diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cpu.c | 29 | ||||
| -rw-r--r-- | kernel/module.c | 20 | ||||
| -rw-r--r-- | kernel/panic.c | 4 | ||||
| -rw-r--r-- | kernel/profile.c | 53 | ||||
| -rw-r--r-- | kernel/softlockup.c | 2 | ||||
| -rw-r--r-- | kernel/sys.c | 327 |
6 files changed, 301 insertions, 134 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 8be22bd809335e..fe2b8d0bfe4ce3 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -18,7 +18,7 @@ /* This protects CPUs going up and down... */ static DECLARE_MUTEX(cpucontrol); -static struct notifier_block *cpu_chain; +static BLOCKING_NOTIFIER_HEAD(cpu_chain); #ifdef CONFIG_HOTPLUG_CPU static struct task_struct *lock_cpu_hotplug_owner; @@ -71,21 +71,13 @@ EXPORT_SYMBOL_GPL(lock_cpu_hotplug_interruptible); /* Need to know about CPUs going up/down? */ int register_cpu_notifier(struct notifier_block *nb) { - int ret; - - if ((ret = lock_cpu_hotplug_interruptible()) != 0) - return ret; - ret = notifier_chain_register(&cpu_chain, nb); - unlock_cpu_hotplug(); - return ret; + return blocking_notifier_chain_register(&cpu_chain, nb); } EXPORT_SYMBOL(register_cpu_notifier); void unregister_cpu_notifier(struct notifier_block *nb) { - lock_cpu_hotplug(); - notifier_chain_unregister(&cpu_chain, nb); - unlock_cpu_hotplug(); + blocking_notifier_chain_unregister(&cpu_chain, nb); } EXPORT_SYMBOL(unregister_cpu_notifier); @@ -141,7 +133,7 @@ int cpu_down(unsigned int cpu) goto out; } - err = notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE, + err = blocking_notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE, (void *)(long)cpu); if (err == NOTIFY_BAD) { printk("%s: attempt to take down CPU %u failed\n", @@ -159,7 +151,7 @@ int cpu_down(unsigned int cpu) p = __stop_machine_run(take_cpu_down, NULL, cpu); if (IS_ERR(p)) { /* CPU didn't die: tell everyone. Can't complain. */ - if (notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED, + if (blocking_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED, (void *)(long)cpu) == NOTIFY_BAD) BUG(); @@ -182,8 +174,8 @@ int cpu_down(unsigned int cpu) put_cpu(); /* CPU is completely dead: tell everyone. Too late to complain. */ - if (notifier_call_chain(&cpu_chain, CPU_DEAD, (void *)(long)cpu) - == NOTIFY_BAD) + if (blocking_notifier_call_chain(&cpu_chain, CPU_DEAD, + (void *)(long)cpu) == NOTIFY_BAD) BUG(); check_for_tasks(cpu); @@ -211,7 +203,7 @@ int __devinit cpu_up(unsigned int cpu) goto out; } - ret = notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu); + ret = blocking_notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu); if (ret == NOTIFY_BAD) { printk("%s: attempt to bring up CPU %u failed\n", __FUNCTION__, cpu); @@ -226,11 +218,12 @@ int __devinit cpu_up(unsigned int cpu) BUG_ON(!cpu_online(cpu)); /* Now call notifier in preparation. */ - notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu); + blocking_notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu); out_notify: if (ret != 0) - notifier_call_chain(&cpu_chain, CPU_UP_CANCELED, hcpu); + blocking_notifier_call_chain(&cpu_chain, + CPU_UP_CANCELED, hcpu); out: unlock_cpu_hotplug(); return ret; diff --git a/kernel/module.c b/kernel/module.c index ddfe45ac2fd1d9..4fafd58038a03a 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -64,26 +64,17 @@ static DEFINE_SPINLOCK(modlist_lock); static DEFINE_MUTEX(module_mutex); static LIST_HEAD(modules); -static DEFINE_MUTEX(notify_mutex); -static struct notifier_block * module_notify_list; +static BLOCKING_NOTIFIER_HEAD(module_notify_list); int register_module_notifier(struct notifier_block * nb) { - int err; - mutex_lock(¬ify_mutex); - err = notifier_chain_register(&module_notify_list, nb); - mutex_unlock(¬ify_mutex); - return err; + return blocking_notifier_chain_register(&module_notify_list, nb); } EXPORT_SYMBOL(register_module_notifier); int unregister_module_notifier(struct notifier_block * nb) { - int err; - mutex_lock(¬ify_mutex); - err = notifier_chain_unregister(&module_notify_list, nb); - mutex_unlock(¬ify_mutex); - return err; + return blocking_notifier_chain_unregister(&module_notify_list, nb); } EXPORT_SYMBOL(unregister_module_notifier); @@ -1816,9 +1807,8 @@ sys_init_module(void __user *umod, /* Drop lock so they can recurse */ mutex_unlock(&module_mutex); - mutex_lock(¬ify_mutex); - notifier_call_chain(&module_notify_list, MODULE_STATE_COMING, mod); - mutex_unlock(¬ify_mutex); + blocking_notifier_call_chain(&module_notify_list, + MODULE_STATE_COMING, mod); /* Start the module */ if (mod->init != NULL) diff --git a/kernel/panic.c b/kernel/panic.c index acd95adddb9387..f895c7c01d5b18 