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_device.h>
  41#include <target/target_core_tpg.h>
  42#include <target/target_core_transport.h>
  43
  44#include "target_core_hba.h"
  45
  46static LIST_HEAD(subsystem_list);
  47static DEFINE_MUTEX(subsystem_mutex);
  48
  49static u32 hba_id_counter;
  50
  51static DEFINE_SPINLOCK(hba_lock);
  52static LIST_HEAD(hba_list);
  53
  54int transport_subsystem_register(struct se_subsystem_api *sub_api)
  55{
  56        struct se_subsystem_api *s;
  57
  58        INIT_LIST_HEAD(&sub_api->sub_api_list);
  59
  60        mutex_lock(&subsystem_mutex);
  61        list_for_each_entry(s, &subsystem_list, sub_api_list) {
  62                if (!strcmp(s->name, sub_api->name)) {
  63                        pr_err("%p is already registered with"
  64                                " duplicate name %s, unable to process"
  65                                " request\n", s, s->name);
  66                        mutex_unlock(&subsystem_mutex);
  67                        return -EEXIST;
  68                }
  69        }
  70        list_add_tail(&sub_api->sub_api_list, &subsystem_list);
  71        mutex_unlock(&subsystem_mutex);
  72
  73        pr_debug("TCM: Registered subsystem plugin: %s struct module:"
  74                        " %p\n", sub_api->name, sub_api->owner);
  75        return 0;
  76}
  77EXPORT_SYMBOL(transport_subsystem_register);
  78
  79void transport_subsystem_release(struct se_subsystem_api *sub_api)
  80{
  81        mutex_lock(&subsystem_mutex);
  82        list_del(&sub_api->sub_api_list);
  83        mutex_unlock(&subsystem_mutex);
  84}
  85EXPORT_SYMBOL(transport_subsystem_release);
  86
  87static struct se_subsystem_api *core_get_backend(const char *sub_name)
  88{
  89        struct se_subsystem_api *s;
  90
  91        mutex_lock(&subsystem_mutex);
  92        list_for_each_entry(s, &subsystem_list, sub_api_list) {
  93                if (!strcmp(s->name, sub_name))
  94                        goto found;
  95        }
  96        mutex_unlock(&subsystem_mutex);
  97        return NULL;
  98found:
  99        if (s->owner && !try_module_get(s->owner))
 100                s = NULL;
 101        mutex_unlock(&subsystem_mutex);
 102        return s;
 103}
 104
 105struct se_hba *
 106core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
 107{
 108        struct se_hba *hba;
 109        int ret = 0;
 110
 111        hba = kzalloc(sizeof(*hba), GFP_KERNEL);
 112        if (!hba) {
 113                pr_err("Unable to allocate struct se_hba\n");
 114                return ERR_PTR(-ENOMEM);
 115        }
 116
 117        INIT_LIST_HEAD(&hba->hba_dev_list);
 118        spin_lock_init(&hba->device_lock);
 119        mutex_init(&hba->hba_access_mutex);
 120
 121        hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
 122        hba->hba_flags |= hba_flags;
 123
 124        hba->transport = core_get_backend(plugin_name);
 125        if (!hba->transport) {
 126                ret = -EINVAL;
 127                goto out_free_hba;
 128        }
 129
 130        ret = hba->transport->attach_hba(hba, plugin_dep_id);
 131        if (ret < 0)
 132                goto out_module_put;
 133
 134        spin_lock(&hba_lock);
 135        hba->hba_id = hba_id_counter++;
 136        list_add_tail(&hba->hba_node, &hba_list);
 137        spin_unlock(&hba_lock);
 138
 139        pr_debug("CORE_HBA[%d] - Attached HBA to Generic Target"
 140                        " Core\n", hba->hba_id);
 141
 142        return hba;
 143
 144out_module_put:
 145        if (hba->transport->owner)
 146                module_put(hba->transport->owner);
 147        hba->transport = NULL;
 148out_free_hba:
 149        kfree(hba);
 150        return ERR_PTR(ret);
 151}
 152
 153int
 154core_delete_hba(struct se_hba *hba)
 155{
 156        if (!list_empty(&hba->hba_dev_list))
 157                dump_stack();
 158
 159        hba->transport->detach_hba(hba);
 160
 161        spin_lock(&hba_lock);
 162        list_del(&hba->hba_node);
 163        spin_unlock(&hba_lock);
 164
 165        pr_debug("CORE_HBA[%d] - Detached HBA from Generic Target"
 166                        " Core\n", hba->hba_id);
 167
 168        if (hba->transport->owner)
 169                module_put(hba->transport->owner);
 170
 171        hba->transport = NULL;
 172        kfree(hba);
 173        return 0;
 174}
 175