Re: kernel BUG under 2.6.1-mm5

From: Andrey Borzenkov
Date: Sun Feb 01 2004 - 14:14:01 EST

On Wed, Jan 21, 2004 at 02:48:04PM -0800, Andrew Morton wrote:
> Jim Faulkner <jfaulkne@xxxxxxxxxxx> wrote:
> >
> >
> > Hello,
> >
> > I am seeing some scary looking kernel bug entries in my dmesg under
> > 2.6.1-mm5.
> > ...
>
> > kernel BUG at fs/dcache.c:760!
> > invalid operand: 0000 [#1]
> > PREEMPT SMP
> > CPU: 0
> > EIP: 0060:[<c0179627>] Not tainted VLI
> > EFLAGS: 00010287
> > EIP is at d_instantiate+0x17/0x90
> > eax: f7baf200 ebx: c1b8bac0 ecx: 000021a4 edx: 00000000
> > esi: f7a4f868 edi: f7baf200 ebp: f7a4f840 esp: f7a79e3c
> > ds: 007b es: 007b ss: 0068
> > Process hotplug (pid: 24, threadinfo=f7a78000 task=c1b06d00)
> > Stack: 00000000 f7a992e4 c1b8bac0 c1b35940 f7a78000 f7a4f840 c01ad6de
> > f7a4f840
> > f7baf200 f7a4f840 f7a41e1c c1bbeb40 00000000 c1b06d00 c011f5b0
> > 00000000
> > 00000000 f7a96d00 c1b06d00 c011bb7d 00000000 c1b06d00 c011f5b0
> > 00000000
> > Call Trace:
> > [<c01ad6de>] devfs_d_revalidate_wait+0xbe/0x1b0
> > [<c011f5b0>] default_wake_function+0x0/0x20
> > [<c011bb7d>] do_page_fault+0x32d/0x512
> > [<c011f5b0>] default_wake_function+0x0/0x20
> > [<c016e868>] do_lookup+0x68/0xb0
> > [<c016ede8>] link_path_walk+0x538/0xa30
> > [<c016fd03>] open_namei+0x83/0x420
> > [<c011b850>] do_page_fault+0x0/0x512
> > [<c040d4cb>] error_code+0x2f/0x38
> > [<c015e61e>] filp_open+0x3e/0x70
> > [<c015eb9b>] sys_open+0x5b/0x90
> > [<c040c992>] sysenter_past_esp+0x43/0x65
>
> hmm. There was a patch in that area which I have subsequently dropped
> because it was really fixing devfs problems in the wrong place.
>
> Perhaps Andrey can ask you to test a subsequent patch if he takes another
> look at this.
>
>

good. here is extended version that includes the same fix + some
cleanup. It removes dead code, removes long obsolete attempt to manage
module refcounting, unifies bdev and cdev - they are treated equal now.

andrew please consider for -mm for testing.

More cleanup will follow.


-andrey

diff -Nrup ../tmp/linux-2.6.2-rc3/fs/devfs/base.c linux-2.6.2-rc2/fs/devfs/base.c
--- ../tmp/linux-2.6.2-rc3/fs/devfs/base.c 2004-01-28 21:35:07.000000000 +0300
+++ linux-2.6.2-rc2/fs/devfs/base.c 2004-02-01 17:03:51.557348456 +0300
@@ -676,6 +676,7 @@
#include <linux/smp.h>
#include <linux/rwsem.h>
#include <linux/sched.h>
+#include <linux/namei.h>

#include <asm/uaccess.h>
#include <asm/io.h>
@@ -685,9 +686,7 @@
#include <asm/bitops.h>
#include <asm/atomic.h>

-#include "internal.h"
-
-#define DEVFS_VERSION "1.22 (20021013)"
+#define DEVFS_VERSION "2004-01-31"

#define DEVFS_NAME "devfs"

@@ -762,18 +761,6 @@ struct directory_type
unsigned char no_more_additions:1;
};

