diff options
Diffstat (limited to 'drivers/staging/dst/dcore.c')
| -rw-r--r-- | drivers/staging/dst/dcore.c | 995 |
1 files changed, 995 insertions, 0 deletions
diff --git a/drivers/staging/dst/dcore.c b/drivers/staging/dst/dcore.c new file mode 100644 index 000000000000..fad25b753042 --- /dev/null +++ b/drivers/staging/dst/dcore.c @@ -0,0 +1,995 @@ +/* + * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net> + * All rights reserved. + * + * 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; either version 2 of the License, or + * (at your option) any later version. + * + * 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. + */ + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/blkdev.h> +#include <linux/bio.h> +#include <linux/buffer_head.h> +#include <linux/connector.h> +#include <linux/dst.h> +#include <linux/device.h> +#include <linux/jhash.h> +#include <linux/idr.h> +#include <linux/init.h> +#include <linux/namei.h> +#include <linux/slab.h> +#include <linux/socket.h> + +#include <linux/in.h> +#include <linux/in6.h> + +#include <net/sock.h> + +static int dst_major; + +static DEFINE_MUTEX(dst_hash_lock); +static struct list_head *dst_hashtable; +static unsigned int dst_hashtable_size = 128; +module_param(dst_hashtable_size, uint, 0644); + +static char dst_name[] = "Dementianting goldfish"; + +static DEFINE_IDR(dst_index_idr); +static struct cb_id cn_dst_id = { CN_DST_IDX, CN_DST_VAL }; + +/* + * DST sysfs tree for device called 'storage': + * + * /sys/bus/dst/devices/storage/ + * /sys/bus/dst/devices/storage/type : 192.168.4.80:1025 + * /sys/bus/dst/devices/storage/size : 800 + * /sys/bus/dst/devices/storage/name : storage + */ + +static int dst_dev_match(struct device *dev, struct device_driver *drv) +{ + return 1; +} + +static struct bus_type dst_dev_bus_type = { + .name = "dst", + .match = &dst_dev_match, +}; + +static void dst_node_release(struct device *dev) +{ + struct dst_info *info = container_of(dev, struct dst_info, device); + + kfree(info); +} + +static struct device dst_node_dev = { + .bus = &dst_dev_bus_type, + .release = &dst_node_release +}; + +/* + * Setting size of the node after it was changed. + */ +static void dst_node_set_size(struct dst_node *n) +{ + struct block_device *bdev; + + set_capacity(n->disk, n->size >> 9); + + bdev = bdget_disk(n->disk, 0); + if (bdev) { + mutex_lock(&bdev->bd_inode->i_mutex); + i_size_write(bdev->bd_inode, n->size); + mutex_unlock(&bdev->bd_inode->i_mutex); + bdput(bdev); + } +} + +/* + * Distributed storage request processing function. + */ +static int dst_request(struct request_queue *q, struct bio *bio) +{ + struct dst_node *n = q->queuedata; + int err = -EIO; + + if (bio_empty_barrier(bio) && !q->prepare_discard_fn) { + /* + * This is a dirty^Wnice hack, but if we complete this + * operation with -EOPNOTSUPP like intended, XFS + * will stuck and freeze the machine. This may be + * not particulary XFS problem though, but it is the + * only FS which sends empty barrier at umount time + * I worked with. + * + * Empty barriers are not allowed anyway, see 51fd77bd9f512 + * for example, although later it was changed to bio_discard() + * only, which does not work in this case. + */ + //err = -EOPNOTSUPP; + err = 0; + goto end_io; + } + + bio_get(bio); + + return dst_process_bio(n, bio); + +end_io: + bio_endio(bio, err); + return err; +} + +/* + * Open/close callbacks for appropriate block device. + */ +static int dst_bdev_open(struct block_device *bdev, fmode_t mode) +{ + struct dst_node *n = bdev->bd_disk->private_data; + + dst_node_get(n); + return 0; +} + +static int dst_bdev_release(struct gendisk *disk, fmode_t mode) +{ + struct dst_node *n = disk->private_data; + + dst_node_put(n); + return 0; +} + +static