hppfs pass vfsmount to dentry_open()

Here's patch for hppfs that uses vfs_kern_mount to make sure it always has a
procfs instance and passed the vfsmount on through the inode private data.
Also fixes a procfs file_system_type leak for every attempted hppfs mount.

[ jdike - gave this file a style workover, plus deleted hppfs_dentry_ops ]

Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/hppfs/hppfs_kern.c

@@ -1,23 +1,25 @@
 /*
- * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  * Licensed under the GPL
  */
 
-#include <linux/fs.h>
-#include <linux/file.h>
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/slab.h>
-#include <linux/list.h>
-#include <linux/kernel.h>
 #include <linux/ctype.h>
 #include <linux/dcache.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
 #include <linux/statfs.h>
+#include <linux/types.h>
 #include <asm/uaccess.h>
-#include <asm/fcntl.h>
 #include "os.h"
 
-static int init_inode(struct inode *inode, struct dentry *dentry);
+static int init_inode(struct inode *inode, struct dentry *dentry,
+		      struct vfsmount *mnt);
 
 struct hppfs_data {
 	struct list_head list;
@@ -33,6 +35,7 @@ struct hppfs_private {
 
 struct hppfs_inode_info {
         struct dentry *proc_dentry;
+	struct vfsmount *proc_mnt;
 	struct inode vfs_inode;
 };
 
@@ -52,13 +55,13 @@ static int is_pid(struct dentry *dentry)
 
 	sb = dentry->d_sb;
 	if ((sb->s_op != &hppfs_sbops) || (dentry->d_parent != sb->s_root))
-		return(0);
+		return 0;
 
 	for (i = 0; i < dentry->d_name.len; i++) {
 		if (!isdigit(dentry->d_name.name[i]))
-			return(0);
+			return 0;
 	}
-	return(1);
+	return 1;
 }
 
 static char *dentry_name(struct dentry *dentry, int extra)
@@ -80,7 +83,8 @@ static char *dentry_name(struct dentry *dentry, int extra)
 	root = "proc";
 	len += strlen(root);
 	name = kmalloc(len + extra + 1, GFP_KERNEL);
-	if(name == NULL) return(NULL);
+	if (name == NULL)
+		return NULL;
 
 	name[len] = '\0';
 	parent = dentry;
@@ -100,24 +104,22 @@ static char *dentry_name(struct dentry *dentry, int extra)
 		parent = parent->d_parent;
 	}
 	strncpy(name, root, strlen(root));
-	return(name);
+	return name;
 }
 
-struct dentry_operations hppfs_dentry_ops = {
-};
-
 static int file_removed(struct dentry *dentry, const char *file)
 {
 	char *host_file;
 	int extra, fd;
 
 	extra = 0;
-	if(file != NULL) extra += strlen(file) + 1;
+	if (file != NULL)
+		extra += strlen(file) + 1;
 
 	host_file = dentry_name(dentry, extra + strlen("/remove"));
 	if (host_file == NULL) {
-		printk("file_removed : allocation failed\n");
+		printk(KERN_ERR "file_removed : allocation failed\n");
-		return(-ENOMEM);
+		return -ENOMEM;
 	}
 
 	if (file != NULL) {
@@ -130,9 +132,9 @@ static int file_removed(struct dentry *dentry, const char *file)
 	kfree(host_file);
 	if (fd > 0) {
 		os_close_file(fd);
-		return(1);
+		return 1;
 	}
-	return(0);
+	return 0;
 }
 
 static void hppfs_read_inode(struct inode *ino)
@@ -178,9 +180,9 @@ static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
 
 	deleted = file_removed(dentry, NULL);
 	if (deleted < 0)
-		return(ERR_PTR(deleted));
+		return ERR_PTR(deleted);
 	else if (deleted)
-		return(ERR_PTR(-ENOENT));
+		return ERR_PTR(-ENOENT);
 
 	err = -ENOMEM;
 	parent = HPPFS_I(ino)->proc_dentry;
@@ -202,7 +204,7 @@ static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
 	mutex_unlock(&parent->d_inode->i_mutex);
 
 	if (IS_ERR(proc_dentry))
-		return(proc_dentry);
+		return proc_dentry;
 
 	inode = hppfs_iget(ino->i_sb);
 	if (IS_ERR(inode)) {
@@ -210,22 +212,21 @@ static struct dentry *hppfs_lookup(struct inode *ino, struct dentry *dentry,
 		goto out_dput;
 	}
 
