Re: [PATCH 1/4] block: remove the osdblk driver

[Boaz Harrosh <ooo@electrozaur.com>]

On 04/12/2017 07:01 PM, Christoph Hellwig wrote:
> This was just a proof of concept user for the SCSI OSD library, and
> never had any real users.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Yes please remove this driver

ACK-by Boaz Harrosh <ooo@electrozaur.com>

> ---
>  drivers/block/Kconfig  |  16 --
>  drivers/block/Makefile |   1 -
>  drivers/block/osdblk.c | 693 -------------------------------------------------
>  3 files changed, 710 deletions(-)
>  delete mode 100644 drivers/block/osdblk.c
> 
> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
> index a1c2e816128f..58e24c354933 100644
> --- a/drivers/block/Kconfig
> +++ b/drivers/block/Kconfig
> @@ -312,22 +312,6 @@ config BLK_DEV_SKD
>  
>  	Use device /dev/skd$N amd /dev/skd$Np$M.
>  
> -config BLK_DEV_OSD
> -	tristate "OSD object-as-blkdev support"
> -	depends on SCSI_OSD_ULD
> -	---help---
> -	  Saying Y or M here will allow the exporting of a single SCSI
> -	  OSD (object-based storage) object as a Linux block device.
> -
> -	  For example, if you create a 2G object on an OSD device,
> -	  you can then use this module to present that 2G object as
> -	  a Linux block device.
> -
> -	  To compile this driver as a module, choose M here: the
> -	  module will be called osdblk.
> -
> -	  If unsure, say N.
> -
>  config BLK_DEV_SX8
>  	tristate "Promise SATA SX8 support"
>  	depends on PCI
> diff --git a/drivers/block/Makefile b/drivers/block/Makefile
> index b12c772bbeb3..42e8cee1cbc7 100644
> --- a/drivers/block/Makefile
> +++ b/drivers/block/Makefile
> @@ -22,7 +22,6 @@ obj-$(CONFIG_CDROM_PKTCDVD)	+= pktcdvd.o
>  obj-$(CONFIG_MG_DISK)		+= mg_disk.o
>  obj-$(CONFIG_SUNVDC)		+= sunvdc.o
>  obj-$(CONFIG_BLK_DEV_SKD)	+= skd.o
> -obj-$(CONFIG_BLK_DEV_OSD)	+= osdblk.o
>  
>  obj-$(CONFIG_BLK_DEV_UMEM)	+= umem.o
>  obj-$(CONFIG_BLK_DEV_NBD)	+= nbd.o
> diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c
> deleted file mode 100644
> index 8127b8201a01..000000000000
> --- a/drivers/block/osdblk.c
> +++ /dev/null
> @@ -1,693 +0,0 @@
> -
> -/*
> -   osdblk.c -- Export a single SCSI OSD object as a Linux block device
> -
> -
> -   Copyright 2009 Red Hat, Inc.
> -
> -   This program is free software; you can redistribute it and/or modify
> -   it under the terms of the GNU General Public License as published by
> -   the Free Software Foundation.
> -
> -   This program is distributed in the hope that it will be useful,
> -   but WITHOUT ANY WARRANTY; without even the implied warranty of
> -   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> -   GNU General Public License for more details.
> -
> -   You should have received a copy of the GNU General Public License
> -   along with this program; see the file COPYING.  If not, write to
> -   the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
> -
> -
> -   Instructions for use
> -   --------------------
> -
> -   1) Map a Linux block device to an existing OSD object.
> -
> -      In this example, we will use partition id 1234, object id 5678,
> -      OSD device /dev/osd1.
> -
> -      $ echo "1234 5678 /dev/osd1" > /sys/class/osdblk/add
> -
> -
> -   2) List all active blkdev<->object mappings.
> -
> -      In this example, we have performed step #1 twice, creating two blkdevs,
> -      mapped to two separate OSD objects.
> -
> -      $ cat /sys/class/osdblk/list
> -      0 174 1234 5678 /dev/osd1
> -      1 179 1994 897123 /dev/osd0
> -
> -      The columns, in order, are:
> -      - blkdev unique id
> -      - blkdev assigned major
> -      - OSD object partition id
> -      - OSD object id
> -      - OSD device
> -
> -
> -   3) Remove an active blkdev<->object mapping.
