From fe9d4f576324999ac521c931f3b3eee0c8e45544 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Thu, 18 Oct 2007 23:39:16 -0700 Subject: Add kernel/notifier.c There is separate notifier header, but no separate notifier .c file. Extract notifier code out of kernel/sys.c which will remain for misc syscalls I hope. Merge kernel/die_notifier.c into kernel/notifier.c. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sys.c | 531 ----------------------------------------------------------- 1 file changed, 531 deletions(-) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index bc8879c822a..b8fcbc64019 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -106,537 +106,6 @@ EXPORT_SYMBOL(cad_pid); void (*pm_power_off_prepare)(void); -/* - * Notifier list for kernel code which wants to be called - * at shutdown. This is used to stop any idling DMA operations - * and the like. - */ - -static BLOCKING_NOTIFIER_HEAD(reboot_notifier_list); - -/* - * Notifier chain core routines. The exported routines below - * are layered on top of these, with appropriate locking added. - */ - -static int notifier_chain_register(struct notifier_block **nl, - struct notifier_block *n) -{ - while ((*nl) != NULL) { - if (n->priority > (*nl)->priority) - break; - nl = &((*nl)->next); - } - n->next = *nl; - rcu_assign_pointer(*nl, n); - return 0; -} - -static int notifier_chain_unregister(struct notifier_block **nl, - struct notifier_block *n) -{ - while ((*nl) != NULL) { - if ((*nl) == n) { - rcu_assign_pointer(*nl, n->next); - return 0; - } - nl = &((*nl)->next); - } - return -ENOENT; -} - -/** - * notifier_call_chain - Informs the registered notifiers about an event. - * @nl: Pointer to head of the blocking notifier chain - * @val: Value passed unmodified to notifier function - * @v: Pointer passed unmodified to notifier function - * @nr_to_call: Number of notifier functions to be called. Don't care - * value of this parameter is -1. - * @nr_calls: Records the number of notifications sent. Don't care - * value of this field is NULL. - * @returns: notifier_call_chain returns the value returned by the - * last notifier function called. - */ - -static int __kprobes notifier_call_chain(struct notifier_block **nl, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) -{ - int ret = NOTIFY_DONE; - struct notifier_block *nb, *next_nb; - - nb = rcu_dereference(*nl); - - while (nb && nr_to_call) { - next_nb = rcu_dereference(nb->next); - ret = nb->notifier_call(nb, val, v); - - if (nr_calls) - (*nr_calls)++; - - if ((ret & NOTIFY_STOP_MASK) == NOTIFY_STOP_MASK) - break; - nb = next_nb; - nr_to_call--; - } - return ret; -} - -/* - * Atomic notifier chain routines. Registration and unregistration - * use a spinlock, and call_chain is synchronized by RCU (no locks). - */ - -/** - * atomic_notifier_chain_register - Add notifier to an atomic notifier chain - * @nh: Pointer to head of the atomic notifier chain - * @n: New entry in notifier chain - * - * Adds a notifier to an atomic notifier chain. - * - * Currently always returns zero. - */ - -int atomic_notifier_chain_register(struct atomic_notifier_head *nh, - struct notifier_block *n) -{ - unsigned long flags; - int ret; - - spin_lock_irqsave(&nh->lock, flags); - ret = notifier_chain_register(&nh->head, n); - spin_unlock_irqrestore(&nh->lock, flags); - return ret; -} - -EXPORT_SYMBOL_GPL(atomic_notifier_chain_register); - -/** - * atomic_notifier_chain_unregister - Remove notifier from an atomic notifier chain - * @nh: Pointer to head of the atomic notifier chain - * @n: Entry to remove from notifier chain - * - * Removes a notifier from an atomic notifier chain. - * - * Returns zero on success or %-ENOENT on failure. - */ -int atomic_notifier_chain_unregister(struct atomic_notifier_head *nh, - struct notifier_block *n) -{ - unsigned long flags; - int ret; - - spin_lock_irqsave(&nh->lock, flags); - ret = notifier_chain_unregister(&nh->head, n); - spin_unlock_irqrestore(&nh->lock, flags); - synchronize_rcu(); - return ret; -} - -EXPORT_SYMBOL_GPL(atomic_notifier_chain_unregister); - -/** - * __atomic_notifier_call_chain - Call functions in an