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  * (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
  42 static LIST_HEAD(subsystem_list);
  43 static DEFINE_MUTEX(subsystem_mutex);
  44
  45 static u32 hba_id_counter;
  46
  47 static DEFINE_SPINLOCK(hba_lock);
  48 static LIST_HEAD(hba_list);
  49
  50 int 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 }
  73 EXPORT_SYMBOL(transport_subsystem_register);
  74
  75 void 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 }
  81 EXPORT_SYMBOL(transport_subsystem_release);
  82
  83 static 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;
  94 found:
  95         if (s->owner && !try_module_get(s->owner))
  96                 s = NULL;
  97         mutex_unlock(&subsystem_mutex);
  98         return s;
  99 }
 100
 101 struct se_hba *
 102 core_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
 139 out_module_put:
 140         if (hba->transport->owner)
 141                 module_put(hba->transport->owner);
 142         hba->transport = NULL;
 143 out_free_hba:
 144         kfree(hba);
 145         return ERR_PTR(ret);
 146 }
 147
 148 int
 149 core_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 }