[PATCH] devfs: introduce devfs_mk_bdev

Replaces devfs_register for block devices.  Note that we do NOT pass in
an operaion vector here - it was unused in devfs_register already
and our block device code fundamentally ties the operations to the
gendisk.  There will be only very few callers of this one anyway..

fs/devfs/base.c

@@ -763,7 +763,6 @@ struct directory_type
 
 struct bdev_type
 {
-    struct block_device_operations *ops;
     dev_t dev;
 };
 
@@ -1491,7 +1490,6 @@ devfs_handle_t devfs_register (devfs_handle_t dir, const char *name,
     } else if (S_ISBLK (mode)) {
 	de->u.bdev.dev = dev;
 	de->u.cdev.autogen = devnum != 0;
-	de->u.bdev.ops = ops;
     } else {
 	PRINTK ("(%s): illegal mode: %x\n", name, mode);
 	devfs_put (de);
@@ -1517,6 +1515,52 @@ devfs_handle_t devfs_register (devfs_handle_t dir, const char *name,
 }   /*  End Function devfs_register  */
 
 
+int devfs_mk_bdev(dev_t dev, umode_t mode, const char *fmt, ...)
+{
+	struct devfs_entry *dir = NULL, *de;
+	char buf[64];
+	va_list args;
+	int error, n;
+
+	if (!S_ISBLK(mode)) {
+		printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
+				__FUNCTION__, mode, buf);
+		return -EINVAL;
+	}
+
+	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;
+	}
+
+	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.bdev.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;
+}
+
+EXPORT_SYMBOL(devfs_mk_bdev);
+
+
 /**
  *	_devfs_unhook - Unhook a device entry from its parents list
  *	@de: The entry to unhook.

include/linux/devfs_fs_kernel.h

@@ -25,6 +25,8 @@ extern devfs_handle_t devfs_register (devfs_handle_t dir, const char *name,
 				      unsigned int flags,
 				      unsigned int major, unsigned int minor,
 				      umode_t mode, void *ops, void *info);
+extern int devfs_mk_bdev(dev_t dev, umode_t mode, const char *fmt, ...)
+	__attribute__((format (printf, 3, 4)));
 extern int devfs_mk_symlink (const char *name, const char *link);
 extern devfs_handle_t devfs_mk_dir(const char *fmt, ...)
 	__attribute__((format (printf, 1, 2)));
@@ -49,6 +51,10 @@ static inline devfs_handle_t devfs_register (devfs_handle_t dir,
 {
     return NULL;
 }
+static inline int devfs_mk_bdev(dev_t dev, umode_t mode, const char *fmt, ...)
+{
+	return 0;
+}
 static inline int devfs_mk_symlink (const char *name, const char *link)
 {
     return 0;