-	err = init_inode(inode, proc_dentry);
+	err = init_inode(inode, proc_dentry, HPPFS_I(ino)->proc_mnt);
 	if (err)
 		goto out_put;
 
 	hppfs_read_inode(inode);
 
  	d_add(dentry, inode);
-	dentry->d_op = &hppfs_dentry_ops;
+	return NULL;
-	return(NULL);
 
  out_put:
 	iput(inode);
  out_dput:
 	dput(proc_dentry);
  out:
-	return(ERR_PTR(err));
+	return ERR_PTR(err);
 }
 
 static const struct inode_operations hppfs_file_iops = {
@@ -247,7 +248,8 @@ static ssize_t read_proc(struct file *file, char __user *buf, ssize_t count,
 	if (!is_user)
 		set_fs(USER_DS);
 
-	if(ppos) *ppos = file->f_pos;
+	if (ppos)
+		*ppos = file->f_pos;
 	return n;
 }
 
@@ -260,7 +262,7 @@ static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
 	n = -ENOMEM;
 	new_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (new_buf == NULL) {
-		printk("hppfs_read_file : kmalloc failed\n");
+		printk(KERN_ERR "hppfs_read_file : kmalloc failed\n");
 		goto out;
 	}
 	n = 0;
@@ -268,12 +270,11 @@ static ssize_t hppfs_read_file(int fd, char __user *buf, ssize_t count)
 		cur = min_t(ssize_t, count, PAGE_SIZE);
 		err = os_read_file(fd, new_buf, cur);
 		if (err < 0) {
-			printk("hppfs_read : read failed, errno = %d\n",
+			printk(KERN_ERR "hppfs_read : read failed, "
-			       err);
+			       "errno = %d\n", err);
 			n = err;
 			goto out_free;
-		}
+		} else if (err == 0)
-		else if(err == 0)
 			break;
 
 		if (copy_to_user(buf, new_buf, err)) {
@@ -298,7 +299,8 @@ static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
 	int err;
 
 	if (hppfs->contents != NULL) {
-		if(*ppos >= hppfs->len) return(0);
+		if (*ppos >= hppfs->len)
+			return 0;
 
 		data = hppfs->contents;
 		off = *ppos;
@@ -312,12 +314,12 @@ static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
 			count = hppfs->len - off;
 		copy_to_user(buf, &data->contents[off], count);
 		*ppos += count;
-	}
+	} else if (hppfs->host_fd != -1) {
-	else if(hppfs->host_fd != -1){
 		err = os_seek_file(hppfs->host_fd, *ppos);
 		if (err) {
-			printk("hppfs_read : seek failed, errno = %d\n", err);
+			printk(KERN_ERR "hppfs_read : seek failed, "
-			return(err);
+			       "errno = %d\n", err);
+			return err;
 		}
 		count = hppfs_read_file(hppfs->host_fd, buf, count);
 		if (count > 0)
@@ -325,7 +327,7 @@ static ssize_t hppfs_read(struct file *file, char __user *buf, size_t count,
 	}
 	else count = read_proc(hppfs->proc_file, buf, count, ppos, 1);
 
-	return(count);
+	return count;
 }
 
 static ssize_t hppfs_write(struct file *file, const char __user *buf, size_t len,
@@ -342,7 +344,7 @@ static ssize_t hppfs_write(struct file *file, const char __user *buf, size_t len
 	err = (*write)(proc_file, buf, len, &proc_file->f_pos);
 	file->f_pos = proc_file->f_pos;
 
