| /* |
| * Routines to manage notifier chains for passing status changes to any |
| * interested routines. We need this instead of hard coded call lists so |
| * that modules can poke their nose into the innards. The network devices |
| * needed them so here they are for the rest of you. |
| * |
| * Alan Cox <Alan.Cox@linux.org> |
| */ |
| |
| #ifndef _LINUX_NOTIFIER_H |
| #define _LINUX_NOTIFIER_H |
| #include <linux/errno.h> |
| #include <linux/mutex.h> |
| #include <linux/rwsem.h> |
| #include <linux/srcu.h> |
| |
| /* |
| * Notifier chains are of four types: |
| * |
| * Atomic notifier chains: Chain callbacks run in interrupt/atomic |
| * context. Callouts are not allowed to block. |
| * Blocking notifier chains: Chain callbacks run in process context. |
| * Callouts are allowed to block. |
| * Raw notifier chains: There are no restrictions on callbacks, |
| * registration, or unregistration. All locking and protection |
| * must be provided by the caller. |
| * SRCU notifier chains: A variant of blocking notifier chains, with |
| * the same restrictions. |
| * |
| * atomic_notifier_chain_register() may be called from an atomic context, |
| * but blocking_notifier_chain_register() and srcu_notifier_chain_register() |
| * must be called from a process context. Ditto for the corresponding |
| * _unregister() routines. |
| * |
| * atomic_notifier_chain_unregister(), blocking_notifier_chain_unregister(), |
| * and srcu_notifier_chain_unregister() _must not_ be called from within |
| * the call chain. |
| * |
| * SRCU notifier chains are an alternative form of blocking notifier chains. |
| * They use SRCU (Sleepable Read-Copy Update) instead of rw-semaphores for |
| * protection of the chain links. This means there is _very_ low overhead |
| * in srcu_notifier_call_chain(): no cache bounces and no memory barriers. |
| * As compensation, srcu_notifier_chain_unregister() is rather expensive. |
| * SRCU notifier chains should be used when the chain will be called very |
| * often but notifier_blocks will seldom be removed. Also, SRCU notifier |
| * chains are slightly more difficult to use because they require special |
| * runtime initialization. |
| */ |
| |
| struct notifier_block { |
| int (*notifier_call)(struct notifier_block *, unsigned long, void *); |
| struct notifier_block __rcu *next; |
| int priority; |
| }; |
| |
| struct atomic_notifier_head { |
| spinlock_t lock; |
| struct notifier_block __rcu *head; |
| }; |
| |
| struct blocking_notifier_head { |
| struct rw_semaphore rwsem; |
| struct notifier_block __rcu *head; |
| }; |
| |
| struct raw_notifier_head { |
| struct notifier_block __rcu *head; |
| }; |
| |
| struct srcu_notifier_head { |
| struct mutex mutex; |
| struct srcu_struct srcu; |
| struct notifier_block __rcu *head; |
| }; |
| |
| #define ATOMIC_INIT_NOTIFIER_HEAD(name) do { \ |
| spin_lock_init(&(name)->lock); \ |
| (name)->head = NULL; \ |
| } while (0) |
| #define BLOCKING_INIT_NOTIFIER_HEAD(name) do { \ |
| init_rwsem(&(name)->rwsem); \ |
| (name)->head = NULL; \ |
| } while (0) |
| #define RAW_INIT_NOTIFIER_HEAD(name) do { \ |
| (name)->head = NULL; \ |
| } while (0) |
| |
| /* srcu_notifier_heads must be initialized and cleaned up dynamically */ |
| extern void srcu_init_notifier_head(struct srcu_notifier_head *nh); |
| #define srcu_cleanup_notifier_head(name) \ |
| cleanup_srcu_struct(&(name)->srcu); |
| |
