Import 2.1.15

[davej-history.git] / drivers / net / eql.c

/*
 * Equalizer Load-balancer for serial network interfaces.
 *
 * (c) Copyright 1995 Simon "Guru Aleph-Null" Janes
 * NCM: Network and Communications Management, Inc.
 *
 *
 * This software may be used and distributed according to the terms
 * of the GNU Public License, incorporated herein by reference.
 * 
 * The author may be reached as simon@ncm.com, or C/O
 * NCM
 * Attn: Simon Janes
 * 6803 Whittier Ave
 * McLean VA 22101
 * Phone: 1-703-847-0040 ext 103
 */

static const char*version =
"Equalizer1996: $Revision: 1.2.1 $ $Date: 1996/09/22 13:52:00 $ Simon Janes (simon@ncm.com)\n";

/*
 * Sources:
 * skeleton.c by Donald Becker.
 * Inspirations:
 * The Harried and Overworked Alan Cox
 * Conspiracies:
 * The Alan Cox and Mike McLagan plot to get someone else to do the code, 
 * which turned out to be me.
 */

/*
 * $Log: eql.c,v $
 * Revision 1.2 1996/04/11 17:51:52 guru
 * Added one-line eql_remove_slave patch.
 *
 * Revision 1.1 1996/04/11 17:44:17 guru
 * Initial revision
 *
 * Revision 3.13 1996/01/21 15:17:18 alan
 * tx_queue_len changes.
 * reformatted.
 *
 * Revision 3.12 1995/03/22 21:07:51 anarchy
 * Added suser() checks on configuration.
 * Moved header file.
 *
 * Revision 3.11 1995/01/19 23:14:31 guru
 * slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
 * (priority_Bps) + bytes_queued * 8;
 *
 * Revision 3.10 1995/01/19 23:07:53 guru
 * back to
 * slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
 * (priority_Bps) + bytes_queued;
 *
 * Revision 3.9 1995/01/19 22:38:20 guru
 * slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
 * (priority_Bps) + bytes_queued * 4;
 *
 * Revision 3.8 1995/01/19 22:30:55 guru
 * slave_load = (ULONG_MAX - (ULONG_MAX / 2)) -
 * (priority_Bps) + bytes_queued * 2;
 *
 * Revision 3.7 1995/01/19 21:52:35 guru
 * printk's trimmed out.
 *
 * Revision 3.6 1995/01/19 21:49:56 guru
 * This is working pretty well. I gained 1 K/s in speed.. now it's just
 * robustness and printk's to be diked out.
 *
 * Revision 3.5 1995/01/18 22:29:59 guru
 * still crashes the kernel when the lock_wait thing is woken up.
 *
 * Revision 3.4 1995/01/18 21:59:47 guru
 * Broken set-bit locking snapshot
 *
 * Revision 3.3 1995/01/17 22:09:18 guru
 * infinite sleep in a lock somewhere..
 *
 * Revision 3.2 1995/01/15 16:46:06 guru
 * Log trimmed of non-pertinent 1.x branch messages
 *
 * Revision 3.1 1995/01/15 14:41:45 guru
 * New Scheduler and timer stuff...
 *
 * Revision 1.15 1995/01/15 14:29:02 guru
 * Will make 1.14 (now 1.15) the 3.0 branch, and the 1.12 the 2.0 branch, the one
 * with the dumber scheduler
 *
 * Revision 1.14 1995/01/15 02:37:08 guru
 * shock.. the kept-new-versions could have zonked working
 * stuff.. shudder
 *
 * Revision 1.13 1995/01/15 02:36:31 guru
 * big changes
 *
 * scheduler was torn out and replaced with something smarter
 *
 * global names not prefixed with eql_ were renamed to protect
 * against namespace collisions
 *
 * a few more abstract interfaces were added to facilitate any
 * potential change of datastructure. the driver is still using
 * a linked list of slaves. going to a heap would be a bit of
 * an overkill.
 *
 * this compiles fine with no warnings.
 *
 * the locking mechanism and timer stuff must be written however,
 * this version will not work otherwise
 *
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/malloc.h>
#include <linux/string.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/uaccess.h>
#include <linux/errno.h> 

