[RFC 03/11] slim down debugfs

From: Arnd Bergmann
Date: Mon Feb 18 2008 - 23:14:53 EST


With most of debugfs now copied to generic code in libfs,
we can remove the original copy and replace it with thin
wrappers around libfs.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Index: linux-2.6/fs/Kconfig
===================================================================
--- linux-2.6.orig/fs/Kconfig
+++ linux-2.6/fs/Kconfig
@@ -1001,6 +1001,14 @@ config CONFIGFS_FS
Both sysfs and configfs can and should exist together on the
same system. One is not a replacement for the other.

+config LIBFS
+ tristate
+ default m
+ help
+ libfs is a helper library used by many of the simpler file
+ systems. Parts of libfs can be modular when all of its users
+ are modules as well, and the users should select this symbol.
+
endmenu

menu "Miscellaneous filesystems"
Index: linux-2.6/fs/debugfs/file.c
===================================================================
--- linux-2.6.orig/fs/debugfs/file.c
+++ linux-2.6/fs/debugfs/file.c
@@ -19,55 +19,6 @@
#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,
-};
-
-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");
-
/**
* 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.
@@ -95,22 +46,10 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs
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);
+ return debugfs_create_file(name, mode, parent, value, &simple_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");
-
/**
* 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.
@@ -138,22 +77,10 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugf
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);
+ return debugfs_create_file(name, mode, parent, value, &simple_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");
-
/**
* 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.
@@ -181,23 +108,10 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugf
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);
+ return debugfs_create_file(name, mode, parent, value, &simple_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");
-
/**
* 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.
@@ -225,16 +139,10 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugf
struct dentry *debugfs_create_u64(const char *name, mode_t mode,
struct dentry *parent, u64 *value)
{
- return debugfs_create_file(name, mode, parent, value, &fops_u64);
+ return debugfs_create_file(name, mode, parent, value, &simple_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_x16, debugfs_u16_get, debugfs_u16_set, "0x%04llx\n");
-
-DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugfs_u32_get, debugfs_u32_set, "0x%08llx\n");
-
/*
* debugfs_create_x{8,16,32} - create a debugfs file that is used to read and write an unsigned {8,16,32}-bit value
*
@@ -256,7 +164,7 @@ DEFINE_SIMPLE_ATTRIBUTE(fops_x32, debugf
struct dentry *debugfs_create_x8(const char *name, mode_t mode,
struct dentry *parent, u8 *value)
{
- return debugfs_create_file(name, mode, parent, value, &fops_x8);
+ return debugfs_create_file(name, mode, parent, value, &simple_fops_x8);
}
EXPORT_SYMBOL_GPL(debugfs_create_x8);

@@ -273,7 +181,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_x8);
struct dentry *debugfs_create_x16(const char *name, mode_t mode,
struct dentry *parent, u16 *value)
{
- return debugfs_create_file(name, mode, parent, value, &fops_x16);
+ return debugfs_create_file(name, mode, parent, value, &simple_fops_x16);
}
EXPORT_SYMBOL_GPL(debugfs_create_x16);

@@ -290,58 +198,10 @@ EXPORT_SYMBOL_GPL(debugfs_create_x16);
struct dentry *debugfs_create_x32(const char *name, mode_t mode,
struct dentry *parent, u32 *value)
{
- return debugfs_create_file(name, mode, parent, value, &fops_x32);
+ return debugfs_create_file(name, mode, parent, value, &simple_fops_x32);
}
EXPORT_SYMBOL_GPL(debugfs_create_x32);

