linux/net/hsr/hsr_device.c
Sebastian Andrzej Siewior fd888e85fe net: Write lock dev_base_lock without disabling bottom halves.
The writer acquires dev_base_lock with disabled bottom halves.
The reader can acquire dev_base_lock without disabling bottom halves
because there is no writer in softirq context.

On PREEMPT_RT the softirqs are preemptible and local_bh_disable() acts
as a lock to ensure that resources, that are protected by disabling
bottom halves, remain protected.
This leads to a circular locking dependency if the lock acquired with
disabled bottom halves (as in write_lock_bh()) and somewhere else with
enabled bottom halves (as by read_lock() in netstat_show()) followed by
disabling bottom halves (cxgb_get_stats() -> t4_wr_mbox_meat_timeout()
-> spin_lock_bh()). This is the reverse locking order.

All read_lock() invocation are from sysfs callback which are not invoked
from softirq context. Therefore there is no need to disable bottom
halves while acquiring a write lock.

Acquire the write lock of dev_base_lock without disabling bottom halves.

Reported-by: Pei Zhang <pezhang@redhat.com>
Reported-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-29 12:12:36 +00:00

563 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright 2011-2014 Autronica Fire and Security AS
*
* Author(s):
* 2011-2014 Arvid Brodin, arvid.brodin@alten.se
* This file contains device methods for creating, using and destroying
* virtual HSR or PRP devices.
*/
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/pkt_sched.h>
#include "hsr_device.h"
#include "hsr_slave.h"
#include "hsr_framereg.h"
#include "hsr_main.h"
#include "hsr_forward.h"
static bool is_admin_up(struct net_device *dev)
{
return dev && (dev->flags & IFF_UP);
}
static bool is_slave_up(struct net_device *dev)
{
return dev && is_admin_up(dev) && netif_oper_up(dev);
}
static void __hsr_set_operstate(struct net_device *dev, int transition)
{
write_lock(&dev_base_lock);
if (dev->operstate != transition) {
dev->operstate = transition;
write_unlock(&dev_base_lock);
netdev_state_change(dev);
} else {
write_unlock(&dev_base_lock);
}
}
static void hsr_set_operstate(struct hsr_port *master, bool has_carrier)
{
if (!is_admin_up(master->dev)) {
__hsr_set_operstate(master->dev, IF_OPER_DOWN);
return;
}
if (has_carrier)
__hsr_set_operstate(master->dev, IF_OPER_UP);
else
__hsr_set_operstate(master->dev, IF_OPER_LOWERLAYERDOWN);
}
static bool hsr_check_carrier(struct hsr_port *master)
{
struct hsr_port *port;
ASSERT_RTNL();
hsr_for_each_port(master->hsr, port) {
if (port->type != HSR_PT_MASTER && is_slave_up(port->dev)) {
netif_carrier_on(master->dev);
return true;
}
}
netif_carrier_off(master->dev);
return false;
}
static void hsr_check_announce(struct net_device *hsr_dev,
unsigned char old_operstate)
{
struct hsr_priv *hsr;
hsr = netdev_priv(hsr_dev);
if (hsr_dev->operstate == IF_OPER_UP && old_operstate != IF_OPER_UP) {
/* Went up */
hsr->announce_count = 0;
mod_timer(&hsr->announce_timer,
jiffies + msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL));
}
if (hsr_dev->operstate != IF_OPER_UP && old_operstate == IF_OPER_UP)
/* Went down */
del_timer(&hsr->announce_timer);
}
void hsr_check_carrier_and_operstate(struct hsr_priv *hsr)
{
struct hsr_port *master;
unsigned char old_operstate;
bool has_carrier;
master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
/* netif_stacked_transfer_operstate() cannot be used here since
* it doesn't set IF_OPER_LOWERLAYERDOWN (?)
