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linux-stable/drivers/net/bonding/bonding.h
Neil Horman e843fa5088 bonding: Fix deadlock in bonding driver resulting from internal locking when using netpoll 
The monitoring paths in the bonding driver take write locks that are shared by
the tx path.  If netconsole is in use, these paths can call printk which puts us
in the netpoll tx path, which, if netconsole is attached to the bonding driver,
result in deadlock (the xmit_lock guards are useless in netpoll_send_skb, as the
monitor paths in the bonding driver don't claim the xmit_lock, nor should they).
The solution is to use a per cpu flag internal to the driver to indicate when a
cpu is holding the lock in a path that might recusrse into the tx path for the
driver via netconsole.  By checking this flag on transmit, we can defer the
sending of the netconsole frames until a later time using the retransmit feature
of netpoll_send_skb that is triggered on the return code NETDEV_TX_BUSY.  I've
tested this and am able to transmit via netconsole while causing failover
conditions on the bond slave links.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-10-18 08:32:07 -07:00

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/*
* Bond several ethernet interfaces into a Cisco, running 'Etherchannel'.
*
* Portions are (c) Copyright 1995 Simon "Guru Aleph-Null" Janes
* NCM: Network and Communications Management, Inc.
*
* BUT, I'm the one who modified it for ethernet, so:
* (c) Copyright 1999, Thomas Davis, tadavis@lbl.gov
*
* This software may be used and distributed according to the terms
* of the GNU Public License, incorporated herein by reference.
*
*/
#ifndef _LINUX_BONDING_H
#define _LINUX_BONDING_H
#include <linux/timer.h>
#include <linux/proc_fs.h>
#include <linux/if_bonding.h>
#include <linux/kobject.h>
#include <linux/cpumask.h>
#include <linux/in6.h>
#include "bond_3ad.h"
#include "bond_alb.h"
#define DRV_VERSION "3.7.0"
#define DRV_RELDATE "June 2, 2010"
#define DRV_NAME "bonding"
#define DRV_DESCRIPTION "Ethernet Channel Bonding Driver"
#define BOND_MAX_ARP_TARGETS 16
#define IS_UP(dev) \
((((dev)->flags & IFF_UP) == IFF_UP) && \
netif_running(dev) && \
netif_carrier_ok(dev))
/*
* Checks whether bond is ready for transmit.
*
* Caller must hold bond->lock
*/
#define BOND_IS_OK(bond) \
(((bond)->dev->flags & IFF_UP) && \
netif_running((bond)->dev) && \
((bond)->slave_cnt > 0))
/*
* Checks whether slave is ready for transmit.
*/
#define SLAVE_IS_OK(slave) \
(((slave)->dev->flags & IFF_UP) && \
netif_running((slave)->dev) && \
((slave)->link == BOND_LINK_UP) && \
((slave)->state == BOND_STATE_ACTIVE))
#define USES_PRIMARY(mode) \
(((mode) == BOND_MODE_ACTIVEBACKUP) || \
((mode) == BOND_MODE_TLB) || \
((mode) == BOND_MODE_ALB))
#define TX_QUEUE_OVERRIDE(mode) \
(((mode) == BOND_MODE_ACTIVEBACKUP) || \
((mode) == BOND_MODE_ROUNDROBIN))
/*
* Less bad way to call ioctl from within the kernel; this needs to be
* done some other way to get the call out of interrupt context.
* Needs "ioctl" variable to be supplied by calling context.
*/
#define IOCTL(dev, arg, cmd) ({ \
int res = 0; \
mm_segment_t fs = get_fs(); \
set_fs(get_ds()); \
res = ioctl(dev, arg, cmd); \
set_fs(fs); \
res; })
/**
* bond_for_each_slave_from - iterate the slaves list from a starting point
* @bond: the bond holding this list.
* @pos: current slave.
* @cnt: counter for max number of moves
* @start: starting point.
*
* Caller must hold bond->lock
*/
#define bond_for_each_slave_from(bond, pos, cnt, start) \
for (cnt = 0, pos = start; \
cnt < (bond)->slave_cnt; \
cnt++, pos = (pos)->next)
/**
* bond_for_each_slave_from_to - iterate the slaves list from start point to stop point
* @bond: the bond holding this list.
* @pos: current slave.
* @cnt: counter for number max of moves
* @start: start point.
* @stop: stop point.
*
* Caller must hold bond->lock
*/
#define bond_for_each_slave_from_to(bond, pos, cnt, start, stop) \
for (cnt = 0, pos = start; \
((cnt < (bond)->slave_cnt) && (pos != (stop)->next)); \
cnt++, pos = (pos)->next)
/**
* bond_for_each_slave - iterate the slaves list from head
* @bond: the bond holding this list.
* @pos: current slave.
* @cnt: counter for max number of moves
*
* Caller must hold bond->lock
*/
#define bond_for_each_slave(bond, pos, cnt) \
bond_for_each_slave_from(bond, pos, cnt, (bond)->first_slave)
#ifdef CONFIG_NET_POLL_CONTROLLER
extern cpumask_var_t netpoll_block_tx;
static inline void block_netpoll_tx(void)
{
preempt_disable();
BUG_ON(cpumask_test_and_set_cpu(smp_processor_id(),
netpoll_block_tx));
}
static inline void unblock_netpoll_tx(void)
{
BUG_ON(!cpumask_test_and_clear_cpu(smp_processor_id(),
netpoll_block_tx));
preempt_enable();
}
static inline int is_netpoll_tx_blocked(struct net_device *dev)
{
if (unlikely(dev->priv_flags & IFF_IN_NETPOLL))
return cpumask_test_cpu(smp_processor_id(), netpoll_block_tx);
return 0;
}
#else
#define block_netpoll_tx()
#define unblock_netpoll_tx()
#define is_netpoll_tx_blocked(dev) (0)
#endif
struct bond_params {
int mode;
int xmit_policy;
int miimon;
int num_grat_arp;
int num_unsol_na;
int arp_interval;
int arp_validate;
int use_carrier;
int fail_over_mac;
int updelay;
int downdelay;
int lacp_fast;
int ad_select;
char primary[IFNAMSIZ];
int primary_reselect;
__be32 arp_targets[BOND_MAX_ARP_TARGETS];
int tx_queues;
int all_slaves_active;
int resend_igmp;
};
struct bond_parm_tbl {
char *modename;
int mode;
};
#define BOND_MAX_MODENAME_LEN 20
struct vlan_entry {
struct list_head vlan_list;
__be32 vlan_ip;
unsigned short vlan_id;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
struct in6_addr vlan_ipv6;
#endif
};
struct slave {
struct net_device *dev; /* first - useful for panic debug */
struct slave *next;
struct slave *prev;
int delay;
unsigned long jiffies;
unsigned long last_arp_rx;
s8 link; /* one of BOND_LINK_XXXX */
s8 new_link;
s8 state; /* one of BOND_STATE_XXXX */
u32 original_mtu;
u32 link_failure_count;
u8 perm_hwaddr[ETH_ALEN];
u16 speed;
u8 duplex;
u16 queue_id;
struct ad_slave_info ad_info; /* HUGE - better to dynamically alloc */
struct tlb_slave_info tlb_info;
};
/*
* Link pseudo-state only used internally by monitors
*/
#define BOND_LINK_NOCHANGE -1
/*
* Here are the locking policies for the two bonding locks:
*
* 1) Get bond->lock when reading/writing slave list.
* 2) Get bond->curr_slave_lock when reading/writing bond->curr_active_slave.
* (It is unnecessary when the write-lock is put with bond->lock.)
* 3) When we lock with bond->curr_slave_lock, we must lock with bond->lock
* beforehand.
*/
struct bonding {
struct net_device *dev; /* first - useful for panic debug */
struct slave *first_slave;
struct slave *curr_active_slave;
struct slave *current_arp_slave;
struct slave *primary_slave;
bool force_primary;
s32 slave_cnt; /* never change this value outside the attach/detach wrappers */
rwlock_t lock;
rwlock_t curr_slave_lock;
s8 kill_timers;
s8 send_grat_arp;
s8 send_unsol_na;
s8 setup_by_slave;
s8 igmp_retrans;
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *proc_entry;
char proc_file_name[IFNAMSIZ];
#endif /* CONFIG_PROC_FS */
struct list_head bond_list;
struct netdev_hw_addr_list mc_list;
int (*xmit_hash_policy)(struct sk_buff *, int);
__be32 master_ip;
u16 flags;
u16 rr_tx_counter;
struct ad_bond_info ad_info;
struct alb_bond_info alb_info;
struct bond_params params;
struct list_head vlan_list;
struct vlan_group *vlgrp;
struct packet_type arp_mon_pt;
struct workqueue_struct *wq;
struct delayed_work mii_work;
struct delayed_work arp_work;
struct delayed_work alb_work;
struct delayed_work ad_work;
struct delayed_work mcast_work;
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
struct in6_addr master_ipv6;
#endif
};
/**
* Returns NULL if the net_device does not belong to any of the bond's slaves
*
* Caller must hold bond lock for read
*/
static inline struct slave *bond_get_slave_by_dev(struct bonding *bond, struct net_device *slave_dev)
{
struct slave *slave = NULL;
int i;
bond_for_each_slave(bond, slave, i) {
if (slave->dev == slave_dev) {
break;
}
}
return slave;
}
static inline struct bonding *bond_get_bond_by_slave(struct slave *slave)
{
if (!slave || !slave->dev->master) {
return NULL;
}
return (struct bonding *)netdev_priv(slave->dev->master);
}
static inline bool bond_is_lb(const struct bonding *bond)
{
return (bond->params.mode == BOND_MODE_TLB ||
bond->params.mode == BOND_MODE_ALB);
}
#define BOND_PRI_RESELECT_ALWAYS 0
#define BOND_PRI_RESELECT_BETTER 1
#define BOND_PRI_RESELECT_FAILURE 2
#define BOND_FOM_NONE 0
#define BOND_FOM_ACTIVE 1
#define BOND_FOM_FOLLOW 2
#define BOND_ARP_VALIDATE_NONE 0
#define BOND_ARP_VALIDATE_ACTIVE (1 << BOND_STATE_ACTIVE)
#define BOND_ARP_VALIDATE_BACKUP (1 << BOND_STATE_BACKUP)
#define BOND_ARP_VALIDATE_ALL (BOND_ARP_VALIDATE_ACTIVE | \
BOND_ARP_VALIDATE_BACKUP)
static inline int slave_do_arp_validate(struct bonding *bond,
struct slave *slave)
{
return bond->params.arp_validate & (1 << slave->state);
}
static inline unsigned long slave_last_rx(struct bonding *bond,
struct slave *slave)
{
if (slave_do_arp_validate(bond, slave))
return slave->last_arp_rx;
return slave->dev->last_rx;
}
static inline void bond_set_slave_inactive_flags(struct slave *slave)
{
struct bonding *bond = netdev_priv(slave->dev->master);
if (!bond_is_lb(bond))
slave->state = BOND_STATE_BACKUP;
if (!bond->params.all_slaves_active)
slave->dev->priv_flags |= IFF_SLAVE_INACTIVE;
if (slave_do_arp_validate(bond, slave))
slave->dev->priv_flags |= IFF_SLAVE_NEEDARP;
}
static inline void bond_set_slave_active_flags(struct slave *slave)
{
slave->state = BOND_STATE_ACTIVE;
slave->dev->priv_flags &= ~(IFF_SLAVE_INACTIVE | IFF_SLAVE_NEEDARP);
}
static inline void bond_set_master_3ad_flags(struct bonding *bond)
{
bond->dev->priv_flags |= IFF_MASTER_8023AD;
}
static inline void bond_unset_master_3ad_flags(struct bonding *bond)
{
bond->dev->priv_flags &= ~IFF_MASTER_8023AD;
}
static inline void bond_set_master_alb_flags(struct bonding *bond)
{
bond->dev->priv_flags |= IFF_MASTER_ALB;
}
static inline void bond_unset_master_alb_flags(struct bonding *bond)
{
bond->dev->priv_flags &= ~IFF_MASTER_ALB;
}
struct vlan_entry *bond_next_vlan(struct bonding *bond, struct vlan_entry *curr);
int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb, struct net_device *slave_dev);
int bond_create(struct net *net, const char *name);
int bond_release_and_destroy(struct net_device *bond_dev, struct net_device *slave_dev);
int bond_create_sysfs(void);
void bond_destroy_sysfs(void);
void bond_prepare_sysfs_group(struct bonding *bond);
int bond_create_slave_symlinks(struct net_device *master, struct net_device *slave);
void bond_destroy_slave_symlinks(struct net_device *master, struct net_device *slave);
int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev);
int bond_release(struct net_device *bond_dev, struct net_device *slave_dev);
void bond_mii_monitor(struct work_struct *);
void bond_loadbalance_arp_mon(struct work_struct *);
void bond_activebackup_arp_mon(struct work_struct *);
void bond_set_mode_ops(struct bonding *bond, int mode);
int bond_parse_parm(const char *mode_arg, const struct bond_parm_tbl *tbl);
void bond_select_active_slave(struct bonding *bond);
void bond_change_active_slave(struct bonding *bond, struct slave *new_active);
void bond_register_arp(struct bonding *);
void bond_unregister_arp(struct bonding *);
struct bond_net {
struct net * net; /* Associated network namespace */
struct list_head dev_list;
#ifdef CONFIG_PROC_FS
struct proc_dir_entry * proc_dir;
#endif
};
/* exported from bond_main.c */
extern int bond_net_id;
extern const struct bond_parm_tbl bond_lacp_tbl[];
extern const struct bond_parm_tbl bond_mode_tbl[];
extern const struct bond_parm_tbl xmit_hashtype_tbl[];
extern const struct bond_parm_tbl arp_validate_tbl[];
extern const struct bond_parm_tbl fail_over_mac_tbl[];
extern const struct bond_parm_tbl pri_reselect_tbl[];
extern struct bond_parm_tbl ad_select_tbl[];
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
void bond_send_unsolicited_na(struct bonding *bond);
void bond_register_ipv6_notifier(void);
void bond_unregister_ipv6_notifier(void);
#else
static inline void bond_send_unsolicited_na(struct bonding *bond)
{
return;
}
static inline void bond_register_ipv6_notifier(void)
{
return;
}
static inline void bond_unregister_ipv6_notifier(void)
{
return;
}
#endif
#endif /* _LINUX_BONDING_H */
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