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Date:	Fri, 7 Jan 2005 21:47:39 -0800
To: linux-usb-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org

ChangeSet 1.1938.444.6, 2004/12/16 13:16:18-08:00, greg@kroah.com

debugfs: add debugfs

debugfs is a filesystem that is just for debug data. Start moving stuff out of proc and sysfs now :)

Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

 Documentation/DocBook/kernel-api.tmpl | 9
 fs/Makefile | 1
 fs/debugfs/Makefile | 4
 fs/debugfs/file.c | 262 ++++++++++++++++++++++++++++
 fs/debugfs/inode.c | 315 ++++++++++++++++++++++++++++++++++
 include/linux/debugfs.h | 90 +++++++++
 lib/Kconfig.debug | 10 +
 7 files changed, 691 insertions(+)

diff -Nru a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl
--- a/Documentation/DocBook/kernel-api.tmpl 2005-01-07 15:47:39 -08:00
+++ b/Documentation/DocBook/kernel-api.tmpl 2005-01-07 15:47:39 -08:00
@@ -105,6 +105,15 @@
      </sect1>
   </chapter>
 
+ <chapter id="debugfs">
+ <title>The debugfs filesystem</title>
+
+ <sect1><title>debugfs interface</title>
+!Efs/debugfs/inode.c
+!Efs/debugfs/file.c
+ </sect1>
+ </chapter>
+
   <chapter id="vfs">
      <title>The Linux VFS</title>
      <sect1><title>The Directory Cache</title>
diff -Nru a/fs/Makefile b/fs/Makefile
--- a/fs/Makefile 2005-01-07 15:47:39 -08:00
+++ b/fs/Makefile 2005-01-07 15:47:39 -08:00
@@ -94,3 +94,4 @@
 obj-$(CONFIG_BEFS_FS) += befs/
 obj-$(CONFIG_HOSTFS) += hostfs/
 obj-$(CONFIG_HPPFS) += hppfs/
+obj-$(CONFIG_DEBUG_FS) += debugfs/
diff -Nru a/fs/debugfs/Makefile b/fs/debugfs/Makefile
--- /dev/null Wed Dec 31 16:00:00 196900
+++ b/fs/debugfs/Makefile 2005-01-07 15:47:39 -08:00
@@ -0,0 +1,4 @@
+debugfs-objs := inode.o file.o
+
+obj-$(CONFIG_DEBUG_FS) += debugfs.o
+
diff -Nru a/fs/debugfs/file.c b/fs/debugfs/file.c
--- /dev/null Wed Dec 31 16:00:00 196900
+++ b/fs/debugfs/file.c 2005-01-07 15:47:39 -08:00
@@ -0,0 +1,262 @@
+/*
+ * 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/config.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/pagemap.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->u.generic_ip)
+ file->private_data = inode->u.generic_ip;
+
+ return 0;
+}
+
+struct file_operations debugfs_file_operations = {
+ .read = default_read_file,
+ .write = default_write_file,
+ .open = default_open,
+};
+
+#define simple_type(type, format, temptype, strtolfn) \
+static ssize_t read_file_##type(struct file *file, char __user *user_buf, \
+ size_t count, loff_t *ppos) \
+{ \
+ char buf[32]; \
+ type *val = file->private_data; \
+ \
+ snprintf(buf, sizeof(buf), format, *val); \
+ return simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));\
+} \
+static ssize_t write_file_##type(struct file *file, const char __user *user_buf,\
+ size_t count, loff_t *ppos) \
+{ \
+ char *endp; \
+ char buf[32]; \
+ int buf_size; \
+ type *val = file->private_data; \
+ temptype tmp; \
+ \
+ memset(buf, 0x00, sizeof(buf)); \
+ buf_size = min(count, (sizeof(buf)-1)); \
+ if (copy_from_user(buf, user_buf, buf_size)) \
+ return -EFAULT; \
+ \
+ tmp = strtolfn(buf, &endp, 0); \
+ if ((endp == buf) || ((type)tmp != tmp)) \
+ return -EINVAL; \
+ *val = tmp; \
+ return count; \
+} \
+static struct file_operations fops_##type = { \
+ .read = read_file_##type, \
+ .write = write_file_##type, \
+ .open = default_open, \
+};
+simple_type(u8, "%c", unsigned long, simple_strtoul);
+simple_type(u16, "%hi", unsigned long, simple_strtoul);
+simple_type(u32, "%i", unsigned long, simple_strtoul);
+
+/**
+ * debugfs_create_u8 - create a file in the debugfs filesystem that is used to read and write a 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 paramater 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)
+{
+ return debugfs_create_file(name, mode, parent, value, &fops_u8);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u8);
+
+/**
+ * debugfs_create_u16 - create a file in the debugfs filesystem that is used to read and write a 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 paramater 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)
+{
+ return debugfs_create_file(name, mode, parent, value, &fops_u16);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u16);
+
+/**
+ * debugfs_create_u32 - create a file in the debugfs filesystem that is used to read and write a 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 paramater 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)
+{