-	return(err);
+	return err;
 }
 
 static int open_host_sock(char *host_file, int *filter_out)
@@ -355,12 +357,12 @@ static int open_host_sock(char *host_file, int *filter_out)
 	*filter_out = 1;
 	fd = os_connect_socket(host_file);
 	if (fd > 0)
-		return(fd);
+		return fd;
 
 	strcpy(end, "/r");
 	*filter_out = 0;
 	fd = os_connect_socket(host_file);
-	return(fd);
+	return fd;
 }
 
 static void free_contents(struct hppfs_data *head)
@@ -368,7 +370,8 @@ static void free_contents(struct hppfs_data *head)
 	struct hppfs_data *data;
 	struct list_head *ele, *next;
 
-	if(head == NULL) return;
+	if (head == NULL)
+		return;
 
 	list_for_each_safe(ele, next, &head->list) {
 		data = list_entry(ele, struct hppfs_data, list);
@@ -388,7 +391,7 @@ static struct hppfs_data *hppfs_get_data(int fd, int filter,
 	err = -ENOMEM;
 	data = kmalloc(sizeof(*data), GFP_KERNEL);
 	if (data == NULL) {
-		printk("hppfs_get_data : head allocation failed\n");
+		printk(KERN_ERR "hppfs_get_data : head allocation failed\n");
 		goto failed;
 	}
 
@@ -403,7 +406,7 @@ static struct hppfs_data *hppfs_get_data(int fd, int filter,
 			os_write_file(fd, data->contents, n);
 		err = os_shutdown_socket(fd, 0, 1);
 		if (err) {
-			printk("hppfs_get_data : failed to shut down "
+			printk(KERN_ERR "hppfs_get_data : failed to shut down "
 			       "socket\n");
 			goto failed_free;
 		}
@@ -412,11 +415,10 @@ static struct hppfs_data *hppfs_get_data(int fd, int filter,
 		n = os_read_file(fd, data->contents, sizeof(data->contents));
 		if (n < 0) {
 			err = n;
-			printk("hppfs_get_data : read failed, errno = %d\n",
+			printk(KERN_ERR "hppfs_get_data : read failed, "
-			       err);
+			       "errno = %d\n", err);
 			goto failed_free;
-		}
+		} else if (n == 0)
-		else if(n == 0)
 			break;
 
 		*size_out += n;
@@ -426,7 +428,8 @@ static struct hppfs_data *hppfs_get_data(int fd, int filter,
 
 		new = kmalloc(sizeof(*data), GFP_KERNEL);
 		if (new == 0) {
-			printk("hppfs_get_data : data allocation failed\n");
+			printk(KERN_ERR "hppfs_get_data : data allocation "
+			       "failed\n");
 			err = -ENOMEM;
 			goto failed_free;
 		}
@@ -435,12 +438,12 @@ static struct hppfs_data *hppfs_get_data(int fd, int filter,
 		list_add(&new->list, &data->list);
 		data = new;
 	}
-	return(head);
+	return head;
 
  failed_free:
 	free_contents(head);
  failed:
-	return(ERR_PTR(err));
+	return ERR_PTR(err);
 }
 
 static struct hppfs_private *hppfs_data(void)
@@ -449,29 +452,30 @@ static struct hppfs_private *hppfs_data(void)
 
 	data = kmalloc(sizeof(*data), GFP_KERNEL);
 	if (data == NULL)
-		return(data);
+		return data;
 
 	*data = ((struct hppfs_private ) { .host_fd  		= -1,
 					   .len  		= -1,
 					   .contents 		= NULL } );
-	return(data);
+	return data;
 }
 
 static int file_mode(int fmode)
 {
 	if (fmode == (FMODE_READ | FMODE_WRITE))
-		return(O_RDWR);
+		return O_RDWR;
 	if (fmode == FMODE_READ)
-		return(O_RDONLY);
+		return O_RDONLY;
 	if (fmode == FMODE_WRITE)
-		return(O_WRONLY);
+		return O_WRONLY;
-	return(0);
+	return 0;
 }
 
 static int hppfs_open(struct inode *inode, struct file *file)
 {
 	struct hppfs_private *data;
 	struct dentry *proc_dentry;
+	struct vfsmount *proc_mnt;
 	char *host_file;
 	int err, fd, type, filter;
 