struct block_device_operations dst_blk_ops = { + .open = dst_bdev_open, + .release = dst_bdev_release, + .owner = THIS_MODULE, +}; + +/* + * Block layer binding - disk is created when array is fully configured + * by userspace request. + */ +static int dst_node_create_disk(struct dst_node *n) +{ + int err = -ENOMEM; + u32 index = 0; + + n->queue = blk_init_queue(NULL, NULL); + if (!n->queue) + goto err_out_exit; + + n->queue->queuedata = n; + blk_queue_make_request(n->queue, dst_request); + blk_queue_max_phys_segments(n->queue, n->max_pages); + blk_queue_max_hw_segments(n->queue, n->max_pages); + + err = -ENOMEM; + n->disk = alloc_disk(1); + if (!n->disk) + goto err_out_free_queue; + + if (!(n->state->permissions & DST_PERM_WRITE)) { + printk(KERN_INFO "DST node %s attached read-only.\n", n->name); + set_disk_ro(n->disk, 1); + } + + if (!idr_pre_get(&dst_index_idr, GFP_KERNEL)) + goto err_out_put; + + mutex_lock(&dst_hash_lock); + err = idr_get_new(&dst_index_idr, NULL, &index); + mutex_unlock(&dst_hash_lock); + if (err) + goto err_out_put; + + n->disk->major = dst_major; + n->disk->first_minor = index; + n->disk->fops = &dst_blk_ops; + n->disk->queue = n->queue; + n->disk->private_data = n; + snprintf(n->disk->disk_name, sizeof(n->disk->disk_name), "dst-%s", n->name); + + return 0; + +err_out_put: + put_disk(n->disk); +err_out_free_queue: + blk_cleanup_queue(n->queue); +err_out_exit: + return err; +} + +/* + * Sysfs machinery: show device's size. + */ +static ssize_t dst_show_size(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dst_info *info = container_of(dev, struct dst_info, device); + + return sprintf(buf, "%llu\n", info->size); +} + +/* + * Show local exported device. + */ +static ssize_t dst_show_local(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dst_info *info = container_of(dev, struct dst_info, device); + + return sprintf(buf, "%s\n", info->local); +} + +/* + * Shows type of the remote node - device major/minor number + * for local nodes and address (af_inet ipv4/ipv6 only) for remote nodes. + */ +static ssize_t dst_show_type(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dst_info *info = container_of(dev, struct dst_info, device); + int family = info->net.addr.sa_family; + + if (family == AF_INET) { + struct sockaddr_in *sin = (struct sockaddr_in *)&info->net.addr; + return sprintf(buf, "%u.%u.%u.%u:%d\n", + NIPQUAD(sin->sin_addr.s_addr), ntohs(sin->sin_port)); + } else if (family == AF_INET6) { + struct sockaddr_in6 *sin = (struct sockaddr_in6 *)&info->net.addr; + return sprintf(buf, + "%pi6:%d\n", + &sin->sin6_addr, ntohs(sin->sin6_port)); + } else { + int i, sz = PAGE_SIZE - 2; /* 0 symbol and '\n' below */ + int size, addrlen = info->net.addr.sa_data_len; + unsigned char *a = (unsigned char *)&info->net.addr.sa_data; + char *buf_orig = buf; + + size = snprintf(buf, sz, "family: %d, addrlen: %u, addr: ", + family, addrlen); + sz -= size; + buf += size; + + for (i=0; i<addrlen; ++i) { + if (sz < 3) + break; + + size = snprintf(buf, sz, "%02x ", a[i]); + sz -= size; + buf += size; + } + buf += sprintf(buf, "\n"); + + return buf - buf_orig; + } + return 0; +} + +static struct device_attribute dst_node_attrs[] = { + __ATTR(size, 0444, dst_show_size, NULL), + __ATTR(type, 0444, dst_show_type, NULL), + __ATTR(local, 0444, dst_show_local, NULL), +}; + +static int dst_create_node_attributes(struct dst_node *n) +{ + int err, i; + + for (i=0; i<ARRAY_SIZE(dst_node_attrs); ++i) { + err = device_create_file(&n->info->device, + &dst_node_attrs[i]); + if (err) + goto err_out_remove_all; + } + return 0; + +err_out_remove_all: + while (--i >= 0) + device_remove_file(&n->info->device, + &dst_node_attrs[i]); + + return err; +} + +static void