drivers/target/target_core_hba.c

   1 /*******************************************************************************
   2  * Filename:  target_core_hba.c
   3  *
   4  * This file copntains the iSCSI 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 <net/sock.h>
  36 #include <net/tcp.h>
  37
  38 #include <target/target_core_base.h>
  39 #include <target/target_core_device.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 int transport_subsystem_register(struct se_subsystem_api *sub_api)
  50 {
  51         struct se_subsystem_api *s;
  52
  53         INIT_LIST_HEAD(&sub_api->sub_api_list);
  54
  55         mutex_lock(&subsystem_mutex);
  56         list_for_each_entry(s, &subsystem_list, sub_api_list) {
  57                 if (!(strcmp(s->name, sub_api->name))) {
  58                         printk(KERN_ERR "%p is already registered with"
  59                                 " duplicate name %s, unable to process"
  60                                 " request\n", s, s->name);
  61                         mutex_unlock(&subsystem_mutex);
  62                         return -EEXIST;
  63                 }
  64         }
  65         list_add_tail(&sub_api->sub_api_list, &subsystem_list);
  66         mutex_unlock(&subsystem_mutex);
  67
  68         printk(KERN_INFO "TCM: Registered subsystem plugin: %s struct module:"
  69                         " %p\n", sub_api->name, sub_api->owner);
  70         return 0;
  71 }
  72 EXPORT_SYMBOL(transport_subsystem_register);
  73
  74 void transport_subsystem_release(struct se_subsystem_api *sub_api)
  75 {
  76         mutex_lock(&subsystem_mutex);
  77         list_del(&sub_api->sub_api_list);
  78         mutex_unlock(&subsystem_mutex);
  79 }
  80 EXPORT_SYMBOL(transport_subsystem_release);
  81
  82 static struct se_subsystem_api *core_get_backend(const char *sub_name)
  83 {
  84         struct se_subsystem_api *s;
  85
  86         mutex_lock(&subsystem_mutex);
  87         list_for_each_entry(s, &subsystem_list, sub_api_list) {
  88                 if (!strcmp(s->name, sub_name))
  89                         goto found;
  90         }
  91         mutex_unlock(&subsystem_mutex);
  92         return NULL;
  93 found:
  94         if (s->owner && !try_module_get(s->owner))
  95                 s = NULL;
  96         mutex_unlock(&subsystem_mutex);
  97         return s;
  98 }
  99
 100 struct se_hba *
 101 core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
 102 {
 103         struct se_hba *hba;
 104         int ret = 0;
 105
 106         hba = kzalloc(sizeof(*hba), GFP_KERNEL);
 107         if (!hba) {
 108                 printk(KERN_ERR "Unable to allocate struct se_hba\n");
 109                 return ERR_PTR(-ENOMEM);
 110         }
 111
 112         INIT_LIST_HEAD(&hba->hba_dev_list);
 113         spin_lock_init(&hba->device_lock);
 114         spin_lock_init(&hba->hba_queue_lock);
 115         mutex_init(&hba->hba_access_mutex);
 116
 117         hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
 118         hba->hba_flags |= hba_flags;
 119
 120         atomic_set(&hba->max_queue_depth, 0);
 121         atomic_set(&hba->left_queue_depth, 0);
 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(&se_global->hba_lock);
 134         hba->hba_id = se_global->g_hba_id_counter++;
 135         list_add_tail(&hba->hba_list, &se_global->g_hba_list);
 136         spin_unlock(&se_global->hba_lock);
 137
 138         printk(KERN_INFO "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         struct se_device *dev, *dev_tmp;
 156
 157         spin_lock(&hba->device_lock);
 158         list_for_each_entry_safe(dev, dev_tmp, &hba->hba_dev_list, dev_list) {
 159
 160                 se_clear_dev_ports(dev);
 161                 spin_unlock(&hba->device_lock);
 162
 163                 se_release_device_for_hba(dev);
 164
 165                 spin_lock(&hba->device_lock);
 166         }
 167         spin_unlock(&hba->device_lock);
 168
 169         hba->transport->detach_hba(hba);
 170
 171         spin_lock(&se_global->hba_lock);
 172         list_del(&hba->hba_list);
 173         spin_unlock(&se_global->hba_lock);
 174
 175         printk(KERN_INFO "CORE_HBA[%d] - Detached HBA from Generic Target"
 176                         " Core\n", hba->hba_id);
 177
 178         if (hba->transport->owner)
 179                 module_put(hba->transport->owner);
 180
 181         hba->transport = NULL;
 182         kfree(hba);
 183         return 0;
 184 }