> -
> -      In this example, we remove the mapping with blkdev unique id 1.
> -
> -      $ echo 1 > /sys/class/osdblk/remove
> -
> -
> -   NOTE:  The actual creation and deletion of OSD objects is outside the scope
> -   of this driver.
> -
> - */
> -
> -#include <linux/kernel.h>
> -#include <linux/device.h>
> -#include <linux/module.h>
> -#include <linux/fs.h>
> -#include <linux/slab.h>
> -#include <scsi/osd_initiator.h>
> -#include <scsi/osd_attributes.h>
> -#include <scsi/osd_sec.h>
> -#include <scsi/scsi_device.h>
> -
> -#define DRV_NAME "osdblk"
> -#define PFX DRV_NAME ": "
> -
> -/* #define _OSDBLK_DEBUG */
> -#ifdef _OSDBLK_DEBUG
> -#define OSDBLK_DEBUG(fmt, a...) \
> -	printk(KERN_NOTICE "osdblk @%s:%d: " fmt, __func__, __LINE__, ##a)
> -#else
> -#define OSDBLK_DEBUG(fmt, a...) \
> -	do { if (0) printk(fmt, ##a); } while (0)
> -#endif
> -
> -MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
> -MODULE_DESCRIPTION("block device inside an OSD object osdblk.ko");
> -MODULE_LICENSE("GPL");
> -
> -struct osdblk_device;
> -
> -enum {
> -	OSDBLK_MINORS_PER_MAJOR	= 256,		/* max minors per blkdev */
> -	OSDBLK_MAX_REQ		= 32,		/* max parallel requests */
> -	OSDBLK_OP_TIMEOUT	= 4 * 60,	/* sync OSD req timeout */
> -};
> -
> -struct osdblk_request {
> -	struct request		*rq;		/* blk layer request */
> -	struct bio		*bio;		/* cloned bio */
> -	struct osdblk_device	*osdev;		/* associated blkdev */
> -};
> -
> -struct osdblk_device {
> -	int			id;		/* blkdev unique id */
> -
> -	int			major;		/* blkdev assigned major */
> -	struct gendisk		*disk;		/* blkdev's gendisk and rq */
> -	struct request_queue	*q;
> -
> -	struct osd_dev		*osd;		/* associated OSD */
> -
> -	char			name[32];	/* blkdev name, e.g. osdblk34 */
> -
> -	spinlock_t		lock;		/* queue lock */
> -
> -	struct osd_obj_id	obj;		/* OSD partition, obj id */
> -	uint8_t			obj_cred[OSD_CAP_LEN]; /* OSD cred */
> -
> -	struct osdblk_request	req[OSDBLK_MAX_REQ]; /* request table */
> -
> -	struct list_head	node;
> -
> -	char			osd_path[0];	/* OSD device path */
> -};
> -
> -static struct class *class_osdblk;		/* /sys/class/osdblk */
> -static DEFINE_MUTEX(ctl_mutex);	/* Serialize open/close/setup/teardown */
> -static LIST_HEAD(osdblkdev_list);
> -
> -static const struct block_device_operations osdblk_bd_ops = {
> -	.owner		= THIS_MODULE,
> -};
> -
> -static const struct osd_attr g_attr_logical_length = ATTR_DEF(
> -	OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
> -
> -static void osdblk_make_credential(u8 cred_a[OSD_CAP_LEN],
> -				   const struct osd_obj_id *obj)
> -{
> -	osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
> -}
> -
> -/* copied from exofs; move to libosd? */
> -/*
> - * Perform a synchronous OSD operation.  copied from exofs; move to libosd?
> - */
> -static int osd_sync_op(struct osd_request *or, int timeout, uint8_t *credential)
> -{
> -	int ret;
> -
> -	or->timeout = timeout;
> -	ret = osd_finalize_request(or, 0, credential, NULL);
> -	if (ret)
> -		return ret;
> -
> -	ret = osd_execute_request(or);
> -
> -	/* osd_req_decode_sense(or, ret); */
> -	return ret;
> -}
> -
> -/*
> - * Perform an asynchronous OSD operation.  copied from exofs; move to libosd?