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -29,7 +29,7 @@ static DEFINE_SPINLOCK(pause_on_oops_lock); int panic_timeout; EXPORT_SYMBOL(panic_timeout); -struct notifier_block *panic_notifier_list; +ATOMIC_NOTIFIER_HEAD(panic_notifier_list); EXPORT_SYMBOL(panic_notifier_list); @@ -97,7 +97,7 @@ NORET_TYPE void panic(const char * fmt, ...) smp_send_stop(); #endif - notifier_call_chain(&panic_notifier_list, 0, buf); + atomic_notifier_call_chain(&panic_notifier_list, 0, buf); if (!panic_blink) panic_blink = no_blink; diff --git a/kernel/profile.c b/kernel/profile.c index ad81f799a9b4ad..5a730fdb1a2cec 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -87,72 +87,52 @@ void __init profile_init(void) #ifdef CONFIG_PROFILING -static DECLARE_RWSEM(profile_rwsem); -static DEFINE_RWLOCK(handoff_lock); -static struct notifier_block * task_exit_notifier; -static struct notifier_block * task_free_notifier; -static struct notifier_block * munmap_notifier; +static BLOCKING_NOTIFIER_HEAD(task_exit_notifier); +static ATOMIC_NOTIFIER_HEAD(task_free_notifier); +static BLOCKING_NOTIFIER_HEAD(munmap_notifier); void profile_task_exit(struct task_struct * task) { - down_read(&profile_rwsem); - notifier_call_chain(&task_exit_notifier, 0, task); - up_read(&profile_rwsem); + blocking_notifier_call_chain(&task_exit_notifier, 0, task); } int profile_handoff_task(struct task_struct * task) { int ret; - read_lock(&handoff_lock); - ret = notifier_call_chain(&task_free_notifier, 0, task); - read_unlock(&handoff_lock); + ret = atomic_notifier_call_chain(&task_free_notifier, 0, task); return (ret == NOTIFY_OK) ? 1 : 0; } void profile_munmap(unsigned long addr) { - down_read(&profile_rwsem); - notifier_call_chain(&munmap_notifier, 0, (void *)addr); - up_read(&profile_rwsem); + blocking_notifier_call_chain(&munmap_notifier, 0, (void *)addr); } int task_handoff_register(struct notifier_block * n) { - int err = -EINVAL; - - write_lock(&handoff_lock); - err = notifier_chain_register(&task_free_notifier, n); - write_unlock(&handoff_lock); - return err; + return atomic_notifier_chain_register(&task_free_notifier, n); } int task_handoff_unregister(struct notifier_block * n) { - int err = -EINVAL; - - write_lock(&handoff_lock); - err = notifier_chain_unregister(&task_free_notifier, n); - write_unlock(&handoff_lock); - return err; + return atomic_notifier_chain_unregister(&task_free_notifier, n); } int profile_event_register(enum profile_type type, struct notifier_block * n) { int err = -EINVAL; - down_write(&profile_rwsem); - switch (type) { case PROFILE_TASK_EXIT: - err = notifier_chain_register(&task_exit_notifier, n); + err = blocking_notifier_chain_register( + &task_exit_notifier, n); break; case PROFILE_MUNMAP: - err = notifier_chain_register(&munmap_notifier, n); + err = blocking_notifier_chain_register( + &munmap_notifier, n); break; } - up_write(&profile_rwsem); - return err; } @@ -161,18 +141,17 @@ int profile_event_unregister(enum profile_type type, struct notifier_block * n) { int err = -EINVAL; - down_write(&profile_rwsem); - switch (type) { case PROFILE_TASK_EXIT: - err = notifier_chain_unregister(&task_exit_notifier, n); + err = blocking_notifier_chain_unregister( + &task_exit_notifier, n); break; case PROFILE_MUNMAP: - err = notifier_chain_unregister(&munmap_notifier, n); + err = blocking_notifier_chain_unregister( + &munmap_notifier, n); break; } - up_write(&profile_rwsem); return err; } diff --git a/kernel/softlockup.c b/kernel/softlockup.c index d9b3d5847ed871..ced91e1ff56473 100644 --- a/kernel/softlockup.c +++ b/kernel/softlockup.c @@ -152,5 +152,5 @@ __init void spawn_softlockup_task(void) cpu_callback(&cpu_nfb, CPU_ONLINE, cpu); register_cpu_notifier(&cpu_nfb); - notifier_chain_register(&panic_notifier_list, &panic_block); + atomic_notifier_chain_register(&panic_notifier_list, &panic_block); } diff --git a/kernel/sys.c b/kernel/sys.c index 38bc73ede2badd..c93d37f71aef98 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -95,99 +95,304 @@ int cad_pid = 1; * and the like. */ -static struct notifier_block *reboot_notifier_list; -static DEFINE_RWLOCK(notifier_lock); +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; +} + +static int __kprobes notifier_call_chain(struct notifier_block **nl, + unsigned long val, void *v) +{ + int ret = NOTIFY_DONE; + struct notifier_block *nb; + + nb = rcu_dereference(*nl); + while (nb) { + ret = nb->notifier_call(nb, val, v); + if ((ret & NOTIFY_STOP_MASK) == NOTIFY_STOP_MASK) + break; + nb = rcu_dereference(nb->next); + } + return ret; +} + +/* + * Atomic notifier chain routines. Registration and unregistration + * use a mutex, and call_chain