 e6d265e850
			
		
	
	
	e6d265e850
	
	
	
		
			
			This patch resolves two sets of race conditions. Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com> reported the first, as follows: The bond_close() calls cancel_delayed_work() to cancel delayed works. It, however, cannot cancel works that were already queued in workqueue. The bond_open() initializes work->data, and proccess_one_work() refers get_work_cwq(work)->wq->flags. The get_work_cwq() returns NULL when work->data has been initialized. Thus, a panic occurs. He included a patch that converted the cancel_delayed_work calls in bond_close to flush_delayed_work_sync, which eliminated the above problem. His patch is incorporated, at least in principle, into this patch. In this patch, we use cancel_delayed_work_sync in place of flush_delayed_work_sync, and also convert bond_uninit in addition to bond_close. This conversion to _sync, however, opens new races between bond_close and three periodically executing workqueue functions: bond_mii_monitor, bond_alb_monitor and bond_activebackup_arp_mon. The race occurs because bond_close and bond_uninit are always called with RTNL held, and these workqueue functions may acquire RTNL to perform failover-related activities. If bond_close or bond_uninit is waiting in cancel_delayed_work_sync, deadlock occurs. These deadlocks are resolved by having the workqueue functions acquire RTNL conditionally. If the rtnl_trylock() fails, the functions reschedule and return immediately. For the cases that are attempting to perform link failover, a delay of 1 is used; for the other cases, the normal interval is used (as those activities are not as time critical). Additionally, the bond_mii_monitor function now stores the delay in a variable (mimicing the structure of activebackup_arp_mon). Lastly, all of the above renders the kill_timers sentinel moot, and therefore it has been removed. Tested-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com> Signed-off-by: Jay Vosburgh <fubar@us.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
		
			
				
	
	
		
			450 lines
		
	
	
	
		
			12 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			450 lines
		
	
	
	
		