> - */
> -static int osd_async_op(struct osd_request *or, osd_req_done_fn *async_done,
> -		   void *caller_context, u8 *cred)
> -{
> -	int ret;
> -
> -	ret = osd_finalize_request(or, 0, cred, NULL);
> -	if (ret)
> -		return ret;
> -
> -	ret = osd_execute_request_async(or, async_done, caller_context);
> -
> -	return ret;
> -}
> -
> -/* copied from exofs; move to libosd? */
> -static int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
> -{
> -	struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
> -	void *iter = NULL;
> -	int nelem;
> -
> -	do {
> -		nelem = 1;
> -		osd_req_decode_get_attr_list(or, &cur_attr, &nelem, &iter);
> -		if ((cur_attr.attr_page == attr->attr_page) &&
> -		    (cur_attr.attr_id == attr->attr_id)) {
> -			attr->len = cur_attr.len;
> -			attr->val_ptr = cur_attr.val_ptr;
> -			return 0;
> -		}
> -	} while (iter);
> -
> -	return -EIO;
> -}
> -
> -static int osdblk_get_obj_size(struct osdblk_device *osdev, u64 *size_out)
> -{
> -	struct osd_request *or;
> -	struct osd_attr attr;
> -	int ret;
> -
> -	/* start request */
> -	or = osd_start_request(osdev->osd, GFP_KERNEL);
> -	if (!or)
> -		return -ENOMEM;
> -
> -	/* create a get-attributes(length) request */
> -	osd_req_get_attributes(or, &osdev->obj);
> -
> -	osd_req_add_get_attr_list(or, &g_attr_logical_length, 1);
> -
> -	/* execute op synchronously */
> -	ret = osd_sync_op(or, OSDBLK_OP_TIMEOUT, osdev->obj_cred);
> -	if (ret)
> -		goto out;
> -
> -	/* extract length from returned attribute info */
> -	attr = g_attr_logical_length;
> -	ret = extract_attr_from_req(or, &attr);
> -	if (ret)
> -		goto out;
> -
> -	*size_out = get_unaligned_be64(attr.val_ptr);
> -
> -out:
> -	osd_end_request(or);
> -	return ret;
> -
> -}
> -
> -static void osdblk_osd_complete(struct osd_request *or, void *private)
> -{
> -	struct osdblk_request *orq = private;
> -	struct osd_sense_info osi;
> -	int ret = osd_req_decode_sense(or, &osi);
> -
> -	if (ret) {
> -		ret = -EIO;
> -		OSDBLK_DEBUG("osdblk_osd_complete with err=%d\n", ret);
> -	}
> -
> -	/* complete OSD request */
> -	osd_end_request(or);
> -
> -	/* complete request passed to osdblk by block layer */
> -	__blk_end_request_all(orq->rq, ret);
> -}
> -
> -static void bio_chain_put(struct bio *chain)
> -{
> -	struct bio *tmp;
> -
> -	while (chain) {
> -		tmp = chain;
> -		chain = chain->bi_next;
> -
> -		bio_put(tmp);
> -	}
> -}
> -
> -static struct bio *bio_chain_clone(struct bio *old_chain, gfp_t gfpmask)
> -{
> -	struct bio *tmp, *new_chain = NULL, *tail = NULL;
> -
> -	while (old_chain) {
> -		tmp = bio_clone_kmalloc(old_chain, gfpmask);
> -		if (!tmp)
> -			goto err_out;
> -
> -		tmp->bi_bdev = NULL;
> -		gfpmask &= ~__GFP_DIRECT_RECLAIM;
> -		tmp->bi_next = NULL;
> -
> -		if (!new_chain)
> -			new_chain = tail = tmp;
> -		else {
> -			tail->bi_next = tmp;
> -			tail = tmp;
> -		}
> -
> -		old_chain = old_chain->bi_next;
> -	}
> -
> -	return new_chain;
> -
> -err_out:
> -	OSDBLK_DEBUG("bio_chain_clone with err\n");
> -	bio_chain_put(new_chain);
> -	return NULL;
> -}
> -
> -static void osdblk_rq_fn(struct request_queue *q)
> -{
> -	struct osdblk_device *osdev = q->queuedata;
> -
> -	while (1) {
> -		struct request *rq;
> -		struct osdblk_request *orq;
> -		struct osd_request *or;
> -		struct bio *bio;
> -		bool do_write, do_flush;
> -
> -		/* peek at request from block layer */
> -		rq = blk_fetch_request(q);
> -		if (!rq)
> -			break;
> -
> -		/* deduce our operation (read, write, flush) */
> -		/* I wish the block layer simplified cmd_type/cmd_flags/cmd[]
> -		 * into a clearly defined set of RPC commands:
> -		 * read, write, flush, scsi command, power mgmt req,
> -		 * driver-specific, etc.