#include <linux/netdevice.h>
#include <linux/if.h>
#include <linux/if_arp.h>
#include <linux/timer.h>

#include <linux/if_eql.h>

#ifndef EQL_DEBUG
/* #undef EQL_DEBUG -* print nothing at all, not even a boot-banner */
/* #define EQL_DEBUG 1 -* print only the boot-banner */
/* #define EQL_DEBUG 5 -* print major function entries */
/* #define EQL_DEBUG 20 -* print subfunction entries */
/* #define EQL_DEBUG 50 -* print utility entries */
/* #define EQL_DEBUG 100 -* print voluminous function entries */
#define EQL_DEBUG 1
#endif
static unsigned int eql_debug = EQL_DEBUG;

inteql_init(struct device *dev);/* */
static inteql_open(struct device *dev);/* */
static inteql_close(struct device *dev);/* */
static inteql_ioctl(struct device *dev,struct ifreq *ifr,int cmd);/* */
static inteql_slave_xmit(struct sk_buff *skb,struct device *dev);/* */

static struct enet_statistics *eql_get_stats(struct device *dev);/* */

/* ioctl() handlers
 ---------------- */
static inteql_enslave(struct device *dev, slaving_request_t *srq);/* */
static inteql_emancipate(struct device *dev, slaving_request_t *srq);/* */

static inteql_g_slave_cfg(struct device *dev, slave_config_t *sc);/* */
static inteql_s_slave_cfg(struct device *dev, slave_config_t *sc);/* */

static inteql_g_master_cfg(struct device *dev, master_config_t *mc);/* */
static inteql_s_master_cfg(struct device *dev, master_config_t *mc);/* */

staticinlineinteql_is_slave(struct device *dev);/* */
staticinlineinteql_is_master(struct device *dev);/* */

static slave_t *eql_new_slave(void);/* */
static voideql_delete_slave(slave_t *slave);/* */

/* static long eql_slave_priority(slave_t *slave); -* */
staticinlineinteql_number_slaves(slave_queue_t *queue);/* */

staticinlineinteql_is_empty(slave_queue_t *queue);/* */
staticinlineinteql_is_full(slave_queue_t *queue);/* */

static slave_queue_t *eql_new_slave_queue(struct device *dev);/* */
static voideql_delete_slave_queue(slave_queue_t *queue);/* */

static inteql_insert_slave(slave_queue_t *queue, slave_t *slave);/* */
static slave_t *eql_remove_slave(slave_queue_t *queue, slave_t *slave);/* */

/* static int eql_insert_slave_dev(slave_queue_t *queue, struct device *dev); -* */
static inteql_remove_slave_dev(slave_queue_t *queue,struct device *dev);/* */

staticinlinestruct device *eql_best_slave_dev(slave_queue_t *queue);/* */
staticinline slave_t *eql_best_slave(slave_queue_t *queue);/* */
staticinline slave_t *eql_first_slave(slave_queue_t *queue);/* */
staticinline slave_t *eql_next_slave(slave_queue_t *queue, slave_t *slave);/* */

staticinlinevoideql_set_best_slave(slave_queue_t *queue, slave_t *slave);/* */
staticinlinevoideql_schedule_slaves(slave_queue_t *queue);/* */

static slave_t *eql_find_slave_dev(slave_queue_t *queue,struct device *dev);/* */

/* static inline eql_lock_slave_queue(slave_queue_t *queue); -* */
/* static inline eql_unlock_slave_queue(slave_queue_t *queue); -* */

static voideql_timer(unsigned long param);/* */
\f
/* struct device * interface functions 
 ---------------------------------------------------------
 */

inteql_init(struct device *dev)
{
static unsigned version_printed =0;
/* static unsigned num_masters = 0; */
 equalizer_t *eql =0;
int i;

if( version_printed++ ==0&& eql_debug >0)
printk(version);
/*
 * Initialize the device structure. 
 */
 dev->priv =kmalloc(sizeof(equalizer_t), GFP_KERNEL);
if(dev->priv == NULL)
return-ENOMEM;
memset(dev->priv,0,sizeof(equalizer_t));
 eql = (equalizer_t *) dev->priv;

 eql->stats =kmalloc(sizeof(struct enet_statistics), GFP_KERNEL);
if(eql->stats == NULL)
{
kfree(dev->priv);
 dev->priv = NULL;
return-ENOMEM;
}
memset(eql->stats,0,sizeof(struct enet_statistics));

init_timer(&eql->timer);
 eql->timer.data = (unsigned long) dev->priv;
 eql->timer.expires = jiffies+EQL_DEFAULT_RESCHED_IVAL;
 eql->timer.function = &eql_timer;
 eql->timer_on =0;

 dev->open = eql_open;
 dev->stop = eql_close;
 dev->do_ioctl = eql_ioctl;
 dev->hard_start_xmit = eql_slave_xmit;
 dev->get_stats = eql_get_stats;

