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 * (c) Copyright 2003-2012 RisingTide Systems LLC.
   7 *
   8 * Nicholas A. Bellinger <nab@kernel.org>
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License as published by
  12 * the Free Software Foundation; either version 2 of the License, or
  13 * (at your option) any later version.
  14 *
  15 * This program is distributed in the hope that it will be useful,
  16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 * GNU General Public License for more details.
  19 *
  20 * You should have received a copy of the GNU General Public License
  21 * along with this program; if not, write to the Free Software
  22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23 *
  24 ******************************************************************************/
  25
  26#include <linux/net.h>
  27#include <linux/string.h>
  28#include <linux/timer.h>
  29#include <linux/slab.h>
  30#include <linux/spinlock.h>
  31#include <linux/in.h>
  32#include <linux/module.h>
  33#include <net/sock.h>
  34#include <net/tcp.h>
  35
  36#include <target/target_core_base.h>
  37#include <target/target_core_backend.h>
  38#include <target/target_core_fabric.h>
  39
  40#include "target_core_internal.h"
  41
  42static LIST_HEAD(subsystem_list);
  43static DEFINE_MUTEX(subsystem_mutex);
  44
  45static u32 hba_id_counter;
  46
  47static DEFINE_SPINLOCK(hba_lock);
  48static LIST_HEAD(hba_list);
  49
  50int transport_subsystem_register(struct se_subsystem_api *sub_api)
  51{
  52        struct se_subsystem_api *s;
  53
  54        INIT_LIST_HEAD(&sub_api->sub_api_list);
  55
  56        mutex_lock(&subsystem_mutex);
  57        list_for_each_entry(s, &subsystem_list, sub_api_list) {
  58                if (!strcmp(s->name, sub_api->name)) {
  59                        pr_err("%p is already registered with"
  60                                " duplicate name %s, unable to process"
  61                                " request\n", s, s->name);
  62                        mutex_unlock(&subsystem_mutex);
  63                        return -EEXIST;
  64                }
  65        }
  66        list_add_tail(&sub_api->sub_api_list, &subsystem_list);
  67        mutex_unlock(&subsystem_mutex);
  68
  69        pr_debug("TCM: Registered subsystem plugin: %s struct module:"
  70                        " %p\n", sub_api->name, sub_api->owner);
  71        return 0;
  72}
  73EXPORT_SYMBOL(transport_subsystem_register);
  74
  75void transport_subsystem_release(struct se_subsystem_api *sub_api)
  76{
  77        mutex_lock(&subsystem_mutex);
  78        list_del(&sub_api->sub_api_list);
  79        mutex_unlock(&subsystem_mutex);
  80}
  81EXPORT_SYMBOL(transport_subsystem_release);
  82
  83static struct se_subsystem_api *core_get_backend(const char *sub_name)
  84{
  85        struct se_subsystem_api *s;
  86
  87        mutex_lock(&subsystem_mutex);
  88        list_for_each_entry(s, &subsystem_list, sub_api_list) {
  89                if (!strcmp(s->name, sub_name))
  90                        goto found;
  91        }
  92        mutex_unlock(&subsystem_mutex);
  93        return NULL;
  94found:
  95        if (s->owner && !try_module_get(s->owner))
  96                s = NULL;
  97        mutex_unlock(&subsystem_mutex);
  98        return s;
  99}
 100
 101struct se_hba *
 102core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
 103{
 104        struct se_hba *hba;
 105        int ret = 0;
 106
 107        hba = kzalloc(sizeof(*hba), GFP_KERNEL);
 108        if (!hba) {
 109                pr_err("Unable to allocate struct se_hba\n");
 110                return ERR_PTR(-ENOMEM);
 111        }
 112
 113        spin_lock_init(&hba->device_lock);
 114        mutex_init(&hba->hba_access_mutex);
 115
 116        hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
 117        hba->hba_flags |= hba_flags;
 118
 119        hba->transport = core_get_backend(plugin_name);
 120        if (!hba->transport) {
 121                ret = -EINVAL;
 122                goto out_free_hba;
 123        }
 124
 125        ret = hba->transport->attach_hba(hba, plugin_dep_id);
 126        if (ret < 0)
 127                goto out_module_put;
 128
 129        spin_lock(&hba_lock);
 130        hba->hba_id = hba_id_counter++;
 131        list_add_tail(&hba->hba_node, &hba_list);
 132        spin_unlock(&hba_lock);
 133
 134        pr_debug("CORE_HBA[%d] - Attached HBA to Generic Target"
 135                        " Core\n", hba->hba_id);
 136
 137        return hba;
 138
 139out_module_put:
 140        if (hba->transport->owner)
 141                module_put(hba->transport->owner);
 142        hba->transport = NULL;
 143out_free_hba:
 144        kfree(hba);
 145        return ERR_PTR(ret);
 146}
 147
 148int
 149core_delete_hba(struct se_hba *hba)
 150{
 151        WARN_ON(hba->dev_count);
 152
 153        hba->transport->detach_hba(hba);
 154
 155        spin_lock(&hba_lock);
 156        list_del(&hba->hba_node);
 157        spin_unlock(&hba_lock);
 158
 159        pr_debug("CORE_HBA[%d] - Detached HBA from Generic Target"
 160                        " Core\n", hba->hba_id);
 161
 162        if (hba->transport->owner)
 163                module_put(hba->transport->owner);
 164
 165        hba->transport = NULL;
 166        kfree(hba);
 167        return 0;
 168}
 169