> -		 */
> -
> -		do_flush = (req_op(rq) == REQ_OP_FLUSH);
> -		do_write = (rq_data_dir(rq) == WRITE);
> -
> -		if (!do_flush) { /* osd_flush does not use a bio */
> -			/* a bio clone to be passed down to OSD request */
> -			bio = bio_chain_clone(rq->bio, GFP_ATOMIC);
> -			if (!bio)
> -				break;
> -		} else
> -			bio = NULL;
> -
> -		/* alloc internal OSD request, for OSD command execution */
> -		or = osd_start_request(osdev->osd, GFP_ATOMIC);
> -		if (!or) {
> -			bio_chain_put(bio);
> -			OSDBLK_DEBUG("osd_start_request with err\n");
> -			break;
> -		}
> -
> -		orq = &osdev->req[rq->tag];
> -		orq->rq = rq;
> -		orq->bio = bio;
> -		orq->osdev = osdev;
> -
> -		/* init OSD command: flush, write or read */
> -		if (do_flush)
> -			osd_req_flush_object(or, &osdev->obj,
> -					     OSD_CDB_FLUSH_ALL, 0, 0);
> -		else if (do_write)
> -			osd_req_write(or, &osdev->obj, blk_rq_pos(rq) * 512ULL,
> -				      bio, blk_rq_bytes(rq));
> -		else
> -			osd_req_read(or, &osdev->obj, blk_rq_pos(rq) * 512ULL,
> -				     bio, blk_rq_bytes(rq));
> -
> -		OSDBLK_DEBUG("%s 0x%x bytes at 0x%llx\n",
> -			do_flush ? "flush" : do_write ?
> -				"write" : "read", blk_rq_bytes(rq),
> -			blk_rq_pos(rq) * 512ULL);
> -
> -		/* begin OSD command execution */
> -		if (osd_async_op(or, osdblk_osd_complete, orq,
> -				 osdev->obj_cred)) {
> -			osd_end_request(or);
> -			blk_requeue_request(q, rq);
> -			bio_chain_put(bio);
> -			OSDBLK_DEBUG("osd_execute_request_async with err\n");
> -			break;
> -		}
> -
> -		/* remove the special 'flush' marker, now that the command
> -		 * is executing
> -		 */
> -		rq->special = NULL;
> -	}
> -}
> -
> -static void osdblk_free_disk(struct osdblk_device *osdev)
> -{
> -	struct gendisk *disk = osdev->disk;
> -
> -	if (!disk)
> -		return;
> -
> -	if (disk->flags & GENHD_FL_UP)
> -		del_gendisk(disk);
> -	if (disk->queue)
> -		blk_cleanup_queue(disk->queue);
> -	put_disk(disk);
> -}
> -
> -static int osdblk_init_disk(struct osdblk_device *osdev)
> -{
> -	struct gendisk *disk;
> -	struct request_queue *q;
> -	int rc;
> -	u64 obj_size = 0;
> -
> -	/* contact OSD, request size info about the object being mapped */
> -	rc = osdblk_get_obj_size(osdev, &obj_size);
> -	if (rc)
> -		return rc;
> -
> -	/* create gendisk info */
> -	disk = alloc_disk(OSDBLK_MINORS_PER_MAJOR);
> -	if (!disk)
> -		return -ENOMEM;
> -
> -	sprintf(disk->disk_name, DRV_NAME "%d", osdev->id);
> -	disk->major = osdev->major;
> -	disk->first_minor = 0;
> -	disk->fops = &osdblk_bd_ops;
> -	disk->private_data = osdev;
> -
> -	/* init rq */
> -	q = blk_init_queue(osdblk_rq_fn, &osdev->lock);
> -	if (!q) {
> -		put_disk(disk);
> -		return -ENOMEM;
> -	}
> -
> -	/* switch queue to TCQ mode; allocate tag map */
> -	rc = blk_queue_init_tags(q, OSDBLK_MAX_REQ, NULL, BLK_TAG_ALLOC_FIFO);
> -	if (rc) {
> -		blk_cleanup_queue(q);
> -		put_disk(disk);
> -		return rc;
> -	}
> -
> -	/* Set our limits to the lower device limits, because osdblk cannot
> -	 * sleep when allocating a lower-request and therefore cannot be
> -	 * bouncing.