atomic notifier chain - * @nh: Pointer to head of the atomic notifier chain - * @val: Value passed unmodified to notifier function - * @v: Pointer passed unmodified to notifier function - * @nr_to_call: See the comment for notifier_call_chain. - * @nr_calls: See the comment for notifier_call_chain. - * - * Calls each function in a notifier chain in turn. The functions - * run in an atomic context, so they must not block. - * This routine uses RCU to synchronize with changes to the chain. - * - * If the return value of the notifier can be and'ed - * with %NOTIFY_STOP_MASK then atomic_notifier_call_chain() - * will return immediately, with the return value of - * the notifier function which halted execution. - * Otherwise the return value is the return value - * of the last notifier function called. - */ - -int __kprobes __atomic_notifier_call_chain(struct atomic_notifier_head *nh, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) -{ - int ret; - - rcu_read_lock(); - ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); - rcu_read_unlock(); - return ret; -} - -EXPORT_SYMBOL_GPL(__atomic_notifier_call_chain); - -int __kprobes atomic_notifier_call_chain(struct atomic_notifier_head *nh, - unsigned long val, void *v) -{ - return __atomic_notifier_call_chain(nh, val, v, -1, NULL); -} - -EXPORT_SYMBOL_GPL(atomic_notifier_call_chain); -/* - * Blocking notifier chain routines. All access to the chain is - * synchronized by an rwsem. - */ - -/** - * blocking_notifier_chain_register - Add notifier to a blocking notifier chain - * @nh: Pointer to head of the blocking notifier chain - * @n: New entry in notifier chain - * - * Adds a notifier to a blocking notifier chain. - * Must be called in process context. - * - * Currently always returns zero. - */ - -int blocking_notifier_chain_register(struct blocking_notifier_head *nh, - struct notifier_block *n) -{ - int ret; - - /* - * This code gets used during boot-up, when task switching is - * not yet working and interrupts must remain disabled. At - * such times we must not call down_write(). - */ - if (unlikely(system_state == SYSTEM_BOOTING)) - return notifier_chain_register(&nh->head, n); - - down_write(&nh->rwsem); - ret = notifier_chain_register(&nh->head, n); - up_write(&nh->rwsem); - return ret; -} - -EXPORT_SYMBOL_GPL(blocking_notifier_chain_register); - -/** - * blocking_notifier_chain_unregister - Remove notifier from a blocking notifier chain - * @nh: Pointer to head of the blocking notifier chain - * @n: Entry to remove from notifier chain - * - * Removes a notifier from a blocking notifier chain. - * Must be called from process context. - * - * Returns zero on success or %-ENOENT on failure. - */ -int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh, - struct notifier_block *n) -{ - int ret; - - /* - * This code gets used during boot-up, when task switching is - * not yet working and interrupts must remain disabled. At - * such times we must not call down_write(). - */ - if (unlikely(system_state == SYSTEM_BOOTING)) - return notifier_chain_unregister(&nh->head, n); - - down_write(&nh->rwsem); - ret = notifier_chain_unregister(&nh->head, n); - up_write(&nh->rwsem); - return ret; -} - -EXPORT_SYMBOL_GPL(blocking_notifier_chain_unregister); - -/** - * __blocking_notifier_call_chain - Call functions in a blocking notifier chain - * @nh: Pointer to head of the blocking notifier chain - * @val: Value passed unmodified to notifier function - * @v: Pointer passed unmodified to notifier function - * @nr_to_call: See comment for notifier_call_chain. - * @nr_calls: See comment for notifier_call_chain. - * - * Calls each function in a notifier chain in turn. The functions - * run in a process context, so they are allowed to block. - * - * If the return value of the notifier can be and'ed - * with %NOTIFY_STOP_MASK then blocking_notifier_call_chain() - * will return immediately, with the return value of - * the notifier function which halted execution. - * Otherwise the return value is the return value - * of the last notifier function called. - */ - -int __blocking_notifier_call_chain(struct blocking_notifier_head *nh, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) -{ - int ret = NOTIFY_DONE; - - /* - * We check the head outside the lock, but if this access is - * racy then it does not matter what the result of the test - * is, we re-check the list after having taken the lock anyway: - */ - if (rcu_dereference(nh->head)) { - down_read(&nh->rwsem); - ret = notifier_call_chain(&nh->head, val, v, nr_to_call, - nr_calls); - up_read(&nh->rwsem); - } - return ret; -} -EXPORT_SYMBOL_GPL(__blocking_notifier_call_chain); - -int blocking_notifier_call_chain(struct blocking_notifier_head *nh, - unsigned long val, void *v) -{ - return __blocking_notifier_call_chain(nh, val, v, -1, NULL); -} -EXPORT_SYMBOL_GPL(blocking_notifier_call_chain); - -/* - * Raw notifier chain routines. There is no protection; - * the caller must provide it. Use at your own risk! - */ - -/** - * raw_notifier_chain_register - Add notifier to a raw notifier chain - * @nh: Pointer to head of the raw notifier chain - * @n: New entry in notifier chain - * - * Adds a notifier to a raw notifier chain. - * All locking must be provided by the caller. - * - * Currently always returns zero. - */ - -int raw_notifier_chain_register(struct raw_notifier_head *nh, - struct notifier_block *n) -{ - return notifier_chain_register(&nh->head, n); -} - -EXPORT_SYMBOL_GPL(raw_notifier_chain_register); - -/** - * raw_notifier_chain_unregister - Remove notifier from a raw notifier chain - * @nh: Pointer to head of the raw notifier chain - * @n: Entry to remove from notifier chain - * - * Removes a notifier from a raw notifier chain. - * All locking must be provided by the caller. - * - * Returns zero on success or %-ENOENT on failure. - */ -int raw_notifier_chain_unregister(struct raw_notifier_head *nh, - struct notifier_block *n) -{ - return notifier_chain_unregister(&nh->head, n); -} - -EXPORT_SYMBOL_GPL(raw_notifier_chain_unregister); - -/** - * __raw_notifier_call_chain - Call functions in a raw notifier chain - * @nh: Pointer to head of the raw notifier chain - * @val: Value passed unmodified to notifier function - * @v: Pointer passed unmodified to notifier function - * @nr_to_call: See comment for notifier_call_chain. - * @nr_calls: See comment for notifier_call_chain - * - * Calls each function in a notifier chain in turn. The functions - * run in an undefined context. - * All locking must be provided by the caller. - * - * If the return value of the notifier can be and'ed - * with %NOTIFY_STOP_MASK then raw_notifier_call_chain() - * will return immediately, with the return value of - * the notifier function which halted execution. - * Otherwise the return value is the return value - * of the last notifier function called. - */ - -int __raw_notifier_call_chain(struct raw_notifier_head *nh, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) -{ - return notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); -} - -EXPORT_SYMBOL_GPL(__raw_notifier_call_chain); - -int raw_notifier_call_chain(struct raw_notifier_head *nh, - unsigned long val, void *v) -{ - return __raw_notifier_call_chain(nh, val, v, -1, NULL); -} - -EXPORT_SYMBOL_GPL(raw_notifier_call_chain); - -/* - * SRCU notifier chain routines. Registration and unregistration - * use a mutex, and call_chain is synchronized by SRCU (no locks). - */ - -/** - * srcu_notifier_chain_register - Add notifier to an SRCU notifier chain - * @nh: Pointer to head of the SRCU notifier chain - * @n: New entry in notifier chain - * - * Adds a notifier to an SRCU notifier chain. - * Must be called in process context. - * - * Currently always returns zero. - */ - -int srcu_notifier_chain_register(struct srcu_notifier_head *nh, - struct notifier_block *n) -{ - int ret; - - /* - * This code gets used during boot-up, when task switching is - * not yet working and interrupts must remain disabled. At - * such times we must not call mutex_lock(). - */ - if (unlikely(system_state == SYSTEM_BOOTING)) - return notifier_chain_register(&nh->head, n); - - mutex_lock(&nh->mutex); - ret = notifier_chain_register(&nh->head, n); - mutex_unlock(&nh->mutex); - return