initial_commit

3 files changed, 1075 insertions, 0 deletions

diff --git a/fs/debugfs/Makefile b/fs/debugfs/Makefile
new file mode 100644
index 00000000..840c4569
--- /dev/null
+++ b/fs/debugfs/Makefile
@@ -0,0 +1,4 @@
+debugfs-objs	:= inode.o file.o
+
+obj-$(CONFIG_DEBUG_FS)	+= debugfs.o
+
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
new file mode 100644
index 00000000..90f76575
--- /dev/null
+++ b/fs/debugfs/file.c
@@ -0,0 +1,527 @@
+/*
+ *  file.c - part of debugfs, a tiny little debug file system
+ *
+ *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
+ *  Copyright (C) 2004 IBM Inc.
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License version
+ *	2 as published by the Free Software Foundation.
+ *
+ *  debugfs is for people to use instead of /proc or /sys.
+ *  See Documentation/DocBook/filesystems for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/namei.h>
+#include <linux/debugfs.h>
+
+static ssize_t default_read_file(struct file *file, char __user *buf,
+				 size_t count, loff_t *ppos)
+{
+	return 0;
+}
+
+static ssize_t default_write_file(struct file *file, const char __user *buf,
+				   size_t count, loff_t *ppos)
+{
+	return count;
+}
+
+static int default_open(struct inode *inode, struct file *file)
+{
+	if (inode->i_private)
+		file->private_data = inode->i_private;
+
+	return 0;
+}
+
+const struct file_operations debugfs_file_operations = {
+	.read =		default_read_file,
+	.write =	default_write_file,
+	.open =		default_open,
+	.llseek =	noop_llseek,
+};
+
+static void *debugfs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	nd_set_link(nd, dentry->d_inode->i_private);
+	return NULL;
+}
+
+const struct inode_operations debugfs_link_operations = {
+	.readlink       = generic_readlink,
+	.follow_link    = debugfs_follow_link,
+};
+
+static int debugfs_u8_set(void *data, u64 val)
+{
+	*(u8 *)data = val;
+	return 0;
+}
+static int debugfs_u8_get(void *data, u64 *val)
+{
+	*val = *(u8 *)data;
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u8_ro, debugfs_u8_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u8_wo, NULL, debugfs_u8_set, "%llu\n");
+
+/**
+ * debugfs_create_u8 - create a debugfs file that is used to read and write an unsigned 8-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.  It is not wise to check for this value, but rather, check for
+ * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *debugfs_create_u8(const char *name, mode_t mode,
+				 struct dentry *parent, u8 *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_u8_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_u8_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_u8);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u8);
+
+static int debugfs_u16_set(void *data, u64 val)
+{
+	*(u16 *)data = val;
+	return 0;
+}
+static int debugfs_u16_get(void *data, u64 *val)
+{
+	*val = *(u16 *)data;
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u16_ro, debugfs_u16_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u16_wo, NULL, debugfs_u16_set, "%llu\n");
+
+/**
+ * debugfs_create_u16 - create a debugfs file that is used to read and write an unsigned 16-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.  It is not wise to check for this value, but rather, check for
+ * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *debugfs_create_u16(const char *name, mode_t mode,
+				  struct dentry *parent, u16 *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_u16_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_u16_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_u16);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u16);
+
+static int debugfs_u32_set(void *data, u64 val)
+{
+	*(u32 *)data = val;
+	return 0;
+}
+static int debugfs_u32_get(void *data, u64 *val)
+{
+	*val = *(u32 *)data;
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u32_ro, debugfs_u32_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u32_wo, NULL, debugfs_u32_set, "%llu\n");
+
+/**
+ * debugfs_create_u32 - create a debugfs file that is used to read and write an unsigned 32-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.  It is not wise to check for this value, but rather, check for
+ * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *debugfs_create_u32(const char *name, mode_t mode,
+				 struct dentry *parent, u32 *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_u32_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_u32_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_u32);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u32);
+
+static int debugfs_u64_set(void *data, u64 val)
+{
+	*(u64 *)data = val;
+	return 0;
+}
+
+static int debugfs_u64_get(void *data, u64 *val)
+{
+	*val = *(u64 *)data;
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u64_ro, debugfs_u64_get, NULL, "%llu\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_u64_wo, NULL, debugfs_u64_set, "%llu\n");
+
+/**
+ * debugfs_create_u64 - create a debugfs file that is used to read and write an unsigned 64-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.  It is not wise to check for this value, but rather, check for
+ * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *debugfs_create_u64(const char *name, mode_t mode,
+				 struct dentry *parent, u64 *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_u64_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_u64_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_u64);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u64);
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_x8, debugfs_u8_get, debugfs_u8_set, "0x%02llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x8_ro, debugfs_u8_get, NULL, "0x%02llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x8_wo, NULL, debugfs_u8_set, "0x%02llx\n");
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x16_ro, debugfs_u16_get, NULL, "0x%04llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x16_wo, NULL, debugfs_u16_set, "0x%04llx\n");
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x32_ro, debugfs_u32_get, NULL, "0x%08llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(fops_x32_wo, NULL, debugfs_u32_set, "0x%08llx\n");
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_x64, debugfs_u64_get, debugfs_u64_set, "0x%016llx\n");
+
+/*
+ * debugfs_create_x{8,16,32,64} - create a debugfs file that is used to read and write an unsigned {8,16,32,64}-bit value
+ *
+ * These functions are exactly the same as the above functions (but use a hex
+ * output for the decimal challenged). For details look at the above unsigned
+ * decimal functions.
