drivers/target/target_core_hba.c

   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
  45 static LIST_HEAD(subsystem_list);
  46 static DEFINE_MUTEX(subsystem_mutex);
  47
  48 static u32 hba_id_counter;
  49
  50 static DEFINE_SPINLOCK(hba_lock);
  51 static LIST_HEAD(hba_list);
  52
  53 int 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 }
  76 EXPORT_SYMBOL(transport_subsystem_register);
  77
  78 void 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 }
  84 EXPORT_SYMBOL(transport_subsystem_release);
  85
  86 static 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;
  97 found:
  98         if (s->owner && !try_module_get(s->owner))
  99                 s = NULL;
 100         mutex_unlock(&subsystem_mutex);
 101         return s;
 102 }
 103
 104 struct se_hba *
 105 core_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
 143 out_module_put:
 144         if (hba->transport->owner)
 145                 module_put(hba->transport->owner);
 146         hba->transport = NULL;
 147 out_free_hba:
 148         kfree(hba);
 149         return ERR_PTR(ret);
 150 }
 151
 152 int
 153 core_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 }