> -	 */
> -	blk_queue_stack_limits(q, osd_request_queue(osdev->osd));
> -
> -	blk_queue_prep_rq(q, blk_queue_start_tag);
> -	blk_queue_write_cache(q, true, false);
> -
> -	disk->queue = q;
> -
> -	q->queuedata = osdev;
> -
> -	osdev->disk = disk;
> -	osdev->q = q;
> -
> -	/* finally, announce the disk to the world */
> -	set_capacity(disk, obj_size / 512ULL);
> -	add_disk(disk);
> -
> -	printk(KERN_INFO "%s: Added of size 0x%llx\n",
> -		disk->disk_name, (unsigned long long)obj_size);
> -
> -	return 0;
> -}
> -
> -/********************************************************************
> - * /sys/class/osdblk/
> - *                   add	map OSD object to blkdev
> - *                   remove	unmap OSD object
> - *                   list	show mappings
> - *******************************************************************/
> -
> -static void class_osdblk_release(struct class *cls)
> -{
> -	kfree(cls);
> -}
> -
> -static ssize_t class_osdblk_list(struct class *c,
> -				struct class_attribute *attr,
> -				char *data)
> -{
> -	int n = 0;
> -	struct list_head *tmp;
> -
> -	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
> -
> -	list_for_each(tmp, &osdblkdev_list) {
> -		struct osdblk_device *osdev;
> -
> -		osdev = list_entry(tmp, struct osdblk_device, node);
> -
> -		n += sprintf(data+n, "%d %d %llu %llu %s\n",
> -			osdev->id,
> -			osdev->major,
> -			osdev->obj.partition,
> -			osdev->obj.id,
> -			osdev->osd_path);
> -	}
> -
> -	mutex_unlock(&ctl_mutex);
> -	return n;
> -}
> -
> -static ssize_t class_osdblk_add(struct class *c,
> -				struct class_attribute *attr,
> -				const char *buf, size_t count)
> -{
> -	struct osdblk_device *osdev;
> -	ssize_t rc;
> -	int irc, new_id = 0;
> -	struct list_head *tmp;
> -
> -	if (!try_module_get(THIS_MODULE))
> -		return -ENODEV;
> -
> -	/* new osdblk_device object */
> -	osdev = kzalloc(sizeof(*osdev) + strlen(buf) + 1, GFP_KERNEL);
> -	if (!osdev) {
> -		rc = -ENOMEM;
> -		goto err_out_mod;
> -	}
> -
> -	/* static osdblk_device initialization */
> -	spin_lock_init(&osdev->lock);
> -	INIT_LIST_HEAD(&osdev->node);
> -
> -	/* generate unique id: find highest unique id, add one */
> -
> -	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
> -
> -	list_for_each(tmp, &osdblkdev_list) {
> -		struct osdblk_device *osdev;
> -
> -		osdev = list_entry(tmp, struct osdblk_device, node);
> -		if (osdev->id > new_id)
> -			new_id = osdev->id + 1;
> -	}
> -
> -	osdev->id = new_id;
> -
> -	/* add to global list */
> -	list_add_tail(&osdev->node, &osdblkdev_list);
> -
> -	mutex_unlock(&ctl_mutex);
> -
> -	/* parse add command */
> -	if (sscanf(buf, "%llu %llu %s", &osdev->obj.partition, &osdev->obj.id,
> -		   osdev->osd_path) != 3) {
> -		rc = -EINVAL;
> -		goto err_out_slot;
> -	}
> -
> -	/* initialize rest of new object */
> -	sprintf(osdev->name, DRV_NAME "%d", osdev->id);
> -
> -	/* contact requested OSD */
> -	osdev->osd = osduld_path_lookup(osdev->osd_path);
> -	if (IS_ERR(osdev->osd)) {
> -		rc = PTR_ERR(osdev->osd);
> -		goto err_out_slot;
> -	}
> -
> -	/* build OSD credential */
> -	osdblk_make_credential(osdev->obj_cred, &osdev->obj);
> -
> -	/* register our block device */