-struct bdev_type
-{
- dev_t dev;
-};
-
-struct cdev_type
-{
- struct file_operations *ops;
- dev_t dev;
- unsigned char autogen:1;
-};
-
struct symlink_type
{
unsigned int length; /* Not including the NULL-termimator */
@@ -801,8 +788,7 @@ struct devfs_entry
union
{
struct directory_type dir;
- struct bdev_type bdev;
- struct cdev_type cdev;
+ dev_t dev;
struct symlink_type symlink;
const char *name; /* Only used for (mode == 0) */
}
@@ -813,7 +799,7 @@ struct devfs_entry
struct devfs_inode inode;
umode_t mode;
unsigned short namelen; /* I think 64k+ filenames are a way off... */
- unsigned char vfs_deletable:1;/* Whether the VFS may delete the entry */
+ unsigned char vfs:1;/* Whether the VFS may delete the entry */
char name[1]; /* This is just a dummy: the allocated array
is bigger. This is NULL-terminated */
};
@@ -925,8 +911,6 @@ static void devfs_put (devfs_handle_t de
de->name, de, de->parent,
de->parent ? de->parent->name : "no parent");
if ( S_ISLNK (de->mode) ) kfree (de->u.symlink.linkname);
- if ( S_ISCHR (de->mode) && de->u.cdev.autogen )
- devfs_dealloc_devnum (de->mode, de->u.cdev.dev);
WRITE_ENTRY_MAGIC (de, 0);
#ifdef CONFIG_DEVFS_DEBUG
spin_lock (&stat_lock);
@@ -1063,46 +1047,40 @@ static int _devfs_append_entry (devfs_ha
return retval;
} /* End Function _devfs_append_entry */

-
/**
* _devfs_get_root_entry - Get the root devfs entry.
*
* Returns the root devfs entry on success, else %NULL.
+ *
+ * TODO it must be called asynchronously due to the fact
+ * that devfs is initialized relatively late. Proper way
+ * is to remove module_init from init_devfs_fs and manually
+ * call it early enough during system init
*/

-static struct devfs_entry *_devfs_get_root_entry (void)
+static struct devfs_entry *_devfs_get_root_entry(void)
{
- struct devfs_entry *new;
- static spinlock_t root_lock = SPIN_LOCK_UNLOCKED;
+ struct devfs_entry *new;
+ static spinlock_t root_lock = SPIN_LOCK_UNLOCKED;

- /* Always ensure the root is created */
- if (root_entry) return root_entry;
- if ( ( new = _devfs_alloc_entry (NULL, 0,MODE_DIR) ) == NULL ) return NULL;
- spin_lock (&root_lock);
- if (root_entry)
- {
- spin_unlock (&root_lock);
- devfs_put (new);
- return (root_entry);
- }
- root_entry = new;
- spin_unlock (&root_lock);
- /* And create the entry for ".devfsd" */
- if ( ( new = _devfs_alloc_entry (".devfsd", 0, S_IFCHR |S_IRUSR |S_IWUSR) )
- == NULL ) return NULL;
- new->u.cdev.dev = devfs_alloc_devnum (S_IFCHR |S_IRUSR |S_IWUSR);
- new->u.cdev.ops = &devfsd_fops;
- _devfs_append_entry (root_entry, new, NULL);
-#ifdef CONFIG_DEVFS_DEBUG
- if ( ( new = _devfs_alloc_entry (".stat", 0, S_IFCHR | S_IRUGO | S_IWUGO) )
- == NULL ) return NULL;
- new->u.cdev.dev = devfs_alloc_devnum (S_IFCHR | S_IRUGO | S_IWUGO);
- new->u.cdev.ops = &stat_fops;
- _devfs_append_entry (root_entry, new, NULL);
-#endif
- return root_entry;
-} /* End Function _devfs_get_root_entry */
+ if (root_entry)
+ return root_entry;
+
+ new = _devfs_alloc_entry(NULL, 0, MODE_DIR);
+ if (new == NULL )
+ return NULL;
+
+ spin_lock(&root_lock);
+ if (root_entry) {
+ spin_unlock(&root_lock);
+ devfs_put(new);
+ return root_entry;
+ }
+ root_entry = new;
+ spin_unlock(&root_lock);

+ return root_entry;
+} /* End Function _devfs_get_root_entry */

/**
* _devfs_descend - Descend down a tree using the next component name.
@@ -1237,6 +1215,7 @@ static devfs_handle_t _devfs_walk_path (
}
if (S_ISLNK (de->mode) && traverse_symlink)
{ /* Need to follow the link: this is a stack chomper */
+ /* FIXME what if it puts outside of mounted tree? */
link = _devfs_walk_path (dir, de->u.symlink.linkname,
de->u.symlink.length, TRUE);
devfs_put (de);
@@ -1444,27 +1423,19 @@ static void devfsd_notify (struct devfs_
current->egid, &fs_info);
}

-int devfs_mk_bdev(dev_t dev, umode_t mode, const char *fmt, ...)
+static int devfs_mk_dev(dev_t dev, umode_t mode, const char *fmt, va_list args)
{
struct devfs_entry *dir = NULL, *de;
char buf[64];
- va_list args;
int error, n;