*/
old_operstate = master->dev->operstate;
has_carrier = hsr_check_carrier(master);
hsr_set_operstate(master, has_carrier);
hsr_check_announce(master->dev, old_operstate);
}
int hsr_get_max_mtu(struct hsr_priv *hsr)
{
unsigned int mtu_max;
struct hsr_port *port;
mtu_max = ETH_DATA_LEN;
hsr_for_each_port(hsr, port)
if (port->type != HSR_PT_MASTER)
mtu_max = min(port->dev->mtu, mtu_max);
if (mtu_max < HSR_HLEN)
return 0;
return mtu_max - HSR_HLEN;
}
static int hsr_dev_change_mtu(struct net_device *dev, int new_mtu)
{
struct hsr_priv *hsr;
hsr = netdev_priv(dev);
if (new_mtu > hsr_get_max_mtu(hsr)) {
netdev_info(dev, "A HSR master's MTU cannot be greater than the smallest MTU of its slaves minus the HSR Tag length (%d octets).\n",
HSR_HLEN);
return -EINVAL;
}
dev->mtu = new_mtu;
return 0;
}
static int hsr_dev_open(struct net_device *dev)
{
struct hsr_priv *hsr;
struct hsr_port *port;
char designation;
hsr = netdev_priv(dev);
designation = '\0';
hsr_for_each_port(hsr, port) {
if (port->type == HSR_PT_MASTER)
continue;
switch (port->type) {
case HSR_PT_SLAVE_A:
designation = 'A';
break;
case HSR_PT_SLAVE_B:
designation = 'B';
break;
default:
designation = '?';
}
if (!is_slave_up(port->dev))
netdev_warn(dev, "Slave %c (%s) is not up; please bring it up to get a fully working HSR network\n",
designation, port->dev->name);
}
if (designation == '\0')
netdev_warn(dev, "No slave devices configured\n");
return 0;
}
static int hsr_dev_close(struct net_device *dev)
{
/* Nothing to do here. */
return 0;
}
static netdev_features_t hsr_features_recompute(struct hsr_priv *hsr,
netdev_features_t features)
{
netdev_features_t mask;
struct hsr_port *port;
mask = features;
/* Mask out all features that, if supported by one device, should be
* enabled for all devices (see NETIF_F_ONE_FOR_ALL).
*
* Anything that's off in mask will not be enabled - so only things
* that were in features originally, and also is in NETIF_F_ONE_FOR_ALL,
* may become enabled.
*/
features &= ~NETIF_F_ONE_FOR_ALL;
hsr_for_each_port(hsr, port)
features = netdev_increment_features(features,
port->dev->features,
mask);
return features;
}
static netdev_features_t hsr_fix_features(struct net_device *dev,
netdev_features_t features)
{
struct hsr_priv *hsr = netdev_priv(dev);
return hsr_features_recompute(hsr, features);
}
static netdev_tx_t hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct hsr_priv *hsr = netdev_priv(dev);
struct hsr_port *master;
master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
if (master) {
skb->dev = master->dev;
skb_reset_mac_header(skb);
skb_reset_mac_len(skb);
hsr_forward_skb(skb, master);
} else {
atomic_long_inc(&dev->tx_dropped);
dev_kfree_skb_any(skb);
}
return NETDEV_TX_OK;
}
static const struct header_ops hsr_header_ops = {
.create = eth_header,
.parse = eth_header_parse,
};
static struct sk_buff *hsr_init_skb(struct hsr_port *master)
{
struct hsr_priv *hsr = master->hsr;
struct sk_buff *skb;
int hlen, tlen;
hlen = LL_RESERVED_SPACE(master->dev);
tlen = master->dev->needed_tailroom;
/* skb size is same for PRP/HSR frames, only difference
* being, for PRP it is a trailer and for HSR it is a
* header
*/
skb = dev_alloc_skb(sizeof(struct hsr_sup_tag) +
sizeof(struct hsr_sup_payload) + hlen + tlen);
if (!skb)
return skb;
skb_reserve(skb, hlen);
skb->dev = master->dev;
skb->priority = TC_PRIO_CONTROL;
if (dev_hard_header(skb, skb->dev, ETH_P_PRP,
hsr->sup_multicast_addr,
skb->dev->dev_addr, skb->len) <= 0)
goto out;
skb_reset_mac_header(skb);
skb_reset_mac_len(skb);
skb_reset_network_header(skb);
skb_reset_transport_header(skb);
return skb;
out:
kfree_skb(skb);
return NULL;
}
static void send_hsr_supervision_frame(struct hsr_port *master,
unsigned long *interval)
{
struct hsr_priv *hsr = master->hsr;
__u8 type = HSR_TLV_LIFE_CHECK;
struct hsr_sup_payload *hsr_sp;
struct hsr_sup_tag *hsr_stag;
unsigned long irqflags;
struct sk_buff *skb;
*interval = msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
if (hsr->announce_count < 3 && hsr->prot_version == 0) {
type = HSR_TLV_ANNOUNCE;
*interval = msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
hsr->announce_count++;
}
skb = hsr_init_skb(master);
if (!skb) {
WARN_ONCE(1, "HSR: Could not send supervision frame\n");
return;
}
hsr_stag = skb_put(skb, sizeof(struct hsr_sup_tag));
set_hsr_stag_path(hsr_stag, (hsr->prot_version ? 0x0 : 0xf));
set_hsr_stag_HSR_ver(hsr_stag, hsr->prot_version);
/* From HSRv1 on we have separate supervision sequence numbers. */
spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
if (hsr->prot_version > 0) {
hsr_stag->sequence_nr = htons(hsr->sup_sequence_nr);
hsr->sup_sequence_nr++;
} else {
hsr_stag->sequence_nr = htons(hsr->sequence_nr);
hsr->sequence_nr++;
}
spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
hsr_stag->tlv.HSR_TLV_type = type;
/* TODO: Why 12 in HSRv0? */
hsr_stag->tlv.HSR_TLV_length = hsr->prot_version ?
sizeof(struct hsr_sup_payload) : 12;
/* Payload: MacAddressA */
hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
ether_addr_copy(hsr_sp->macaddress_A, master->dev->dev_addr);
if (skb_put_padto(skb, ETH_ZLEN))
return;
hsr_forward_skb(skb, master);
return;
}
static void send_prp_supervision_frame(struct hsr_port *master,
unsigned long *interval)
{
struct hsr_priv *hsr = master->hsr;
struct hsr_sup_payload *hsr_sp;
struct hsr_sup_tag *hsr_stag;
unsigned long irqflags;
struct sk_buff *skb;
skb = hsr_init_skb(master);
if (!skb) {
WARN_ONCE(1, "PRP: Could not send supervision frame\n");
return;
}
*interval = msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
hsr_stag = skb_put(skb, sizeof(struct hsr_sup_tag));
set_hsr_stag_path(hsr_stag, (hsr->prot_version ? 0x0 : 0xf));
set_hsr_stag_HSR_ver(hsr_stag, (hsr->prot_version ? 1 : 0));
/* From HSRv1 on we have separate supervision sequence numbers. */
spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
hsr_stag->sequence_nr = htons(hsr->sup_sequence_nr);
hsr->sup_sequence_nr++;
hsr_stag->tlv.HSR_TLV_type = PRP_TLV_LIFE_CHECK_DD;
hsr_stag->tlv.HSR_TLV_length = sizeof(struct hsr_sup_payload);
/* Payload: MacAddressA */
hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
ether_addr_copy(hsr_sp->macaddress_A, master->dev->dev_addr);
if (skb_put_padto(skb, ETH_ZLEN)) {
spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
return;
}
spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
hsr_forward_skb(skb, master);
}
/* Announce (supervision frame) timer function
*/
static void hsr_announce(struct timer_list *t)
{
struct hsr_priv *hsr;
struct hsr_port *master;
unsigned long interval;
hsr = from_timer(hsr, t, announce_timer);
rcu_read_lock();
master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
hsr->proto_ops->send_sv_frame(master, &interval);
if (is_admin_up(master->dev))
mod_timer(&hsr->announce_timer, jiffies + interval);
rcu_read_unlock();
}
void hsr_del_ports(struct hsr_priv *hsr)
{
struct hsr_port *port;
port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_A);
if (port)
hsr_del_port(port);
port = hsr_port_get_hsr(hsr, HSR_PT_SLAVE_B);
if (port)
hsr_del_port(port);
port = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
if (port)
hsr_del_port(port);
}
static const struct net_device_ops hsr_device_ops = {
.ndo_change_mtu = hsr_dev_change_mtu,
.ndo_open = hsr_dev_open,
.ndo_stop = hsr_dev_close,
.ndo_start_xmit = hsr_dev_xmit,
.ndo_fix_features = hsr_fix_features,
};
static struct device_type hsr_type = {
.name = "hsr",
};
static struct hsr_proto_ops hsr_ops = {
.send_sv_frame = send_hsr_supervision_frame,
.create_tagged_frame = hsr_create_tagged_frame,
.get_untagged_frame = hsr_get_untagged_frame,
.drop_frame = hsr_drop_frame,
.fill_frame_info = hsr_fill_frame_info,
.invalid_dan_ingress_frame = hsr_invalid_dan_ingress_frame,
};
static struct hsr_proto_ops prp_ops = {
.send_sv_frame = send_prp_supervision_frame,
.create_tagged_frame = prp_create_tagged_frame,
.get_untagged_frame = prp_get_untagged_frame,
.drop_frame = prp_drop_frame,
.fill_frame_info = prp_fill_frame_info,
.handle_san_frame = prp_handle_san_frame,
.update_san_info = prp_update_san_info,
};
void hsr_dev_setup(struct net_device *dev)
{
eth_hw_addr_random(dev);
ether_setup(dev);
dev->min_mtu = 0;
dev->header_ops = &hsr_header_ops;
dev->netdev_ops = &hsr_device_ops;
SET_NETDEV_DEVTYPE(dev, &hsr_type);
dev->priv_flags |= IFF_NO_QUEUE;
dev->needs_free_netdev = true;
dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA |
NETIF_F_GSO_MASK | NETIF_F_HW_CSUM |
NETIF_F_HW_VLAN_CTAG_TX;
dev->features = dev->hw_features;
/* Prevent recursive tx locking */
dev->features |= NETIF_F_LLTX;
/* VLAN on top of HSR needs testing and probably some work on
* hsr_header_create() etc.