dst_remove_node_attributes(struct dst_node *n) +{ + int i; + + for (i=0; i<ARRAY_SIZE(dst_node_attrs); ++i) + device_remove_file(&n->info->device, + &dst_node_attrs[i]); +} + +/* + * Sysfs cleanup and initialization. + * Shows number of useful parameters. + */ +static void dst_node_sysfs_exit(struct dst_node *n) +{ + if (n->info) { + dst_remove_node_attributes(n); + device_unregister(&n->info->device); + n->info = NULL; + } +} + +static int dst_node_sysfs_init(struct dst_node *n) +{ + int err; + + n->info = kzalloc(sizeof(struct dst_info), GFP_KERNEL); + if (!n->info) + return -ENOMEM; + + memcpy(&n->info->device, &dst_node_dev, sizeof(struct device)); + n->info->size = n->size; + + dev_set_name(&n->info->device, "dst-%s", n->name); + err = device_register(&n->info->device); + if (err) { + dprintk(KERN_ERR "Failed to register node '%s', err: %d.\n", + n->name, err); + goto err_out_exit; + } + + dst_create_node_attributes(n); + + return 0; + +err_out_exit: + kfree(n->info); + n->info = NULL; + return err; +} + +/* + * DST node hash tables machinery. + */ +static inline unsigned int dst_hash(char *str, unsigned int size) +{ + return (jhash(str, size, 0) % dst_hashtable_size); +} + +static void dst_node_remove(struct dst_node *n) +{ + mutex_lock(&dst_hash_lock); + list_del_init(&n->node_entry); + mutex_unlock(&dst_hash_lock); +} + +static void dst_node_add(struct dst_node *n) +{ + unsigned hash = dst_hash(n->name, sizeof(n->name)); + + mutex_lock(&dst_hash_lock); + list_add_tail(&n->node_entry, &dst_hashtable[hash]); + mutex_unlock(&dst_hash_lock); +} + +/* + * Cleaning node when it is about to be freed. + * There are still users of the socket though, + * so connection cleanup should be protected. + */ +static void dst_node_cleanup(struct dst_node *n) +{ + struct dst_state *st = n->state; + + if (!st) + return; + + if (n->queue) { + blk_cleanup_queue(n->queue); + + mutex_lock(&dst_hash_lock); + idr_remove(&dst_index_idr, n->disk->first_minor); + mutex_unlock(&dst_hash_lock); + + put_disk(n->disk); + } + + if (n->bdev) { + sync_blockdev(n->bdev); + blkdev_put(n->bdev, FMODE_READ|FMODE_WRITE); + } + + dst_state_lock(st); + st->need_exit = 1; + dst_state_exit_connected(st); + dst_state_unlock(st); + + wake_up(&st->thread_wait); + + dst_state_put(st); + n->state = NULL; +} + +/* + * Free security attributes attached to given node. + */ +static void dst_security_exit(struct dst_node *n) +{ + struct dst_secure *s, *tmp; + + list_for_each_entry_safe(s, tmp, &n->security_list, sec_entry) { + list_del(&s->sec_entry); + kfree(s); + } +} + +/* + * Free node when there are no more users. + * Actually node has to be freed on behalf od userspace process, + * since there are number of threads, which are embedded in the + * node, so they can not exit and free node from there, that is + * why there is a wakeup if reference counter is not equal to zero. + */ +void dst_node_put(struct dst_node *n) +{ + if (unlikely(!n)) + return; + + dprintk("%s: n: %p, refcnt: %d.\n", + __func__, n, atomic_read(&n->refcnt)); + + if (atomic_dec_and_test(&n->refcnt)) { + dst_node_remove(n); + n->trans_scan_timeout = 0; + dst_node_cleanup(n); + thread_pool_destroy(n->pool); + dst_node_sysfs_exit(n); + dst_node_crypto_exit(n); + dst_security_exit(n); + dst_node_trans_exit(n); + + kfree(n); + + dprintk("%s: freed n: %p.