- va_start(args, fmt);
- n = vsnprintf(buf, 64, fmt, args);
- if (n >= 64 || !buf[0]) {
- printk(KERN_WARNING "%s: invalid format string\n",
- __FUNCTION__);
+ n = vsnprintf(buf, sizeof(buf), fmt, args);
+ if (n >= sizeof(buf) || !buf[0]) {
+ printk(KERN_WARNING "%s: invalid format string %s\n",
+ __FUNCTION__, fmt);
return -EINVAL;
}

- if (!S_ISBLK(mode)) {
- printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
- __FUNCTION__, mode, buf);
- return -EINVAL;
- }
-
de = _devfs_prepare_leaf(&dir, buf, mode);
if (!de) {
printk(KERN_WARNING "%s: could not prepare leaf for %s\n",
@@ -1472,7 +1443,7 @@ int devfs_mk_bdev(dev_t dev, umode_t mod
return -ENOMEM; /* could be more accurate... */
}

- de->u.bdev.dev = dev;
+ de->u.dev = dev;

error = _devfs_append_entry(dir, de, NULL);
if (error) {
@@ -1487,50 +1458,35 @@ int devfs_mk_bdev(dev_t dev, umode_t mod
return error;
}

+int devfs_mk_bdev(dev_t dev, umode_t mode, const char *fmt, ...)
+{
+ va_list args;
+
+ if (!S_ISBLK(mode)) {
+ printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
+ __FUNCTION__, mode, fmt);
+ return -EINVAL;
+ }
+
+ va_start(args, fmt);
+ return devfs_mk_dev(dev, mode, fmt, args);
+}
+
EXPORT_SYMBOL(devfs_mk_bdev);


int devfs_mk_cdev(dev_t dev, umode_t mode, const char *fmt, ...)
{
- struct devfs_entry *dir = NULL, *de;
- char buf[64];
va_list args;
- int error, n;
-
- va_start(args, fmt);
- n = vsnprintf(buf, 64, fmt, args);
- if (n >= 64 || !buf[0]) {
- printk(KERN_WARNING "%s: invalid format string\n",
- __FUNCTION__);
- return -EINVAL;
- }

if (!S_ISCHR(mode)) {
printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
- __FUNCTION__, mode, buf);
+ __FUNCTION__, mode, fmt);
return -EINVAL;
}

- de = _devfs_prepare_leaf(&dir, buf, mode);
- if (!de) {
- printk(KERN_WARNING "%s: could not prepare leaf for %s\n",
- __FUNCTION__, buf);
- return -ENOMEM; /* could be more accurate... */
- }
-
- de->u.cdev.dev = dev;
-
- error = _devfs_append_entry(dir, de, NULL);
- if (error) {
- printk(KERN_WARNING "%s: could not append to parent for %s\n",
- __FUNCTION__, buf);
- goto out;
- }
-
- devfsd_notify(de, DEVFSD_NOTIFY_REGISTERED);
- out:
- devfs_put(dir);
- return error;
+ va_start(args, fmt);
+ return devfs_mk_dev(dev, mode, fmt, args);
}

EXPORT_SYMBOL(devfs_mk_cdev);
@@ -1663,7 +1619,7 @@ int devfs_mk_symlink(const char *from, c

err = devfs_do_symlink(NULL, from, to, &de);
if (!err) {
- de->vfs_deletable = TRUE;
+ de->vfs = TRUE;
devfsd_notify(de, DEVFSD_NOTIFY_REGISTERED);
}

@@ -1732,8 +1688,8 @@ void devfs_remove(const char *fmt, ...)
int n;

va_start(args, fmt);
- n = vsnprintf(buf, 64, fmt, args);
- if (n < 64 && buf[0]) {
+ n = vsnprintf(buf, sizeof(buf), fmt, args);
+ if (n < sizeof(buf) && buf[0]) {
devfs_handle_t de = _devfs_find_entry(NULL, buf, 0);

if (!de) {
@@ -1784,33 +1740,6 @@ static int devfs_generate_path (devfs_ha
return pos;
} /* End Function devfs_generate_path */