| #define ATOMIC_NOTIFIER_INIT(name) { \ |
| .lock = __SPIN_LOCK_UNLOCKED(name.lock), \ |
| .head = NULL } |
| #define BLOCKING_NOTIFIER_INIT(name) { \ |
| .rwsem = __RWSEM_INITIALIZER((name).rwsem), \ |
| .head = NULL } |
| #define RAW_NOTIFIER_INIT(name) { \ |
| .head = NULL } |
| /* srcu_notifier_heads cannot be initialized statically */ |
| |
| #define ATOMIC_NOTIFIER_HEAD(name) \ |
| struct atomic_notifier_head name = \ |
| ATOMIC_NOTIFIER_INIT(name) |
| #define BLOCKING_NOTIFIER_HEAD(name) \ |
| struct blocking_notifier_head name = \ |
| BLOCKING_NOTIFIER_INIT(name) |
| #define RAW_NOTIFIER_HEAD(name) \ |
| struct raw_notifier_head name = \ |
| RAW_NOTIFIER_INIT(name) |
| |
| #ifdef __KERNEL__ |
| |
| extern int atomic_notifier_chain_register(struct atomic_notifier_head *nh, |
| struct notifier_block *nb); |
| extern int blocking_notifier_chain_register(struct blocking_notifier_head *nh, |
| struct notifier_block *nb); |
| extern int raw_notifier_chain_register(struct raw_notifier_head *nh, |
| struct notifier_block *nb); |
| extern int srcu_notifier_chain_register(struct srcu_notifier_head *nh, |
| struct notifier_block *nb); |
| |
| extern int blocking_notifier_chain_cond_register( |
| struct blocking_notifier_head *nh, |
| struct notifier_block *nb); |
| |
| extern int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh, |
| struct notifier_block *nb); |
| extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh, |
| struct notifier_block *nb); |
| extern int raw_notifier_chain_unregister(struct raw_notifier_head *nh, |
| struct notifier_block *nb); |
| extern int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh, |
| struct notifier_block *nb); |
| |
| extern int atomic_notifier_call_chain(struct atomic_notifier_head *nh, |
| unsigned long val, void *v); |
| extern int __atomic_notifier_call_chain(struct atomic_notifier_head *nh, |
| unsigned long val, void *v, int nr_to_call, int *nr_calls); |
| extern int blocking_notifier_call_chain(struct blocking_notifier_head *nh, |
| unsigned long val, void *v); |
| extern int __blocking_notifier_call_chain(struct blocking_notifier_head *nh, |
| unsigned long val, void *v, int nr_to_call, int *nr_calls); |
| extern int raw_notifier_call_chain(struct raw_notifier_head *nh, |
| unsigned long val, void *v); |
| extern int __raw_notifier_call_chain(struct raw_notifier_head *nh, |
| unsigned long val, void *v, int nr_to_call, int *nr_calls); |
| extern int srcu_notifier_call_chain(struct srcu_notifier_head *nh, |
| unsigned long val, void *v); |
| extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh, |
| unsigned long val, void *v, int nr_to_call, int *nr_calls); |
| |
| #define NOTIFY_DONE 0x0000 /* Don't care */ |
| #define NOTIFY_OK 0x0001 /* Suits me */ |
| #define NOTIFY_STOP_MASK 0x8000 /* Don't call further */ |
| #define NOTIFY_BAD (NOTIFY_STOP_MASK|0x0002) |
| /* Bad/Veto action */ |
| /* |
| * Clean way to return from the notifier and stop further calls. |
| */ |
| #define NOTIFY_STOP (NOTIFY_OK|NOTIFY_STOP_MASK) |
| |
| /* Encapsulate (negative) errno value (in particular, NOTIFY_BAD <=> EPERM). */ |
| static inline int notifier_from_errno(int err) |
| { |
| if (err) |
| return NOTIFY_STOP_MASK | (NOTIFY_OK - err); |
| |
| return NOTIFY_OK; |
| } |
| |
| /* Restore (negative) errno value from notify return value. */ |
| static inline int notifier_to_errno(int ret) |