			12 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Bond several ethernet interfaces into a Cisco, running 'Etherchannel'.
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|  *
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|  * Portions are (c) Copyright 1995 Simon "Guru Aleph-Null" Janes
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|  * NCM: Network and Communications Management, Inc.
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|  *
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|  * BUT, I'm the one who modified it for ethernet, so:
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|  * (c) Copyright 1999, Thomas Davis, tadavis@lbl.gov
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|  *
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|  *	This software may be used and distributed according to the terms
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|  *	of the GNU Public License, incorporated herein by reference.
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|  *
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|  */
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| 
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| #ifndef _LINUX_BONDING_H
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| #define _LINUX_BONDING_H
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| 
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| #include <linux/timer.h>
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| #include <linux/proc_fs.h>
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| #include <linux/if_bonding.h>
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| #include <linux/cpumask.h>
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| #include <linux/in6.h>
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| #include <linux/netpoll.h>
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| #include "bond_3ad.h"
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| #include "bond_alb.h"
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| 
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| #define DRV_VERSION	"3.7.1"
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| #define DRV_RELDATE	"April 27, 2011"
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| #define DRV_NAME	"bonding"
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| #define DRV_DESCRIPTION	"Ethernet Channel Bonding Driver"
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| 
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| #define bond_version DRV_DESCRIPTION ": v" DRV_VERSION " (" DRV_RELDATE ")\n"
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| 
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| #define BOND_MAX_ARP_TARGETS	16
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| 
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| #define IS_UP(dev)					   \
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| 	      ((((dev)->flags & IFF_UP) == IFF_UP)	&& \
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| 	       netif_running(dev)			&& \
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| 	       netif_carrier_ok(dev))
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| 
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| /*
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|  * Checks whether slave is ready for transmit.
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|  */
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| #define SLAVE_IS_OK(slave)			        \
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| 		    (((slave)->dev->flags & IFF_UP)  && \
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| 		     netif_running((slave)->dev)     && \
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| 		     ((slave)->link == BOND_LINK_UP) && \
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| 		     bond_is_active_slave(slave))
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| 
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| 
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| #define USES_PRIMARY(mode)				\
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| 		(((mode) == BOND_MODE_ACTIVEBACKUP) ||	\
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| 		 ((mode) == BOND_MODE_TLB)          ||	\
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| 		 ((mode) == BOND_MODE_ALB))
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| 
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| #define TX_QUEUE_OVERRIDE(mode)				\
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| 			(((mode) == BOND_MODE_ACTIVEBACKUP) ||	\
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| 			 ((mode) == BOND_MODE_ROUNDROBIN))
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| /*
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|  * Less bad way to call ioctl from within the kernel; this needs to be
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|  * done some other way to get the call out of interrupt context.
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|  * Needs "ioctl" variable to be supplied by calling context.
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|  */
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| #define IOCTL(dev, arg, cmd) ({		\
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| 	int res = 0;			\
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| 	mm_segment_t fs = get_fs();	\
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| 	set_fs(get_ds());		\
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| 	res = ioctl(dev, arg, cmd);	\
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| 	set_fs(fs);			\
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| 	res; })
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| 
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| /**
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|  * bond_for_each_slave_from - iterate the slaves list from a starting point
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|  * @bond:	the bond holding this list.
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|  * @pos:	current slave.
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|  * @cnt:	counter for max number of moves
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|  * @start:	starting point.
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|  *
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|  * Caller must hold bond->lock
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|  */
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| #define bond_for_each_slave_from(bond, pos, cnt, start)	\
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| 	for (cnt = 0, pos = start;				\
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| 	     cnt < (bond)->slave_cnt;				\
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|              cnt++, pos = (pos)->next)
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| 
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| /**
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|  * bond_for_each_slave_from_to - iterate the slaves list from start point to stop point
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|  * @bond:	the bond holding this list.
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|  * @pos:	current slave.
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|  * @cnt:	counter for number max of moves
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|  * @start:	start point.
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|  * @stop:	stop point.
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|  *
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|  * Caller must hold bond->lock
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|  */
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| #define bond_for_each_slave_from_to(bond, pos, cnt, start, stop)	\
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| 	for (cnt = 0, pos = start;					\
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| 	     ((cnt < (bond)->slave_cnt) && (pos != (stop)->next));	\
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|              cnt++, pos = (pos)->next)
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| 
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| /**
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|  * bond_for_each_slave - iterate the slaves list from head
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|  * @bond:	the bond holding this list.
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|  * @pos:	current slave.
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|  * @cnt:	counter for max number of moves
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|  *
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|  * Caller must hold bond->lock
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|  */
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| #define bond_for_each_slave(bond, pos, cnt)	\
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| 		bond_for_each_slave_from(bond, pos, cnt, (bond)->first_slave)