-
-/**
- * devfs_get_ops - Get the device operations for a devfs entry.
- * @de: The handle to the device entry.
- *
- * Returns a pointer to the device operations on success, else NULL.
- * The use count for the module owning the operations will be incremented.
- */
-
-static struct file_operations *devfs_get_ops (devfs_handle_t de)
-{
- struct file_operations *ops = de->u.cdev.ops;
- struct module *owner;
-
- if (!ops)
- return NULL;
- owner = ops->owner;
- read_lock (&de->parent->u.dir.lock); /* Prevent module from unloading */
- if ( (de->next == de) || !try_module_get (owner) )
- { /* Entry is already unhooked or module is unloading */
- read_unlock (&de->parent->u.dir.lock);
- return NULL;
- }
- read_unlock (&de->parent->u.dir.lock); /* Module can continue unloading*/
- return ops;
-} /* End Function devfs_get_ops */
-
/**
* devfs_setup - Process kernel boot options.
* @str: The boot options after the "devfs=".
@@ -1876,7 +1805,6 @@ static int __init devfs_setup (char *str

__setup("devfs=", devfs_setup);

-EXPORT_SYMBOL(devfs_put);
EXPORT_SYMBOL(devfs_mk_symlink);
EXPORT_SYMBOL(devfs_mk_dir);
EXPORT_SYMBOL(devfs_remove);
@@ -1996,6 +1924,7 @@ static struct inode *_devfs_get_vfs_inod
iput (inode);
return NULL;
}
+ /* FIXME where is devfs_put? */
inode->u.generic_ip = devfs_get (de);
inode->i_ino = de->inode.ino;
DPRINTK (DEBUG_I_GET, "(%d): VFS inode: %p devfs_entry: %p\n",
@@ -2003,26 +1932,25 @@ static struct inode *_devfs_get_vfs_inod
inode->i_blocks = 0;
inode->i_blksize = FAKE_BLOCK_SIZE;
inode->i_op = &devfs_iops;
- inode->i_fop = &devfs_fops;
- if ( S_ISCHR (de->mode) )
- {
- inode->i_rdev = de->u.cdev.dev;
- }
- else if ( S_ISBLK (de->mode) )
- init_special_inode(inode, de->mode, de->u.bdev.dev);
- else if ( S_ISFIFO (de->mode) )
- inode->i_fop = &def_fifo_fops;
- else if ( S_ISDIR (de->mode) )
- {
- inode->i_op = &devfs_dir_iops;
- inode->i_fop = &devfs_dir_fops;
- }
- else if ( S_ISLNK (de->mode) )
- {
- inode->i_op = &devfs_symlink_iops;
- inode->i_size = de->u.symlink.length;
- }
inode->i_mode = de->mode;
+ if (S_ISDIR(de->mode)) {
+ inode->i_op = &devfs_dir_iops;
+ inode->i_fop = &devfs_dir_fops;
+ } else if (S_ISLNK(de->mode)) {
+ inode->i_op = &devfs_symlink_iops;
+ inode->i_size = de->u.symlink.length;
+ } else if (S_ISCHR(de->mode) || S_ISBLK(de->mode)) {
+ init_special_inode(inode, de->mode, de->u.dev);
+ } else if (S_ISFIFO(de->mode) || S_ISSOCK(de->mode)) {
+ init_special_inode(inode, de->mode, 0);
+ } else {
+ PRINTK("(%s): unknown mode %o de: %p\n",
+ de->name, de->mode, de);
+ iput(inode);
+ devfs_put(de);
+ return NULL;
+ }
+
inode->i_uid = de->inode.uid;
inode->i_gid = de->inode.gid;
inode->i_atime = de->inode.atime;
@@ -2098,29 +2026,37 @@ static int devfs_readdir (struct file *f
return stored;
} /* End Function devfs_readdir */

+/* Open devfs specific special files */
static int devfs_open (struct inode *inode, struct file *file)
{
- int err = -ENODEV;
- struct devfs_entry *de;
- struct file_operations *ops;
+ int err;
+ int minor = MINOR(inode->i_rdev);
+ struct file_operations *old_fops, *new_fops;

- de = get_devfs_entry_from_vfs_inode (inode);
- if (de == NULL) return -ENODEV;
- if ( S_ISDIR (de->mode) ) return 0;
- file->private_data = de->info;
- if (S_ISCHR(inode->i_mode)) {
- ops = devfs_get_ops (de); /* Now have module refcount */
- file->f_op = ops;
- if (file->f_op)
- {
- lock_kernel ();
- err = file->f_op->open ? (*file->f_op->open) (inode, file) : 0;
- unlock_kernel ();
+ switch (minor) {
+ case 0: /* /dev/.devfsd */
+ new_fops = fops_get(&devfsd_fops);
+ break;
+#ifdef CONFIG_DEVFS_DEBUG
+ case 1: /* /dev/.stat */
+ new_fops = fops_get(&stat_fops);
+ break;
+#endif
+ default:
+ return -ENODEV;
}
- else
- err = chrdev_open (inode, file);
- }
- return err;
+
+ if (new_fops == NULL)
+ return -ENODEV;
+ old_fops = file->f_op;
+ file->f_op = new_fops;
+ err = new_fops->open ? new_fops->open(inode, file) : 0;
+ if (err) {
+ file->f_op = old_fops;
+ fops_put(new_fops);
+ } else
+ fops_put(old_fops);
+ return err;
} /* End Function devfs_open */