/*
 * Fill in the fields of the device structure with 
 * eql-generic values. This should be in a common 
 * file instead of per-driver. 
 */

for(i =0; i < DEV_NUMBUFFS; i++)
skb_queue_head_init(&dev->buffs[i]);

/*
 * Now we undo some of the things that eth_setup does
 * that we don't like 
 */

 dev->mtu = EQL_DEFAULT_MTU;/* set to 576 in eql.h */
 dev->flags = IFF_MASTER;

 dev->family = AF_INET;
 dev->pa_addr =0;
 dev->pa_brdaddr =0;
 dev->pa_mask =0;
 dev->pa_alen =4;

 dev->type = ARPHRD_SLIP;
 dev->tx_queue_len =5;/* Hands them off fast */

return0;
}

static inteql_open(struct device *dev)
{
 equalizer_t *eql = (equalizer_t *) dev->priv;
 slave_queue_t *new_queue;

#ifdef EQL_DEBUG
if(eql_debug >=5)
printk("%s: open\n", dev->name);
#endif

printk("%s: remember to turn off Van-Jacobson compression on your slave devices.\n", dev->name);

 new_queue =eql_new_slave_queue(dev);

if(new_queue !=0)
{
 new_queue->master_dev = dev;
 eql->queue = new_queue;
 eql->queue->lock =0;
 eql->min_slaves =1;
 eql->max_slaves = EQL_DEFAULT_MAX_SLAVES;/* 4 usually... */

printk("%s: adding timer\n", dev->name);
 eql->timer_on =1;
add_timer(&eql->timer);

 MOD_INC_USE_COUNT;
return0;
}
return1;
}


static inteql_close(struct device *dev)
{
 equalizer_t *eql = (equalizer_t *) dev->priv;

#ifdef EQL_DEBUG
if( eql_debug >=5)
printk("%s: close\n", dev->name);
#endif
/*
 * The timer has to be stopped first before we start hacking away
 * at the data structure it scans every so often... 
 */

#ifdef EQL_DEBUG
printk("%s: stopping timer\n", dev->name);
#endif 
 eql->timer_on =0;
del_timer(&eql->timer);

eql_delete_slave_queue(eql->queue);

 MOD_DEC_USE_COUNT;
return0;
}


static inteql_ioctl(struct device *dev,struct ifreq *ifr,int cmd)
{
if(!suser() && cmd!=EQL_GETMASTRCFG && cmd!=EQL_GETSLAVECFG)
return-EPERM;
switch(cmd)
{
case EQL_ENSLAVE:
returneql_enslave(dev, (slaving_request_t *) ifr->ifr_data);
case EQL_EMANCIPATE:
returneql_emancipate(dev, (slaving_request_t *) ifr->ifr_data);
case EQL_GETSLAVECFG:
returneql_g_slave_cfg(dev, (slave_config_t *) ifr->ifr_data);
case EQL_SETSLAVECFG:
returneql_s_slave_cfg(dev, (slave_config_t *) ifr->ifr_data);
case EQL_GETMASTRCFG:
returneql_g_master_cfg(dev, (master_config_t *) ifr->ifr_data);
case EQL_SETMASTRCFG:
returneql_s_master_cfg(dev, (master_config_t *) ifr->ifr_data);
default:
return-EOPNOTSUPP;
}
}


static inteql_slave_xmit(struct sk_buff *skb,struct device *dev)
{
 equalizer_t *eql = (equalizer_t *) dev->priv;
struct device *slave_dev =0;
 slave_t *slave;

if(skb == NULL)
return0;

eql_schedule_slaves(eql->queue);