| { |
| ret &= ~NOTIFY_STOP_MASK; |
| return ret > NOTIFY_OK ? NOTIFY_OK - ret : 0; |
| } |
| |
| /* |
| * Declared notifiers so far. I can imagine quite a few more chains |
| * over time (eg laptop power reset chains, reboot chain (to clean |
| * device units up), device [un]mount chain, module load/unload chain, |
| * low memory chain, screenblank chain (for plug in modular screenblankers) |
| * VC switch chains (for loadable kernel svgalib VC switch helpers) etc... |
| */ |
| |
| /* CPU notfiers are defined in include/linux/cpu.h. */ |
| |
| /* netdevice notifier chain. Please remember to update the rtnetlink |
| * notification exclusion list in rtnetlink_event() when adding new |
| * types. |
| */ |
| #define NETDEV_UP 0x0001 /* For now you can't veto a device up/down */ |
| #define NETDEV_DOWN 0x0002 |
| #define NETDEV_REBOOT 0x0003 /* Tell a protocol stack a network interface |
| detected a hardware crash and restarted |
| - we can use this eg to kick tcp sessions |
| once done */ |
| #define NETDEV_CHANGE 0x0004 /* Notify device state change */ |
| #define NETDEV_REGISTER 0x0005 |
| #define NETDEV_UNREGISTER 0x0006 |
| #define NETDEV_CHANGEMTU 0x0007 |
| #define NETDEV_CHANGEADDR 0x0008 |
| #define NETDEV_GOING_DOWN 0x0009 |
| #define NETDEV_CHANGENAME 0x000A |
| #define NETDEV_FEAT_CHANGE 0x000B |
| #define NETDEV_BONDING_FAILOVER 0x000C |
| #define NETDEV_PRE_UP 0x000D |
| #define NETDEV_PRE_TYPE_CHANGE 0x000E |
| #define NETDEV_POST_TYPE_CHANGE 0x000F |
| #define NETDEV_POST_INIT 0x0010 |
| #define NETDEV_UNREGISTER_BATCH 0x0011 |
| #define NETDEV_RELEASE 0x0012 |
| #define NETDEV_NOTIFY_PEERS 0x0013 |
| #define NETDEV_JOIN 0x0014 |
| |
| #define SYS_DOWN 0x0001 /* Notify of system down */ |
| #define SYS_RESTART SYS_DOWN |
| #define SYS_HALT 0x0002 /* Notify of system halt */ |
| #define SYS_POWER_OFF 0x0003 /* Notify of system power off */ |
| |
| #define NETLINK_URELEASE 0x0001 /* Unicast netlink socket released */ |
| |
| /* Hibernation and suspend events */ |
| #define PM_HIBERNATION_PREPARE 0x0001 /* Going to hibernate */ |
| #define PM_POST_HIBERNATION 0x0002 /* Hibernation finished */ |
| #define PM_SUSPEND_PREPARE 0x0003 /* Going to suspend the system */ |
| #define PM_POST_SUSPEND 0x0004 /* Suspend finished */ |
| #define PM_RESTORE_PREPARE 0x0005 /* Going to restore a saved image */ |
| #define PM_POST_RESTORE 0x0006 /* Restore failed */ |
| |
| /* Console keyboard events. |
| * Note: KBD_KEYCODE is always sent before KBD_UNBOUND_KEYCODE, KBD_UNICODE and |
| * KBD_KEYSYM. */ |
| #define KBD_KEYCODE 0x0001 /* Keyboard keycode, called before any other */ |
| #define KBD_UNBOUND_KEYCODE 0x0002 /* Keyboard keycode which is not bound to any other */ |
| #define KBD_UNICODE 0x0003 /* Keyboard unicode */ |
| #define KBD_KEYSYM 0x0004 /* Keyboard keysym */ |
| #define KBD_POST_KEYSYM 0x0005 /* Called after keyboard keysym interpretation */ |
| |
| extern struct blocking_notifier_head reboot_notifier_list; |
| |
| /* Virtual Terminal events. */ |
| #define VT_ALLOCATE 0x0001 /* Console got allocated */ |
| #define VT_DEALLOCATE 0x0002 /* Console will be deallocated */ |
| #define VT_WRITE 0x0003 /* A char got output */ |
| #define VT_UPDATE 0x0004 /* A bigger update occurred */ |
| #define VT_PREWRITE 0x0005 /* A char is about to be written to the console */ |
| |
| #endif /* __KERNEL__ */ |
| #endif /* _LINUX_NOTIFIER_H */ |