+ */
+
+/**
+ * debugfs_create_x8 - create a debugfs file that is used to read and write an unsigned 8-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+struct dentry *debugfs_create_x8(const char *name, mode_t mode,
+				 struct dentry *parent, u8 *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_x8_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_x8_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_x8);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_x8);
+
+/**
+ * debugfs_create_x16 - create a debugfs file that is used to read and write an unsigned 16-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+struct dentry *debugfs_create_x16(const char *name, mode_t mode,
+				 struct dentry *parent, u16 *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_x16_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_x16_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_x16);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_x16);
+
+/**
+ * debugfs_create_x32 - create a debugfs file that is used to read and write an unsigned 32-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+struct dentry *debugfs_create_x32(const char *name, mode_t mode,
+				 struct dentry *parent, u32 *value)
+{
+	/* if there are no write bits set, make read only */
+	if (!(mode & S_IWUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_x32_ro);
+	/* if there are no read bits set, make write only */
+	if (!(mode & S_IRUGO))
+		return debugfs_create_file(name, mode, parent, value, &fops_x32_wo);
+
+	return debugfs_create_file(name, mode, parent, value, &fops_x32);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_x32);
+
+/**
+ * debugfs_create_x64 - create a debugfs file that is used to read and write an unsigned 64-bit value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+struct dentry *debugfs_create_x64(const char *name, mode_t mode,
+				 struct dentry *parent, u64 *value)
+{
+	return debugfs_create_file(name, mode, parent, value, &fops_x64);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_x64);
+
+
+static int debugfs_size_t_set(void *data, u64 val)
+{
+	*(size_t *)data = val;
+	return 0;
+}
+static int debugfs_size_t_get(void *data, u64 *val)
+{
+	*val = *(size_t *)data;
+	return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(fops_size_t, debugfs_size_t_get, debugfs_size_t_set,
+			"%llu\n");	/* %llu and %zu are more or less the same */
+
+/**
+ * debugfs_create_size_t - create a debugfs file that is used to read and write an size_t value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ */
+struct dentry *debugfs_create_size_t(const char *name, mode_t mode,
+				     struct dentry *parent, size_t *value)
+{
+	return debugfs_create_file(name, mode, parent, value, &fops_size_t);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_size_t);
+
+
+static ssize_t read_file_bool(struct file *file, char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	char buf[3];
+	u32 *val = file->private_data;
+	
+	if (*val)
+		buf[0] = 'Y';
+	else
+		buf[0] = 'N';
+	buf[1] = '\n';
+	buf[2] = 0x00;
+	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
+}
+
+static ssize_t write_file_bool(struct file *file, const char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	char buf[32];
+	size_t buf_size;
+	bool bv;
+	u32 *val = file->private_data;
+
+	buf_size = min(count, (sizeof(buf)-1));
+	if (copy_from_user(buf, user_buf, buf_size))
+		return -EFAULT;
+
+	if (strtobool(buf, &bv) == 0)
+		*val = bv;
+
+	return count;
+}
+
+static const struct file_operations fops_bool = {
+	.read =		read_file_bool,
+	.write =	write_file_bool,
+	.open =		default_open,
+	.llseek =	default_llseek,
+};
+
+/**
+ * debugfs_create_bool - create a debugfs file that is used to read and write a boolean value
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @value: a pointer to the variable that the file should read to and write
+ *         from.