@@ -485,9 +489,10 @@ static int hppfs_open(struct inode *inode, struct file *file)
 		goto out_free2;
 
 	proc_dentry = HPPFS_I(inode)->proc_dentry;
+	proc_mnt = HPPFS_I(inode)->proc_mnt;
 
 	/* XXX This isn't closed anywhere */
-	data->proc_file = dentry_open(dget(proc_dentry), NULL,
+	data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
 				      file_mode(file->f_mode));
 	err = PTR_ERR(data->proc_file);
 	if (IS_ERR(data->proc_file))
@@ -498,12 +503,12 @@ static int hppfs_open(struct inode *inode, struct file *file)
 		fd = os_open_file(host_file, of_read(OPENFLAGS()), 0);
 		if (fd >= 0)
 			data->host_fd = fd;
-		else printk("hppfs_open : failed to open '%s', errno = %d\n",
+		else
-			    host_file, -fd);
+			printk(KERN_ERR "hppfs_open : failed to open '%s', "
+			       "errno = %d\n", host_file, -fd);
 
 		data->contents = NULL;
-	}
+	} else if (type == OS_TYPE_DIR) {
-	else if(type == OS_TYPE_DIR){
 		fd = open_host_sock(host_file, &filter);
 		if (fd > 0) {
 			data->contents = hppfs_get_data(fd, filter,
@@ -511,14 +516,14 @@ static int hppfs_open(struct inode *inode, struct file *file)
 							file, &data->len);
 			if (!IS_ERR(data->contents))
 				data->host_fd = fd;
-		}
+		} else
-		else printk("hppfs_open : failed to open a socket in "
+			printk(KERN_ERR "hppfs_open : failed to open a socket "
-			    "'%s', errno = %d\n", host_file, -fd);
+			       "in '%s', errno = %d\n", host_file, -fd);
 	}
 	kfree(host_file);
 
 	file->private_data = data;
-	return(0);
+	return 0;
 
  out_free1:
 	kfree(host_file);
@@ -526,13 +531,14 @@ static int hppfs_open(struct inode *inode, struct file *file)
 	free_contents(data->contents);
 	kfree(data);
  out:
-	return(err);
+	return err;
 }
 
 static int hppfs_dir_open(struct inode *inode, struct file *file)
 {
 	struct hppfs_private *data;
 	struct dentry *proc_dentry;
+	struct vfsmount *proc_mnt;
 	int err;
 
 	err = -ENOMEM;
@@ -541,19 +547,20 @@ static int hppfs_dir_open(struct inode *inode, struct file *file)
 		goto out;
 
 	proc_dentry = HPPFS_I(inode)->proc_dentry;
-	data->proc_file = dentry_open(dget(proc_dentry), NULL,
+	proc_mnt = HPPFS_I(inode)->proc_mnt;
+	data->proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt),
 				      file_mode(file->f_mode));
 	err = PTR_ERR(data->proc_file);
 	if (IS_ERR(data->proc_file))
 		goto out_free;
 
 	file->private_data = data;
-	return(0);
+	return 0;
 
  out_free:
 	kfree(data);
  out:
-	return(err);
+	return err;
 }
 
 static loff_t hppfs_llseek(struct file *file, loff_t off, int where)
@@ -567,10 +574,10 @@ static loff_t hppfs_llseek(struct file *file, loff_t off, int where)
 	if (llseek != NULL) {
 		ret = (*llseek)(proc_file, off, where);
 		if (ret < 0)
-			return(ret);
+			return ret;
 	}
 