\n", __func__, n); + } else { + wake_up(&n->wait); + } +} + +/* + * This function finds devices major/minor numbers for given pathname. + */ +static int dst_lookup_device(const char *path, dev_t *dev) +{ + int err; + struct nameidata nd; + struct inode *inode; + + err = path_lookup(path, LOOKUP_FOLLOW, &nd); + if (err) + return err; + + inode = nd.path.dentry->d_inode; + if (!inode) { + err = -ENOENT; + goto out; + } + + if (!S_ISBLK(inode->i_mode)) { + err = -ENOTBLK; + goto out; + } + + *dev = inode->i_rdev; + +out: + path_put(&nd.path); + return err; +} + +/* + * Setting up export device: lookup by the name, get its size + * and setup listening socket, which will accept clients, which + * will submit IO for given storage. + */ +static int dst_setup_export(struct dst_node *n, struct dst_ctl *ctl, + struct dst_export_ctl *le) +{ + int err; + dev_t dev = 0; /* gcc likes to scream here */ + + snprintf(n->info->local, sizeof(n->info->local), "%s", le->device); + + err = dst_lookup_device(le->device, &dev); + if (err) + return err; + + n->bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE); + if (!n->bdev) + return -ENODEV; + + if (n->size != 0) + n->size = min_t(loff_t, n->bdev->bd_inode->i_size, n->size); + else + n->size = n->bdev->bd_inode->i_size; + + n->info->size = n->size; + err = dst_node_init_listened(n, le); + if (err) + goto err_out_cleanup; + + return 0; + +err_out_cleanup: + blkdev_put(n->bdev, FMODE_READ|FMODE_WRITE); + n->bdev = NULL; + + return err; +} + +/* Empty thread pool callbacks for the network processing threads. */ +static inline void *dst_thread_network_init(void *data) +{ + dprintk("%s: data: %p.\n", __func__, data); + return data; +} + +static inline void dst_thread_network_cleanup(void *data) +{ + dprintk("%s: data: %p.\n", __func__, data); +} + +/* + * Allocate DST node and initialize some of its parameters. + */ +static struct dst_node *dst_alloc_node(struct dst_ctl *ctl, + int (*start)(struct dst_node *), + int num) +{ + struct dst_node *n; + int err; + + n = kzalloc(sizeof(struct dst_node), GFP_KERNEL); + if (!n) + return NULL; + + INIT_LIST_HEAD(&n->node_entry); + + INIT_LIST_HEAD(&n->security_list); + mutex_init(&n->security_lock); + + init_waitqueue_head(&n->wait); + + n->trans_scan_timeout = msecs_to_jiffies(ctl->trans_scan_timeout); + if (!n->trans_scan_timeout) + n->trans_scan_timeout = HZ; + + n->trans_max_retries = ctl->trans_max_retries; + if (!n->trans_max_retries) + n->trans_max_retries = 10; + + /* + * Pretty much arbitrary default numbers. + * 32 matches maximum number of pages in bio originated from ext3 (31). + */ + n->max_pages = ctl->max_pages; + if (!n->max_pages) + n->max_pages = 32; + + if (n->max_pages > 1024) + n->max_pages = 1024; + + n->start = start; + n->size = ctl->size; + + atomic_set(&n->refcnt, 1); + atomic_long_set(&n->gen, 0); + snprintf(n->name, sizeof(n->name), "%s", ctl->name); + + err = dst_node_sysfs_init(n); + if (err) + goto err_out_free; + + n->pool = thread_pool_create(num, n->name, dst_thread_network_init, + dst_thread_network_cleanup, n); + if (IS_ERR(n->pool)) { + err = PTR_ERR(n->pool); + goto err_out_sysfs_exit; + } + + dprintk("%s: n: %p, name: %s.\n", __func__, n, n->name); + + return n; + +err_out_sysfs_exit: + dst_node_sysfs_exit(n); +err_out_free: + kfree(n); + return NULL; +} + +/* + * Starting a node, connected to the remote server: + * register block device and initialize transaction mechanism. + * In revers order though. + * + * It will autonegotiate some parameters with the remote node + * and update local if needed. + * + * Transaction initialization should be the last thing before + * starting the node, since transaction should include not only + * block IO, but also crypto related data (if any), which are + * initialized separately. + */ +static int dst_start_remote(struct dst_node *n) +{ + int err; + + err = dst_node_trans_init(n, sizeof(struct dst_trans)); + if (err) + return err; + + err = dst_node_create_disk(n); + if (err) + return err; + + dst_node_set_size(n); + add_disk(n->disk); + + dprintk("DST: started remote node '%s', minor: %d.