 slave_dev =eql_best_slave_dev(eql->queue);
 slave =eql_best_slave(eql->queue);

if( slave_dev !=0)
{
#ifdef EQL_DEBUG
if(eql_debug >=100)
printk("%s: %d slaves xmitng %ld B %s\n",
 dev->name,eql_number_slaves(eql->queue), skb->len,
 slave_dev->name);
#endif
 skb->dev = slave_dev;
 skb->priority =1;
dev_queue_xmit(skb);
 eql->stats->tx_packets++;
 slave->bytes_queued += skb->len;
}
else
{
/*
 * The alternative for this is the return 1 and have
 * dev_queue_xmit just queue it up on the eql's queue. 
 */

 eql->stats->tx_dropped++;
dev_kfree_skb(skb, FREE_WRITE);
}
return0;
}


static struct enet_statistics *eql_get_stats(struct device *dev)
{
 equalizer_t *eql = (equalizer_t *) dev->priv;
return eql->stats;
}

/*
 * Private ioctl functions
 */

static inteql_enslave(struct device *dev, slaving_request_t *srqp)
{
struct device *master_dev;
struct device *slave_dev;
 slaving_request_t srq;
int err;

 err =verify_area(VERIFY_READ, (void*)srqp,sizeof(slaving_request_t));
if(err)
{
#ifdef EQL_DEBUG
if(eql_debug >=20)
printk("EQL enslave: error detected by verify_area\n");
#endif 
return err;
}
copy_from_user(&srq, srqp,sizeof(slaving_request_t));

#ifdef EQL_DEBUG
if(eql_debug >=20)
printk("%s: enslave '%s' %ld bps\n", dev->name,
 srq.slave_name, srq.priority);
#endif 
 master_dev = dev;/* for "clarity" */
 slave_dev =dev_get(srq.slave_name);

if(master_dev !=0&& slave_dev !=0)
{
if((master_dev->flags & IFF_UP) == IFF_UP)
{
/*slave is not a master & not already a slave:*/
if(!eql_is_master(slave_dev) &&
!eql_is_slave(slave_dev) )
{
 slave_t *s =eql_new_slave();
 equalizer_t *eql =
(equalizer_t *) master_dev->priv;
 s->dev = slave_dev;
 s->priority = srq.priority;
 s->priority_bps = srq.priority;
 s->priority_Bps = srq.priority /8;
 slave_dev->flags |= IFF_SLAVE;
eql_insert_slave(eql->queue, s);
return0;
}
#ifdef EQL_DEBUG
else if(eql_debug >=20)
printk("EQL enslave: slave is master or slave is already slave\n");
#endif 
}
#ifdef EQL_DEBUG
else if(eql_debug >=20)
printk("EQL enslave: master device not up!\n");
#endif 
}
#ifdef EQL_DEBUG
else if(eql_debug >=20)
printk("EQL enslave: master or slave are NULL");
#endif 
return-EINVAL;
}

static inteql_emancipate(struct device *dev, slaving_request_t *srqp)
{
struct device *master_dev;
struct device *slave_dev;
 slaving_request_t srq;
int err;

 err =verify_area(VERIFY_READ, (void*)srqp,sizeof(slaving_request_t));
if(err)
return err;

copy_from_user(&srq, srqp,sizeof(slaving_request_t));
#ifdef EQL_DEBUG
if(eql_debug >=20)
printk("%s: emancipate `%s`\n", dev->name, srq.slave_name);
#endif
 master_dev = dev;/* for "clarity" */
 slave_dev =dev_get(srq.slave_name);

if(eql_is_slave(slave_dev) )/* really is a slave */
{
 equalizer_t *eql = (equalizer_t *) master_dev->priv;
 slave_dev->flags = slave_dev->flags & ~IFF_SLAVE;
eql_remove_slave_dev(eql->queue, slave_dev);
return0;
}
return-EINVAL;
}


static inteql_g_slave_cfg(struct device *dev, slave_config_t *scp)
{
 slave_t *slave;
 equalizer_t *eql;
struct device *slave_dev;
 slave_config_t sc;
int err;

 err =verify_area(VERIFY_READ, (void*)scp,sizeof(slave_config_t));
if(err)
return err;

