Home » Mailing lists » Devel » [PATCH] Add kernel/notifier.c
| [PATCH] Add kernel/notifier.c [message #15131] |
Thu, 19 July 2007 16:46  |
Alexey Dobriyan
Messages: 195
Registered: August 2006
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Senior Member |
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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.
Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
---
include/linux/notifier.h | 2
kernel/Makefile | 4
kernel/die_notifier.c | 38 ---
kernel/notifier.c | 569 +++++++++++++++++++++++++++++++++++++++++++++++
kernel/sys.c | 531 -------------------------------------------
5 files changed, 573 insertions(+), 571 deletions(-)
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -212,5 +212,7 @@ extern int __srcu_notifier_call_chain(struct srcu_notifier_head *nh,
#define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN)
#define CPU_DYING_FROZEN (CPU_DYING | CPU_TASKS_FROZEN)
+extern struct blocking_notifier_head reboot_notifier_list;
+
#endif /* __KERNEL__ */
#endif /* _LINUX_NOTIFIER_H */
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -8,8 +8,8 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
signal.o sys.o kmod.o workqueue.o pid.o \
rcupdate.o extable.o params.o posix-timers.o \
kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
- hrtimer.o rwsem.o latency.o nsproxy.o srcu.o die_notifier.o \
- utsname.o
+ hrtimer.o rwsem.o latency.o nsproxy.o srcu.o \
+ utsname.o notifier.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += time/
deleted file mode 100644
--- a/kernel/die_notifier.c
+++ /dev/null
@@ -1,38 +0,0 @@
-
-#include <linux/module.h>
-#include <linux/notifier.h>
-#include <linux/vmalloc.h>
-#include <linux/kdebug.h>
-
-
-static ATOMIC_NOTIFIER_HEAD(die_chain);
-
-int notify_die(enum die_val val, const char *str,
- struct pt_regs *regs, long err, int trap, int sig)
-{
- struct die_args args = {
- .regs = regs,
- .str = str,
- .err = err,
- .trapnr = trap,
- .signr = sig,
-
- };
-
- return atomic_notifier_call_chain(&die_chain, val, &args);
-}
-
-int register_die_notifier(struct notifier_block *nb)
-{
- vmalloc_sync_all();
- return atomic_notifier_chain_register(&die_chain, nb);
-}
-EXPORT_SYMBOL_GPL(register_die_notifier);
-
-int unregister_die_notifier(struct notifier_block *nb)
-{
- return atomic_notifier_chain_unregister(&die_chain, nb);
-}
-EXPORT_SYMBOL_GPL(unregister_die_notifier);
-
-
--- /dev/null
+++ b/kernel/notifier.c
@@ -0,0 +1,569 @@
+#include <linux/kdebug.h>
+#include <linux/kprobes.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/rcupdate.h>
+#include <linux/vmalloc.h>
+
+/*
+ * Notifier list for kernel code which wants to be called
+ * at shutdown. This is used to stop any idling DMA operations
+ * and the like.
+ */
+
+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 fu
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