\n", n->name, n->disk->first_minor); + + return 0; +} + +/* + * Adding remote node and initialize connection. + */ +static int dst_add_remote(struct dst_node *n, struct dst_ctl *ctl, + void *data, unsigned int size) +{ + int err; + struct dst_network_ctl *rctl = data; + + if (n) + return -EEXIST; + + if (size != sizeof(struct dst_network_ctl)) + return -EINVAL; + + n = dst_alloc_node(ctl, dst_start_remote, 1); + if (!n) + return -ENOMEM; + + memcpy(&n->info->net, rctl, sizeof(struct dst_network_ctl)); + err = dst_node_init_connected(n, rctl); + if (err) + goto err_out_free; + + dst_node_add(n); + + return 0; + +err_out_free: + dst_node_put(n); + return err; +} + +/* + * Adding export node: initializing block device and listening socket. + */ +static int dst_add_export(struct dst_node *n, struct dst_ctl *ctl, + void *data, unsigned int size) +{ + int err; + struct dst_export_ctl *le = data; + + if (n) + return -EEXIST; + + if (size != sizeof(struct dst_export_ctl)) + return -EINVAL; + + n = dst_alloc_node(ctl, dst_start_export, 2); + if (!n) + return -EINVAL; + + err = dst_setup_export(n, ctl, le); + if (err) + goto err_out_free; + + dst_node_add(n); + + return 0; + +err_out_free: + dst_node_put(n); + return err; +} + +static int dst_node_remove_unload(struct dst_node *n) +{ + printk(KERN_INFO "STOPPED name: '%s', size: %llu.\n", + n->name, n->size); + + if (n->disk) + del_gendisk(n->disk); + + dst_node_remove(n); + dst_node_sysfs_exit(n); + + /* + * This is not a hack. Really. + * Node's reference counter allows to implement fine grained + * node freeing, but since all transactions (which hold node's + * reference counter) are processed in the dedicated thread, + * it is possible that reference will hit zero in that thread, + * so we will not be able to exit thread and cleanup the node. + * + * So, we remove disk, so no new activity is possible, and + * wait until all pending transaction are completed (either + * in receiving thread or by timeout in workqueue), in this + * case reference counter will be less or equal to 2 (once set in + * dst_alloc_node() and then in connector message parser; + * or when we force module unloading, and connector message + * parser does not hold a reference, in this case reference + * counter will be equal to 1), + * and subsequent dst_node_put() calls will free the node. + */ + dprintk("%s: going to sleep with %d refcnt.\n", __func__, atomic_read(&n->refcnt)); + wait_event(n->wait, atomic_read(&n->refcnt) <= 2); + + dst_node_put(n); + return 0; +} + +/* + * Remove node from the hash table. + */ +static int dst_del_node(struct dst_node *n, struct dst_ctl *ctl, + void *data, unsigned int size) +{ + if (!n) + return -ENODEV; + + return dst_node_remove_unload(n); +} + +/* + * Initialize crypto processing for given node. + */ +static int dst_crypto_init(struct dst_node *n, struct dst_ctl *ctl, + void *data, unsigned int size) +{ + struct dst_crypto_ctl *crypto = data; + + if (!n) + return -ENODEV; + + if (size != sizeof(struct dst_crypto_ctl) + crypto->hash_keysize + + crypto->cipher_keysize) + return -EINVAL; + + if (n->trans_cache) + return -EEXIST; + + return dst_node_crypto_init(n, crypto); +} + +/* + * Security attributes for given node. + */ +static int dst_security_init(struct dst_node *n, struct dst_ctl *ctl, + void *data, unsigned int size) +{ + struct dst_secure *s; + + if (!n) + return -ENODEV; + + if (size != sizeof(struct dst_secure_user)) + return -EINVAL; + + s = kmalloc(sizeof(struct dst_secure), GFP_KERNEL); + if (!s) + return -ENOMEM; + + memcpy(&s->sec, data, size); + + mutex_lock(&n->security_lock); + list_add_tail(&s->sec_entry, &n->security_list); + mutex_unlock(&n->security_lock); + + return 0; +} + +/* + * Kill'em all! + */ +static int dst_start_node(struct dst_node *n, struct dst_ctl *ctl, + void *data, unsigned int size) +{ + int err; + + if (!n) + return -ENODEV; + + if (n->trans_cache) + return 0; + + err = n->start(n); + if (err) + return err; + + printk(KERN_INFO "STARTED name: '%s', size: %llu.