copy_from_user(&sc, scp,sizeof(slave_config_t));
#ifdef EQL_DEBUG
if(eql_debug >=20)
printk("%s: get config for slave `%s'\n", dev->name, sc.slave_name);
#endif
 eql = (equalizer_t *) dev->priv;
 slave_dev =dev_get(sc.slave_name);

if(eql_is_slave(slave_dev) )
{
 slave =eql_find_slave_dev(eql->queue, slave_dev);
if(slave !=0)
{
 sc.priority = slave->priority;
 err =verify_area(VERIFY_WRITE, (void*)scp,sizeof(slave_config_t));
if(err)
return err;
copy_to_user(scp, &sc,sizeof(slave_config_t));
return0;
}
}
return-EINVAL;
}


static inteql_s_slave_cfg(struct device *dev, slave_config_t *scp)
{
 slave_t *slave;
 equalizer_t *eql;
struct device *slave_dev;
 slave_config_t sc;
int err;

 err =verify_area(VERIFY_READ, (void*)scp,sizeof(slave_config_t));
if(err)
return err;

#ifdef EQL_DEBUG
if(eql_debug >=20)
printk("%s: set config for slave `%s'\n", dev->name, sc.slave_name);
#endif

copy_from_user(&sc, scp,sizeof(slave_config_t));

 eql = (equalizer_t *) dev->priv;
 slave_dev =dev_get(sc.slave_name);

if(eql_is_slave(slave_dev) )
{
 slave =eql_find_slave_dev(eql->queue, slave_dev);
if(slave !=0)
{
 slave->priority = sc.priority;
 slave->priority_bps = sc.priority;
 slave->priority_Bps = sc.priority /8;
return0;
}
}
return-EINVAL;
}


static inteql_g_master_cfg(struct device *dev, master_config_t *mcp)
{
 equalizer_t *eql;
 master_config_t mc;

#if EQL_DEBUG
if(eql_debug >=20)
printk("%s: get master config\n", dev->name);
#endif

if(eql_is_master(dev) )
{
int err;
 err =verify_area(VERIFY_WRITE, (void*)mcp,sizeof(master_config_t));
if(err)
return err;
 eql = (equalizer_t *) dev->priv;
 mc.max_slaves = eql->max_slaves;
 mc.min_slaves = eql->min_slaves;
copy_to_user(mcp, &mc,sizeof(master_config_t));
return0;
}
return-EINVAL;
}


static inteql_s_master_cfg(struct device *dev, master_config_t *mcp)
{
 equalizer_t *eql;
 master_config_t mc;
int err;

 err =verify_area(VERIFY_READ, (void*)mcp,sizeof(master_config_t));
if(err)
return err;
#if EQL_DEBUG
if(eql_debug >=20)
printk("%s: set master config\n", dev->name);
#endif
copy_from_user(&mc, mcp,sizeof(master_config_t));
if(eql_is_master(dev) )
{
 eql = (equalizer_t *) dev->priv;
 eql->max_slaves = mc.max_slaves;
 eql->min_slaves = mc.min_slaves;
return0;
}
return-EINVAL;
}

/*
 * Private device support functions
 */

staticinlineinteql_is_slave(struct device *dev)
{
if(dev)
{
if((dev->flags & IFF_SLAVE) == IFF_SLAVE)
return1;
}
return0;
}


staticinlineinteql_is_master(struct device *dev)
{
if(dev)
{
if((dev->flags & IFF_MASTER) == IFF_MASTER)
return1;
}
return0;
}


static slave_t *eql_new_slave(void)
{
 slave_t *slave;

 slave = (slave_t *)kmalloc(sizeof(slave_t), GFP_KERNEL);
if(slave)
{
memset(slave,0,sizeof(slave_t));
return slave;
}
return0;
}


static voideql_delete_slave(slave_t *slave)
{
kfree(slave);
}


#if 0/* not currently used, will be used
 when we really use a priority queue */
static longslave_Bps(slave_t *slave)
{
return(slave->priority_Bps);
}

static longslave_bps(slave_t *slave)
{
return(slave->priority_bps);
}

#endif

staticinlineinteql_number_slaves(slave_queue_t *queue)
{
return queue->num_slaves;
}

staticinlineinteql_is_empty(slave_queue_t *queue)
{
if(eql_number_slaves(queue) ==0)
return1;
return0;
}