*/
dev->features |= NETIF_F_VLAN_CHALLENGED;
/* Not sure about this. Taken from bridge code. netdev_features.h says
* it means "Does not change network namespaces".
*/
dev->features |= NETIF_F_NETNS_LOCAL;
}
/* Return true if dev is a HSR master; return false otherwise.
*/
bool is_hsr_master(struct net_device *dev)
{
return (dev->netdev_ops->ndo_start_xmit == hsr_dev_xmit);
}
EXPORT_SYMBOL(is_hsr_master);
/* Default multicast address for HSR Supervision frames */
static const unsigned char def_multicast_addr[ETH_ALEN] __aligned(2) = {
0x01, 0x15, 0x4e, 0x00, 0x01, 0x00
};
int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
unsigned char multicast_spec, u8 protocol_version,
struct netlink_ext_ack *extack)
{
bool unregister = false;
struct hsr_priv *hsr;
int res;
hsr = netdev_priv(hsr_dev);
INIT_LIST_HEAD(&hsr->ports);
INIT_LIST_HEAD(&hsr->node_db);
INIT_LIST_HEAD(&hsr->self_node_db);
spin_lock_init(&hsr->list_lock);
eth_hw_addr_set(hsr_dev, slave[0]->dev_addr);
/* initialize protocol specific functions */
if (protocol_version == PRP_V1) {
/* For PRP, lan_id has most significant 3 bits holding
* the net_id of PRP_LAN_ID
*/
hsr->net_id = PRP_LAN_ID << 1;
hsr->proto_ops = &prp_ops;
} else {
hsr->proto_ops = &hsr_ops;
}
/* Make sure we recognize frames from ourselves in hsr_rcv() */
res = hsr_create_self_node(hsr, hsr_dev->dev_addr,
slave[1]->dev_addr);
if (res < 0)
return res;
spin_lock_init(&hsr->seqnr_lock);
/* Overflow soon to find bugs easier: */
hsr->sequence_nr = HSR_SEQNR_START;
hsr->sup_sequence_nr = HSR_SUP_SEQNR_START;
timer_setup(&hsr->announce_timer, hsr_announce, 0);
timer_setup(&hsr->prune_timer, hsr_prune_nodes, 0);
ether_addr_copy(hsr->sup_multicast_addr, def_multicast_addr);
hsr->sup_multicast_addr[ETH_ALEN - 1] = multicast_spec;
hsr->prot_version = protocol_version;
/* Make sure the 1st call to netif_carrier_on() gets through */
netif_carrier_off(hsr_dev);
res = hsr_add_port(hsr, hsr_dev, HSR_PT_MASTER, extack);
if (res)
goto err_add_master;
res = register_netdevice(hsr_dev);
if (res)
goto err_unregister;
unregister = true;
res = hsr_add_port(hsr, slave[0], HSR_PT_SLAVE_A, extack);
if (res)
goto err_unregister;
res = hsr_add_port(hsr, slave[1], HSR_PT_SLAVE_B, extack);
if (res)
goto err_unregister;
hsr_debugfs_init(hsr, hsr_dev);
mod_timer(&hsr->prune_timer, jiffies + msecs_to_jiffies(PRUNE_PERIOD));
return 0;
err_unregister:
hsr_del_ports(hsr);
err_add_master:
hsr_del_self_node(hsr);
if (unregister)
unregister_netdevice(hsr_dev);
return res;
}