static struct file_operations devfs_fops =
@@ -2132,7 +2068,6 @@ static struct file_operations devfs_dir_
{
.read = generic_read_dir,
.readdir = devfs_readdir,
- .open = devfs_open,
};


@@ -2223,6 +2158,34 @@ static int devfs_d_revalidate_wait (stru
devfs_handle_t parent = get_devfs_entry_from_vfs_inode (dir);
struct devfs_lookup_struct *lookup_info = dentry->d_fsdata;
DECLARE_WAITQUEUE (wait, current);
+ int need_lock;
+
+ /*
+ * FIXME HACK
+ *
+ * make sure that
+ * d_instantiate always runs under lock
+ * we release i_sem lock before going to sleep
+ *
+ * unfortunately sometimes d_revalidate is called with
+ * and sometimes without i_sem lock held. The following checks
+ * attempt to deduce when we need to add (and drop resp.) lock
+ * here. This relies on current (2.6.2) calling coventions:
+ *
+ * lookup_hash is always run under i_sem and is passing NULL
+ * as nd
+ *
+ * open(...,O_CREATE,...) calls _lookup_hash under i_sem
+ * and sets flags to LOOKUP_OPEN|LOOKUP_CREATE
+ *
+ * all other invocations of ->d_revalidate seem to happen
+ * outside of i_sem
+ */
+ need_lock = nd &&
+ (!(nd->flags & LOOKUP_CREATE) || (nd->flags & LOOKUP_PARENT));
+
+ if (need_lock)
+ down(&dir->i_sem);

if ( is_devfsd_or_child (fs_info) )
{
@@ -2233,33 +2196,40 @@ static int devfs_d_revalidate_wait (stru
"(%s): dentry: %p inode: %p de: %p by: \"%s\"\n",
dentry->d_name.name, dentry, dentry->d_inode, de,
current->comm);
- if (dentry->d_inode) return 1;
+ if (dentry->d_inode)
+ goto out;
if (de == NULL)
{
read_lock (&parent->u.dir.lock);
de = _devfs_search_dir (parent, dentry->d_name.name,
dentry->d_name.len);
read_unlock (&parent->u.dir.lock);
- if (de == NULL) return 1;
+ if (de == NULL)
+ goto out;
lookup_info->de = de;
}
/* Create an inode, now that the driver information is available */
inode = _devfs_get_vfs_inode (dir->i_sb, de, dentry);
- if (!inode) return 1;
+ if (!inode)
+ goto out;
DPRINTK (DEBUG_I_LOOKUP,
"(%s): new VFS inode(%u): %p de: %p by: \"%s\"\n",
de->name, de->inode.ino, inode, de, current->comm);
d_instantiate (dentry, inode);
- return 1;
+ goto out;
}
- if (lookup_info == NULL) return 1; /* Early termination */
+ if (lookup_info == NULL)
+ goto out; /* Early termination */
read_lock (&parent->u.dir.lock);
if (dentry->d_fsdata)
{
set_current_state (TASK_UNINTERRUPTIBLE);
add_wait_queue (&lookup_info->wait_queue, &wait);
read_unlock (&parent->u.dir.lock);
+ /* at this point it is always (hopefully) locked */
+ up(&dir->i_sem);
schedule ();
+ down(&dir->i_sem);
/*
* This does not need nor should remove wait from wait_queue.
* Wait queue head is never reused - nothing is ever added to it
@@ -2271,6 +2241,10 @@ static int devfs_d_revalidate_wait (stru

}
else read_unlock (&parent->u.dir.lock);
+
+out:
+ if (need_lock)
+ up(&dir->i_sem);
return 1;
} /* End Function devfs_d_revalidate_wait */

