#ifndef _LINUX_NOTIFIER_H
#define _LINUX_NOTIFIER_H
#include <linux/errno.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/srcu.h>
-struct notifier_block
-{
- int (*notifier_call)(struct notifier_block *self, unsigned long, void *);
+/*
+ * 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 *next;
int priority;
};
+struct atomic_notifier_head {
+ spinlock_t lock;
+ struct notifier_block *head;
+};
+
+struct blocking_notifier_head {
+ struct rw_semaphore rwsem;
+ struct notifier_block *head;
+};
+
+struct raw_notifier_head {
+ struct notifier_block *head;
+};
+
+struct srcu_notifier_head {
+ struct mutex mutex;
+ struct srcu_struct srcu;
+ struct notifier_block *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 notifier_chain_register(struct notifier_block **list, struct notifier_block *n);
-extern int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n);
-extern int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v);
+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 */
+#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)
+{
+ return NOTIFY_STOP_MASK | (NOTIFY_OK - err);
+}
+
+/* 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
#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_BONDING_OLDTYPE 0x000E
+#define NETDEV_BONDING_NEWTYPE 0x000F
+#define NETDEV_POST_INIT 0x0010
+#define NETDEV_UNREGISTER_BATCH 0x0011
#define SYS_DOWN 0x0001 /* Notify of system down */
#define SYS_RESTART SYS_DOWN
#define CPU_DOWN_PREPARE 0x0005 /* CPU (unsigned)v going down */
#define CPU_DOWN_FAILED 0x0006 /* CPU (unsigned)v NOT going down */
#define CPU_DEAD 0x0007 /* CPU (unsigned)v dead */
+#define CPU_DYING 0x0008 /* CPU (unsigned)v not running any task,
+ * not handling interrupts, soon dead.
+ * Called on the dying cpu, interrupts
+ * are already disabled. Must not
+ * sleep, must not fail */
+#define CPU_POST_DEAD 0x0009 /* CPU (unsigned)v dead, cpu_hotplug
+ * lock is dropped */
+#define CPU_STARTING 0x000A /* CPU (unsigned)v soon running.
+ * Called on the new cpu, just before
+ * enabling interrupts. Must not sleep,
+ * must not fail */
+
+/* Used for CPU hotplug events occuring while tasks are frozen due to a suspend
+ * operation in progress
+ */
+#define CPU_TASKS_FROZEN 0x0010
+
+#define CPU_ONLINE_FROZEN (CPU_ONLINE | CPU_TASKS_FROZEN)
+#define CPU_UP_PREPARE_FROZEN (CPU_UP_PREPARE | CPU_TASKS_FROZEN)
+#define CPU_UP_CANCELED_FROZEN (CPU_UP_CANCELED | CPU_TASKS_FROZEN)
+#define CPU_DOWN_PREPARE_FROZEN (CPU_DOWN_PREPARE | CPU_TASKS_FROZEN)
+#define CPU_DOWN_FAILED_FROZEN (CPU_DOWN_FAILED | CPU_TASKS_FROZEN)
+#define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN)
+#define CPU_DYING_FROZEN (CPU_DYING | CPU_TASKS_FROZEN)
+#define CPU_STARTING_FROZEN (CPU_STARTING | CPU_TASKS_FROZEN)
+
+/* 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 */
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