ret; -} - -EXPORT_SYMBOL_GPL(srcu_notifier_chain_register); - -/** - * srcu_notifier_chain_unregister - Remove notifier from an SRCU notifier chain - * @nh: Pointer to head of the SRCU notifier chain - * @n: Entry to remove from notifier chain - * - * Removes a notifier from an SRCU notifier chain. - * Must be called from process context. - * - * Returns zero on success or %-ENOENT on failure. - */ -int srcu_notifier_chain_unregister(struct srcu_notifier_head *nh, - struct notifier_block *n) -{ - int ret; - - /* - * This code gets used during boot-up, when task switching is - * not yet working and interrupts must remain disabled. At - * such times we must not call mutex_lock(). - */ - if (unlikely(system_state == SYSTEM_BOOTING)) - return notifier_chain_unregister(&nh->head, n); - - mutex_lock(&nh->mutex); - ret = notifier_chain_unregister(&nh->head, n); - mutex_unlock(&nh->mutex); - synchronize_srcu(&nh->srcu); - return ret; -} - -EXPORT_SYMBOL_GPL(srcu_notifier_chain_unregister); - -/** - * __srcu_notifier_call_chain - Call functions in an SRCU notifier chain - * @nh: Pointer to head of the SRCU notifier chain - * @val: Value passed unmodified to notifier function - * @v: Pointer passed unmodified to notifier function - * @nr_to_call: See comment for notifier_call_chain. - * @nr_calls: See comment for notifier_call_chain - * - * Calls each function in a notifier chain in turn. The functions - * run in a process context, so they are allowed to block. - * - * If the return value of the notifier can be and'ed - * with %NOTIFY_STOP_MASK then srcu_notifier_call_chain() - * will return immediately, with the return value of - * the notifier function which halted execution. - * Otherwise the return value is the return value - * of the last notifier function called. - */ - -int __srcu_notifier_call_chain(struct srcu_notifier_head *nh, - unsigned long val, void *v, - int nr_to_call, int *nr_calls) -{ - int ret; - int idx; - - idx = srcu_read_lock(&nh->srcu); - ret = notifier_call_chain(&nh->head, val, v, nr_to_call, nr_calls); - srcu_read_unlock(&nh->srcu, idx); - return ret; -} -EXPORT_SYMBOL_GPL(__srcu_notifier_call_chain); - -int srcu_notifier_call_chain(struct srcu_notifier_head *nh, - unsigned long val, void *v) -{ - return __srcu_notifier_call_chain(nh, val, v, -1, NULL); -} -EXPORT_SYMBOL_GPL(srcu_notifier_call_chain); - -/** - * srcu_init_notifier_head - Initialize an SRCU notifier head - * @nh: Pointer to head of the srcu notifier chain - * - * Unlike other sorts of notifier heads, SRCU notifier heads require - * dynamic initialization. Be sure to call this routine before - * calling any of the other SRCU notifier routines for this head. - * - * If an SRCU notifier head is deallocated, it must first be cleaned - * up by calling srcu_cleanup_notifier_head(). Otherwise the head's - * per-cpu data (used by the SRCU mechanism) will leak. - */ - -void srcu_init_notifier_head(struct srcu_notifier_head *nh) -{ - mutex_init(&nh->mutex); - if (init_srcu_struct(&nh->srcu) < 0) - BUG(); - nh->head = NULL; -} - -EXPORT_SYMBOL_GPL(srcu_init_notifier_head); - -/** - * register_reboot_notifier - Register function to be called at reboot time - * @nb: Info about notifier function to be called - * - * Registers a function with the list of functions - * to be called at reboot time. - * - * Currently always returns zero, as blocking_notifier_chain_register() - * always returns zero. - */ - -int register_reboot_notifier(struct notifier_block * nb) -{ - return blocking_notifier_chain_register(&reboot_notifier_list, nb); -} - -EXPORT_SYMBOL(register_reboot_notifier); - -/** - * unregister_reboot_notifier - Unregister previously registered reboot notifier - * @nb: Hook to be unregistered - * - * Unregisters a previously registered reboot - * notifier function. - * - * Returns zero on success, or %-ENOENT on failure. - */ - -int unregister_reboot_notifier(struct notifier_block * nb) -{ - return blocking_notifier_chain_unregister(&reboot_notifier_list, nb); -} - -EXPORT_SYMBOL(unregister_reboot_notifier); - static int set_one_prio(struct task_struct *p, int niceval, int error) { int no_nice; -- cgit v1.2.3