-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 const struct file_operations fops_bool = {
- .read = read_file_bool,
- .write = write_file_bool,
- .open = default_open,
-};
-
/**
* 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.
@@ -369,23 +229,10 @@ static const struct file_operations fops
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);
+ return debugfs_create_file(name, mode, parent, value, &simple_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,
-};
-
/**
* debugfs_create_blob - create a debugfs file that is used to read and write a binary blob
* @name: a pointer to a string containing the name of the file to create.
@@ -412,8 +259,8 @@ static const struct file_operations fops
*/
struct dentry *debugfs_create_blob(const char *name, mode_t mode,
struct dentry *parent,
- struct debugfs_blob_wrapper *blob)
+ struct simple_blob_wrapper *blob)
{
- return debugfs_create_file(name, mode, parent, blob, &fops_blob);
+ return debugfs_create_file(name, mode, parent, blob, &simple_fops_blob);
}
EXPORT_SYMBOL_GPL(debugfs_create_blob);
Index: linux-2.6/fs/debugfs/inode.c
===================================================================
--- linux-2.6.orig/fs/debugfs/inode.c
+++ linux-2.6/fs/debugfs/inode.c
@@ -29,164 +29,7 @@

#define DEBUGFS_MAGIC 0x64626720

-/* declared over in file.c */
-extern struct file_operations debugfs_file_operations;
-extern struct inode_operations debugfs_link_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_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_IFLNK:
- inode->i_op = &debugfs_link_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) */
- inc_nlink(inode);
- break;
- }
- }
- return inode;
-}
-
-/* SMP-safe */
-static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
- int mode, dev_t dev)
-{
- struct inode *inode;
- int error = -EPERM;
-
- if (dentry->d_inode)
- return -EEXIST;
-
- inode = debugfs_get_inode(dir->i_sb, mode, dev);
- 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) {
- inc_nlink(dir);
- fsnotify_mkdir(dir, dentry);
- }
- return res;
-}
-
-static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode)
-{
- mode = (mode & S_IALLUGO) | S_IFLNK;
- return debugfs_mknod(dir, dentry, mode, 0);
-}
-
-static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode)
-{
- int res;
-
- mode = (mode & S_IALLUGO) | S_IFREG;
- res = debugfs_mknod(dir, dentry, mode, 0);
- 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 int debug_get_sb(struct file_system_type *fs_type,
- int flags, const char *dev_name,
- void *data, struct vfsmount *mnt)
-{
- return get_sb_single(fs_type, flags, data, debug_fill_super, mnt);
-}
-
-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;
- 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);
- break;
- case S_IFLNK:
- error = debugfs_link(parent->d_inode, *dentry, mode);
- break;
- default:
- error = debugfs_create(parent->d_inode, *dentry, mode);
- break;
- }
- dput(*dentry);
- } else
- error = PTR_ERR(*dentry);
- mutex_unlock(&parent->d_inode->i_mutex);
-
- return error;
-}
+static struct dentry *debugfs_root;

/**
* debugfs_create_file - create a file in the debugfs filesystem
@@ -219,28 +62,20 @@ struct dentry *debugfs_create_file(const
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;
+ /* If the parent is not specified, we create it in the root.
+ * of the standard debugfs */
+ if (!parent)
+ parent = debugfs_root;

- error = debugfs_create_by_name(name, mode, parent, &dentry);
- if (error) {
- dentry = NULL;
- simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+ if (!parent) {
+ pr_debug("debugfs: Ah! can not find a parent!\n");
goto exit;
}

- if (dentry->d_inode) {
- if (data)
- dentry->d_inode->i_private = data;
- if (fops)
- dentry->d_inode->i_fop = fops;
- }
+ dentry = simple_create_file(name, mode, parent, data, fops);
exit:
return dentry;
}
@@ -266,7 +101,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_file);
*/
struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
{
- return debugfs_create_file(name,
+ return debugfs_create_file(name,
S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
parent, NULL, NULL);
}
@@ -328,38 +163,7 @@ EXPORT_SYMBOL_GPL(debugfs_create_symlink
*/
void debugfs_remove(struct dentry *dentry)
{
- struct dentry *parent;
- int ret = 0;
-
- if (!dentry)
- return;
-
- parent = dentry->d_parent;
- if (!parent || !parent->d_inode)
- return;
-
- mutex_lock(&parent->d_inode->i_mutex);
- 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);
- }
- }
- mutex_unlock(&parent->d_inode->i_mutex);
- simple_release_fs(&debugfs_mount, &debugfs_mount_count);
+ return simple_remove(dentry);
}
EXPORT_SYMBOL_GPL(debugfs_remove);

