTSUPP;
return dsa_port_do_mdb_add(dp, info->mdb);
}
static int dsa_switch_mdb_del(struct dsa_switch *ds,
struct dsa_notifier_mdb_info *info)
{
int port = dsa_towards_port(ds, info->sw_index, info->port);
struct dsa_port *dp = dsa_to_port(ds, port);
if (!ds->ops->port_mdb_del)
return -EOPNOTSUPP;
return dsa_port_do_mdb_del(dp, info->mdb);
}
static int dsa_switch_host_mdb_add(struct dsa_switch *ds,
struct dsa_notifier_mdb_info *info)
{
struct dsa_port *dp;
int err = 0;
if (!ds->ops->port_mdb_add)
return -EOPNOTSUPP;
dsa_switch_for_each_port(dp, ds) {
if (dsa_port_host_address_match(dp, info->sw_index,
info->port)) {
err = dsa_port_do_mdb_add(dp, info->mdb);
if (err)
break;
}
}
return err;
}
static int dsa_switch_host_mdb_del(struct dsa_switch *ds,
struct dsa_notifier_mdb_info *info)
{
struct dsa_port *dp;
int err = 0;
if (!ds->ops->port_mdb_del)
return -EOPNOTSUPP;
dsa_switch_for_each_port(dp, ds) {
if (dsa_port_host_address_match(dp, info->sw_index,
info->port)) {
err = dsa_port_do_mdb_del(dp, info->mdb);
if (err)
break;
}
}
return err;
}
static bool dsa_port_vlan_match(struct dsa_port *dp,
struct dsa_notifier_vlan_info *info)
{
if (dp->ds->index == info->sw_index && dp->index == info->port)
return true;
if (dsa_port_is_dsa(dp))
return true;
return false;
}
static int dsa_switch_vlan_add(struct dsa_switch *ds,
struct dsa_notifier_vlan_info *info)
{
struct dsa_port *dp;
int err;
if (!ds->ops->port_vlan_add)
return -EOPNOTSUPP;
dsa_switch_for_each_port(dp, ds) {
if (dsa_port_vlan_match(dp, info)) {
err = ds->ops->port_vlan_add(ds, dp->index, info->vlan,
info->extack);
if (err)
return err;
}
}
return 0;
}
static int dsa_switch_vlan_del(struct dsa_switch *ds,
struct dsa_notifier_vlan_info *info)
{
if (!ds->ops->port_vlan_del)
return -EOPNOTSUPP;
if (ds->index == info->sw_index)
return ds->ops->port_vlan_del(ds, info->port, info->vlan);
/* Do not deprogram the DSA links as they may be used as conduit
* for other VLAN members in the fabric.
*/
return 0;
}
static int dsa_switch_change_tag_proto(struct dsa_switch *ds,
struct dsa_notifier_tag_proto_info *info)
{
const struct dsa_device_ops *tag_ops = info->tag_ops;
struct dsa_port *dp, *cpu_dp;
int err;
if (!ds->ops->change_tag_protocol)
return -EOPNOTSUPP;
ASSERT_RTNL();
dsa_switch_for_each_cpu_port(cpu_dp, ds) {
err = ds->ops->change_tag_protocol(ds, cpu_dp->index,
tag_ops->proto);
if (err)
return err;
dsa_port_set_tag_protocol(cpu_dp, tag_ops);
}
/* Now that changing the tag protocol can no longer fail, let's update
* the remaining bits which are "duplicated for faster access", and the
* bits that depend on the tagger, such as the MTU.
