[PATCH 1/2] add tunable_notifier function ,take2

[PATCH 1/2] add tunable_notifier function ,take2

[Takenori Nagano]

This patch adds new notifier function tunable_notifier_chain. Its base is
atomic_notifier_chain.

Thanks,

---

Signed-off-by: Takenori Nagano <t-nagano@ah.jp.nec.com>

---
diff -uprN linux-2.6.23.orig/include/linux/notifier.h
linux-2.6.23/include/linux/notifier.h
--- linux-2.6.23.orig/include/linux/notifier.h	2007-10-10 05:31:38.000000000 +0900
+++ linux-2.6.23/include/linux/notifier.h	2007-10-18 09:59:13.732000000 +0900
@@ -13,6 +13,7 @@
 #include <linux/mutex.h>
 #include <linux/rwsem.h>
 #include <linux/srcu.h>
+#include <linux/kobject.h>

 /*
  * Notifier chains are of four types:
@@ -53,6 +54,14 @@ struct notifier_block {
 	int priority;
 };

+struct tunable_atomic_notifier_block {
+	struct notifier_block *nb;
+	struct tunable_atomic_notifier_head *head;
+	struct dentry *dir;
+	struct dentry *pri_dentry;
+	struct dentry *desc_dentry;
+};
+
 struct atomic_notifier_head {
 	spinlock_t lock;
 	struct notifier_block *head;
@@ -63,6 +72,13 @@ struct blocking_notifier_head {
 	struct notifier_block *head;
 };

+struct tunable_atomic_notifier_head {
+	spinlock_t lock;
+	struct notifier_block *head;
+	char *name;
+	struct dentry *dir;
+};
+
 struct raw_notifier_head {
 	struct notifier_block *head;
 };
@@ -81,6 +97,12 @@ struct srcu_notifier_head {
 		init_rwsem(&(name)->rwsem);	\
 		(name)->head = NULL;		\
 	} while (0)
+#define TUNABLE_ATOMIC_INIT_NOTIFIER(val1, val2) do {	\
+		spin_lock_init(&(val1)->lock);		\
+		(val1)->head = NULL;			\
+		(val1)->name = val2;			\
+		(val1)->dir = NULL;			\
+	} while (0)
 #define RAW_INIT_NOTIFIER_HEAD(name) do {	\
 		(name)->head = NULL;		\
 	} while (0)
@@ -96,6 +118,11 @@ extern void srcu_init_notifier_head(stru
 #define BLOCKING_NOTIFIER_INIT(name) {				\
 		.rwsem = __RWSEM_INITIALIZER((name).rwsem),	\
 		.head = NULL }
+#define TUNABLE_ATOMIC_NOTIFIER_INIT(val1, val2) {			\
+		.lock =__SPIN_LOCK_UNLOCKED(val1.lock),		\
+		.head = NULL,					\
+		.name = val2,						\
+		.dir = NULL }
 #define RAW_NOTIFIER_INIT(name)	{				\
 		.head = NULL }
 /* srcu_notifier_heads cannot be initialized statically */
@@ -106,6 +133,9 @@ extern void srcu_init_notifier_head(stru
 #define BLOCKING_NOTIFIER_HEAD(name)				\
 	struct blocking_notifier_head name =			\
 		BLOCKING_NOTIFIER_INIT(name)
+#define TUNABLE_ATOMIC_NOTIFIER_HEAD(name, val)			\
+	struct tunable_atomic_notifier_head name =			\
+		TUNABLE_ATOMIC_NOTIFIER_INIT(name, val)
 #define RAW_NOTIFIER_HEAD(name)					\
 	struct raw_notifier_head name =				\
 		RAW_NOTIFIER_INIT(name)
@@ -116,6 +146,10 @@ extern int atomic_notifier_chain_registe
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 		struct notifier_block *nb);
+extern int tunable_atomic_notifier_chain_register(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_notifier_block *nb,
+				char *name, char *desc);
 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,
@@ -125,6 +159,9 @@ extern int atomic_notifier_chain_unregis
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
 		struct notifier_block *nb);
+extern int tunable_atomic_notifier_chain_unregister(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_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,
@@ -138,6 +175,13 @@ extern int blocking_notifier_call_chain(
 		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 tunable_atomic_notifier_call_chain(
+				struct tunable_atomic_notifier_head *nh,
+				unsigned long val, void *v);
+extern int __tunable_atomic_notifier_call_chain(
+				struct tunable_atomic_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,
diff -uprN linux-2.6.23.orig/kernel/sys.c linux-2.6.23/kernel/sys.c
--- linux-2.6.23.orig/kernel/sys.c	2007-10-10 05:31:38.000000000 +0900
+++ linux-2.6.23/kernel/sys.c	2007-10-18 10:08:52.728000000 +0900
@@ -38,6 +38,7 @@
 #include <linux/syscalls.h>
 #include <linux/kprobes.h>
 #include <linux/user_namespace.h>
+#include <linux/debugfs.h>

 #include <asm/uaccess.h>
 #include <asm/io.h>
@@ -393,6 +394,243 @@ int blocking_notifier_call_chain(struct
 EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);

 /*
+ *	Tunable atomic notifier chain routines. Registration and unregistration
+ *	use a spinlock, and call_chain is synchronized by RCU (no locks).
+ *	User can change the list order to use /sys/kernel/debug/list-name/.
+ */
+
+static ssize_t priority_read(struct file *file,
+			char __user *user_buf, size_t count, loff_t *ppos)
+{
+	struct tunable_atomic_notifier_block *n =
+					file->f_dentry->d_inode->i_private;
+	int priority = n->nb->priority;
+	char buf[64], *s;
+
+	s = buf;
+	s += sprintf(s, "%d\n", priority);
+
+	return simple_read_from_buffer((void __user *)user_buf, count,
+							ppos, buf, s - buf);
+}
+
+static ssize_t priority_write(struct file *file,
+		const char __user *user_buf, size_t count, loff_t *ppos)
+{
+	struct tunable_atomic_notifier_block *n =
+					file->f_dentry->d_inode->i_private;
+	struct tunable_atomic_notifier_head *nh = n->head;
+	char *buf, *end;
+	int ret = -ENOMEM, priority;
+	unsigned long tmp, flags;
+
+	buf = kmalloc(count + 1, GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	buf[count] = 0;
+	ret = -EFAULT;
+	if (copy_from_user(buf, user_buf, count))
+		goto out_free;
+
+	ret = -EINVAL;
+	tmp = simple_strtoul(buf, &end, 10);
+	if ((end == buf) || (tmp > INT_MAX))
+		goto out_free;
+
+	priority = (int)tmp;
+	n->nb->priority = priority;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_unregister(&nh->head, n->nb);
+	if (ret)
+		goto out_unlock;
+	ret = notifier_chain_register(&nh->head, n->nb);
+	if (!ret)
+		ret = count;
+
+out_unlock:
+	spin_unlock_irqrestore(&nh->lock, flags);
+out_free:
+	kfree(buf);
+out:
+	return ret;
+
+}
+
+static const struct file_operations pri_fops = {
+	.read = priority_read,
+	.write = priority_write,
+};
+
+static ssize_t description_read(struct file *file,
+			char __user *user_buf, size_t count, loff_t *ppos)
+{
+	char *desc = file->f_dentry->d_inode->i_private;
+	int avail = strlen(desc);
+
+	return simple_read_from_buffer(user_buf, count, ppos, desc, avail);
+}
+
+static const struct file_operations desc_fops = {
+	.read = description_read,
+};
+
+/**
+ *	tunable_atomic_notifier_chain_register
+ *				- Add notifier to an tunable notifier chain
+ *	@nh: Pointer to head of the tunable notifier chain
+ *	@n: New entry in notifier chain
+ *	@name: Pointer to the name of the new notifier entry
+ *	@desc: Pointer to the description of new entry
+ *
+ *	Adds a notifier to an tunable notifier chain and makes control dir.
+ *
+ *	Returns zero on success or %-ENODEV on failure.
+ */
+
+int tunable_atomic_notifier_chain_register(
+		struct tunable_atomic_notifier_head *nh,
+		struct tunable_atomic_notifier_block *n, char *name, char *desc)
+{
+	unsigned long flags;
+	int ret = -EINVAL;
+	struct dentry *nh_dir, *nb_dir, *pri_dentry, *desc_dentry = NULL;
+
+	if (!name)
+		goto nb_fail;
+
+	ret = -ENOMEM;
+	if (!nh->dir) {
+		nh_dir = debugfs_create_dir(nh->name, NULL);
+		if (!nh_dir)
+			return ret;
+		nh->dir = nh_dir;
+	} else
+		nh_dir = nh->dir;
+
+	nb_dir = debugfs_create_dir(name, nh_dir);
+	if (!nb_dir)
+		goto nb_fail;
+	n->dir = nb_dir;
+
+	pri_dentry = debugfs_create_file("priority",0600, nb_dir, n, &pri_fops);
+	if (!pri_dentry)
+		goto pri_fail;
+	n->pri_dentry = pri_dentry;
+
+	if (desc) {
+		desc_dentry = debugfs_create_file("description", 0400, nb_dir,
+							desc, &desc_fops);
+		if (!desc_dentry)
+			goto desc_fail;
+		n->desc_dentry = desc_dentry;
+	}
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n->nb);
+	spin_unlock_irqrestore(&nh->lock, flags);
+
+	if (ret)
+		goto reg_fail;
+	
+	n->head = nh;
+
+	return ret;
+
+reg_fail:
+	debugfs_remove(desc_dentry);
+desc_fail:
+	debugfs_remove(pri_dentry);
+pri_fail:
+	debugfs_remove(nb_dir);
+nb_fail:
+	return ret;
+}
+
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_chain_register);
+
+/**
+ *	tunable_atomic_notifier_chain_unregister
+ *				- Remove notifier from a tunable notifier chain
+ *	@nh: Pointer to head of the tunable notifier chain
+ *	@n: Entry to remove from notifier chain
+ *
+ *	Removes a notifier from a tunable notifier chain.
+ *
+ *	Retunrns zero on success or %-ENOENT on failure.
+ */
+
+int tunable_atomic_notifier_chain_unregister(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_unregister(&nh->head, n->nb);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	synchronize_rcu();
+
+	if (ret)
+		return ret;
+
+	debugfs_remove(n->desc_dentry);
+	debugfs_remove(n->pri_dentry);
+	debugfs_remove(n->dir);
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_chain_unregister);
+
+/**
+ *	__tunable_atomic_notifier_call_chain
+ *				- Call functions in a tunable notifier chain
+ *	@nh: Pointer to head of the tunable notifier chain
+ *	@val: Value passed unmodified to notifier function
+ *	@v: Pointer passed unmodified to notifier function
+ *	@nt_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 tunable_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 __tunable_atomic_notifier_call_chain(
+					struct tunable_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(__tunable_atomic_notifier_call_chain);
+
+int __kprobes tunable_atomic_notifier_call_chain(
+					struct tunable_atomic_notifier_head *nh,
+					unsigned long val, void *v)
+{
+	return __tunable_atomic_notifier_call_chain(nh, val, v, -1, NULL);
+}
+
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_call_chain);
+
+/*
  *	Raw notifier chain routines.  There is no protection;
  *	the caller must provide it.  Use at your own risk!
  */