-	return(default_llseek(file, off, where));
+	return default_llseek(file, off, where);
 }
 
 static const struct file_operations hppfs_file_fops = {
@@ -593,10 +600,10 @@ static int hppfs_filldir(void *d, const char *name, int size,
 	struct hppfs_dirent *dirent = d;
 
 	if (file_removed(dirent->dentry, name))
-		return(0);
+		return 0;
 
-	return((*dirent->filldir)(dirent->vfs_dirent, name, size, offset,
+	return (*dirent->filldir)(dirent->vfs_dirent, name, size, offset,
-				  inode, type));
+				  inode, type);
 }
 
 static int hppfs_readdir(struct file *file, void *ent, filldir_t filldir)
@@ -607,7 +614,8 @@ static int hppfs_readdir(struct file *file, void *ent, filldir_t filldir)
 	struct hppfs_dirent dirent = ((struct hppfs_dirent)
 		                      { .vfs_dirent  	= ent,
 					.filldir 	= filldir,
-					.dentry  	= file->f_path.dentry } );
+					.dentry  	= file->f_path.dentry
+				      });
 	int err;
 
 	readdir = proc_file->f_path.dentry->d_inode->i_fop->readdir;
@@ -616,12 +624,12 @@ static int hppfs_readdir(struct file *file, void *ent, filldir_t filldir)
 	err = (*readdir)(proc_file, &dirent, hppfs_filldir);
 	file->f_pos = proc_file->f_pos;
 
-	return(err);
+	return err;
 }
 
 static int hppfs_fsync(struct file *file, struct dentry *dentry, int datasync)
 {
-	return(0);
+	return 0;
 }
 
 static const struct file_operations hppfs_dir_fops = {
@@ -639,7 +647,7 @@ static int hppfs_statfs(struct dentry *dentry, struct kstatfs *sf)
 	sf->f_files = 0;
 	sf->f_ffree = 0;
 	sf->f_type = HPPFS_SUPER_MAGIC;
-	return(0);
+	return 0;
 }
 
 static struct inode *hppfs_alloc_inode(struct super_block *sb)
@@ -647,12 +655,13 @@ static struct inode *hppfs_alloc_inode(struct super_block *sb)
 	struct hppfs_inode_info *hi;
 
 	hi = kmalloc(sizeof(*hi), GFP_KERNEL);
-	if(hi == NULL)
+	if (!hi)
-		return(NULL);
+		return NULL;
 
-	*hi = ((struct hppfs_inode_info) { .proc_dentry	= NULL });
+	hi->proc_dentry = NULL;
+	hi->proc_mnt = NULL;
 	inode_init_once(&hi->vfs_inode);
-	return(&hi->vfs_inode);
+	return &hi->vfs_inode;
 }
 
 void hppfs_delete_inode(struct inode *ino)
@@ -665,21 +674,31 @@ static void hppfs_destroy_inode(struct inode *inode)
 	kfree(HPPFS_I(inode));
 }
 
+static void hppfs_put_super(struct super_block *sb)
+{
+	mntput(HPPFS_I(sb->s_root->d_inode)->proc_mnt);
+}
+
 static const struct super_operations hppfs_sbops = {
 	.alloc_inode	= hppfs_alloc_inode,
 	.destroy_inode	= hppfs_destroy_inode,
 	.delete_inode	= hppfs_delete_inode,
 	.statfs		= hppfs_statfs,
+	.put_super	= hppfs_put_super,
 };
 
-static int hppfs_readlink(struct dentry *dentry, char __user *buffer, int buflen)
+static int hppfs_readlink(struct dentry *dentry, char __user *buffer,
+			  int buflen)
 {
 	struct file *proc_file;
 	struct dentry *proc_dentry;
+	struct vfsmount *proc_mnt;
 	int ret;
 
 	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
-	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
+	proc_mnt = HPPFS_I(dentry->d_inode)->proc_mnt;
+
+	proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt), O_RDONLY);
 	if (IS_ERR(proc_file))
 		return PTR_ERR(proc_file);
 