+ *
+ * This function creates a file in debugfs with the given name that
+ * contains the value of the variable @value.  If the @mode variable is so
+ * set, it can be read from, and written to.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.  It is not wise to check for this value, but rather, check for
+ * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *debugfs_create_bool(const char *name, mode_t mode,
+				   struct dentry *parent, u32 *value)
+{
+	return debugfs_create_file(name, mode, parent, value, &fops_bool);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_bool);
+
+static ssize_t read_file_blob(struct file *file, char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	struct debugfs_blob_wrapper *blob = file->private_data;
+	return simple_read_from_buffer(user_buf, count, ppos, blob->data,
+			blob->size);
+}
+
+static const struct file_operations fops_blob = {
+	.read =		read_file_blob,
+	.open =		default_open,
+	.llseek =	default_llseek,
+};
+
+/**
+ * debugfs_create_blob - create a debugfs file that is used to read a binary blob
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this parameter is %NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @blob: a pointer to a struct debugfs_blob_wrapper which contains a pointer
+ *        to the blob data and the size of the data.
+ *
+ * This function creates a file in debugfs with the given name that exports
+ * @blob->data as a binary blob. If the @mode variable is so set it can be
+ * read from. Writing is not supported.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.  It is not wise to check for this value, but rather, check for
+ * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling
+ * code.
+ */
+struct dentry *debugfs_create_blob(const char *name, mode_t mode,
+				   struct dentry *parent,
+				   struct debugfs_blob_wrapper *blob)
+{
+	return debugfs_create_file(name, mode, parent, blob, &fops_blob);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_blob);
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
new file mode 100644
index 00000000..e7a7a2f0
--- /dev/null
+++ b/fs/debugfs/inode.c
@@ -0,0 +1,544 @@
+/*
+ *  file.c - part of debugfs, a tiny little debug file system
+ *
+ *  Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
+ *  Copyright (C) 2004 IBM Inc.
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License version
+ *	2 as published by the Free Software Foundation.
+ *
+ *  debugfs is for people to use instead of /proc or /sys.
+ *  See Documentation/DocBook/kernel-api for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/kobject.h>
+#include <linux/namei.h>
+#include <linux/debugfs.h>
+#include <linux/fsnotify.h>
+#include <linux/string.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+
+static struct vfsmount *debugfs_mount;
+static int debugfs_mount_count;
+static bool debugfs_registered;
+
+static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev,
+				       void *data, const struct file_operations *fops)
+
+{
+	struct inode *inode = new_inode(sb);
+
+	if (inode) {
+		inode->i_ino = get_next_ino();
+		inode->i_mode = mode;
+		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+		switch (mode & S_IFMT) {
+		default:
+			init_special_inode(inode, mode, dev);
+			break;
+		case S_IFREG:
+			inode->i_fop = fops ? fops : &debugfs_file_operations;
+			inode->i_private = data;
+			break;
+		case S_IFLNK:
+			inode->i_op = &debugfs_link_operations;
+			inode->i_fop = fops;
+			inode->i_private = data;
+			break;
+		case S_IFDIR:
+			inode->i_op = &simple_dir_inode_operations;
+			inode->i_fop = fops ? fops : &simple_dir_operations;
+			inode->i_private = data;
+
+			/* directory inodes start off with i_nlink == 2
+			 * (for "." entry) */
+			inc_nlink(inode);
+			break;
+		}
+	}
+	return inode; 
+}
+
+/* SMP-safe */
+static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
+			 int mode, dev_t dev, void *data,
+			 const struct file_operations *fops)
+{
+	struct inode *inode;
+	int error = -EPERM;
+
+	if (dentry->d_inode)
+		return -EEXIST;
+
+	inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
+	if (inode) {
+		d_instantiate(dentry, inode);
+		dget(dentry);
+		error = 0;
+	}
+	return error;
+}
+
+static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode,
+			 void *data, const struct file_operations *fops)
+{
+	int res;
+
+	mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