+ return debugfs_create_file(name, mode, parent, value, &fops_u32);
+}
+EXPORT_SYMBOL_GPL(debugfs_create_u32);
+
+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];
+ int buf_size;
+ u32 *val = file->private_data;
+
+ buf_size = min(count, (sizeof(buf)-1));
+ if (copy_from_user(buf, user_buf, buf_size))
+ return -EFAULT;
+
+ switch (buf[0]) {
+ case 'y':
+ case 'Y':
+ case '1':
+ *val = 1;
+ break;
+ case 'n':
+ case 'N':
+ case '0':
+ *val = 0;
+ break;
+ }
+
+ return count;
+}
+
+static struct file_operations fops_bool = {
+ .read = read_file_bool,
+ .write = write_file_bool,
+ .open = default_open,
+};
+
+/**
+ * debugfs_create_bool - create a file in the debugfs filesystem 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 paramater 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);
+
diff -Nru a/fs/debugfs/inode.c b/fs/debugfs/inode.c
--- /dev/null Wed Dec 31 16:00:00 196900
+++ b/fs/debugfs/inode.c 2005-01-07 15:47:39 -08:00
@@ -0,0 +1,315 @@
+/*
+ * 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.
+ *
+ */
+
+/* uncomment to get debug messages from the debug filesystem, ah the irony. */
+/* #define DEBUG */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/namei.h>
+#include <linux/debugfs.h>
+
+#define DEBUGFS_MAGIC 0x64626720
+
+/* declared over in file.c */
+extern struct file_operations debugfs_file_operations;
+
+static struct vfsmount *debugfs_mount;
+static int debugfs_mount_count;
+
+static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev)
+{
+ struct inode *inode = new_inode(sb);
+
+ if (inode) {
+ inode->i_mode = mode;
+ inode->i_uid = 0;
+ inode->i_gid = 0;
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = 0;
+ 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 = &debugfs_file_operations;
+ break;
+ case S_IFDIR:
+ inode->i_op = &simple_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+
+ /* directory inodes start off with i_nlink == 2 (for "." entry) */
+ inode->i_nlink++;
+ break;
+ }
+ }
+ return inode;
+}
+
+/* SMP-safe */
+static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
+ int mode, dev_t dev)
+{
+ struct inode *inode = debugfs_get_inode(dir->i_sb, mode, dev);
+ int error = -EPERM;
+
+ if (dentry->d_inode)
+ return -EEXIST;
+
+ if (inode) {
+ d_instantiate(dentry, inode);
+ dget(dentry);
+ error = 0;
+ }
+ return error;
+}
+
+static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+ int res;
+
+ mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
+ res = debugfs_mknod(dir, dentry, mode, 0);
+ if (!res)
+ dir->i_nlink++;
+ return res;
+}
+
+static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode)
+{
+ mode = (mode & S_IALLUGO) | S_IFREG;
+ return debugfs_mknod(dir, dentry, mode, 0);
+}
+
+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 * get_dentry(struct dentry *parent, const char *name)
+{
+ struct qstr qstr;
+
+ qstr.name = name;
+ qstr.len = strlen(name);
+ qstr.hash = full_name_hash(name,qstr.len);
+ return lookup_hash(&qstr,parent);
+}
+
+static struct super_block *debug_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name,
+ void *data)
+{
+ return get_sb_single(fs_type, flags, data, debug_fill_super);
+}
+
+static struct file_system_type debug_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "debugfs",
+ .get_sb = debug_get_sb,
+ .kill_sb = kill_litter_super,
+};
+
+static int debugfs_create_by_name(const char *name, mode_t mode,
+ struct dentry *parent,
+ struct dentry **dentry)
+{
+ 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 ) {
+ if (debugfs_mount && debugfs_mount->mnt_sb) {
+ parent = debugfs_mount->mnt_sb->s_root;
+ }
+ }
+ if (!parent) {
+ pr_debug("debugfs: Ah! can not find a parent!\n");
+ return -EFAULT;
+ }
+
+ *dentry = NULL;
+ down(&parent->d_inode->i_sem);
+ *dentry = get_dentry (parent, name);
+ if (!IS_ERR(dentry)) {
+ if ((mode & S_IFMT) == S_IFDIR)
+ error = debugfs_mkdir(parent->d_inode, *dentry, mode);
+ else
+ error = debugfs_create(parent->d_inode, *dentry, mode);
+ } else
+ error = PTR_ERR(dentry);
+ up(&parent->d_inode->i_sem);
+
+ 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.u.generic_ip 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 createing 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. 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_file(const char *name, mode_t mode,
+ struct dentry *parent, void *data,
+ struct file_operations *fops)
+{
+ struct dentry *dentry = NULL;
+ int error;
+
+ pr_debug("debugfs: creating file '%s'\n",name);