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| 
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| 
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| #ifdef CONFIG_NET_POLL_CONTROLLER
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| extern atomic_t netpoll_block_tx;
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| 
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| static inline void block_netpoll_tx(void)
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| {
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| 	atomic_inc(&netpoll_block_tx);
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| }
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| 
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| static inline void unblock_netpoll_tx(void)
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| {
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| 	atomic_dec(&netpoll_block_tx);
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| }
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| 
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| static inline int is_netpoll_tx_blocked(struct net_device *dev)
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| {
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| 	if (unlikely(netpoll_tx_running(dev)))
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| 		return atomic_read(&netpoll_block_tx);
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| 	return 0;
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| }
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| #else
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| #define block_netpoll_tx()
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| #define unblock_netpoll_tx()
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| #define is_netpoll_tx_blocked(dev) (0)
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| #endif
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| 
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| struct bond_params {
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| 	int mode;
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| 	int xmit_policy;
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| 	int miimon;
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| 	u8 num_peer_notif;
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| 	int arp_interval;
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| 	int arp_validate;
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| 	int use_carrier;
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| 	int fail_over_mac;
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| 	int updelay;
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| 	int downdelay;
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| 	int lacp_fast;
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| 	unsigned int min_links;
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| 	int ad_select;
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| 	char primary[IFNAMSIZ];
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| 	int primary_reselect;
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| 	__be32 arp_targets[BOND_MAX_ARP_TARGETS];
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| 	int tx_queues;
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| 	int all_slaves_active;
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| 	int resend_igmp;
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| };
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| 
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| struct bond_parm_tbl {
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| 	char *modename;
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| 	int mode;
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| };
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| 
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| #define BOND_MAX_MODENAME_LEN 20
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| 
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| struct vlan_entry {
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| 	struct list_head vlan_list;
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| 	__be32 vlan_ip;
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| 	unsigned short vlan_id;
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| };
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| 
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| struct slave {
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| 	struct net_device *dev; /* first - useful for panic debug */
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| 	struct slave *next;
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| 	struct slave *prev;
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| 	struct bonding *bond; /* our master */
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| 	int    delay;
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| 	unsigned long jiffies;
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| 	unsigned long last_arp_rx;
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| 	s8     link;    /* one of BOND_LINK_XXXX */
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| 	s8     new_link;
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| 	u8     backup:1,   /* indicates backup slave. Value corresponds with
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| 			      BOND_STATE_ACTIVE and BOND_STATE_BACKUP */
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| 	       inactive:1; /* indicates inactive slave */
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| 	u8     duplex;
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| 	u32    original_mtu;
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| 	u32    link_failure_count;
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| 	u32    speed;
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| 	u16    queue_id;
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| 	u8     perm_hwaddr[ETH_ALEN];
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| 	struct ad_slave_info ad_info; /* HUGE - better to dynamically alloc */
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| 	struct tlb_slave_info tlb_info;
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| #ifdef CONFIG_NET_POLL_CONTROLLER
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| 	struct netpoll *np;
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| #endif
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| };
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| 
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| /*
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|  * Link pseudo-state only used internally by monitors
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|  */
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| #define BOND_LINK_NOCHANGE -1
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| 
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| /*
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|  * Here are the locking policies for the two bonding locks:
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|  *
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|  * 1) Get bond->lock when reading/writing slave list.
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|  * 2) Get bond->curr_slave_lock when reading/writing bond->curr_active_slave.
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|  *    (It is unnecessary when the write-lock is put with bond->lock.)
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|  * 3) When we lock with bond->curr_slave_lock, we must lock with bond->lock
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|  *    beforehand.
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|  */
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| struct bonding {
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| 	struct   net_device *dev; /* first - useful for panic debug */
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| 	struct   slave *first_slave;
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| 	struct   slave *curr_active_slave;
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| 	struct   slave *current_arp_slave;
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| 	struct   slave *primary_slave;
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| 	bool     force_primary;
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| 	s32      slave_cnt; /* never change this value outside the attach/detach wrappers */
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| 	void     (*recv_probe)(struct sk_buff *, struct bonding *,
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| 			       struct slave *);
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| 	rwlock_t lock;
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| 	rwlock_t curr_slave_lock;
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| 	u8	 send_peer_notif;
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| 	s8	 setup_by_slave;
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| 	s8       igmp_retrans;
