Commit 9f961b57 authored by Artem Bityutskiy's avatar Artem Bityutskiy
Browse files

UBI: add UBI control device 



This patch is a preparation to make UBI devices dynamic. It
adds an UBI control device which has dynamically allocated
major number and registers itself as "ubi_ctrl". It does not
do anything so far. The idea is that this device will allow
to attach/detach MTD devices from userspace.

This is symilar to what the Linux device mapper has.

The next things to do are:
* Fix UBI, because it now assumes UBI devices cannot go away
* Implement control device ioctls which will attach/detach MTD
  devices

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 16f557ec

drivers/mtd/ubi/build.c

+42 −10
Original line number Diff line number Diff line
@@ -21,11 +21,16 @@ 
 */



/*

 * This file includes UBI initialization and building of UBI devices. At the

 * moment UBI devices may only be added while UBI is initialized, but dynamic

 * device add/remove functionality is planned. Also, at the moment we only

 * attach UBI devices by scanning, which will become a bottleneck when flashes

 * reach certain large size. Then one may improve UBI and add other methods.

 * This file includes UBI initialization and building of UBI devices.

 *

 * When UBI is initialized, it attaches all the MTD devices specified as the

 * module load parameters or the kernel boot parameters. If MTD devices were

 * specified, UBI does not attach any MTD device, but it is possible to do

 * later using the "UBI control device".

 *

 * At the moment we only attach UBI devices by scanning, which will become a

 * bottleneck when flashes reach certain large size. Then one may improve UBI

 * and add other methods, although it does not seem to be easy to do.

 */



#include <linux/err.h>
@@ -33,6 +38,7 @@ 
#include <linux/moduleparam.h>

#include <linux/stringify.h>

#include <linux/stat.h>

#include <linux/miscdevice.h>

#include <linux/log2.h>

#include "ubi.h"
@@ -70,6 +76,12 @@ struct kmem_cache *ubi_ltree_slab; 
/* Slab cache for wear-leveling entries */

struct kmem_cache *ubi_wl_entry_slab;



/* UBI control character device */

static struct miscdevice ubi_ctrl_cdev = {

	.minor = MISC_DYNAMIC_MINOR,

	.name = "ubi_ctrl",

	.fops = &ubi_ctrl_cdev_operations,

};



/* "Show" method for files in '/<sysfs>/class/ubi/' */

static ssize_t ubi_version_show(struct class *class, char *buf)
@@ -701,19 +713,31 @@ static int __init ubi_init(void) 
		return -EINVAL;

	}



	/* Create base sysfs directory and sysfs files */

	ubi_class = class_create(THIS_MODULE, UBI_NAME_STR);

	if (IS_ERR(ubi_class))

		return PTR_ERR(ubi_class);

	if (IS_ERR(ubi_class)) {

		err = PTR_ERR(ubi_class);

		printk(KERN_ERR "UBI error: cannot create UBI class\n");

		goto out;

	}



	err = class_create_file(ubi_class, &ubi_version);

	if (err)

	if (err) {

		printk(KERN_ERR "UBI error: cannot create sysfs file\n");

		goto out_class;

	}



	err = misc_register(&ubi_ctrl_cdev);

	if (err) {

		printk(KERN_ERR "UBI error: cannot register device\n");

		goto out_version;

	}



	ubi_ltree_slab = kmem_cache_create("ubi_ltree_slab",

					   sizeof(struct ubi_ltree_entry), 0,

					   0, &ltree_entry_ctor);

	if (!ubi_ltree_slab)

		goto out_version;

		goto out_dev_unreg;



	ubi_wl_entry_slab = kmem_cache_create("ubi_wl_entry_slab",

						sizeof(struct ubi_wl_entry),
@@ -727,9 +751,12 @@ static int __init ubi_init(void) 


		cond_resched();

		err = attach_mtd_dev(p->name, p->vid_hdr_offs, p->data_offs);

		if (err)

		if (err) {

			printk(KERN_ERR "UBI error: cannot attach %s\n",

			       p->name);

			goto out_detach;

		}

	}



	return 0;
@@ -739,10 +766,14 @@ out_detach: 
	kmem_cache_destroy(ubi_wl_entry_slab);

out_ltree:

	kmem_cache_destroy(ubi_ltree_slab);

out_dev_unreg:

	misc_deregister(&ubi_ctrl_cdev);

out_version:

	class_remove_file(ubi_class, &ubi_version);

out_class:

	class_destroy(ubi_class);

out:

	printk(KERN_ERR "UBI error: cannot initialize UBI, error %d\n", err);

	return err;

}

module_init(ubi_init);
@@ -756,6 +787,7 @@ static void __exit ubi_exit(void) 
			detach_mtd_dev(ubi_devices[i]);

	kmem_cache_destroy(ubi_wl_entry_slab);

	kmem_cache_destroy(ubi_ltree_slab);

	misc_deregister(&ubi_ctrl_cdev);

	class_remove_file(ubi_class, &ubi_version);

	class_destroy(ubi_class);

}

drivers/mtd/ubi/cdev.c

+10 −0
Original line number Diff line number Diff line
@@ -28,6 +28,11 @@ 
 *

 * Major and minor numbers are assigned dynamically to both UBI and volume

 * character devices.

 *

 * Well, there is the third kind of character devices - the UBI control

 * character device, which allows to manipulate by UBI devices - create and

 * delete them. In other words, it is used for attaching and detaching MTD

 * devices.

 */



#include <linux/module.h>
@@ -693,6 +698,11 @@ static int ubi_cdev_ioctl(struct inode *inode, struct file *file, 
	return err;

}



/* UBI control character device operations */

struct file_operations ubi_ctrl_cdev_operations = {

	.owner = THIS_MODULE,

};



/* UBI character device operations */

struct file_operations ubi_cdev_operations = {

	.owner = THIS_MODULE,

drivers/mtd/ubi/ubi.h

+2 −1
Original line number Diff line number Diff line
@@ -235,7 +235,7 @@ struct ubi_wl_entry; 


/**

 * struct ubi_device - UBI device description structure

 * @dev: class device object to use the the Linux device model

 * @dev: UBI device object to use the the Linux device model

 * @cdev: character device object to create character device

 * @ubi_num: UBI device number

 * @ubi_name: UBI device name
@@ -398,6 +398,7 @@ struct ubi_device { 


extern struct kmem_cache *ubi_ltree_slab;

extern struct kmem_cache *ubi_wl_entry_slab;

extern struct file_operations ubi_ctrl_cdev_operations;

extern struct file_operations ubi_cdev_operations;

extern struct file_operations ubi_vol_cdev_operations;

extern struct ubi_device *ubi_devices[];

CRA Git | Maintained and supported by SUSTech CRA and CCSE