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_device.h>
  41 #include <target/target_core_tpg.h>
  42 #include <target/target_core_transport.h>
  43
  44 #include "target_core_hba.h"
  45
  46 static LIST_HEAD(subsystem_list);
  47 static DEFINE_MUTEX(subsystem_mutex);
  48
  49 static u32 hba_id_counter;
  50
  51 static DEFINE_SPINLOCK(hba_lock);
  52 static LIST_HEAD(hba_list);
  53
  54 int 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 }
  77 EXPORT_SYMBOL(transport_subsystem_register);
  78
  79 void 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 }
  85 EXPORT_SYMBOL(transport_subsystem_release);
  86
  87 static 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;
  98 found:
  99         if (s->owner && !try_module_get(s->owner))
 100                 s = NULL;
 101         mutex_unlock(&subsystem_mutex);
 102         return s;
 103 }
 104
 105 struct se_hba *
 106 core_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
 144 out_module_put:
 145         if (hba->transport->owner)
 146                 module_put(hba->transport->owner);
 147         hba->transport = NULL;
 148 out_free_hba:
 149         kfree(hba);
 150         return ERR_PTR(ret);
 151 }
 152
 153 int
 154 core_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 }