@@ -694,10 +713,13 @@ static void* hppfs_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
 	struct file *proc_file;
 	struct dentry *proc_dentry;
+	struct vfsmount *proc_mnt;
 	void *ret;
 
 	proc_dentry = HPPFS_I(dentry->d_inode)->proc_dentry;
-	proc_file = dentry_open(dget(proc_dentry), NULL, O_RDONLY);
+	proc_mnt = HPPFS_I(dentry->d_inode)->proc_mnt;
+
+	proc_file = dentry_open(dget(proc_dentry), mntget(proc_mnt), O_RDONLY);
 	if (IS_ERR(proc_file))
 		return proc_file;
 
@@ -717,44 +739,43 @@ static const struct inode_operations hppfs_link_iops = {
 	.follow_link	= hppfs_follow_link,
 };
 
-static int init_inode(struct inode *inode, struct dentry *dentry)
+static int init_inode(struct inode *inode, struct dentry *dentry,
+		struct vfsmount *mnt)
 {
 	if (S_ISDIR(dentry->d_inode->i_mode)) {
 		inode->i_op = &hppfs_dir_iops;
 		inode->i_fop = &hppfs_dir_fops;
-	}
+	} else if (S_ISLNK(dentry->d_inode->i_mode)) {
-	else if(S_ISLNK(dentry->d_inode->i_mode)){
 		inode->i_op = &hppfs_link_iops;
 		inode->i_fop = &hppfs_file_fops;
-	}
+	} else {
-	else {
 		inode->i_op = &hppfs_file_iops;
 		inode->i_fop = &hppfs_file_fops;
 	}
 
 	HPPFS_I(inode)->proc_dentry = dentry;
+	HPPFS_I(inode)->proc_mnt = mnt;
 
-	return(0);
+	return 0;
 }
 
 static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 {
 	struct inode *root_inode;
 	struct file_system_type *procfs;
-	struct super_block *proc_sb;
+	struct vfsmount *proc_mnt;
 	int err;
 
 	err = -ENOENT;
 	procfs = get_fs_type("proc");
-	if(procfs == NULL)
+	if (!procfs)
 		goto out;
 
-	if(list_empty(&procfs->fs_supers))
+	proc_mnt = vfs_kern_mount(procfs, 0, procfs->name, NULL);
+	put_filesystem(procfs);
+	if (IS_ERR(proc_mnt))
 		goto out;
 
-	proc_sb = list_entry(procfs->fs_supers.next, struct super_block,
-			     s_instances);
-
 	sb->s_blocksize = 1024;
 	sb->s_blocksize_bits = 10;
 	sb->s_magic = HPPFS_SUPER_MAGIC;
@@ -766,21 +787,23 @@ static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
 		goto out;
 	}
 
-	err = init_inode(root_inode, proc_sb->s_root);
+	err = init_inode(root_inode, proc_mnt->mnt_sb->s_root, proc_mnt);
 	if (err)
-		goto out_put;
+		goto out_iput;
 
 	err = -ENOMEM;
 	sb->s_root = d_alloc_root(root_inode);
-	if(sb->s_root == NULL)
+	if (!sb->s_root)
-		goto out_put;
+		goto out_iput;
 
 	hppfs_read_inode(root_inode);
 
-	return(0);
+	return 0;
 
- out_put:
+ out_iput:
 	iput(root_inode);
+ out_mntput:
+	mntput(proc_mnt);
  out:
 	return(err);
 }
@@ -802,7 +825,7 @@ static struct file_system_type hppfs_type = {
 
 static int __init init_hppfs(void)
 {
-	return(register_filesystem(&hppfs_type));
+	return register_filesystem(&hppfs_type);
 }
 
 static void __exit exit_hppfs(void)
@@ -813,14 +836,3 @@ static void __exit exit_hppfs(void)
 module_init(init_hppfs)
 module_exit(exit_hppfs)
 MODULE_LICENSE("GPL");
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */