LXR linux/drivers/target/target_core

   1/*******************************************************************************
   2 * Filename:  target_core_hba.c
   3 *
   4 * This file contains the TCM HBA Transport related functions.
   5 *
   6 * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
   7 * Copyright (c) 2005, 2006, 2007 SBE, Inc.
   8 * Copyright (c) 2007-2010 Rising Tide Systems
   9 * Copyright (c) 2008-2010 Linux-iSCSI.org
  10 *
  11 * Nicholas A. Bellinger <nab@kernel.org>
  12 *
  13 * This program is free software; you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2 of the License, or
  16 * (at your option) any later version.
  17 *
  18 * This program is distributed in the hope that it will be useful,
  19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 * GNU General Public License for more details.
  22 *
  23 * You should have received a copy of the GNU General Public License
  24 * along with this program; if not, write to the Free Software
  25 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  26 *
  27 ******************************************************************************/
  28
  29#include <linux/net.h>
  30#include <linux/string.h>
  31#include <linux/timer.h>
  32#include <linux/slab.h>
  33#include <linux/spinlock.h>
  34#include <linux/in.h>
  35#include <linux/module.h>
  36#include <net/sock.h>
  37#include <net/tcp.h>
  38
  39#include <target/target_core_base.h>
  40#include <target/target_core_backend.h>
  41#include <target/target_core_fabric.h>
  42
  43#include "target_core_internal.h"
  44
  45static LIST_HEAD(subsystem_list);
  46static DEFINE_MUTEX(subsystem_mutex);
  47
  48static u32 hba_id_counter;
  49
  50static DEFINE_SPINLOCK(hba_lock);
  51static LIST_HEAD(hba_list);
  52
  53int transport_subsystem_register(struct se_subsystem_api *sub_api)
  54{
  55        struct se_subsystem_api *s;
  56
  57        INIT_LIST_HEAD(&sub_api->sub_api_list);
  58
  59        mutex_lock(&subsystem_mutex);
  60        list_for_each_entry(s, &subsystem_list, sub_api_list) {
  61                if (!strcmp(s->name, sub_api->name)) {
  62                        pr_err("%p is already registered with"
  63                                " duplicate name %s, unable to process"
  64                                " request\n", s, s->name);
  65                        mutex_unlock(&subsystem_mutex);
  66                        return -EEXIST;
  67                }
  68        }
  69        list_add_tail(&sub_api->sub_api_list, &subsystem_list);
  70        mutex_unlock(&subsystem_mutex);
  71
  72        pr_debug("TCM: Registered subsystem plugin: %s struct module:"
  73                        " %p\n", sub_api->name, sub_api->owner);
  74        return 0;
  75}
  76EXPORT_SYMBOL(transport_subsystem_register);
  77
  78void transport_subsystem_release(struct se_subsystem_api *sub_api)
  79{
  80        mutex_lock(&subsystem_mutex);
  81        list_del(&sub_api->sub_api_list);
  82        mutex_unlock(&subsystem_mutex);
  83}
  84EXPORT_SYMBOL(transport_subsystem_release);
  85
  86static struct se_subsystem_api *core_get_backend(const char *sub_name)
  87{
  88        struct se_subsystem_api *s;
  89
  90        mutex_lock(&subsystem_mutex);
  91        list_for_each_entry(s, &subsystem_list, sub_api_list) {
  92                if (!strcmp(s->name, sub_name))
  93                        goto found;
  94        }
  95        mutex_unlock(&subsystem_mutex);
  96        return NULL;
  97found:
  98        if (s->owner && !try_module_get(s->owner))
  99                s = NULL;
 100        mutex_unlock(&subsystem_mutex);
 101        return s;
 102}
 103
 104struct se_hba *
 105core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
 106{
 107        struct se_hba *hba;
 108        int ret = 0;
 109
 110        hba = kzalloc(sizeof(*hba), GFP_KERNEL);
 111        if (!hba) {
 112                pr_err("Unable to allocate struct se_hba\n");
 113                return ERR_PTR(-ENOMEM);
 114        }
 115
 116        INIT_LIST_HEAD(&hba->hba_dev_list);
 117        spin_lock_init(&hba->device_lock);
 118        mutex_init(&hba->hba_access_mutex);
 119
 120        hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
 121        hba->hba_flags |= hba_flags;
 122
 123        hba->transport = core_get_backend(plugin_name);
 124        if (!hba->transport) {
 125                ret = -EINVAL;
 126                goto out_free_hba;
 127        }
 128
 129        ret = hba->transport->attach_hba(hba, plugin_dep_id);
 130        if (ret < 0)
 131                goto out_module_put;
 132
 133        spin_lock(&hba_lock);
 134        hba->hba_id = hba_id_counter++;
 135        list_add_tail(&hba->hba_node, &hba_list);
 136        spin_unlock(&hba_lock);
 137
 138        pr_debug("CORE_HBA[%d] - Attached HBA to Generic Target"
 139                        " Core\n", hba->hba_id);
 140
 141        return hba;
 142
 143out_module_put:
 144        if (hba->transport->owner)
 145                module_put(hba->transport->owner);
 146        hba->transport = NULL;
 147out_free_hba:
 148        kfree(hba);
 149        return ERR_PTR(ret);
 150}
 151
 152int
 153core_delete_hba(struct se_hba *hba)
 154{
 155        if (!list_empty(&hba->hba_dev_list))
 156                dump_stack();
 157
 158        hba->transport->detach_hba(hba);
 159
 160        spin_lock(&hba_lock);
 161        list_del(&hba->hba_node);
 162        spin_unlock(&hba_lock);
 163
 164        pr_debug("CORE_HBA[%d] - Detached HBA from Generic Target"
 165                        " Core\n", hba->hba_id);
 166
 167        if (hba->transport->owner)
 168                module_put(hba->transport->owner);
 169
 170        hba->transport = NULL;
 171        kfree(hba);
 172        return 0;
 173}
 174