@@ -2320,6 +2294,7 @@ static struct dentry *devfs_lookup (stru
revalidation */
up (&dir->i_sem);
wait_for_devfsd_finished (fs_info); /* If I'm not devfsd, must wait */
+ down (&dir->i_sem); /* Grab it again because them's the rules */
de = lookup_info.de;
/* If someone else has been so kind as to make the inode, we go home
early */
@@ -2349,7 +2324,6 @@ out:
dentry->d_fsdata = NULL;
wake_up (&lookup_info.wait_queue);
write_unlock (&parent->u.dir.lock);
- down (&dir->i_sem); /* Grab it again because them's the rules */
devfs_put (de);
return retval;
} /* End Function devfs_lookup */
@@ -2364,7 +2338,7 @@ static int devfs_unlink (struct inode *d
de = get_devfs_entry_from_vfs_inode (inode);
DPRINTK (DEBUG_I_UNLINK, "(%s): de: %p\n", dentry->d_name.name, de);
if (de == NULL) return -ENOENT;
- if (!de->vfs_deletable) return -EPERM;
+ if (!de->vfs) return -EPERM;
write_lock (&de->parent->u.dir.lock);
unhooked = _devfs_unhook (de);
write_unlock (&de->parent->u.dir.lock);
@@ -2392,7 +2366,7 @@ static int devfs_symlink (struct inode *
DPRINTK (DEBUG_DISABLED, "(%s): errcode from <devfs_do_symlink>: %d\n",
dentry->d_name.name, err);
if (err < 0) return err;
- de->vfs_deletable = TRUE;
+ de->vfs = TRUE;
de->inode.uid = current->euid;
de->inode.gid = current->egid;
de->inode.atime = CURRENT_TIME;
@@ -2421,7 +2395,7 @@ static int devfs_mkdir (struct inode *di
if (parent == NULL) return -ENOENT;
de = _devfs_alloc_entry (dentry->d_name.name, dentry->d_name.len, mode);
if (!de) return -ENOMEM;
- de->vfs_deletable = TRUE;
+ de->vfs = TRUE;
if ( ( err = _devfs_append_entry (parent, de, NULL) ) != 0 )
return err;
de->inode.uid = current->euid;
@@ -2451,7 +2425,7 @@ static int devfs_rmdir (struct inode *di
de = get_devfs_entry_from_vfs_inode (inode);
if (de == NULL) return -ENOENT;
if ( !S_ISDIR (de->mode) ) return -ENOTDIR;
- if (!de->vfs_deletable) return -EPERM;
+ if (!de->vfs) return -EPERM;
/* First ensure the directory is empty and will stay that way */
write_lock (&de->u.dir.lock);
if (de->u.dir.first) err = -ENOTEMPTY;
@@ -2485,11 +2459,9 @@ static int devfs_mknod (struct inode *di
if (parent == NULL) return -ENOENT;
de = _devfs_alloc_entry (dentry->d_name.name, dentry->d_name.len, mode);
if (!de) return -ENOMEM;
- de->vfs_deletable = TRUE;
- if (S_ISCHR (mode))
- de->u.cdev.dev = rdev;
- else if (S_ISBLK (mode))
- de->u.bdev.dev = rdev;
+ de->vfs = TRUE;
+ if (S_ISCHR(mode) || S_ISBLK(mode))
+ de->u.dev = rdev;
if ( ( err = _devfs_append_entry (parent, de, NULL) ) != 0 )
return err;
de->inode.uid = current->euid;
@@ -2642,12 +2614,9 @@ static ssize_t devfsd_read (struct file
info->uid = entry->uid;
info->gid = entry->gid;
de = entry->de;
- if (S_ISCHR(de->mode)) {
- info->major = MAJOR(de->u.cdev.dev);
- info->minor = MINOR(de->u.cdev.dev);
- } else if (S_ISBLK (de->mode)) {
- info->major = MAJOR(de->u.bdev.dev);
- info->minor = MINOR(de->u.bdev.dev);
+ if (S_ISCHR(de->mode) || S_ISBLK(de->mode)) {
+ info->major = MAJOR(de->u.dev);
+ info->minor = MINOR(de->u.dev);
}
pos = devfs_generate_path (de, info->devname, DEVFS_PATHLEN);
if (pos < 0) return pos;
@@ -2809,30 +2778,53 @@ static ssize_t stat_read (struct file *f
} /* End Function stat_read */
#endif

-
-static int __init init_devfs_fs (void)
+static int __init init_devfs_fs(void)
{
- int err;
+ int err;
+ int major;
+ struct devfs_entry *devfsd;
+#ifdef CONFIG_DEVFS_DEBUG
+ struct devfs_entry *stat;
+#endif
+
+ if (_devfs_get_root_entry() == NULL)
+ return -ENOMEM;