is synchronized by RCU (no locks). + */ /** - * notifier_chain_register - Add notifier to a notifier chain - * @list: Pointer to root list pointer + * 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 a 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 + * + * 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 notifier_chain_register(struct notifier_block **list, struct notifier_block *n) +int atomic_notifier_call_chain(struct atomic_notifier_head *nh, + unsigned long val, void *v) { - write_lock(¬ifier_lock); - while(*list) - { - if(n->priority > (*list)->priority) - break; - list= &((*list)->next); - } - n->next = *list; - *list=n; - write_unlock(¬ifier_lock); - return 0; + int ret; + + rcu_read_lock(); + ret = notifier_call_chain(&nh->head, val, v); + rcu_read_unlock(); + return ret; } -EXPORT_SYMBOL(notifier_chain_register); +EXPORT_SYMBOL_GPL(atomic_notifier_call_chain); + +/* + * Blocking notifier chain routines. All access to the chain is + * synchronized by an rwsem. + */ /** - * notifier_chain_unregister - Remove notifier from a notifier chain - * @nl: Pointer to root list pointer + * 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 * - * Removes a notifier from a notifier chain. + * Adds a notifier to a blocking notifier chain. + * Must be called in process context. * - * Returns zero on success, or %-ENOENT on failure. + * Currently always returns zero. */ -int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n) +int blocking_notifier_chain_register(struct blocking_notifier_head *nh, + struct notifier_block *n) { - write_lock(¬ifier_lock); - while((*nl)!=NULL) - { - if((*nl)==n) - { - *nl=n->next; - write_unlock(¬ifier_lock); - return 0; - } - nl=&((*nl)->next); - } - write_unlock(¬ifier_lock); - return -ENOENT; + 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(notifier_chain_unregister); +EXPORT_SYMBOL_GPL(blocking_notifier_chain_register); /** - * notifier_call_chain - Call functions in a notifier chain - * @n: Pointer to root pointer of notifier chain + * 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 * - * Calls each function in a notifier chain in turn. + * 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'd - * with %NOTIFY_STOP_MASK, then notifier_call_chain + * 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 + * Otherwise the return value is the return value * of the last notifier function called. */ -int __kprobes notifier_call_chain(struct notifier_block **n, unsigned long val, void *v) +int blocking_notifier_call_chain(struct blocking_notifier_head *nh, + unsigned long val, void *v) { - int ret=NOTIFY_DONE; - struct notifier_block *nb = *n; + int ret; - while(nb) - { - ret=nb->notifier_call(nb,val,v); - if(ret&NOTIFY_STOP_MASK) - { - return ret; - } - nb=nb->next; - } + down_read(&nh->rwsem); + ret = notifier_call_chain(&nh->head, val, v); + up_read(&nh->rwsem); return ret; } -EXPORT_SYMBOL(notifier_call_chain); +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 + * + * 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) +{ + return notifier_call_chain(&nh->head, val, v); +} + +EXPORT_SYMBOL_GPL(raw_notifier_call_chain); /** * register_reboot_notifier - Register function to be called at reboot time @@ -196,13 +401,13 @@ EXPORT_SYMBOL(notifier_call_chain); * Registers a function with the list of functions * to be called at reboot time. * - * Currently always returns zero, as notifier_chain_register + * Currently always returns zero, as blocking_notifier_chain_register * always returns zero. */ int register_reboot_notifier(struct notifier_block * nb) { - return notifier_chain_register(&reboot_notifier_list, nb); + return blocking_notifier_chain_register(&reboot_notifier_list, nb); } EXPORT_SYMBOL(register_reboot_notifier); @@ -219,7 +424,7 @@ EXPORT_SYMBOL(register_reboot_notifier); int unregister_reboot_notifier(struct notifier_block * nb) { - return notifier_chain_unregister(&reboot_notifier_list, nb); + return blocking_notifier_chain_unregister(&reboot_notifier_list, nb); } EXPORT_SYMBOL(unregister_reboot_notifier); @@ -380,7 +585,7 @@ EXPORT_SYMBOL_GPL(emergency_restart); void kernel_restart_prepare(char *cmd) { - notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); + blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); system_state = SYSTEM_RESTART; device_shutdown(); } @@ -430,7 +635,7 @@ EXPORT_SYMBOL_GPL(kernel_kexec); void kernel_shutdown_prepare(enum system_states state) { - notifier_call_chain(&reboot_notifier_list, + blocking_notifier_call_chain(&reboot_notifier_list, (state == SYSTEM_HALT)?SYS_HALT:SYS_POWER_OFF, NULL); system_state = state; device_shutdown(); |