*/
dsa_switch_for_each_user_port(dp, ds) {
struct net_device *slave = dp->slave;
dsa_slave_setup_tagger(slave);
/* rtnl_mutex is held in dsa_tree_change_tag_proto */
dsa_slave_change_mtu(slave, slave->mtu);
}
return 0;
}
static int dsa_switch_mrp_add(struct dsa_switch *ds,
struct dsa_notifier_mrp_info *info)
{
if (!ds->ops->port_mrp_add)
return -EOPNOTSUPP;
if (ds->index == info->sw_index)
return ds->ops->port_mrp_add(ds, info->port, info->mrp);
return 0;
}
static int dsa_switch_mrp_del(struct dsa_switch *ds,
struct dsa_notifier_mrp_info *info)
{
if (!ds->ops->port_mrp_del)
return -EOPNOTSUPP;
if (ds->index == info->sw_index)
return ds->ops->port_mrp_del(ds, info->port, info->mrp);
return 0;
}
static int
dsa_switch_mrp_add_ring_role(struct dsa_switch *ds,
struct dsa_notifier_mrp_ring_role_info *info)
{
if (!ds->ops->port_mrp_add)
return -EOPNOTSUPP;
if (ds->index == info->sw_index)
return ds->ops->port_mrp_add_ring_role(ds, info->port,
info->mrp);
return 0;
}
static int
dsa_switch_mrp_del_ring_role(struct dsa_switch *ds,
struct dsa_notifier_mrp_ring_role_info *info)
{
if (!ds->ops->port_mrp_del)
return -EOPNOTSUPP;
if (ds->index == info->sw_index)
return ds->ops->port_mrp_del_ring_role(ds, info->port,
info->mrp);
return 0;
}
static int dsa_switch_event(struct notifier_block *nb,
unsigned long event, void *info)
{
struct dsa_switch *ds = container_of(nb, struct dsa_switch, nb);
int err;
switch (event) {
case DSA_NOTIFIER_AGEING_TIME:
err = dsa_switch_ageing_time(ds, info);
break;
case DSA_NOTIFIER_BRIDGE_JOIN:
err = dsa_switch_bridge_join(ds, info);
break;
case DSA_NOTIFIER_BRIDGE_LEAVE:
err = dsa_switch_bridge_leave(ds, info);
break;
case DSA_NOTIFIER_FDB_ADD:
err = dsa_switch_fdb_add(ds, info);
break;
case DSA_NOTIFIER_FDB_DEL:
err = dsa_switch_fdb_del(ds, info);
break;
case DSA_NOTIFIER_HOST_FDB_ADD:
err = dsa_switch_host_fdb_add(ds, info);
break;
case DSA_NOTIFIER_HOST_FDB_DEL:
err = dsa_switch_host_fdb_del(ds, info);
break;
case DSA_NOTIFIER_HSR_JOIN:
err = dsa_switch_hsr_join(ds, info);
break;
case DSA_NOTIFIER_HSR_LEAVE:
err = dsa_switch_hsr_leave(ds, info);
break;
case DSA_NOTIFIER_LAG_CHANGE:
err = dsa_switch_lag_change(ds, info);
break;
case DSA_NOTIFIER_LAG_JOIN:
err = dsa_switch_lag_join(ds, info);
break;
case DSA_NOTIFIER_LAG_LEAVE:
err = dsa_switch_lag_leave(ds, info);
break;
case DSA_NOTIFIER_MDB_ADD:
err = dsa_switch_mdb_add(ds, info);
break;
case DSA_NOTIFIER_MDB_DEL:
err = dsa_switch_mdb_del(ds, info);
break;
case DSA_NOTIFIER_HOST_MDB_ADD:
err = dsa_switch_host_mdb_add(ds, info);
break;
case DSA_NOTIFIER_HOST_MDB_DEL:
err = dsa_switch_host_mdb_del(ds, info);
break;
case DSA_NOTIFIER_VLAN_ADD:
err = dsa_switch_vlan_add(ds, info);
break;
case DSA_NOTIFIER_VLAN_DEL:
err = dsa_switch_vlan_del(ds, info);
break;
case DSA_NOTIFIER_MTU:
err = dsa_switch_mtu(ds, info);
break;
case DSA_NOTIFIER_TAG_PROTO:
err = dsa_switch_change_tag_proto(ds, info);
break;
case DSA_NOTIFIER_MRP_ADD:
err = dsa_switch_mrp_add(ds, info);
break;
case DSA_NOTIFIER_MRP_DEL:
err = dsa_switch_mrp_del(ds, info);
break;
case DSA_NOTIFIER_MRP_ADD_RING_ROLE:
err = dsa_switch_mrp_add_ring_role(ds, info);
break;
case DSA_NOTIFIER_MRP_DEL_RING_ROLE:
err = dsa_switch_mrp_del_ring_role(ds, info);
break;
case DSA_NOTIFIER_TAG_8021Q_VLAN_ADD:
err = dsa_switch_tag_8021q_vlan_add(ds, info);
break;
case DSA_NOTIFIER_TAG_8021Q_VLAN_DEL:
err = dsa_switch_tag_8021q_vlan_del(ds, info);
break;
default:
err = -EOPNOTSUPP;
break;
}
if (err)
dev_dbg(ds->dev, "breaking chain for DSA event %lu (%d)\n",
event, err);
return notifier_from_errno(err);
}
int dsa_switch_register_notifier(struct dsa_switch *ds)
{
ds->nb.notifier_call = dsa_switch_event;
return raw_notifier_chain_register(&ds->dst->nh, &ds->nb);
}
void dsa_switch_unregister_notifier(struct dsa_switch *ds)
{
int err;
err = raw_notifier_chain_unregister(&ds->dst->nh, &ds->nb);
if (err)
dev_err(ds->dev, "failed to unregister notifier (%d)\n", err);
}