\n", n->name, n->size); + return 0; +} + +typedef int (*dst_command_func)(struct dst_node *n, struct dst_ctl *ctl, + void *data, unsigned int size); + +/* + * List of userspace commands. + */ +static dst_command_func dst_commands[] = { + [DST_ADD_REMOTE] = &dst_add_remote, + [DST_ADD_EXPORT] = &dst_add_export, + [DST_DEL_NODE] = &dst_del_node, + [DST_CRYPTO] = &dst_crypto_init, + [DST_SECURITY] = &dst_security_init, + [DST_START] = &dst_start_node, +}; + +/* + * Configuration parser. + */ +static void cn_dst_callback(void *data) +{ + struct dst_ctl *ctl; + struct cn_msg *msg = data; + int err; + struct dst_ctl_ack ack; + struct dst_node *n = NULL, *tmp; + unsigned int hash; + + if (msg->len < sizeof(struct dst_ctl)) { + err = -EBADMSG; + goto out; + } + + ctl = (struct dst_ctl *)msg->data; + + if (ctl->cmd >= DST_CMD_MAX) { + err = -EINVAL; + goto out; + } + hash = dst_hash(ctl->name, sizeof(ctl->name)); + + mutex_lock(&dst_hash_lock); + list_for_each_entry(tmp, &dst_hashtable[hash], node_entry) { + if (!memcmp(tmp->name, ctl->name, sizeof(tmp->name))) { + n = tmp; + dst_node_get(n); + break; + } + } + mutex_unlock(&dst_hash_lock); + + err = dst_commands[ctl->cmd](n, ctl, msg->data + sizeof(struct dst_ctl), + msg->len - sizeof(struct dst_ctl)); + + dst_node_put(n); +out: + memcpy(&ack.msg, msg, sizeof(struct cn_msg)); + + ack.msg.ack = msg->ack + 1; + ack.msg.len = sizeof(struct dst_ctl_ack) - sizeof(struct cn_msg); + + ack.error = err; + + cn_netlink_send(&ack.msg, 0, GFP_KERNEL); +} + +/* + * Global initialization: sysfs, hash table, block device registration, + * connector and various caches. + */ +static int __init dst_sysfs_init(void) +{ + return bus_register(&dst_dev_bus_type); +} + +static void dst_sysfs_exit(void) +{ + bus_unregister(&dst_dev_bus_type); +} + +static int __init dst_hashtable_init(void) +{ + unsigned int i; + + dst_hashtable = kcalloc(dst_hashtable_size, sizeof(struct list_head), + GFP_KERNEL); + if (!dst_hashtable) + return -ENOMEM; + + for (i=0; i<dst_hashtable_size; ++i) + INIT_LIST_HEAD(&dst_hashtable[i]); + + return 0; +} + +static void dst_hashtable_exit(void) +{ + unsigned int i; + struct dst_node *n, *tmp; + + for (i=0; i<dst_hashtable_size; ++i) { + list_for_each_entry_safe(n, tmp, &dst_hashtable[i], node_entry) { + dst_node_remove_unload(n); + } + } + + kfree(dst_hashtable); +} + +static int __init dst_sys_init(void) +{ + int err = -ENOMEM; + + err = dst_hashtable_init(); + if (err) + goto err_out_exit; + + err = dst_export_init(); + if (err) + goto err_out_hashtable_exit; + + err = register_blkdev(dst_major, DST_NAME); + if (err < 0) + goto err_out_export_exit; + if (err) + dst_major = err; + + err = dst_sysfs_init(); + if (err) + goto err_out_unregister; + + err = cn_add_callback(&cn_dst_id, "DST", cn_dst_callback); + if (err) + goto err_out_sysfs_exit; + + printk(KERN_INFO "Distributed storage, '%s' release.\n", dst_name); + + return 0; + +err_out_sysfs_exit: + dst_sysfs_exit(); +err_out_unregister: + unregister_blkdev(dst_major, DST_NAME); +err_out_export_exit: + dst_export_exit(); +err_out_hashtable_exit: + dst_hashtable_exit(); +err_out_exit: + return err; +} + +static void __exit dst_sys_exit(void) +{ + cn_del_callback(&cn_dst_id); + unregister_blkdev(dst_major, DST_NAME); + dst_hashtable_exit(); + dst_sysfs_exit(); + dst_export_exit(); +} + +module_init(dst_sys_init); +module_exit(dst_sys_exit); + +MODULE_DESCRIPTION("Distributed storage"); +MODULE_AUTHOR("Evgeniy Polyakov <zbr@ioremap.net>"); +MODULE_LICENSE("GPL"); |