staticinlineinteql_is_full(slave_queue_t *queue)
{
 equalizer_t *eql = (equalizer_t *) queue->master_dev->priv;

if(eql_number_slaves(queue) == eql->max_slaves)
return1;
return0;
}

static slave_queue_t *eql_new_slave_queue(struct device *dev)
{
 slave_queue_t *queue;
 slave_t *head_slave;
 slave_t *tail_slave;

 queue = (slave_queue_t *)kmalloc(sizeof(slave_queue_t), GFP_KERNEL);
if(queue == NULL)
return0;
memset(queue,0,sizeof(slave_queue_t));
 head_slave =eql_new_slave();
 tail_slave =eql_new_slave();

if( head_slave !=0&&
 tail_slave !=0)
{
 head_slave->next = tail_slave;
 tail_slave->next =0;
 queue->head = head_slave;
 queue->num_slaves =0;
 queue->master_dev = dev;
}
else
{
if(head_slave)
kfree(head_slave);
if(tail_slave)
kfree(tail_slave);
kfree(queue);
return0;
}
return queue;
}


static voideql_delete_slave_queue(slave_queue_t *queue)
{
 slave_t *zapped;
/*
 * This should only be called when there isn't a
 * timer running that scans the data periodically.. 
 * dev_close stops the timer... 
 */

while( !eql_is_empty(queue) )
{
 zapped =eql_remove_slave(queue, queue->head->next);
eql_delete_slave(zapped);
}
kfree(queue->head->next);
kfree(queue->head);
kfree(queue);
}

static inteql_insert_slave(slave_queue_t *queue, slave_t *slave)
{
cli();

if( !eql_is_full(queue) )
{
 slave_t *duplicate_slave =0;
 duplicate_slave =eql_find_slave_dev(queue, slave->dev);
if(duplicate_slave !=0)
{
/* printk ("%s: found a duplicate, killing it and replacing\n",
 queue->master_dev->name); */
eql_delete_slave(eql_remove_slave(queue, duplicate_slave));
}
 slave->next = queue->head->next;
 queue->head->next = slave;
 queue->num_slaves++;
sti();
return0;
}
sti();
return1;
}


static slave_t *eql_remove_slave(slave_queue_t *queue, slave_t *slave)
{
 slave_t *prev;
 slave_t *curr;

cli();

 prev = queue->head;
 curr = queue->head->next;
while(curr != slave &&
 curr->dev !=0)
{
/* printk ("%s: remove_slave; searching...\n", queue->master_dev->name); */
 prev = curr;
 curr = curr->next;
}

if(curr == slave)
{
 prev->next = curr->next;
 queue->num_slaves--;
 curr->dev->flags = curr->dev->flags & ~IFF_SLAVE;
sti();
return curr;
}
sti();
return0;/* not found */
}


static inteql_remove_slave_dev(slave_queue_t *queue,struct device *dev)
{
 slave_t *prev;
 slave_t *curr;
 slave_t *target;

 target =eql_find_slave_dev(queue, dev);

if(target !=0)
{
cli();
 prev = queue->head;
 curr = prev->next;
while(curr != target)
{
 prev = curr;
 curr = curr->next;
}
 prev->next = curr->next;
 queue->num_slaves--;
sti();
eql_delete_slave(curr);
return0;
}
return1;
}


staticinlinestruct device *eql_best_slave_dev(slave_queue_t *queue)
{
if(queue->best_slave !=0)
{
if(queue->best_slave->dev !=0)
return queue->best_slave->dev;
else
return0;
}
else
return0;
}


staticinline slave_t *eql_best_slave(slave_queue_t *queue)
{
return queue->best_slave;
}

staticinlinevoideql_schedule_slaves(slave_queue_t *queue)
{
struct device *master_dev = queue->master_dev;
 slave_t *best_slave =0;
 slave_t *slave_corpse =0;

