linux_dsm_epyc7002/net/core/link_watch.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

249 lines
5.3 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linux network device link state notification
*
* Author:
* Stefan Rompf <sux@loplof.de>
*/
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/if.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <linux/rtnetlink.h>
#include <linux/jiffies.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/bitops.h>
#include <linux/types.h>
enum lw_bits {
LW_URGENT = 0,
};
static unsigned long linkwatch_flags;
static unsigned long linkwatch_nextevent;
static void linkwatch_event(struct work_struct *dummy);
static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event);
static LIST_HEAD(lweventlist);
static DEFINE_SPINLOCK(lweventlist_lock);
static unsigned char default_operstate(const struct net_device *dev)
{
if (!netif_carrier_ok(dev))
return (dev->ifindex != dev_get_iflink(dev) ?
IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN);
if (netif_dormant(dev))
return IF_OPER_DORMANT;
return IF_OPER_UP;
}
static void rfc2863_policy(struct net_device *dev)
{
unsigned char operstate = default_operstate(dev);
if (operstate == dev->operstate)
return;
write_lock_bh(&dev_base_lock);
switch(dev->link_mode) {
case IF_LINK_MODE_DORMANT:
if (operstate == IF_OPER_UP)
operstate = IF_OPER_DORMANT;
break;
case IF_LINK_MODE_DEFAULT:
default:
break;
}
dev->operstate = operstate;
write_unlock_bh(&dev_base_lock);
}
void linkwatch_init_dev(struct net_device *dev)
{
/* Handle pre-registration link state changes */
if (!netif_carrier_ok(dev) || netif_dormant(dev))
rfc2863_policy(dev);
}
static bool linkwatch_urgent_event(struct net_device *dev)
{
if (!netif_running(dev))
return false;
if (dev->ifindex != dev_get_iflink(dev))
return true;
if (netif_is_lag_port(dev) || netif_is_lag_master(dev))
return true;
return netif_carrier_ok(dev) && qdisc_tx_changing(dev);
}
static void linkwatch_add_event(struct net_device *dev)
{
unsigned long flags;
spin_lock_irqsave(&lweventlist_lock, flags);
if (list_empty(&dev->link_watch_list)) {
list_add_tail(&dev->link_watch_list, &lweventlist);
dev_hold(dev);
}
spin_unlock_irqrestore(&lweventlist_lock, flags);
}
static void linkwatch_schedule_work(int urgent)
{
unsigned long delay = linkwatch_nextevent - jiffies;
if (test_bit(LW_URGENT, &linkwatch_flags))
return;
/* Minimise down-time: drop delay for up event. */
if (urgent) {
if (test_and_set_bit(LW_URGENT, &linkwatch_flags))
return;
delay = 0;
}
/* If we wrap around we'll delay it by at most HZ. */
if (delay > HZ)
delay = 0;
/*
* If urgent, schedule immediate execution; otherwise, don't
* override the existing timer.
*/
if (test_bit(LW_URGENT, &linkwatch_flags))
mod_delayed_work(system_wq, &linkwatch_work, 0);
else
schedule_delayed_work(&linkwatch_work, delay);
}
static void linkwatch_do_dev(struct net_device *dev)
{
/*
* Make sure the above read is complete since it can be
* rewritten as soon as we clear the bit below.
*/
smp_mb__before_atomic();
/* We are about to handle this device,
* so new events can be accepted
*/
clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
rfc2863_policy(dev);
if (dev->flags & IFF_UP && netif_device_present(dev)) {
if (netif_carrier_ok(dev))
dev_activate(dev);
else
dev_deactivate(dev);
netdev_state_change(dev);
}
dev_put(dev);
}
static void __linkwatch_run_queue(int urgent_only)
{
struct net_device *dev;
LIST_HEAD(wrk);
/*
* Limit the number of linkwatch events to one
* per second so that a runaway driver does not
* cause a storm of messages on the netlink
* socket. This limit does not apply to up events
* while the device qdisc is down.
*/
if (!urgent_only)
linkwatch_nextevent = jiffies + HZ;
/* Limit wrap-around effect on delay. */
else if (time_after(linkwatch_nextevent, jiffies + HZ))
linkwatch_nextevent = jiffies;
clear_bit(LW_URGENT, &linkwatch_flags);
spin_lock_irq(&lweventlist_lock);
list_splice_init(&lweventlist, &wrk);
while (!list_empty(&wrk)) {
dev = list_first_entry(&wrk, struct net_device, link_watch_list);
list_del_init(&dev->link_watch_list);
if (urgent_only && !linkwatch_urgent_event(dev)) {
list_add_tail(&dev->link_watch_list, &lweventlist);
continue;
}
spin_unlock_irq(&lweventlist_lock);
linkwatch_do_dev(dev);
spin_lock_irq(&lweventlist_lock);
}
if (!list_empty(&lweventlist))
linkwatch_schedule_work(0);
spin_unlock_irq(&lweventlist_lock);
}
void linkwatch_forget_dev(struct net_device *dev)
{
unsigned long flags;
int clean = 0;
spin_lock_irqsave(&lweventlist_lock, flags);
if (!list_empty(&dev->link_watch_list)) {
list_del_init(&dev->link_watch_list);
clean = 1;
}
spin_unlock_irqrestore(&lweventlist_lock, flags);
if (clean)
linkwatch_do_dev(dev);
}
/* Must be called with the rtnl semaphore held */
void linkwatch_run_queue(void)
{
__linkwatch_run_queue(0);
}
static void linkwatch_event(struct work_struct *dummy)
{
rtnl_lock();
__linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies));
rtnl_unlock();
}
void linkwatch_fire_event(struct net_device *dev)
{
bool urgent = linkwatch_urgent_event(dev);
if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) {
linkwatch_add_event(dev);
} else if (!urgent)
return;
linkwatch_schedule_work(urgent);
}
EXPORT_SYMBOL(linkwatch_fire_event);