+	res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
+	if (!res) {
+		inc_nlink(dir);
+		fsnotify_mkdir(dir, dentry);
+	}
+	return res;
+}
+
+static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode,
+			void *data, const struct file_operations *fops)
+{
+	mode = (mode & S_IALLUGO) | S_IFLNK;
+	return debugfs_mknod(dir, dentry, mode, 0, data, fops);
+}
+
+static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode,
+			  void *data, const struct file_operations *fops)
+{
+	int res;
+
+	mode = (mode & S_IALLUGO) | S_IFREG;
+	res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
+	if (!res)
+		fsnotify_create(dir, dentry);
+	return res;
+}
+
+static inline int debugfs_positive(struct dentry *dentry)
+{
+	return dentry->d_inode && !d_unhashed(dentry);
+}
+
+static int debug_fill_super(struct super_block *sb, void *data, int silent)
+{
+	static struct tree_descr debug_files[] = {{""}};
+
+	return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
+}
+
+static struct dentry *debug_mount(struct file_system_type *fs_type,
+			int flags, const char *dev_name,
+			void *data)
+{
+	return mount_single(fs_type, flags, data, debug_fill_super);
+}
+
+static struct file_system_type debug_fs_type = {
+	.owner =	THIS_MODULE,
+	.name =		"debugfs",
+	.mount =	debug_mount,
+	.kill_sb =	kill_litter_super,
+};
+
+static int debugfs_create_by_name(const char *name, mode_t mode,
+				  struct dentry *parent,
+				  struct dentry **dentry,
+				  void *data,
+				  const struct file_operations *fops)
+{
+	int error = 0;
+
+	/* If the parent is not specified, we create it in the root.
+	 * We need the root dentry to do this, which is in the super 
+	 * block. A pointer to that is in the struct vfsmount that we
+	 * have around.
+	 */
+	if (!parent)
+		parent = debugfs_mount->mnt_sb->s_root;
+
+	*dentry = NULL;
+	mutex_lock(&parent->d_inode->i_mutex);
+	*dentry = lookup_one_len(name, parent, strlen(name));
+	if (!IS_ERR(*dentry)) {
+		switch (mode & S_IFMT) {
+		case S_IFDIR:
+			error = debugfs_mkdir(parent->d_inode, *dentry, mode,
+					      data, fops);
+			break;
+		case S_IFLNK:
+			error = debugfs_link(parent->d_inode, *dentry, mode,
+					     data, fops);
+			break;
+		default:
+			error = debugfs_create(parent->d_inode, *dentry, mode,
+					       data, fops);
+			break;
+		}
+		dput(*dentry);
+	} else
+		error = PTR_ERR(*dentry);
+	mutex_unlock(&parent->d_inode->i_mutex);
+
+	return error;
+}
+
+/**
+ * debugfs_create_file - create a file in the debugfs filesystem
+ * @name: a pointer to a string containing the name of the file to create.
+ * @mode: the permission that the file should have.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this paramater is NULL, then the
+ *          file will be created in the root of the debugfs filesystem.
+ * @data: a pointer to something that the caller will want to get to later
+ *        on.  The inode.i_private pointer will point to this value on
+ *        the open() call.
+ * @fops: a pointer to a struct file_operations that should be used for
+ *        this file.
+ *
+ * This is the basic "create a file" function for debugfs.  It allows for a
+ * wide range of flexibility in creating a file, or a directory (if you want
+ * to create a directory, the debugfs_create_dir() function is
+ * recommended to be used instead.)
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.
+ */
+struct dentry *debugfs_create_file(const char *name, mode_t mode,
+				   struct dentry *parent, void *data,
+				   const struct file_operations *fops)
+{
+	struct dentry *dentry = NULL;
+	int error;
+
+	pr_debug("debugfs: creating file '%s'\n",name);
+
+	error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
+			      &debugfs_mount_count);
+	if (error)
+		goto exit;
+
+	error = debugfs_create_by_name(name, mode, parent, &dentry,
+				       data, fops);
+	if (error) {
+		dentry = NULL;
+		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+		goto exit;
+	}
+exit:
+	return dentry;
+}
+EXPORT_SYMBOL_GPL(debugfs_create_file);
+
+/**
+ * debugfs_create_dir - create a directory in the debugfs filesystem
+ * @name: a pointer to a string containing the name of the directory to
+ *        create.
+ * @parent: a pointer to the parent dentry for this file.  This should be a
+ *          directory dentry if set.  If this paramater is NULL, then the
+ *          directory will be created in the root of the debugfs filesystem.