#ifdef EQL_DEBUG
if(eql_debug >=100)
printk("%s: schedule %d slaves\n",
 master_dev->name,eql_number_slaves(queue));
#endif
if(eql_is_empty(queue) )
{
/*
 * No slaves to play with 
 */
eql_set_best_slave(queue, (slave_t *)0);
return;
}
else
{
/*
 * Make a pass to set the best slave 
 */
unsigned long best_load = (unsigned long) ULONG_MAX;
 slave_t *slave =0;
int i;

cli();
for(i =1, slave =eql_first_slave(queue);
 i <=eql_number_slaves(queue);
 i++, slave =eql_next_slave(queue, slave))
{
/*
 * Go through the slave list once, updating best_slave 
 * whenever a new best_load is found, whenever a dead
 * slave is found, it is marked to be pulled out of the 
 * queue 
 */

unsigned long slave_load;
unsigned long bytes_queued;
unsigned long priority_Bps;

if(slave !=0)
{
 bytes_queued = slave->bytes_queued;
 priority_Bps = slave->priority_Bps;
if( slave->dev !=0)
{
if((slave->dev->flags & IFF_UP) == IFF_UP )
{
 slave_load = (ULONG_MAX - (ULONG_MAX /2)) -
(priority_Bps) + bytes_queued *8;

if(slave_load < best_load)
{
 best_load = slave_load;
 best_slave = slave;
}
}
else/* we found a dead slave */
{
/* 
 * We only bury one slave at a time, if more than
 * one slave dies, we will bury him on the next 
 * reschedule. slaves don't die all at once that 
 * much anyway 
 */
 slave_corpse = slave;
}
}
}
}/* for */
sti();
eql_set_best_slave(queue, best_slave);
}/* else */
if(slave_corpse !=0)
{
printk("eql: scheduler found dead slave, burying...\n");
eql_delete_slave(eql_remove_slave(queue, slave_corpse));
}
return;
}


static slave_t *eql_find_slave_dev(slave_queue_t *queue,struct device *dev)
{
 slave_t *slave =0;
 slave =eql_first_slave(queue);

while(slave !=0&& slave->dev != dev && slave !=0)
{
#if 0
if(slave->dev !=0)
printk("eql: find_slave_dev; looked at '%s'...\n", slave->dev->name);
else
printk("eql: find_slave_dev; looked at nothing...\n");
#endif
 slave = slave->next;
}
return slave;
}
\f

staticinline slave_t *eql_first_slave(slave_queue_t *queue)
{
return queue->head->next;
}


staticinline slave_t *eql_next_slave(slave_queue_t *queue, slave_t *slave)
{
return slave->next;
}

staticinlinevoideql_set_best_slave(slave_queue_t *queue, slave_t *slave)
{
 queue->best_slave = slave;
}

static voideql_timer(unsigned long param)
{
 equalizer_t *eql = (equalizer_t *) param;
 slave_t *slave;
 slave_t *slave_corpse =0;
int i;

if( !eql_is_empty(eql->queue) )
{
cli();
for(i =1, slave =eql_first_slave(eql->queue);
 i <=eql_number_slaves(eql->queue);
 i++, slave =eql_next_slave(eql->queue, slave))
{
if(slave !=0)
{
if((slave->dev->flags & IFF_UP) == IFF_UP )
{
 slave->bytes_queued -= slave->priority_Bps;
if(slave->bytes_queued <0)
 slave->bytes_queued =0;
}
else
 slave_corpse = slave;
}
}
sti();
if(slave_corpse !=0)
{
printk("eql: timer found dead slave, burying...\n");
eql_delete_slave(eql_remove_slave(eql->queue, slave_corpse));
}
}

if(eql->timer_on !=0)
{
 eql->timer.expires = jiffies+EQL_DEFAULT_RESCHED_IVAL;
add_timer(&eql->timer);
}
}

#ifdef MODULE
static struct device dev_eql =
{
"eql",0,0,0,0,0,0,0,0,0, NULL, eql_init 
};

intinit_module(void)
{
if(register_netdev(&dev_eql) !=0) {
printk("eql: register_netdev() returned non-zero.\n");
return-EIO;
}
return0;
}

voidcleanup_module(void)
{
unregister_netdev(&dev_eql);
}
#endif/* MODULE */

/*
 * Local Variables: 
 * compile-command: "gcc -D__KERNEL__ -I/usr/src/linux/net/inet -Wall -Wstrict-prototypes -O6 -m486 -c eql.c"
 * version-control: t
 * kept-new-versions: 20
 * End:
 */