[PATCH 1/2] add tunable_notifier function ,take2

[Takenori Nagano]

This patch adds new notifier function tunable_notifier_chain. Its base is
atomic_notifier_chain.

Thanks,

---

Signed-off-by: Takenori Nagano <t-nagano@ah.jp.nec.com>

---
diff -uprN linux-2.6.23.orig/include/linux/notifier.h linux-2.6.23/include/linux/notifier.h
--- linux-2.6.23.orig/include/linux/notifier.h	2007-10-10 05:31:38.000000000 +0900
+++ linux-2.6.23/include/linux/notifier.h	2007-10-18 09:59:13.732000000 +0900
@@ -13,6 +13,7 @@
 #include <linux/mutex.h>
 #include <linux/rwsem.h>
 #include <linux/srcu.h>
+#include <linux/kobject.h>
 
 /*
  * Notifier chains are of four types:
@@ -53,6 +54,14 @@ struct notifier_block {
 	int priority;
 };
 
+struct tunable_atomic_notifier_block {
+	struct notifier_block *nb;
+	struct tunable_atomic_notifier_head *head;
+	struct dentry *dir;
+	struct dentry *pri_dentry;
+	struct dentry *desc_dentry;
+};
+
 struct atomic_notifier_head {
 	spinlock_t lock;
 	struct notifier_block *head;
@@ -63,6 +72,13 @@ struct blocking_notifier_head {
 	struct notifier_block *head;
 };
 
+struct tunable_atomic_notifier_head {
+	spinlock_t lock;
+	struct notifier_block *head;
+	char *name;
+	struct dentry *dir;
+};
+
 struct raw_notifier_head {
 	struct notifier_block *head;
 };
@@ -81,6 +97,12 @@ struct srcu_notifier_head {
 		init_rwsem(&(name)->rwsem);	\
 		(name)->head = NULL;		\
 	} while (0)
+#define TUNABLE_ATOMIC_INIT_NOTIFIER(val1, val2) do {	\
+		spin_lock_init(&(val1)->lock);		\
+		(val1)->head = NULL;			\
+		(val1)->name = val2;			\
+		(val1)->dir = NULL;			\
+	} while (0)
 #define RAW_INIT_NOTIFIER_HEAD(name) do {	\
 		(name)->head = NULL;		\
 	} while (0)
@@ -96,6 +118,11 @@ extern void srcu_init_notifier_head(stru
 #define BLOCKING_NOTIFIER_INIT(name) {				\
 		.rwsem = __RWSEM_INITIALIZER((name).rwsem),	\
 		.head = NULL }
+#define TUNABLE_ATOMIC_NOTIFIER_INIT(val1, val2) {			\
+		.lock =__SPIN_LOCK_UNLOCKED(val1.lock),		\
+		.head = NULL,					\
+		.name = val2,						\
+		.dir = NULL }
 #define RAW_NOTIFIER_INIT(name)	{				\
 		.head = NULL }
 /* srcu_notifier_heads cannot be initialized statically */
@@ -106,6 +133,9 @@ extern void srcu_init_notifier_head(stru
 #define BLOCKING_NOTIFIER_HEAD(name)				\
 	struct blocking_notifier_head name =			\
 		BLOCKING_NOTIFIER_INIT(name)
+#define TUNABLE_ATOMIC_NOTIFIER_HEAD(name, val)			\
+	struct tunable_atomic_notifier_head name =			\
+		TUNABLE_ATOMIC_NOTIFIER_INIT(name, val)
 #define RAW_NOTIFIER_HEAD(name)					\
 	struct raw_notifier_head name =				\
 		RAW_NOTIFIER_INIT(name)
@@ -116,6 +146,10 @@ extern int atomic_notifier_chain_registe
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 		struct notifier_block *nb);
+extern int tunable_atomic_notifier_chain_register(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_notifier_block *nb,
+				char *name, char *desc);
 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,
@@ -125,6 +159,9 @@ extern int atomic_notifier_chain_unregis
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
 		struct notifier_block *nb);
+extern int tunable_atomic_notifier_chain_unregister(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_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,
@@ -138,6 +175,13 @@ extern int blocking_notifier_call_chain(
 		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 tunable_atomic_notifier_call_chain(
+				struct tunable_atomic_notifier_head *nh,
+				unsigned long val, void *v);
+extern int __tunable_atomic_notifier_call_chain(
+				struct tunable_atomic_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,
diff -uprN linux-2.6.23.orig/kernel/sys.c linux-2.6.23/kernel/sys.c
--- linux-2.6.23.orig/kernel/sys.c	2007-10-10 05:31:38.000000000 +0900
+++ linux-2.6.23/kernel/sys.c	2007-10-18 10:08:52.728000000 +0900
@@ -38,6 +38,7 @@
 #include <linux/syscalls.h>
 #include <linux/kprobes.h>
 #include <linux/user_namespace.h>
+#include <linux/debugfs.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>
@@ -393,6 +394,243 @@ int blocking_notifier_call_chain(struct 
 EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
 
 /*
+ *	Tunable atomic notifier chain routines. Registration and unregistration
+ *	use a spinlock, and call_chain is synchronized by RCU (no locks).
+ *	User can change the list order to use /sys/kernel/debug/list-name/.
+ */
+
+static ssize_t priority_read(struct file *file,
+			char __user *user_buf, size_t count, loff_t *ppos)
+{
+	struct tunable_atomic_notifier_block *n =
+					file->f_dentry->d_inode->i_private;
+	int priority = n->nb->priority;
+	char buf[64], *s;
+
+	s = buf;
+	s += sprintf(s, "%d\n", priority);
+
+	return simple_read_from_buffer((void __user *)user_buf, count,
+							ppos, buf, s - buf);
+}
+
+static ssize_t priority_write(struct file *file,
+		const char __user *user_buf, size_t count, loff_t *ppos)
+{
+	struct tunable_atomic_notifier_block *n =
+					file->f_dentry->d_inode->i_private;
+	struct tunable_atomic_notifier_head *nh = n->head;
+	char *buf, *end;
+	int ret = -ENOMEM, priority;
+	unsigned long tmp, flags;
+
+	buf = kmalloc(count + 1, GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	buf[count] = 0;
+	ret = -EFAULT;
+	if (copy_from_user(buf, user_buf, count))
+		goto out_free;
+
+	ret = -EINVAL;
+	tmp = simple_strtoul(buf, &end, 10);
+	if ((end == buf) || (tmp > INT_MAX))
+		goto out_free;
+
+	priority = (int)tmp;
+	n->nb->priority = priority;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_unregister(&nh->head, n->nb);
+	if (ret)
+		goto out_unlock;
+	ret = notifier_chain_register(&nh->head, n->nb);
+	if (!ret)
+		ret = count;
+
+out_unlock:
+	spin_unlock_irqrestore(&nh->lock, flags);
+out_free:
+	kfree(buf);
+out:
+	return ret;
+
+}
+
+static const struct file_operations pri_fops = {
+	.read = priority_read,
+	.write = priority_write,
+};
+
+static ssize_t description_read(struct file *file,
+			char __user *user_buf, size_t count, loff_t *ppos)
+{
+	char *desc = file->f_dentry->d_inode->i_private;
+	int avail = strlen(desc);
+
+	return simple_read_from_buffer(user_buf, count, ppos, desc, avail);
+}
+
+static const struct file_operations desc_fops = {
+	.read = description_read,
+};
+
+/**
+ *	tunable_atomic_notifier_chain_register
+ *				- Add notifier to an tunable notifier chain
+ *	@nh: Pointer to head of the tunable notifier chain
+ *	@n: New entry in notifier chain
+ *	@name: Pointer to the name of the new notifier entry
+ *	@desc: Pointer to the description of new entry
+ *
+ *	Adds a notifier to an tunable notifier chain and makes control dir.
+ *
+ *	Returns zero on success or %-ENODEV on failure.
+ */
+
+int tunable_atomic_notifier_chain_register(
+		struct tunable_atomic_notifier_head *nh,
+		struct tunable_atomic_notifier_block *n, char *name, char *desc)
+{
+	unsigned long flags;
+	int ret = -EINVAL;
+	struct dentry *nh_dir, *nb_dir, *pri_dentry, *desc_dentry = NULL;
+
+	if (!name)
+		goto nb_fail;
+
+	ret = -ENOMEM;
+	if (!nh->dir) {
+		nh_dir = debugfs_create_dir(nh->name, NULL);
+		if (!nh_dir)
+			return ret;
+		nh->dir = nh_dir;
+	} else
+		nh_dir = nh->dir;
+
+	nb_dir = debugfs_create_dir(name, nh_dir);
+	if (!nb_dir)
+		goto nb_fail;
+	n->dir = nb_dir;
+
+	pri_dentry = debugfs_create_file("priority",0600, nb_dir, n, &pri_fops);
+	if (!pri_dentry)
+		goto pri_fail;
+	n->pri_dentry = pri_dentry;
+
+	if (desc) {
+		desc_dentry = debugfs_create_file("description", 0400, nb_dir,
+							desc, &desc_fops);
+		if (!desc_dentry)
+			goto desc_fail;
+		n->desc_dentry = desc_dentry;
+	}
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n->nb);
+	spin_unlock_irqrestore(&nh->lock, flags);
+
+	if (ret)
+		goto reg_fail;
+	
+	n->head = nh;
+
+	return ret;
+
+reg_fail:
+	debugfs_remove(desc_dentry);
+desc_fail:
+	debugfs_remove(pri_dentry);
+pri_fail:
+	debugfs_remove(nb_dir);
+nb_fail:
+	return ret;
+}
+
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_chain_register);
+
+/**
+ *	tunable_atomic_notifier_chain_unregister
+ *				- Remove notifier from a tunable notifier chain
+ *	@nh: Pointer to head of the tunable notifier chain
+ *	@n: Entry to remove from notifier chain
+ *
+ *	Removes a notifier from a tunable notifier chain.
+ *
+ *	Retunrns zero on success or %-ENOENT on failure.
+ */
+
+int tunable_atomic_notifier_chain_unregister(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_unregister(&nh->head, n->nb);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	synchronize_rcu();
+
+	if (ret)
+		return ret;
+
+	debugfs_remove(n->desc_dentry);
+	debugfs_remove(n->pri_dentry);
+	debugfs_remove(n->dir);
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_chain_unregister);
+
+/**
+ *	__tunable_atomic_notifier_call_chain
+ *				- Call functions in a tunable notifier chain
+ *	@nh: Pointer to head of the tunable notifier chain
+ *	@val: Value passed unmodified to notifier function
+ *	@v: Pointer passed unmodified to notifier function
+ *	@nt_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 tunable_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 __tunable_atomic_notifier_call_chain(
+					struct tunable_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(__tunable_atomic_notifier_call_chain);
+
+int __kprobes tunable_atomic_notifier_call_chain(
+					struct tunable_atomic_notifier_head *nh,
+					unsigned long val, void *v)
+{
+	return __tunable_atomic_notifier_call_chain(nh, val, v, -1, NULL);
+}
+
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_call_chain);
+
+/*
  *	Raw notifier chain routines.  There is no protection;
  *	the caller must provide it.  Use at your own risk!
  */

Re: [PATCH 1/2] add tunable_notifier function ,take2

[Randy Dunlap]

On Thu, 18 Oct 2007 17:53:00 +0900 Takenori Nagano wrote:

> This patch adds new notifier function tunable_notifier_chain. Its base is
> atomic_notifier_chain.
> 
> Thanks,
> 
> ---
> 
> Signed-off-by: Takenori Nagano <t-nagano@ah.jp.nec.com>
> 
> ---
> diff -uprN linux-2.6.23.orig/kernel/sys.c linux-2.6.23/kernel/sys.c
> --- linux-2.6.23.orig/kernel/sys.c	2007-10-10 05:31:38.000000000 +0900
> +++ linux-2.6.23/kernel/sys.c	2007-10-18 10:08:52.728000000 +0900
> @@ -38,6 +38,7 @@
>  #include <linux/syscalls.h>
>  #include <linux/kprobes.h>
>  #include <linux/user_namespace.h>
> +#include <linux/debugfs.h>
>  
>  #include <asm/uaccess.h>
>  #include <asm/io.h>
> @@ -393,6 +394,243 @@ int blocking_notifier_call_chain(struct 
>  EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);

> +/**
> + *	tunable_atomic_notifier_chain_register
> + *				- Add notifier to an tunable notifier chain

Function name & short description must be on one (long?) line.  :(

> + *	@nh: Pointer to head of the tunable notifier chain
> + *	@n: New entry in notifier chain
> + *	@name: Pointer to the name of the new notifier entry
> + *	@desc: Pointer to the description of new entry
> + *
> + *	Adds a notifier to an tunable notifier chain and makes control dir.
> + *
> + *	Returns zero on success or %-ENODEV on failure.
> + */
> +
> +int tunable_atomic_notifier_chain_register(
> +		struct tunable_atomic_notifier_head *nh,
> +		struct tunable_atomic_notifier_block *n, char *name, char *desc)
> +{

> +}
> +
> +EXPORT_SYMBOL_GPL(tunable_atomic_notifier_chain_register);
> +
> +/**
> + *	tunable_atomic_notifier_chain_unregister
> + *				- Remove notifier from a tunable notifier chain

Ditto.

> + *	@nh: Pointer to head of the tunable notifier chain
> + *	@n: Entry to remove from notifier chain
> + *
> + *	Removes a notifier from a tunable notifier chain.
> + *
> + *	Retunrns zero on success or %-ENOENT on failure.
> + */
> +
> +int tunable_atomic_notifier_chain_unregister(
> +				struct tunable_atomic_notifier_head *nh,
> +				struct tunable_atomic_notifier_block *n)
> +{

> +}
> +
> +EXPORT_SYMBOL_GPL(tunable_atomic_notifier_chain_unregister);
> +
> +/**
> + *	__tunable_atomic_notifier_call_chain
> + *				- Call functions in a tunable notifier chain

Same.

> + *	@nh: Pointer to head of the tunable notifier chain
> + *	@val: Value passed unmodified to notifier function
> + *	@v: Pointer passed unmodified to notifier function
> + *	@nt_to_call: See the comment for notifier_call_chain

	@nr_to_call: ...

> + *	@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 tunable_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 __tunable_atomic_notifier_call_chain(
> +					struct tunable_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(__tunable_atomic_notifier_call_chain);

Blank line is usually omitted before EXPORT_SYMBOL....

---
~Randy

Re: [PATCH 1/2] add tunable_notifier function ,take2

[Takenori Nagano]

Randy Dunlap wrote:
> On Thu, 18 Oct 2007 17:53:00 +0900 Takenori Nagano wrote:
> 
>> This patch adds new notifier function tunable_notifier_chain. Its base is
>> atomic_notifier_chain.
>>
>> Thanks,
>>
>> ---
>>
>> Signed-off-by: Takenori Nagano <t-nagano@ah.jp.nec.com>
>>
>> ---
>> diff -uprN linux-2.6.23.orig/kernel/sys.c linux-2.6.23/kernel/sys.c
>> --- linux-2.6.23.orig/kernel/sys.c	2007-10-10 05:31:38.000000000 +0900
>> +++ linux-2.6.23/kernel/sys.c	2007-10-18 10:08:52.728000000 +0900
>> @@ -38,6 +38,7 @@
>>  #include <linux/syscalls.h>
>>  #include <linux/kprobes.h>
>>  #include <linux/user_namespace.h>
>> +#include <linux/debugfs.h>
>>  
>>  #include <asm/uaccess.h>
>>  #include <asm/io.h>
>> @@ -393,6 +394,243 @@ int blocking_notifier_call_chain(struct 
>>  EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
> 
>> +/**
>> + *	tunable_atomic_notifier_chain_register
>> + *				- Add notifier to an tunable notifier chain
> 
> Function name & short description must be on one (long?) line.  :(

OK. I'll fix next version.

>> +
>> +int __kprobes __tunable_atomic_notifier_call_chain(
>> +					struct tunable_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(__tunable_atomic_notifier_call_chain);
> 
> Blank line is usually omitted before EXPORT_SYMBOL....

OK. I'll fix, too.

Thanks,
  Takenori

> ---
> ~Randy
> 
> 

[PATCH 1/2] add tunable_notifier function ,take2

[Takenori Nagano]

This patch adds new notifier function tunable_notifier_chain. Its base is
atomic_notifier_chain.

Thanks,

---

Signed-off-by: Takenori Nagano <t-nagano@ah.jp.nec.com>

---
diff -uprN linux-2.6.25-rc8-mm1.orig/include/linux/notifier.h linux-2.6.25-rc8-mm1/include/linux/notifier.h
--- linux-2.6.25-rc8-mm1.orig/include/linux/notifier.h	2008-04-08 16:37:43.700000000 +0900
+++ linux-2.6.25-rc8-mm1/include/linux/notifier.h	2008-04-09 20:01:10.328000000 +0900
@@ -13,6 +13,7 @@
 #include <linux/mutex.h>
 #include <linux/rwsem.h>
 #include <linux/srcu.h>
+#include <linux/kobject.h>
 
 /*
  * Notifier chains are of four types:
@@ -53,6 +54,13 @@ struct notifier_block {
 	int priority;
 };
 
+struct tunable_atomic_notifier_block {
+	struct notifier_block *nb;
+	struct tunable_atomic_notifier_head *head;
+	struct kobject kobj;
+	char *desc;
+};
+
 struct atomic_notifier_head {
 	spinlock_t lock;
 	struct notifier_block *head;
@@ -63,6 +71,13 @@ struct blocking_notifier_head {
 	struct notifier_block *head;
 };
 
+struct tunable_atomic_notifier_head {
+	spinlock_t lock;
+	struct notifier_block *head;
+	char *name;
+	struct kset *notifier_sub_kset;
+};
+
 struct raw_notifier_head {
 	struct notifier_block *head;
 };
@@ -73,6 +88,13 @@ struct srcu_notifier_head {
 	struct notifier_block *head;
 };
 
+struct control_file_info {
+	struct tunable_atomic_notifier_head *nh;
+	struct tunable_atomic_notifier_block *n;
+	char *name;
+	struct control_file_info *next;
+};
+
 #define ATOMIC_INIT_NOTIFIER_HEAD(name) do {	\
 		spin_lock_init(&(name)->lock);	\
 		(name)->head = NULL;		\
@@ -81,6 +103,12 @@ struct srcu_notifier_head {
 		init_rwsem(&(name)->rwsem);	\
 		(name)->head = NULL;		\
 	} while (0)
+#define TUNABLE_ATOMIC_INIT_NOTIFIER(val1, val2) do {		\
+		spin_lock_init(&(val1)->lock);			\
+		(val1)->head = NULL;				\
+		(val1)->name = val2;				\
+		(val1)->notifier_sub_kset = NULL;		\
+	} while (0)
 #define RAW_INIT_NOTIFIER_HEAD(name) do {	\
 		(name)->head = NULL;		\
 	} while (0)
@@ -96,6 +124,11 @@ extern void srcu_init_notifier_head(stru
 #define BLOCKING_NOTIFIER_INIT(name) {				\
 		.rwsem = __RWSEM_INITIALIZER((name).rwsem),	\
 		.head = NULL }
+#define TUNABLE_ATOMIC_NOTIFIER_INIT(val1, val2) {		\
+		.lock =__SPIN_LOCK_UNLOCKED(val1.lock),		\
+		.head = NULL,					\
+		.name = val2,					\
+		.notifier_sub_kset = NULL }
 #define RAW_NOTIFIER_INIT(name)	{				\
 		.head = NULL }
 /* srcu_notifier_heads cannot be initialized statically */
@@ -106,6 +139,9 @@ extern void srcu_init_notifier_head(stru
 #define BLOCKING_NOTIFIER_HEAD(name)				\
 	struct blocking_notifier_head name =			\
 		BLOCKING_NOTIFIER_INIT(name)
+#define TUNABLE_ATOMIC_NOTIFIER_HEAD(name, val)			\
+	struct tunable_atomic_notifier_head name =			\
+		TUNABLE_ATOMIC_NOTIFIER_INIT(name, val)
 #define RAW_NOTIFIER_HEAD(name)					\
 	struct raw_notifier_head name =				\
 		RAW_NOTIFIER_INIT(name)
@@ -116,6 +152,10 @@ extern int atomic_notifier_chain_registe
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_register(struct blocking_notifier_head *nh,
 		struct notifier_block *nb);
+extern int tunable_atomic_notifier_chain_register(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_notifier_block *nb,
+				char *name, char *desc);
 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,
@@ -129,6 +169,9 @@ extern int atomic_notifier_chain_unregis
 		struct notifier_block *nb);
 extern int blocking_notifier_chain_unregister(struct blocking_notifier_head *nh,
 		struct notifier_block *nb);
+extern int tunable_atomic_notifier_chain_unregister(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_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,
@@ -142,6 +185,14 @@ extern int blocking_notifier_call_chain(
 		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 tunable_atomic_notifier_call_chain(
+				struct tunable_atomic_notifier_head *nh,
+				unsigned long val, void *v);
+extern int __tunable_atomic_notifier_call_chain(
+				struct tunable_atomic_notifier_head *nh,
+				unsigned long val,  void *v,
+				int nr_to_call, int *nr_calls);
+extern int tunable_atomic_notifier_init(void);
 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,
diff -uprN linux-2.6.25-rc8-mm1.orig/kernel/ksysfs.c linux-2.6.25-rc8-mm1/kernel/ksysfs.c
--- linux-2.6.25-rc8-mm1.orig/kernel/ksysfs.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/kernel/ksysfs.c	2008-04-09 20:11:15.440000000 +0900
@@ -15,6 +15,7 @@
 #include <linux/init.h>
 #include <linux/kexec.h>
 #include <linux/sched.h>
+#include <linux/notifier.h>
 
 #define KERNEL_ATTR_RO(_name) \
 static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
@@ -146,7 +147,10 @@ static int __init ksysfs_init(void)
 	if (error)
 		goto notes_exit;
 
-	return 0;
+	/* create the /sys/kernel/notifiers directory */
+	error = tunable_atomic_notifier_init();
+
+	return error;
 
 notes_exit:
 	if (notes_size > 0)
diff -uprN linux-2.6.25-rc8-mm1.orig/kernel/notifier.c linux-2.6.25-rc8-mm1/kernel/notifier.c
--- linux-2.6.25-rc8-mm1.orig/kernel/notifier.c	2008-04-08 16:37:44.904000000 +0900
+++ linux-2.6.25-rc8-mm1/kernel/notifier.c	2008-04-11 16:31:14.765088353 +0900
@@ -319,6 +319,261 @@ int blocking_notifier_call_chain(struct 
 EXPORT_SYMBOL_GPL(blocking_notifier_call_chain);
 
 /*
+ *	Tunable atomic notifier chain routines. Registration and unregistration
+ *	use a spinlock, and call_chain is synchronized by RCU (no locks).
+ *	User can change the list order to use /sys/kernel/notifiers/list-name/.
+ */
+
+static ssize_t priority_show(struct kobject *kobj, 
+				struct kobj_attribute *attr, const char *buf)
+{
+	struct tunable_atomic_notifier_block *n = container_of(kobj,
+				struct tunable_atomic_notifier_block, kobj);
+
+	return sprintf(buf, "%d\n", n->nb->priority);
+}
+
+static ssize_t priority_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t size)
+{
+	struct tunable_atomic_notifier_block *n = container_of(kobj,
+				struct tunable_atomic_notifier_block, kobj);
+	struct tunable_atomic_notifier_head *nh = n->head;
+	unsigned long flags;
+	int priority, ret;
+
+	sscanf(buf, "%d", &priority);
+	n->nb->priority = priority;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_unregister(&nh->head, n->nb);
+	if (ret)
+		goto out_unlock;
+	ret = notifier_chain_register(&nh->head, n->nb);
+
+out_unlock:
+	spin_unlock_irqrestore(&nh->lock, flags);
+
+	return (ret ? ret : size);
+
+}
+
+static ssize_t description_show(struct kobject *kobj,
+				struct kobj_attribute *attr, const char *buf)
+{
+	struct tunable_atomic_notifier_block *n = container_of(kobj,
+				struct tunable_atomic_notifier_block, kobj);
+
+	if (n->desc)
+		return sprintf(buf, "%s\n", n->desc);
+
+	return sprintf(buf, "Description is not available\n");
+}
+
+static struct kobj_attribute priority_attr = 
+	__ATTR(priority, 0644, priority_show, priority_store);
+static struct kobj_attribute description_attr =
+	__ATTR_RO(description);
+
+static struct attribute *notifiers_attributes[] = {
+	&priority_attr.attr, &description_attr.attr, NULL 
+};
+
+static struct kobj_type notifiers_ktype = {
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_attrs = notifiers_attributes,
+};
+
+static struct kobject *notifiers_kobj;
+struct control_file_info *base;
+
+int notifiers_kobject_create(struct tunable_atomic_notifier_head *nh,
+			struct tunable_atomic_notifier_block *n, char *name)
+{
+	int error = -ENOMEM;
+	struct kobject *kobj = &n->kobj;
+
+	if (!nh->notifier_sub_kset) {
+		nh->notifier_sub_kset = kset_create_and_add(nh->name, NULL,
+							notifiers_kobj);
+		if (!nh->notifier_sub_kset)
+			goto out;
+	}
+
+	memset(kobj, 0, sizeof(struct kobject));
+	kobj->kset = nh->notifier_sub_kset;
+	error = kobject_init_and_add(kobj, &notifiers_ktype, NULL, "%s", name);
+	if (error)
+		kobject_put(kobj);
+
+out:
+	return error;
+}
+
+/**
+ *	tunable_atomic_notifier_chain_register - Add notifier to an tunable notifier chain
+ *	@nh: Pointer to head of the tunable notifier chain
+ *	@n: New entry in notifier chain
+ *	@name: Pointer to the name of the new notifier entry
+ *	@desc: Pointer to the description of new entry
+ *
+ *	Adds a notifier to an tunable notifier chain and makes control dir.
+ *	This function must be called after kmem_cache_init().
+ *
+ *	Returns zero on success or %-ENODEV on failure.
+ */
+
+int tunable_atomic_notifier_chain_register(
+		struct tunable_atomic_notifier_head *nh,
+		struct tunable_atomic_notifier_block *n, char *name, char *desc)
+{
+	unsigned long flags;
+	int ret;
+
+	if (!name)
+		return -EINVAL;
+	if (desc)
+		n->desc = desc;
+
+	if (!notifiers_kobj) {
+		struct control_file_info *temp, *new;
+
+		temp = kmalloc(sizeof(struct control_file_info), GFP_ATOMIC);
+		if (!temp)
+			return -ENOMEM;
+		temp->nh = nh;
+		temp->n = n;
+		temp->name = name;
+		temp->next = NULL;
+		if (!base)
+			base = temp;
+		else {
+			new = base;
+			while (new->next) {	
+				new = new->next;
+			}
+			new->next = temp;
+		}
+		goto regist;
+	}
+
+	ret = notifiers_kobject_create(nh, n, name);
+	if (ret)
+		return ret;
+
+regist:
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_register(&nh->head, n->nb);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	n->head = nh;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_chain_register);
+
+/**
+ *	tunable_atomic_notifier_chain_unregister - Remove notifier from a tunable notifier chain
+ *	@nh: Pointer to head of the tunable notifier chain
+ *	@n: Entry to remove from notifier chain
+ *
+ *	Removes a notifier from a tunable notifier chain.
+ *
+ *	Retunrns zero on success or %-ENOENT on failure.
+ */
+
+int tunable_atomic_notifier_chain_unregister(
+				struct tunable_atomic_notifier_head *nh,
+				struct tunable_atomic_notifier_block *n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&nh->lock, flags);
+	ret = notifier_chain_unregister(&nh->head, n->nb);
+	spin_unlock_irqrestore(&nh->lock, flags);
+	synchronize_rcu();
+
+	if (ret)
+		return ret;
+
+	kobject_del(&n->kobj);
+	kobject_put(&n->kobj);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_chain_unregister);
+
+/**
+ *	__tunable_atomic_notifier_call_chain - Call functions in a tunable notifier chain
+ *	@nh: Pointer to head of the tunable 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 tunable_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 __tunable_atomic_notifier_call_chain(
+					struct tunable_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(__tunable_atomic_notifier_call_chain);
+
+int __kprobes tunable_atomic_notifier_call_chain(
+					struct tunable_atomic_notifier_head *nh,
+					unsigned long val, void *v)
+{
+	return __tunable_atomic_notifier_call_chain(nh, val, v, -1, NULL);
+}
+EXPORT_SYMBOL_GPL(tunable_atomic_notifier_call_chain);
+
+int __init tunable_atomic_notifier_init(void) {
+	struct control_file_info *prev, *temp = base;
+	struct tunable_atomic_notifier_head *nh;
+	struct tunable_atomic_notifier_block *n;
+	char *name;
+	int error;
+
+	notifiers_kobj = kobject_create_and_add("notifiers", kernel_kobj);
+
+	if (!notifiers_kobj)
+		return -ENOMEM;
+
+	while (temp) {
+		nh = temp->nh;
+		n = temp->n;
+		name = temp->name;
+
+		error = notifiers_kobject_create(nh, n, name);
+		if (error)
+			printk("%s: %s is failed to create. err = %d\n",
+							nh->name, name, error);
+		prev = temp;
+		temp = temp->next;
+		kfree(prev);
+	}
+	return 0;
+}
+
+/*
  *	Raw notifier chain routines.  There is no protection;
  *	the caller must provide it.  Use at your own risk!
  */

[PATCH 2/2] implement new notifier function to panic_notifier_list ,take3

[Takenori Nagano]

This patch implements new notifier function to panic_notifier_list. We can
change the list of order by debugfs.

Thanks,

---

Signed-off-by: Takenori Nagano <t-nagano@ah.jp.nec.com>

---
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/alpha/kernel/setup.c linux-2.6.25-rc8-mm1/arch/alpha/kernel/setup.c
--- linux-2.6.25-rc8-mm1.orig/arch/alpha/kernel/setup.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/alpha/kernel/setup.c	2008-04-10 21:30:16.143555075 +0900
@@ -44,14 +44,18 @@
 #include <asm/io.h>
 #include <linux/log2.h>
 
-extern struct atomic_notifier_head panic_notifier_list;
+extern struct tunable_atomic_notifier_head panic_notifier_list;
 static int alpha_panic_event(struct notifier_block *, unsigned long, void *);
-static struct notifier_block alpha_panic_block = {
+static struct notifier_block alpha_panic_block_base = {
 	alpha_panic_event,
         NULL,
         INT_MAX /* try to do it first */
 };
 
+static struct tunable_atomic_notifier_block alpha_panic_block = {
+	.nb = &alpha_panic_block_base
+};
+
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -521,8 +525,8 @@ setup_arch(char **cmdline_p)
 	}
 
 	/* Register a call for panic conditions. */
-	atomic_notifier_chain_register(&panic_notifier_list,
-			&alpha_panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+				&alpha_panic_block, "alpha_panic", NULL);
 
 #ifdef CONFIG_ALPHA_GENERIC
 	/* Assume that we've booted from SRM if we haven't booted from MILO.
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/arm/mach-omap1/board-voiceblue.c linux-2.6.25-rc8-mm1/arch/arm/mach-omap1/board-voiceblue.c
--- linux-2.6.25-rc8-mm1.orig/arch/arm/mach-omap1/board-voiceblue.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/arm/mach-omap1/board-voiceblue.c	2008-04-10 22:01:58.275482847 +0900
@@ -226,14 +226,19 @@ static int panic_event(struct notifier_b
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block panic_block = {
+static struct notifier_block panic_block_base = {
 	.notifier_call	= panic_event,
 };
 
+static struct tunable_atomic_notifier_block panic_block = {
+	.nb             = &panic_block_base
+};
+
 static int __init voiceblue_setup(void)
 {
 	/* Setup panic notifier */
-	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					&panic_block, "VoiceBlue", NULL);
 
 	return 0;
 }
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/mips/lasat/setup.c linux-2.6.25-rc8-mm1/arch/mips/lasat/setup.c
--- linux-2.6.25-rc8-mm1.orig/arch/mips/lasat/setup.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/mips/lasat/setup.c	2008-04-10 21:10:23.147126270 +0900
@@ -106,7 +106,7 @@ static int lasat_panic_prom_monitor(stru
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block lasat_panic_block[] =
+static struct notifier_block lasat_panic_block_base[] =
 {
 	{
 		.notifier_call	= lasat_panic_display,
@@ -117,6 +117,18 @@ static struct notifier_block lasat_panic
 	}
 };
 
+static struct tunable_atomic_notifier_block lasat_panic_block[] = {
+	{
+		.nb		= &lasat_panic_block_base[0]
+	}, {
+		.nb		= &lasat_panic_block_base[1]
+	}
+};
+
+static char* notifier_name[] = {
+	"lasat_panic_display", "lasat_panic_prom_monitor"
+};
+
 void __init plat_time_init(void)
 {
 	mips_hpt_frequency = lasat_board_info.li_cpu_hz / 2;
@@ -134,8 +146,8 @@ void __init plat_mem_setup(void)
 
 	/* Set up panic notifier */
 	for (i = 0; i < ARRAY_SIZE(lasat_panic_block); i++)
-		atomic_notifier_chain_register(&panic_notifier_list,
-				&lasat_panic_block[i]);
+		tunable_notifier_chain_register(&panic_notifier_list,
+				&lasat_panic_block[i], notifier_name[i], NULL);
 
 	lasat_reboot_setup();
 
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/mips/sgi-ip22/ip22-reset.c linux-2.6.25-rc8-mm1/arch/mips/sgi-ip22/ip22-reset.c
--- linux-2.6.25-rc8-mm1.orig/arch/mips/sgi-ip22/ip22-reset.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/mips/sgi-ip22/ip22-reset.c	2008-04-10 22:04:16.570605171 +0900
@@ -226,10 +226,14 @@ static int panic_event(struct notifier_b
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block panic_block = {
+static struct notifier_block panic_block_base = {
 	.notifier_call	= panic_event,
 };
 
+static struct tunable_atomic_notifier_block panic_block = {
+	.nb		= &panic_block_base
+};
+
 static int __init reboot_setup(void)
 {
 	int res;
@@ -246,7 +250,8 @@ static int __init reboot_setup(void)
 
 	init_timer(&blink_timer);
 	blink_timer.function = blink_timeout;
-	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					       &panic_block, "sgi-ip22", NULL);
 
 	return 0;
 }
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/mips/sgi-ip32/ip32-reset.c linux-2.6.25-rc8-mm1/arch/mips/sgi-ip32/ip32-reset.c
--- linux-2.6.25-rc8-mm1.orig/arch/mips/sgi-ip32/ip32-reset.c	2008-04-08 16:37:19.068000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/mips/sgi-ip32/ip32-reset.c	2008-04-10 22:04:37.830470059 +0900
@@ -175,10 +175,14 @@ static int panic_event(struct notifier_b
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block panic_block = {
+static struct notifier_block panic_block_base = {
 	.notifier_call = panic_event,
 };
 
+static struct tunable_atomic_notifier_block panic_block = {
+	.nb		= &panic_block_base
+};
+
 static __init int ip32_reboot_setup(void)
 {
 	/* turn on the green led only */
@@ -193,7 +197,8 @@ static __init int ip32_reboot_setup(void
 
 	init_timer(&blink_timer);
 	blink_timer.function = blink_timeout;
-	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					       &panic_block, "sgi-ip32", NULL);
 
 	if (request_irq(MACEISA_RTC_IRQ, ip32_rtc_int, 0, "rtc", NULL))
 		panic("Can't allocate MACEISA RTC IRQ");
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/parisc/kernel/pdc_chassis.c linux-2.6.25-rc8-mm1/arch/parisc/kernel/pdc_chassis.c
--- linux-2.6.25-rc8-mm1.orig/arch/parisc/kernel/pdc_chassis.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/parisc/kernel/pdc_chassis.c	2008-04-10 21:28:22.068278645 +0900
@@ -101,11 +101,14 @@ static int pdc_chassis_panic_event(struc
 }   
 
 
-static struct notifier_block pdc_chassis_panic_block = {
+static struct notifier_block pdc_chassis_panic_block_base = {
 	.notifier_call = pdc_chassis_panic_event,
 	.priority = INT_MAX,
 };
 
+static struct tunable_atomic_notifier_block pdc_chassis_panic_block = {
+	.nb		= &pdc_chassis_panic_block_base
+};
 
 /**
  * parisc_reboot_event() - Called by the reboot handler.
@@ -144,8 +147,8 @@ void __init parisc_pdc_chassis_init(void
 				PDC_CHASSIS_VER);
 
 		/* initialize panic notifier chain */
-		atomic_notifier_chain_register(&panic_notifier_list,
-				&pdc_chassis_panic_block);
+		tunable_atomic_notifier_chain_register(&panic_notifier_list,
+				&pdc_chassis_panic_block, "pdc_chassis", NULL);
 
 		/* initialize reboot notifier chain */
 		register_reboot_notifier(&pdc_chassis_reboot_block);
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/powerpc/kernel/setup-common.c linux-2.6.25-rc8-mm1/arch/powerpc/kernel/setup-common.c
--- linux-2.6.25-rc8-mm1.orig/arch/powerpc/kernel/setup-common.c	2008-04-08 16:37:20.204000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/powerpc/kernel/setup-common.c	2008-04-08 16:32:35.232000000 +0900
@@ -609,14 +609,19 @@ static int ppc_panic_event(struct notifi
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block ppc_panic_block = {
+static struct notifier_block ppc_panic_block_base = {
 	.notifier_call = ppc_panic_event,
 	.priority = INT_MIN /* may not return; must be done last */
 };
 
+static struct tunable_atomic_notifier_block ppc_panic_block = {
+	.nb		= &ppc_panic_block_base
+};
+
 void __init setup_panic(void)
 {
-	atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					&ppc_panic_block, "powerpc", NULL);
 }
 
 #ifdef CONFIG_CHECK_CACHE_COHERENCY
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/ppc/platforms/prep_setup.c linux-2.6.25-rc8-mm1/arch/ppc/platforms/prep_setup.c
--- linux-2.6.25-rc8-mm1.orig/arch/ppc/platforms/prep_setup.c	2008-04-08 16:37:23.060000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/ppc/platforms/prep_setup.c	2008-04-10 21:31:42.807004709 +0900
@@ -634,12 +634,16 @@ ibm_statusled_panic(struct notifier_bloc
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block ibm_statusled_block = {
+static struct notifier_block ibm_statusled_block_base = {
 	ibm_statusled_panic,
 	NULL,
 	INT_MAX /* try to do it first */
 };
 
+static struct tunable_atomic_notifier_block ibm_statusled_block = {
+	.nb = &ibm_statusled_block_base
+};
+
 static void
 ibm_statusled_progress(char *s, unsigned short hex)
 {
@@ -654,8 +658,9 @@ ibm_statusled_progress(char *s, unsigned
 		hex = 0xfff;
 		if (!notifier_installed) {
 			++notifier_installed;
-			atomic_notifier_chain_register(&panic_notifier_list,
-						&ibm_statusled_block);
+			tunable_atomic_notifier_chain_register(
+				&panic_notifier_list, &ibm_statusled_block,
+				"IBM_statusLED", NULL);
 		}
 	}
 	else
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/s390/kernel/ipl.c linux-2.6.25-rc8-mm1/arch/s390/kernel/ipl.c
--- linux-2.6.25-rc8-mm1.orig/arch/s390/kernel/ipl.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/s390/kernel/ipl.c	2008-04-08 16:32:35.232000000 +0900
@@ -1372,11 +1372,15 @@ static int on_panic_notify(struct notifi
 	return NOTIFY_OK;
 }
 
-static struct notifier_block on_panic_nb = {
+static struct notifier_block on_panic_nb_base = {
 	.notifier_call = on_panic_notify,
 	.priority = 0,
 };
 
+static struct tunable_atomic_notifier_block on_panic_nb = {
+	.nb = &on_panic_nb_base
+};
+
 void __init setup_ipl(void)
 {
 	ipl_info.type = get_ipl_type();
@@ -1402,7 +1406,8 @@ void __init setup_ipl(void)
 		/* We have no info to copy */
 		break;
 	}
-	atomic_notifier_chain_register(&panic_notifier_list, &on_panic_nb);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+						&on_panic_nb, "s390_ipl", NULL);
 }
 
 void __init ipl_save_parameters(void)
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/sparc64/kernel/sstate.c linux-2.6.25-rc8-mm1/arch/sparc64/kernel/sstate.c
--- linux-2.6.25-rc8-mm1.orig/arch/sparc64/kernel/sstate.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/sparc64/kernel/sstate.c	2008-04-10 21:32:20.798763557 +0900
@@ -82,11 +82,15 @@ static int sstate_panic_event(struct not
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block sstate_panic_block = {
+static struct notifier_block sstate_panic_block_base = {
 	.notifier_call	=	sstate_panic_event,
 	.priority	=	INT_MAX,
 };
 
+static struct tunable_atomic_notifier_block sstate_panic_block = {
+	.nb		=	&sstate_panic_block_base
+};
+
 void __init sun4v_sstate_init(void)
 {
 	unsigned long major, minor;
@@ -99,6 +103,6 @@ void __init sun4v_sstate_init(void)
 	hv_supports_soft_state = 1;
 
 	prom_sun4v_guest_soft_state();
-	atomic_notifier_chain_register(&panic_notifier_list,
-				       &sstate_panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					&sstate_panic_block, "sstate" ,NULL);
 }
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/um/drivers/mconsole_kern.c linux-2.6.25-rc8-mm1/arch/um/drivers/mconsole_kern.c
--- linux-2.6.25-rc8-mm1.orig/arch/um/drivers/mconsole_kern.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/um/drivers/mconsole_kern.c	2008-04-08 16:32:35.236000000 +0900
@@ -920,16 +920,20 @@ static int notify_panic(struct notifier_
 	return 0;
 }
 
-static struct notifier_block panic_exit_notifier = {
+static struct notifier_block panic_exit_notifier_base = {
 	.notifier_call 		= notify_panic,
 	.next 			= NULL,
 	.priority 		= 1
 };
 
+static struct tunable_atomic_notifier_block panic_exit_notifier = {
+	.nb			= &panic_exit_notifier_base
+};
+
 static int add_notifier(void)
 {
-	atomic_notifier_chain_register(&panic_notifier_list,
-			&panic_exit_notifier);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					&panic_exit_notifier, "mconsole", NULL);
 	return 0;
 }
 
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/um/kernel/um_arch.c linux-2.6.25-rc8-mm1/arch/um/kernel/um_arch.c
--- linux-2.6.25-rc8-mm1.orig/arch/um/kernel/um_arch.c	2008-04-08 16:37:25.004000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/um/kernel/um_arch.c	2008-04-08 16:32:35.236000000 +0900
@@ -234,12 +234,16 @@ static int panic_exit(struct notifier_bl
 	return 0;
 }
 
-static struct notifier_block panic_exit_notifier = {
+static struct notifier_block panic_exit_notifier_base = {
 	.notifier_call 		= panic_exit,
 	.next 			= NULL,
 	.priority 		= 0
 };
 
+static struct tunable_atomic_notifier_block panic_exit_notifier = {
+	.nb			= &panic_exit_notifier_base
+};
+
 /* Set during early boot */
 unsigned long task_size;
 EXPORT_SYMBOL(task_size);
@@ -357,8 +361,8 @@ int __init linux_main(int argc, char **a
 		printf("Kernel virtual memory size shrunk to %lu bytes\n",
 		       virtmem_size);
 
-	atomic_notifier_chain_register(&panic_notifier_list,
-				       &panic_exit_notifier);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+				       &panic_exit_notifier, "um", NULL);
 
 	uml_postsetup();
 
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/x86/lguest/boot.c linux-2.6.25-rc8-mm1/arch/x86/lguest/boot.c
--- linux-2.6.25-rc8-mm1.orig/arch/x86/lguest/boot.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/x86/lguest/boot.c	2008-04-08 16:32:35.236000000 +0900
@@ -820,17 +820,22 @@ static int lguest_panic(struct notifier_
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block paniced = {
+static struct notifier_block paniced_base = {
 	.notifier_call = lguest_panic
 };
 
+static struct tunable_atomic_notifier_block paniced = {
+	.nb = = &paniced_base
+};
+
 /* Setting up memory is fairly easy. */
 static __init char *lguest_memory_setup(void)
 {
 	/* We do this here and not earlier because lockcheck used to barf if we
 	 * did it before start_kernel().  I think we fixed that, so it'd be
 	 * nice to move it back to lguest_init.  Patch welcome... */
-	atomic_notifier_chain_register(&panic_notifier_list, &paniced);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list, &paniced,
+							"lguest", NULL);
 
 	/* The Linux bootloader header contains an "e820" memory map: the
 	 * Launcher populated the first entry with our memory limit. */
diff -uprN linux-2.6.25-rc8-mm1.orig/arch/xtensa/platforms/iss/setup.c linux-2.6.25-rc8-mm1/arch/xtensa/platforms/iss/setup.c
--- linux-2.6.25-rc8-mm1.orig/arch/xtensa/platforms/iss/setup.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/arch/xtensa/platforms/iss/setup.c	2008-04-10 21:33:24.422359602 +0900
@@ -98,13 +98,18 @@ iss_panic_event(struct notifier_block *t
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block iss_panic_block = {
+static struct notifier_block iss_panic_block_base = {
 	iss_panic_event,
 	NULL,
 	0
 };
 
+static struct tunable_atomic_notifier_block iss_panic_block = {
+	.nb = &iss_panic_block_base
+};
+
 void __init platform_setup(char **p_cmdline)
 {
-	atomic_notifier_chain_register(&panic_notifier_list, &iss_panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					&iss_panic_block, "iss_panic", NULL);
 }
diff -uprN linux-2.6.25-rc8-mm1.orig/drivers/char/ipmi/ipmi_msghandler.c linux-2.6.25-rc8-mm1/drivers/char/ipmi/ipmi_msghandler.c
--- linux-2.6.25-rc8-mm1.orig/drivers/char/ipmi/ipmi_msghandler.c	2008-04-08 16:37:33.228000000 +0900
+++ linux-2.6.25-rc8-mm1/drivers/char/ipmi/ipmi_msghandler.c	2008-04-08 16:32:35.240000000 +0900
@@ -4235,12 +4235,16 @@ static int panic_event(struct notifier_b
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block panic_block = {
+static struct notifier_block panic_block_base = {
 	.notifier_call	= panic_event,
 	.next		= NULL,
 	.priority	= 200	/* priority: INT_MAX >= x >= 0 */
 };
 
+static struct tunable_atomic_notifier_block panic_block = {
+	.nb		= &panic_block_base
+};
+
 static int ipmi_init_msghandler(void)
 {
 	int rv;
@@ -4270,7 +4274,8 @@ static int ipmi_init_msghandler(void)
 	setup_timer(&ipmi_timer, ipmi_timeout, 0);
 	mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
 
-	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					&panic_block, "ipmi_msghandler", NULL);
 
 	initialized = 1;
 
@@ -4290,7 +4295,8 @@ static __exit void cleanup_ipmi(void)
 	if (!initialized)
 		return;
 
-	atomic_notifier_chain_unregister(&panic_notifier_list, &panic_block);
+	tunable_atomic_notifier_chain_unregister(&panic_notifier_list,
+						 &panic_block);
 
 	/*
 	 * This can't be called if any interfaces exist, so no worry
diff -uprN linux-2.6.25-rc8-mm1.orig/drivers/char/ipmi/ipmi_watchdog.c linux-2.6.25-rc8-mm1/drivers/char/ipmi/ipmi_watchdog.c
--- linux-2.6.25-rc8-mm1.orig/drivers/char/ipmi/ipmi_watchdog.c	2008-04-08 16:37:33.240000000 +0900
+++ linux-2.6.25-rc8-mm1/drivers/char/ipmi/ipmi_watchdog.c	2008-04-08 16:32:35.240000000 +0900
@@ -1157,12 +1157,15 @@ static int wdog_panic_handler(struct not
 	return NOTIFY_OK;
 }
 
-static struct notifier_block wdog_panic_notifier = {
+static struct notifier_block wdog_panic_notifier_base = {
 	.notifier_call	= wdog_panic_handler,
 	.next		= NULL,
 	.priority	= 150	/* priority: INT_MAX >= x >= 0 */
 };
 
+static struct tunable_atomic_notifier_block wdog_panic_notifier = {
+	.nb		= &wdog_panic_notifier_base
+};
 
 static void ipmi_new_smi(int if_num, struct device *device)
 {
@@ -1302,8 +1305,8 @@ static int __init ipmi_wdog_init(void)
 	check_parms();
 
 	register_reboot_notifier(&wdog_reboot_notifier);
-	atomic_notifier_chain_register(&panic_notifier_list,
-			&wdog_panic_notifier);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+				&wdog_panic_notifier, "ipmi_wdog", NULL);
 
 	rv = ipmi_smi_watcher_register(&smi_watcher);
 	if (rv) {
@@ -1311,8 +1314,8 @@ static int __init ipmi_wdog_init(void)
 		if (nmi_handler_registered)
 			unregister_die_notifier(&ipmi_nmi_handler);
 #endif
-		atomic_notifier_chain_unregister(&panic_notifier_list,
-						 &wdog_panic_notifier);
+		tunable_atomic_notifier_chain_unregister(&panic_notifier_list,
+						 	 &wdog_panic_notifier);
 		unregister_reboot_notifier(&wdog_reboot_notifier);
 		printk(KERN_WARNING PFX "can't register smi watcher\n");
 		return rv;
@@ -1333,8 +1336,8 @@ static void __exit ipmi_wdog_exit(void)
 		unregister_die_notifier(&ipmi_nmi_handler);
 #endif
 
-	atomic_notifier_chain_unregister(&panic_notifier_list,
-					 &wdog_panic_notifier);
+	tunable_atomic_notifier_chain_unregister(&panic_notifier_list,
+					 	 &wdog_panic_notifier);
 	unregister_reboot_notifier(&wdog_reboot_notifier);
 }
 module_exit(ipmi_wdog_exit);
diff -uprN linux-2.6.25-rc8-mm1.orig/drivers/misc/ibmasm/heartbeat.c linux-2.6.25-rc8-mm1/drivers/misc/ibmasm/heartbeat.c
--- linux-2.6.25-rc8-mm1.orig/drivers/misc/ibmasm/heartbeat.c	2008-04-08 16:37:35.952000000 +0900
+++ linux-2.6.25-rc8-mm1/drivers/misc/ibmasm/heartbeat.c	2008-04-10 21:34:19.254011678 +0900
@@ -48,17 +48,22 @@ static int panic_happened(struct notifie
 	return 0;
 }
 
-static struct notifier_block panic_notifier = { panic_happened, NULL, 1 };
+static struct notifier_block panic_notifier_base = { panic_happened, NULL, 1 };
+
+static struct tunable_atomic_notifier_block panic_notifier = { 
+	.nb = &panic_notifier_base
+};
 
 void ibmasm_register_panic_notifier(void)
 {
-	atomic_notifier_chain_register(&panic_notifier_list, &panic_notifier);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					       &panic_notifier, "ibmasm", NULL);
 }
 
 void ibmasm_unregister_panic_notifier(void)
 {
-	atomic_notifier_chain_unregister(&panic_notifier_list,
-			&panic_notifier);
+	tunable_atomic_notifier_chain_unregister(&panic_notifier_list,
+						 &panic_notifier);
 }
 
 
diff -uprN linux-2.6.25-rc8-mm1.orig/drivers/parisc/power.c linux-2.6.25-rc8-mm1/drivers/parisc/power.c
--- linux-2.6.25-rc8-mm1.orig/drivers/parisc/power.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/drivers/parisc/power.c	2008-04-10 21:34:44.089854095 +0900
@@ -189,11 +189,14 @@ static int parisc_panic_event(struct not
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block parisc_panic_block = {
+static struct notifier_block parisc_panic_block_base = {
 	.notifier_call	= parisc_panic_event,
 	.priority	= INT_MAX,
 };
 
+static struct tunable_atomic_notifier_block parisc_panic_block = {
+	.nb		= &parisc_panic_block_base
+};
 
 static int __init power_init(void)
 {
@@ -231,8 +234,8 @@ static int __init power_init(void)
 	}
 
 	/* Register a call for panic conditions. */
-	atomic_notifier_chain_register(&panic_notifier_list,
-			&parisc_panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+				&parisc_panic_block, "parisc_panic", NULL);
 
 	return 0;
 }
@@ -241,8 +244,8 @@ static void __exit power_exit(void)
 {
 	kthread_stop(power_task);
 
-	atomic_notifier_chain_unregister(&panic_notifier_list,
-			&parisc_panic_block);
+	tunable_atomic_notifier_chain_unregister(&panic_notifier_list,
+						 &parisc_panic_block);
 
 	pdc_soft_power_button(0);
 }
diff -uprN linux-2.6.25-rc8-mm1.orig/include/linux/kernel.h linux-2.6.25-rc8-mm1/include/linux/kernel.h
--- linux-2.6.25-rc8-mm1.orig/include/linux/kernel.h	2008-04-08 16:37:43.508000000 +0900
+++ linux-2.6.25-rc8-mm1/include/linux/kernel.h	2008-04-08 16:32:35.244000000 +0900
@@ -129,7 +129,7 @@ extern int _cond_resched(void);
 		(__x < 0) ? -__x : __x;		\
 	})
 
-extern struct atomic_notifier_head panic_notifier_list;
+extern struct tunable_atomic_notifier_head panic_notifier_list;
 extern long (*panic_blink)(long time);
 NORET_TYPE void panic(const char * fmt, ...)
 	__attribute__ ((NORET_AND format (printf, 1, 2))) __cold;
diff -uprN linux-2.6.25-rc8-mm1.orig/kernel/panic.c linux-2.6.25-rc8-mm1/kernel/panic.c
--- linux-2.6.25-rc8-mm1.orig/kernel/panic.c	2008-04-08 16:37:44.916000000 +0900
+++ linux-2.6.25-rc8-mm1/kernel/panic.c	2008-04-08 16:32:35.248000000 +0900
@@ -30,7 +30,7 @@ static DEFINE_SPINLOCK(pause_on_oops_loc
 
 int panic_timeout;
 
-ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
+TUNABLE_ATOMIC_NOTIFIER_HEAD(panic_notifier_list, "panic_notifier_list");
 
 EXPORT_SYMBOL(panic_notifier_list);
 
@@ -98,7 +98,7 @@ NORET_TYPE void panic(const char * fmt, 
 	smp_send_stop();
 #endif
 
-	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
+	tunable_atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
 
 	if (!panic_blink)
 		panic_blink = no_blink;
diff -uprN linux-2.6.25-rc8-mm1.orig/kernel/softlockup.c linux-2.6.25-rc8-mm1/kernel/softlockup.c
--- linux-2.6.25-rc8-mm1.orig/kernel/softlockup.c	2008-04-02 04:44:26.000000000 +0900
+++ linux-2.6.25-rc8-mm1/kernel/softlockup.c	2008-04-08 16:32:35.248000000 +0900
@@ -35,8 +35,12 @@ softlock_panic(struct notifier_block *th
 	return NOTIFY_DONE;
 }
 
-static struct notifier_block panic_block = {
-	.notifier_call = softlock_panic,
+static struct notifier_block panic_block_base = {
+	.notifier_call = softlock_panic
+};
+
+static struct tunable_atomic_notifier_block panic_block = {
+	.nb		= &panic_block_base
 };
 
 /*
@@ -310,5 +314,6 @@ __init void spawn_softlockup_task(void)
 	cpu_callback(&cpu_nfb, CPU_ONLINE, cpu);
 	register_cpu_notifier(&cpu_nfb);
 
-	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
+	tunable_atomic_notifier_chain_register(&panic_notifier_list,
+					&panic_block, "softlockup", NULL);
 }

Re: [PATCH 1/2] add tunable_notifier function ,take2

[Greg KH]

On Fri, Apr 11, 2008 at 04:53:52PM +0900, Takenori Nagano wrote:
> This patch adds new notifier function tunable_notifier_chain. Its base is
> atomic_notifier_chain.

You are adding sysfs files, not debugfs files, please change your
announcement text.

Also, as you are adding new sysfs files, we need some documentation to
be added to Documentation/ABI/ describing what these files are, what are
in them, and how to use them.

thanks,

greg k-h