- printk (KERN_INFO "%s: v%s Richard Gooch (rgooch@xxxxxxxxxxxxx)\n",
- DEVFS_NAME, DEVFS_VERSION);
- devfsd_buf_cache = kmem_cache_create ("devfsd_event",
+ printk(KERN_INFO "%s: %s Richard Gooch (rgooch@xxxxxxxxxxxxx)\n",
+ DEVFS_NAME, DEVFS_VERSION);
+ devfsd_buf_cache = kmem_cache_create("devfsd_event",
sizeof (struct devfsd_buf_entry),
0, 0, NULL, NULL);
- if (!devfsd_buf_cache) OOPS ("(): unable to allocate event slab\n");
+ if (!devfsd_buf_cache)
+ OOPS("(): unable to allocate event slab\n");
#ifdef CONFIG_DEVFS_DEBUG
- devfs_debug = devfs_debug_init;
- printk (KERN_INFO "%s: devfs_debug: 0x%0x\n", DEVFS_NAME, devfs_debug);
+ devfs_debug = devfs_debug_init;
+ printk(KERN_INFO "%s: devfs_debug: 0x%0x\n", DEVFS_NAME, devfs_debug);
#endif
- printk (KERN_INFO "%s: boot_options: 0x%0x\n", DEVFS_NAME, boot_options);
- err = register_filesystem (&devfs_fs_type);
- if (!err)
- {
- struct vfsmount *devfs_mnt = kern_mount (&devfs_fs_type);
- err = PTR_ERR (devfs_mnt);
- if ( !IS_ERR (devfs_mnt) ) err = 0;
- }
- return err;
+ printk(KERN_INFO "%s: boot_options: 0x%0x\n", DEVFS_NAME, boot_options);
+
+ /* register special device for devfsd communication */
+ major = register_chrdev(0, "devfs", &devfs_fops);
+ if (major < 0)
+ return major;
+
+ /* And create the entry for ".devfsd" */
+ devfsd = _devfs_alloc_entry(".devfsd", 0, S_IFCHR|S_IRUSR|S_IWUSR);
+ if (devfsd == NULL )
+ return -ENOMEM;
+ devfsd->u.dev = MKDEV(major, 0);
+ _devfs_append_entry(root_entry, devfsd, NULL);
+
+#ifdef CONFIG_DEVFS_DEBUG
+ stat = _devfs_alloc_entry(".stat", 0, S_IFCHR|S_IRUGO);
+ if (stat == NULL )
+ return -ENOMEM;
+ stat->u.dev = MKDEV(major, 1);
+ _devfs_append_entry (root_entry, stat, NULL);
+#endif
+
+ err = register_filesystem(&devfs_fs_type);
+ return err;
} /* End Function init_devfs_fs */

void __init mount_devfs_fs (void)
diff -Nrup ../tmp/linux-2.6.2-rc3/fs/devfs/internal.h linux-2.6.2-rc2/fs/devfs/internal.h
--- ../tmp/linux-2.6.2-rc3/fs/devfs/internal.h 2003-12-18 05:59:25.000000000 +0300
+++ linux-2.6.2-rc2/fs/devfs/internal.h 1970-01-01 03:00:00.000000000 +0300
@@ -1,3 +0,0 @@
-
-extern dev_t devfs_alloc_devnum(umode_t mode);
-extern void devfs_dealloc_devnum(umode_t mode, dev_t devnum);
diff -Nrup ../tmp/linux-2.6.2-rc3/fs/devfs/util.c linux-2.6.2-rc2/fs/devfs/util.c
--- ../tmp/linux-2.6.2-rc3/fs/devfs/util.c 2003-12-18 05:58:56.000000000 +0300
+++ linux-2.6.2-rc2/fs/devfs/util.c 2004-02-01 16:59:55.105294632 +0300
@@ -72,7 +72,6 @@
#include <linux/vmalloc.h>
#include <linux/genhd.h>
#include <asm/bitops.h>
-#include "internal.h"


int devfs_register_tape(const char *name)
@@ -96,161 +95,3 @@ void devfs_unregister_tape(int num)
}