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| #ifdef CONFIG_PROC_FS
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| 	struct   proc_dir_entry *proc_entry;
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| 	char     proc_file_name[IFNAMSIZ];
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| #endif /* CONFIG_PROC_FS */
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| 	struct   list_head bond_list;
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| 	struct   netdev_hw_addr_list mc_list;
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| 	int      (*xmit_hash_policy)(struct sk_buff *, int);
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| 	__be32   master_ip;
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| 	u16      rr_tx_counter;
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| 	struct   ad_bond_info ad_info;
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| 	struct   alb_bond_info alb_info;
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| 	struct   bond_params params;
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| 	struct   list_head vlan_list;
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| 	struct   workqueue_struct *wq;
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| 	struct   delayed_work mii_work;
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| 	struct   delayed_work arp_work;
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| 	struct   delayed_work alb_work;
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| 	struct   delayed_work ad_work;
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| 	struct   delayed_work mcast_work;
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| #ifdef CONFIG_DEBUG_FS
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| 	/* debugging suport via debugfs */
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| 	struct	 dentry *debug_dir;
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| #endif /* CONFIG_DEBUG_FS */
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| };
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| 
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| static inline bool bond_vlan_used(struct bonding *bond)
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| {
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| 	return !list_empty(&bond->vlan_list);
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| }
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| 
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| #define bond_slave_get_rcu(dev) \
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| 	((struct slave *) rcu_dereference(dev->rx_handler_data))
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| 
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| /**
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|  * Returns NULL if the net_device does not belong to any of the bond's slaves
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|  *
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|  * Caller must hold bond lock for read
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|  */
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| static inline struct slave *bond_get_slave_by_dev(struct bonding *bond,
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| 						  struct net_device *slave_dev)
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| {
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| 	struct slave *slave = NULL;
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| 	int i;
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| 
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| 	bond_for_each_slave(bond, slave, i) {
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| 		if (slave->dev == slave_dev) {
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| 			return slave;
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| 		}
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| 	}
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| 
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| 	return NULL;
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| }
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| 
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| static inline struct bonding *bond_get_bond_by_slave(struct slave *slave)
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| {
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| 	if (!slave || !slave->dev->master) {
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| 		return NULL;
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| 	}
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| 
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| 	return netdev_priv(slave->dev->master);
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| }
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| 
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| static inline bool bond_is_lb(const struct bonding *bond)
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| {
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| 	return (bond->params.mode == BOND_MODE_TLB ||
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| 		bond->params.mode == BOND_MODE_ALB);
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| }
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| 
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| static inline void bond_set_active_slave(struct slave *slave)
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| {
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| 	slave->backup = 0;
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| }
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| 
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| static inline void bond_set_backup_slave(struct slave *slave)
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| {
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| 	slave->backup = 1;
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| }
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| 
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| static inline int bond_slave_state(struct slave *slave)
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| {
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| 	return slave->backup;
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| }
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| 
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| static inline bool bond_is_active_slave(struct slave *slave)
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| {
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| 	return !bond_slave_state(slave);
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| }
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| 
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| #define BOND_PRI_RESELECT_ALWAYS	0
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| #define BOND_PRI_RESELECT_BETTER	1
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| #define BOND_PRI_RESELECT_FAILURE	2
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| 
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| #define BOND_FOM_NONE			0
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| #define BOND_FOM_ACTIVE			1
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| #define BOND_FOM_FOLLOW			2
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| 
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| #define BOND_ARP_VALIDATE_NONE		0
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| #define BOND_ARP_VALIDATE_ACTIVE	(1 << BOND_STATE_ACTIVE)
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| #define BOND_ARP_VALIDATE_BACKUP	(1 << BOND_STATE_BACKUP)
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| #define BOND_ARP_VALIDATE_ALL		(BOND_ARP_VALIDATE_ACTIVE | \
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| 					 BOND_ARP_VALIDATE_BACKUP)
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| 
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| static inline int slave_do_arp_validate(struct bonding *bond,
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| 					struct slave *slave)
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| {
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| 	return bond->params.arp_validate & (1 << bond_slave_state(slave));
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| }
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| 
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| static inline unsigned long slave_last_rx(struct bonding *bond,
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| 					struct slave *slave)
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| {
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| 	if (slave_do_arp_validate(bond, slave))
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| 		return slave->last_arp_rx;
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| 
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| 	return slave->dev->last_rx;
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| }
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| 
