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-rw-r--r--kernel/cpu.c29
-rw-r--r--kernel/module.c20
-rw-r--r--kernel/panic.c4
-rw-r--r--kernel/profile.c53
-rw-r--r--kernel/softlockup.c2
-rw-r--r--kernel/sys.c327
6 files changed, 301 insertions, 134 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 8be22bd80933..fe2b8d0bfe4c 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 ddfe45ac2fd1..4fafd58038a0 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(&notify_mutex);
- err = notifier_chain_register(&module_notify_list, nb);
- mutex_unlock(&notify_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(&notify_mutex);
- err = notifier_chain_unregister(&module_notify_list, nb);
- mutex_unlock(&notify_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(&notify_mutex);
- notifier_call_chain(&module_notify_list, MODULE_STATE_COMING, mod);
- mutex_unlock(&notify_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 acd95adddb93..f895c7c01d5b 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 ad81f799a9b4..5a730fdb1a2c 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 d9b3d5847ed8..ced91e1ff564 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 38bc73ede2ba..c93d37f71aef 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(&notifier_lock);
- while(*list)
- {
- if(n->priority > (*list)->priority)
- break;
- list= &((*list)->next);
- }
- n->next = *list;
- *list=n;
- write_unlock(&notifier_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(&notifier_lock);
- while((*nl)!=NULL)
- {
- if((*nl)==n)
- {
- *nl=n->next;
- write_unlock(&notifier_lock);
- return 0;
- }
- nl=&((*nl)->next);
- }
- write_unlock(&notifier_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();