include/linux/notifier.h

   1 /*
   2  *      Routines to manage notifier chains for passing status changes to any
   3  *      interested routines. We need this instead of hard coded call lists so
   4  *      that modules can poke their nose into the innards. The network devices
   5  *      needed them so here they are for the rest of you.
   6  *
   7  *                              Alan Cox <Alan.Cox@linux.org>
   8  */
   9
  10 #ifndef _LINUX_NOTIFIER_H
  11 #define _LINUX_NOTIFIER_H
  12 #include <linux/errno.h>
  13
  14 struct notifier_block
  15 {
  16         int (*notifier_call)(struct notifier_block *self, unsigned long, void *);
  17         struct notifier_block *next;
  18         int priority;
  19 };
  20
  21
  22 #ifdef __KERNEL__
  23
  24 extern int notifier_chain_register(struct notifier_block **list, struct notifier_block *n);
  25 extern int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n);
  26 extern int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v);
  27
  28 #define NOTIFY_DONE             0x0000          /* Don't care */
  29 #define NOTIFY_OK               0x0001          /* Suits me */
  30 #define NOTIFY_STOP_MASK        0x8000          /* Don't call further */
  31 #define NOTIFY_BAD              (NOTIFY_STOP_MASK|0x0002)       /* Bad/Veto action      */
  32
  33 /*
  34  *      Declared notifiers so far. I can imagine quite a few more chains
  35  *      over time (eg laptop power reset chains, reboot chain (to clean
  36  *      device units up), device [un]mount chain, module load/unload chain,
  37  *      low memory chain, screenblank chain (for plug in modular screenblankers)
  38  *      VC switch chains (for loadable kernel svgalib VC switch helpers) etc...
  39  */
  40
  41 /* netdevice notifier chain */
  42 #define NETDEV_UP       0x0001  /* For now you can't veto a device up/down */
  43 #define NETDEV_DOWN     0x0002
  44 #define NETDEV_REBOOT   0x0003  /* Tell a protocol stack a network interface
  45                                    detected a hardware crash and restarted
  46                                    - we can use this eg to kick tcp sessions
  47                                    once done */
  48 #define NETDEV_CHANGE   0x0004  /* Notify device state change */
  49 #define NETDEV_REGISTER 0x0005
  50 #define NETDEV_UNREGISTER       0x0006
  51 #define NETDEV_CHANGEMTU        0x0007
  52 #define NETDEV_CHANGEADDR       0x0008
  53 #define NETDEV_GOING_DOWN       0x0009
  54 #define NETDEV_CHANGENAME       0x000A
  55
  56 #define SYS_DOWN        0x0001  /* Notify of system down */
  57 #define SYS_RESTART     SYS_DOWN
  58 #define SYS_HALT        0x0002  /* Notify of system halt */
  59 #define SYS_POWER_OFF   0x0003  /* Notify of system power off */
  60
  61 #endif /* __KERNEL__ */
  62 #endif /* _LINUX_NOTIFIER_H */