+ *
+ * This function creates a directory in debugfs with the given name.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the file is
+ * to be removed (no automatic cleanup happens if your module is unloaded,
+ * you are responsible here.)  If an error occurs, %NULL will be returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.
+ */
+struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
+{
+	return debugfs_create_file(name, 
+				   S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
+				   parent, NULL, NULL);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_dir);
+
+/**
+ * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
+ * @name: a pointer to a string containing the name of the symbolic link to
+ *        create.
+ * @parent: a pointer to the parent dentry for this symbolic link.  This
+ *          should be a directory dentry if set.  If this paramater is NULL,
+ *          then the symbolic link will be created in the root of the debugfs
+ *          filesystem.
+ * @target: a pointer to a string containing the path to the target of the
+ *          symbolic link.
+ *
+ * This function creates a symbolic link with the given name in debugfs that
+ * links to the given target path.
+ *
+ * This function will return a pointer to a dentry if it succeeds.  This
+ * pointer must be passed to the debugfs_remove() function when the symbolic
+ * link is to be removed (no automatic cleanup happens if your module is
+ * unloaded, you are responsible here.)  If an error occurs, %NULL will be
+ * returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.
+ */
+struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
+				      const char *target)
+{
+	struct dentry *result;
+	char *link;
+
+	link = kstrdup(target, GFP_KERNEL);
+	if (!link)
+		return NULL;
+
+	result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link,
+				     NULL);
+	if (!result)
+		kfree(link);
+	return result;
+}
+EXPORT_SYMBOL_GPL(debugfs_create_symlink);
+
+static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
+{
+	int ret = 0;
+
+	if (debugfs_positive(dentry)) {
+		if (dentry->d_inode) {
+			dget(dentry);
+			switch (dentry->d_inode->i_mode & S_IFMT) {
+			case S_IFDIR:
+				ret = simple_rmdir(parent->d_inode, dentry);
+				break;
+			case S_IFLNK:
+				kfree(dentry->d_inode->i_private);
+				/* fall through */
+			default:
+				simple_unlink(parent->d_inode, dentry);
+				break;
+			}
+			if (!ret)
+				d_delete(dentry);
+			dput(dentry);
+		}
+	}
+	return ret;
+}
+
+/**
+ * debugfs_remove - removes a file or directory from the debugfs filesystem
+ * @dentry: a pointer to a the dentry of the file or directory to be
+ *          removed.
+ *
+ * This function removes a file or directory in debugfs that was previously
+ * created with a call to another debugfs function (like
+ * debugfs_create_file() or variants thereof.)
+ *
+ * This function is required to be called in order for the file to be
+ * removed, no automatic cleanup of files will happen when a module is
+ * removed, you are responsible here.
+ */
+void debugfs_remove(struct dentry *dentry)
+{
+	struct dentry *parent;
+	int ret;
+
+	if (!dentry)
+		return;
+
+	parent = dentry->d_parent;
+	if (!parent || !parent->d_inode)
+		return;
+
+	mutex_lock(&parent->d_inode->i_mutex);
+	ret = __debugfs_remove(dentry, parent);
+	mutex_unlock(&parent->d_inode->i_mutex);
+	if (!ret)
+		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+}
+EXPORT_SYMBOL_GPL(debugfs_remove);
+
+/**
+ * debugfs_remove_recursive - recursively removes a directory
+ * @dentry: a pointer to a the dentry of the directory to be removed.
+ *
+ * This function recursively removes a directory tree in debugfs that
+ * was previously created with a call to another debugfs function
+ * (like debugfs_create_file() or variants thereof.)
+ *
+ * This function is required to be called in order for the file to be
+ * removed, no automatic cleanup of files will happen when a module is
+ * removed, you are responsible here.
+ */
+void debugfs_remove_recursive(struct dentry *dentry)
+{
+	struct dentry *child;
+	struct dentry *parent;
+
+	if (!dentry)
+		return;
+
+	parent = dentry->d_parent;
+	if (!parent || !parent->d_inode)
+		return;
+
+	parent = dentry;
+	mutex_lock(&parent->d_inode->i_mutex);
+
+	while (1) {
+		/*
+		 * When all dentries under "parent" has been removed,
+		 * walk up the tree until we reach our starting point.