+
+ error = simple_pin_fs("debugfs", &debugfs_mount, &debugfs_mount_count);
+ if (error)
+ goto exit;
+
+ error = debugfs_create_by_name(name, mode, parent, &dentry);
+ if (error) {
+ dentry = NULL;
+ goto exit;
+ }
+
+ if (dentry->d_inode) {
+ if (data)
+ dentry->d_inode->u.generic_ip = data;
+ if (fops)
+ dentry->d_inode->i_fop = fops;
+ }
+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. 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_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_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
+ * debufs_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;
+
+ if (!dentry)
+ return;
+
+ parent = dentry->d_parent;
+ if (!parent || !parent->d_inode)
+ return;
+
+ down(&parent->d_inode->i_sem);
+ if (debugfs_positive(dentry)) {
+ if (dentry->d_inode) {
+ if (S_ISDIR(dentry->d_inode->i_mode))
+ simple_rmdir(parent->d_inode, dentry);
+ else
+ simple_unlink(parent->d_inode, dentry);
+ dput(dentry);
+ }
+ }
+ up(&parent->d_inode->i_sem);
+ simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+}
+EXPORT_SYMBOL_GPL(debugfs_remove);
+
+static int __init debugfs_init(void)
+{
+ return register_filesystem(&debug_fs_type);
+}
+
+static void __exit debugfs_exit(void)
+{
+ simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+ unregister_filesystem(&debug_fs_type);
+}
+
+core_initcall(debugfs_init);
+module_exit(debugfs_exit);
+MODULE_LICENSE("GPL");
+
diff -Nru a/include/linux/debugfs.h b/include/linux/debugfs.h
--- /dev/null Wed Dec 31 16:00:00 196900
+++ b/include/linux/debugfs.h 2005-01-07 15:47:39 -08:00
@@ -0,0 +1,90 @@
+/*
+ * debugfs.h - 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.
+ */
+
+#ifndef _DEBUGFS_H_
+#define _DEBUGFS_H_
+
+#if defined(CONFIG_DEBUG_FS)
+struct dentry *debugfs_create_file(const char *name, mode_t mode,
+ struct dentry *parent, void *data,
+ struct file_operations *fops);
+
+struct dentry *debugfs_create_dir(const char *name, struct dentry *parent);
+
+void debugfs_remove(struct dentry *dentry);
+
+struct dentry *debugfs_create_u8(const char *name, mode_t mode,
+ struct dentry *parent, u8 *value);
+struct dentry *debugfs_create_u16(const char *name, mode_t mode,
+ struct dentry *parent, u16 *value);
+struct dentry *debugfs_create_u32(const char *name, mode_t mode,
+ struct dentry *parent, u32 *value);
+struct dentry *debugfs_create_bool(const char *name, mode_t mode,
+ struct dentry *parent, u32 *value);
+
+#else
+/*
+ * We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
+ * so users have a chance to detect if there was a real error or not. We don't
+ * want to duplicate the design decision mistakes of procfs and devfs again.
+ */
+
+static inline struct dentry *debugfs_create_file(const char *name, mode_t mode,
+ struct dentry *parent,
+ void *data,
+ struct file_operations *fops)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline struct dentry *debugfs_create_dir(const char *name,
+ struct dentry *parent)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline void debugfs_remove(struct dentry *dentry)
+{ }
+
+static inline struct dentry *debugfs_create_u8(const char *name, mode_t mode,
+ struct dentry *parent,
+ u8 *value)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline struct dentry *debugfs_create_u16(const char *name, mode_t mode,
+ struct dentry *parent,
+ u8 *value)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline struct dentry *debugfs_create_u32(const char *name, mode_t mode,
+ struct dentry *parent,
+ u8 *value)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline struct dentry *debugfs_create_bool(const char *name, mode_t mode,
+ struct dentry *parent,
+ u8 *value)
+{
+ return EFF_PTR(-ENODEV);
+}
+
+#endif
+
+#endif
diff -Nru a/lib/Kconfig.debug b/lib/Kconfig.debug
--- a/lib/Kconfig.debug 2005-01-07 15:47:39 -08:00
+++ b/lib/Kconfig.debug 2005-01-07 15:47:39 -08:00
@@ -107,6 +107,16 @@
         If you're truly short on disk space or don't expect to report any
         bugs back to the UML developers, say N, otherwise say Y.
 
+config DEBUG_FS
+ bool "Debug Filesystem"
+ depends on DEBUG_KERNEL
+ help
+ debugfs is a virtual file system that kernel developers use to put
+ debugging files into. Enable this option to be able to read and
+ write to these files.
+
+ If unsure, say N.
+
 if !X86_64
 config FRAME_POINTER
         bool "Compile the kernel with frame pointers"

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