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| #ifdef CONFIG_NET_POLL_CONTROLLER
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| static inline void bond_netpoll_send_skb(const struct slave *slave,
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| 					 struct sk_buff *skb)
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| {
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| 	struct netpoll *np = slave->np;
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| 
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| 	if (np)
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| 		netpoll_send_skb(np, skb);
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| }
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| #else
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| static inline void bond_netpoll_send_skb(const struct slave *slave,
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| 					 struct sk_buff *skb)
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| {
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| }
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| #endif
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| 
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| static inline void bond_set_slave_inactive_flags(struct slave *slave)
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| {
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| 	struct bonding *bond = netdev_priv(slave->dev->master);
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| 	if (!bond_is_lb(bond))
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| 		bond_set_backup_slave(slave);
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| 	if (!bond->params.all_slaves_active)
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| 		slave->inactive = 1;
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| }
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| 
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| static inline void bond_set_slave_active_flags(struct slave *slave)
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| {
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| 	bond_set_active_slave(slave);
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| 	slave->inactive = 0;
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| }
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| 
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| static inline bool bond_is_slave_inactive(struct slave *slave)
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| {
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| 	return slave->inactive;
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| }
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| 
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| struct bond_net;
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| 
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| struct vlan_entry *bond_next_vlan(struct bonding *bond, struct vlan_entry *curr);
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| int bond_dev_queue_xmit(struct bonding *bond, struct sk_buff *skb, struct net_device *slave_dev);
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| int bond_create(struct net *net, const char *name);
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| int bond_create_sysfs(struct bond_net *net);
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| void bond_destroy_sysfs(struct bond_net *net);
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| void bond_prepare_sysfs_group(struct bonding *bond);
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| int bond_create_slave_symlinks(struct net_device *master, struct net_device *slave);
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| void bond_destroy_slave_symlinks(struct net_device *master, struct net_device *slave);
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| int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev);
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| int bond_release(struct net_device *bond_dev, struct net_device *slave_dev);
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| void bond_mii_monitor(struct work_struct *);
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| void bond_loadbalance_arp_mon(struct work_struct *);
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| void bond_activebackup_arp_mon(struct work_struct *);
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| void bond_set_mode_ops(struct bonding *bond, int mode);
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| int bond_parse_parm(const char *mode_arg, const struct bond_parm_tbl *tbl);
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| void bond_select_active_slave(struct bonding *bond);
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| void bond_change_active_slave(struct bonding *bond, struct slave *new_active);
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| void bond_create_debugfs(void);
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| void bond_destroy_debugfs(void);
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| void bond_debug_register(struct bonding *bond);
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| void bond_debug_unregister(struct bonding *bond);
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| void bond_debug_reregister(struct bonding *bond);
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| const char *bond_mode_name(int mode);
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| 
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| struct bond_net {
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| 	struct net *		net;	/* Associated network namespace */
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| 	struct list_head	dev_list;
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| #ifdef CONFIG_PROC_FS
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| 	struct proc_dir_entry *	proc_dir;
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| #endif
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| 	struct class_attribute	class_attr_bonding_masters;
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| };
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| 
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| #ifdef CONFIG_PROC_FS
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| void bond_create_proc_entry(struct bonding *bond);
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| void bond_remove_proc_entry(struct bonding *bond);
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| void bond_create_proc_dir(struct bond_net *bn);
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| void bond_destroy_proc_dir(struct bond_net *bn);
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| #else
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| static inline void bond_create_proc_entry(struct bonding *bond)
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| {
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| }
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| 
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| static inline void bond_remove_proc_entry(struct bonding *bond)
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| {
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| }
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| 
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| static inline void bond_create_proc_dir(struct bond_net *bn)
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| {
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| }
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| 
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| static inline void bond_destroy_proc_dir(struct bond_net *bn)
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| {
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| }
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| #endif
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| 
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| 
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| /* exported from bond_main.c */
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| extern int bond_net_id;
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| extern const struct bond_parm_tbl bond_lacp_tbl[];
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| extern const struct bond_parm_tbl bond_mode_tbl[];
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| extern const struct bond_parm_tbl xmit_hashtype_tbl[];
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| extern const struct bond_parm_tbl arp_validate_tbl[];
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| extern const struct bond_parm_tbl fail_over_mac_tbl[];
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| extern const struct bond_parm_tbl pri_reselect_tbl[];
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| extern struct bond_parm_tbl ad_select_tbl[];
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| 
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| #endif /* _LINUX_BONDING_H */
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