@@ -385,48 +189,12 @@ EXPORT_SYMBOL_GPL(debugfs_remove);
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,
- old_dentry->d_name.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;
+ return simple_rename_named(old_dir, old_dentry, new_dir, new_name);
}
EXPORT_SYMBOL_GPL(debugfs_rename);

static struct kobject *debug_kobj;
+static DEFINE_SIMPLE_FS(debug_fs_type, "debugfs", NULL, DEBUGFS_MAGIC);

static int __init debugfs_init(void)
{
@@ -436,16 +204,18 @@ static int __init debugfs_init(void)
if (!debug_kobj)
return -EINVAL;

- retval = register_filesystem(&debug_fs_type);
- if (retval)
+ retval = 0;
+ debugfs_root = simple_register_filesystem(&debug_fs_type);
+ if (IS_ERR(debugfs_root)) {
kobject_put(debug_kobj);
+ retval = PTR_ERR(debugfs_root);
+ }
return retval;
}

static void __exit debugfs_exit(void)
{
- simple_release_fs(&debugfs_mount, &debugfs_mount_count);
- unregister_filesystem(&debug_fs_type);
+ simple_unregister_filesystem(&debug_fs_type);
kobject_put(debug_kobj);
}

Index: linux-2.6/include/linux/debugfs.h
===================================================================
--- linux-2.6.orig/include/linux/debugfs.h
+++ linux-2.6/include/linux/debugfs.h
@@ -15,18 +15,14 @@
#ifndef _DEBUGFS_H_
#define _DEBUGFS_H_

+#include <linux/libfs.h>
#include <linux/fs.h>

#include <linux/types.h>

struct file_operations;

-struct debugfs_blob_wrapper {
- void *data;
- unsigned long size;
-};
-
-#if defined(CONFIG_DEBUG_FS)
+#if defined(CONFIG_DEBUG_FS) || defined(CONFIG_DEBUG_FS_MODULE)
struct dentry *debugfs_create_file(const char *name, mode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops);
@@ -60,7 +56,7 @@ struct dentry *debugfs_create_bool(const

struct dentry *debugfs_create_blob(const char *name, mode_t mode,
struct dentry *parent,
- struct debugfs_blob_wrapper *blob);
+ struct simple_blob_wrapper *blob);
#else

#include <linux/err.h>
@@ -158,7 +154,7 @@ static inline struct dentry *debugfs_cre

static inline struct dentry *debugfs_create_blob(const char *name, mode_t mode,
struct dentry *parent,
- struct debugfs_blob_wrapper *blob)
+ struct simple_blob_wrapper *blob)
{
return ERR_PTR(-ENODEV);
}
Index: linux-2.6/drivers/net/wireless/rt2x00/rt2x00debug.c
===================================================================
--- linux-2.6.orig/drivers/net/wireless/rt2x00/rt2x00debug.c
+++ linux-2.6/drivers/net/wireless/rt2x00/rt2x00debug.c
@@ -100,8 +100,8 @@ struct rt2x00debug_intf {
* that has been created in advance. This will simplify
* the code since we can use the debugfs functions.
*/
- struct debugfs_blob_wrapper driver_blob;
- struct debugfs_blob_wrapper chipset_blob;
+ struct simple_blob_wrapper driver_blob;
+ struct simple_blob_wrapper chipset_blob;

/*
* Requested offset for each register type.
@@ -381,7 +381,7 @@ static const struct file_operations rt2x
static struct dentry *rt2x00debug_create_file_driver(const char *name,
struct rt2x00debug_intf
*intf,
- struct debugfs_blob_wrapper
+ struct simple_blob_wrapper
*blob)
{
char *data;
@@ -403,7 +403,7 @@ static struct dentry *rt2x00debug_create
struct rt2x00debug_intf
*intf,
struct
- debugfs_blob_wrapper
+ simple_blob_wrapper
*blob)
{
const struct rt2x00debug *debug = intf->debug;

--

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