/*
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/*
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* Routines to manage notifier chains for passing status changes to any
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* Routines to manage notifier chains for passing status changes to any
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* interested routines. We need this instead of hard coded call lists so
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* interested routines. We need this instead of hard coded call lists so
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* that modules can poke their nose into the innards. The network devices
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* that modules can poke their nose into the innards. The network devices
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* needed them so here they are for the rest of you.
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* needed them so here they are for the rest of you.
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*
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*
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* Alan Cox <Alan.Cox@linux.org>
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* Alan Cox <Alan.Cox@linux.org>
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*/
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*/
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#ifndef _LINUX_NOTIFIER_H
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#ifndef _LINUX_NOTIFIER_H
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#define _LINUX_NOTIFIER_H
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#define _LINUX_NOTIFIER_H
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#include <linux/errno.h>
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#include <linux/errno.h>
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struct notifier_block
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struct notifier_block
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{
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{
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int (*notifier_call)(struct notifier_block *this, unsigned long, void *);
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int (*notifier_call)(struct notifier_block *this, unsigned long, void *);
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struct notifier_block *next;
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struct notifier_block *next;
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int priority;
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int priority;
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};
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};
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#ifdef __KERNEL__
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#ifdef __KERNEL__
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#define NOTIFY_DONE 0x0000 /* Don't care */
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#define NOTIFY_DONE 0x0000 /* Don't care */
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#define NOTIFY_OK 0x0001 /* Suits me */
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#define NOTIFY_OK 0x0001 /* Suits me */
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#define NOTIFY_STOP_MASK 0x8000 /* Don't call further */
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#define NOTIFY_STOP_MASK 0x8000 /* Don't call further */
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#define NOTIFY_BAD (NOTIFY_STOP_MASK|0x0002) /* Bad/Veto action */
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#define NOTIFY_BAD (NOTIFY_STOP_MASK|0x0002) /* Bad/Veto action */
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extern __inline__ int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
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extern __inline__ int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
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{
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{
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while(*list)
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while(*list)
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{
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{
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if(n->priority > (*list)->priority)
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if(n->priority > (*list)->priority)
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break;
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break;
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list= &((*list)->next);
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list= &((*list)->next);
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}
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}
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n->next = *list;
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n->next = *list;
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*list=n;
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*list=n;
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return 0;
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return 0;
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}
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}
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/*
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/*
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* Warning to any non GPL module writers out there.. these functions are
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* Warning to any non GPL module writers out there.. these functions are
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* GPL'd
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* GPL'd
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*/
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*/
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extern __inline__ int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
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extern __inline__ int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
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{
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{
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while((*nl)!=NULL)
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while((*nl)!=NULL)
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{
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{
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if((*nl)==n)
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if((*nl)==n)
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{
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{
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*nl=n->next;
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*nl=n->next;
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return 0;
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return 0;
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}
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}
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nl=&((*nl)->next);
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nl=&((*nl)->next);
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}
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}
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return -ENOENT;
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return -ENOENT;
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}
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}
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/*
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/*
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* This is one of these things that is generally shorter inline
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* This is one of these things that is generally shorter inline
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*/
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*/
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extern __inline__ int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
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extern __inline__ int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
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{
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{
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int ret=NOTIFY_DONE;
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int ret=NOTIFY_DONE;
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struct notifier_block *nb = *n;
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struct notifier_block *nb = *n;
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while(nb)
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while(nb)
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{
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{
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ret=nb->notifier_call(nb,val,v);
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ret=nb->notifier_call(nb,val,v);
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if(ret&NOTIFY_STOP_MASK)
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if(ret&NOTIFY_STOP_MASK)
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return ret;
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return ret;
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nb=nb->next;
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nb=nb->next;
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}
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}
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return ret;
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return ret;
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}
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}
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/*
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/*
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* Declared notifiers so far. I can imagine quite a few more chains
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* Declared notifiers so far. I can imagine quite a few more chains
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* over time (eg laptop power reset chains, reboot chain (to clean
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* over time (eg laptop power reset chains, reboot chain (to clean
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* device units up), device [un]mount chain, module load/unload chain,
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* device units up), device [un]mount chain, module load/unload chain,
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* low memory chain, screenblank chain (for plug in modular screenblankers)
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* low memory chain, screenblank chain (for plug in modular screenblankers)
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* VC switch chains (for loadable kernel svgalib VC switch helpers) etc...
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* VC switch chains (for loadable kernel svgalib VC switch helpers) etc...
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*/
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*/
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/* netdevice notifier chain */
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/* netdevice notifier chain */
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#define NETDEV_UP 0x0001 /* For now you can't veto a device up/down */
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#define NETDEV_UP 0x0001 /* For now you can't veto a device up/down */
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#define NETDEV_DOWN 0x0002
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#define NETDEV_DOWN 0x0002
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#define NETDEV_REBOOT 0x0003 /* Tell a protocol stack a network interface
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#define NETDEV_REBOOT 0x0003 /* Tell a protocol stack a network interface
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detected a hardware crash and restarted
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detected a hardware crash and restarted
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- we can use this eg to kick tcp sessions
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- we can use this eg to kick tcp sessions
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once done */
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once done */
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#endif
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#endif
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#endif
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#endif
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