EXPORT_SYMBOL(devfs_unregister_tape);
-
-struct major_list
-{
- spinlock_t lock;
- unsigned long bits[256 / BITS_PER_LONG];
-};
-#if BITS_PER_LONG == 32
-# define INITIALISER64(low,high) (low), (high)
-#else
-# define INITIALISER64(low,high) ( (unsigned long) (high) << 32 | (low) )
-#endif
-
-/* Block majors already assigned:
- 0-3, 7-9, 11-63, 65-99, 101-113, 120-127, 199, 201, 240-255
- Total free: 122
-*/
-static struct major_list block_major_list =
-{SPIN_LOCK_UNLOCKED,
- {INITIALISER64 (0xfffffb8f, 0xffffffff), /* Majors 0-31, 32-63 */
- INITIALISER64 (0xfffffffe, 0xff03ffef), /* Majors 64-95, 96-127 */
- INITIALISER64 (0x00000000, 0x00000000), /* Majors 128-159, 160-191 */
- INITIALISER64 (0x00000280, 0xffff0000), /* Majors 192-223, 224-255 */
- }
-};
-
-/* Char majors already assigned:
- 0-7, 9-151, 154-158, 160-211, 216-221, 224-230, 240-255
- Total free: 19
-*/
-static struct major_list char_major_list =
-{SPIN_LOCK_UNLOCKED,
- {INITIALISER64 (0xfffffeff, 0xffffffff), /* Majors 0-31, 32-63 */
- INITIALISER64 (0xffffffff, 0xffffffff), /* Majors 64-95, 96-127 */
- INITIALISER64 (0x7cffffff, 0xffffffff), /* Majors 128-159, 160-191 */
- INITIALISER64 (0x3f0fffff, 0xffff007f), /* Majors 192-223, 224-255 */
- }
-};
-
-
-/**
- * devfs_alloc_major - Allocate a major number.
- * @mode: The file mode (must be block device or character device).
- * Returns the allocated major, else -1 if none are available.
- * This routine is thread safe and does not block.
- */
-
-
-struct minor_list
-{
- int major;
- unsigned long bits[256 / BITS_PER_LONG];
- struct minor_list *next;
-};
-
-static struct device_list {
- struct minor_list *first;
- struct minor_list *last;
- int none_free;
-} block_list, char_list;
-
-static DECLARE_MUTEX(device_list_mutex);
-
-
-/**
- * devfs_alloc_devnum - Allocate a device number.
- * @mode: The file mode (must be block device or character device).
- *
- * Returns the allocated device number, else NODEV if none are available.
- * This routine is thread safe and may block.
- */
-
-dev_t devfs_alloc_devnum(umode_t mode)
-{
- struct device_list *list;
- struct major_list *major_list;
- struct minor_list *entry;
- int minor;
-
- if (S_ISCHR(mode)) {
- major_list = &char_major_list;
- list = &char_list;
- } else {
- major_list = &block_major_list;
- list = &block_list;
- }
-
- down(&device_list_mutex);
- if (list->none_free)
- goto out_unlock;
-
- for (entry = list->first; entry; entry = entry->next) {
- minor = find_first_zero_bit (entry->bits, 256);
- if (minor >= 256)
- continue;
- goto out_done;
- }
-
- /* Need to allocate a new major */
- entry = kmalloc (sizeof *entry, GFP_KERNEL);
- if (!entry)
- goto out_full;
- memset(entry, 0, sizeof *entry);
-
- spin_lock(&major_list->lock);
- entry->major = find_first_zero_bit(major_list->bits, 256);
- if (entry->major >= 256) {
- spin_unlock(&major_list->lock);
- kfree(entry);
- goto out_full;
- }
- __set_bit(entry->major, major_list->bits);
- spin_unlock(&major_list->lock);
-
- if (!list->first)
- list->first = entry;
- else
- list->last->next = entry;
- list->last = entry;
-
- minor = 0;
- out_done:
- __set_bit(minor, entry->bits);
- up(&device_list_mutex);
- return MKDEV(entry->major, minor);
- out_full:
- list->none_free = 1;
- out_unlock:
- up(&device_list_mutex);
- return 0;
-}
-
-
-/**
- * devfs_dealloc_devnum - Dellocate a device number.
- * @mode: The file mode (must be block device or character device).
- * @devnum: The device number.
- *
- * This routine is thread safe and may block.
- */
-
-void devfs_dealloc_devnum(umode_t mode, dev_t devnum)
-{
- struct device_list *list = S_ISCHR(mode) ? &char_list : &block_list;
- struct minor_list *entry;
-
- if (!devnum)
- return;
-
- down(&device_list_mutex);
- for (entry = list->first; entry; entry = entry->next) {
- if (entry->major == MAJOR(devnum)) {
- if (__test_and_clear_bit(MINOR(devnum), entry->bits))
- list->none_free = 0;
- break;
- }
- }
- up(&device_list_mutex);
-}