+		 */
+		if (list_empty(&parent->d_subdirs)) {
+			mutex_unlock(&parent->d_inode->i_mutex);
+			if (parent == dentry)
+				break;
+			parent = parent->d_parent;
+			mutex_lock(&parent->d_inode->i_mutex);
+		}
+		child = list_entry(parent->d_subdirs.next, struct dentry,
+				d_u.d_child);
+ next_sibling:
+
+		/*
+		 * If "child" isn't empty, walk down the tree and
+		 * remove all its descendants first.
+		 */
+		if (!list_empty(&child->d_subdirs)) {
+			mutex_unlock(&parent->d_inode->i_mutex);
+			parent = child;
+			mutex_lock(&parent->d_inode->i_mutex);
+			continue;
+		}
+		__debugfs_remove(child, parent);
+		if (parent->d_subdirs.next == &child->d_u.d_child) {
+			/*
+			 * Try the next sibling.
+			 */
+			if (child->d_u.d_child.next != &parent->d_subdirs) {
+				child = list_entry(child->d_u.d_child.next,
+						   struct dentry,
+						   d_u.d_child);
+				goto next_sibling;
+			}
+
+			/*
+			 * Avoid infinite loop if we fail to remove
+			 * one dentry.
+			 */
+			mutex_unlock(&parent->d_inode->i_mutex);
+			break;
+		}
+		simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+	}
+
+	parent = dentry->d_parent;
+	mutex_lock(&parent->d_inode->i_mutex);
+	__debugfs_remove(dentry, parent);
+	mutex_unlock(&parent->d_inode->i_mutex);
+	simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+}
+EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
+
+/**
+ * debugfs_rename - rename a file/directory in the debugfs filesystem
+ * @old_dir: a pointer to the parent dentry for the renamed object. This
+ *          should be a directory dentry.
+ * @old_dentry: dentry of an object to be renamed.
+ * @new_dir: a pointer to the parent dentry where the object should be
+ *          moved. This should be a directory dentry.
+ * @new_name: a pointer to a string containing the target name.
+ *
+ * This function renames a file/directory in debugfs.  The target must not
+ * exist for rename to succeed.
+ *
+ * This function will return a pointer to old_dentry (which is updated to
+ * reflect renaming) if it succeeds. If an error occurs, %NULL will be
+ * returned.
+ *
+ * If debugfs is not enabled in the kernel, the value -%ENODEV will be
+ * returned.
+ */
+struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
+		struct dentry *new_dir, const char *new_name)
+{
+	int error;
+	struct dentry *dentry = NULL, *trap;
+	const char *old_name;
+
+	trap = lock_rename(new_dir, old_dir);
+	/* Source or destination directories don't exist? */
+	if (!old_dir->d_inode || !new_dir->d_inode)
+		goto exit;
+	/* Source does not exist, cyclic rename, or mountpoint? */
+	if (!old_dentry->d_inode || old_dentry == trap ||
+	    d_mountpoint(old_dentry))
+		goto exit;
+	dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
+	/* Lookup failed, cyclic rename or target exists? */
+	if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
+		goto exit;
+
+	old_name = fsnotify_oldname_init(old_dentry->d_name.name);
+
+	error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
+		dentry);
+	if (error) {
+		fsnotify_oldname_free(old_name);
+		goto exit;
+	}
+	d_move(old_dentry, dentry);
+	fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
+		S_ISDIR(old_dentry->d_inode->i_mode),
+		NULL, old_dentry);
+	fsnotify_oldname_free(old_name);
+	unlock_rename(new_dir, old_dir);
+	dput(dentry);
+	return old_dentry;
+exit:
+	if (dentry && !IS_ERR(dentry))
+		dput(dentry);
+	unlock_rename(new_dir, old_dir);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(debugfs_rename);
+
+/**
+ * debugfs_initialized - Tells whether debugfs has been registered
+ */
+bool debugfs_initialized(void)
+{
+	return debugfs_registered;
+}
+EXPORT_SYMBOL_GPL(debugfs_initialized);
+
+
+static struct kobject *debug_kobj;
+
+static int __init debugfs_init(void)
+{
+	int retval;
+
+	debug_kobj = kobject_create_and_add("debug", kernel_kobj);
+	if (!debug_kobj)
+		return -EINVAL;
+
+	retval = register_filesystem(&debug_fs_type);
+	if (retval)
+		kobject_put(debug_kobj);
+	else
+		debugfs_registered = true;
+
+	return retval;
+}
+core_initcall(debugfs_init);
+