> -	irc = register_blkdev(0, osdev->name);
> -	if (irc < 0) {
> -		rc = irc;
> -		goto err_out_osd;
> -	}
> -
> -	osdev->major = irc;
> -
> -	/* set up and announce blkdev mapping */
> -	rc = osdblk_init_disk(osdev);
> -	if (rc)
> -		goto err_out_blkdev;
> -
> -	return count;
> -
> -err_out_blkdev:
> -	unregister_blkdev(osdev->major, osdev->name);
> -err_out_osd:
> -	osduld_put_device(osdev->osd);
> -err_out_slot:
> -	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
> -	list_del_init(&osdev->node);
> -	mutex_unlock(&ctl_mutex);
> -
> -	kfree(osdev);
> -err_out_mod:
> -	OSDBLK_DEBUG("Error adding device %s\n", buf);
> -	module_put(THIS_MODULE);
> -	return rc;
> -}
> -
> -static ssize_t class_osdblk_remove(struct class *c,
> -					struct class_attribute *attr,
> -					const char *buf,
> -					size_t count)
> -{
> -	struct osdblk_device *osdev = NULL;
> -	int target_id, rc;
> -	unsigned long ul;
> -	struct list_head *tmp;
> -
> -	rc = kstrtoul(buf, 10, &ul);
> -	if (rc)
> -		return rc;
> -
> -	/* convert to int; abort if we lost anything in the conversion */
> -	target_id = (int) ul;
> -	if (target_id != ul)
> -		return -EINVAL;
> -
> -	/* remove object from list immediately */
> -	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
> -
> -	list_for_each(tmp, &osdblkdev_list) {
> -		osdev = list_entry(tmp, struct osdblk_device, node);
> -		if (osdev->id == target_id) {
> -			list_del_init(&osdev->node);
> -			break;
> -		}
> -		osdev = NULL;
> -	}
> -
> -	mutex_unlock(&ctl_mutex);
> -
> -	if (!osdev)
> -		return -ENOENT;
> -
> -	/* clean up and free blkdev and associated OSD connection */
> -	osdblk_free_disk(osdev);
> -	unregister_blkdev(osdev->major, osdev->name);
> -	osduld_put_device(osdev->osd);
> -	kfree(osdev);
> -
> -	/* release module ref */
> -	module_put(THIS_MODULE);
> -
> -	return count;
> -}
> -
> -static struct class_attribute class_osdblk_attrs[] = {
> -	__ATTR(add,	0200, NULL, class_osdblk_add),
> -	__ATTR(remove,	0200, NULL, class_osdblk_remove),
> -	__ATTR(list,	0444, class_osdblk_list, NULL),
> -	__ATTR_NULL
> -};
> -
> -static int osdblk_sysfs_init(void)
> -{
> -	int ret = 0;
> -
> -	/*
> -	 * create control files in sysfs
> -	 * /sys/class/osdblk/...
> -	 */
> -	class_osdblk = kzalloc(sizeof(*class_osdblk), GFP_KERNEL);
> -	if (!class_osdblk)
> -		return -ENOMEM;
> -
> -	class_osdblk->name = DRV_NAME;
> -	class_osdblk->owner = THIS_MODULE;
> -	class_osdblk->class_release = class_osdblk_release;
> -	class_osdblk->class_attrs = class_osdblk_attrs;
> -
> -	ret = class_register(class_osdblk);
> -	if (ret) {
> -		kfree(class_osdblk);
> -		class_osdblk = NULL;
> -		printk(PFX "failed to create class osdblk\n");
> -		return ret;
> -	}
> -
> -	return 0;
> -}
> -
> -static void osdblk_sysfs_cleanup(void)
> -{
> -	if (class_osdblk)
> -		class_destroy(class_osdblk);
> -	class_osdblk = NULL;
> -}
> -
> -static int __init osdblk_init(void)
> -{
> -	int rc;
> -
> -	rc = osdblk_sysfs_init();
> -	if (rc)
> -		return rc;
> -
> -	return 0;
> -}
> -
> -static void __exit osdblk_exit(void)
> -{
> -	osdblk_sysfs_cleanup();
> -}
> -
> -module_init(osdblk_init);
> -module_exit(osdblk_exit);
> -
>