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/smp_lock.h>
  35 #include <linux/in.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_device.h>
  42 #include <target/target_core_tpg.h>
  43 #include <target/target_core_transport.h>
  44
  45 #include "target_core_hba.h"
  46
  47 static LIST_HEAD(subsystem_list);
  48 static DEFINE_MUTEX(subsystem_mutex);
  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                         printk(KERN_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         printk(KERN_INFO "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                 printk(KERN_ERR "Unable to allocate struct se_hba\n");
 110                 return ERR_PTR(-ENOMEM);
 111         }
 112
 113         INIT_LIST_HEAD(&hba->hba_dev_list);
 114         spin_lock_init(&hba->device_lock);
 115         spin_lock_init(&hba->hba_queue_lock);
 116         mutex_init(&hba->hba_access_mutex);
 117
 118         hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
 119         hba->hba_flags |= hba_flags;
 120
 121         atomic_set(&hba->max_queue_depth, 0);
 122         atomic_set(&hba->left_queue_depth, 0);
 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(&se_global->hba_lock);
 135         hba->hba_id = se_global->g_hba_id_counter++;
 136         list_add_tail(&hba->hba_list, &se_global->g_hba_list);
 137         spin_unlock(&se_global->hba_lock);
 138
 139         printk(KERN_INFO "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         struct se_device *dev, *dev_tmp;
 157
 158         spin_lock(&hba->device_lock);
 159         list_for_each_entry_safe(dev, dev_tmp, &hba->hba_dev_list, dev_list) {
 160
 161                 se_clear_dev_ports(dev);
 162                 spin_unlock(&hba->device_lock);
 163
 164                 se_release_device_for_hba(dev);
 165
 166                 spin_lock(&hba->device_lock);
 167         }
 168         spin_unlock(&hba->device_lock);
 169
 170         hba->transport->detach_hba(hba);
 171
 172         spin_lock(&se_global->hba_lock);
 173         list_del(&hba->hba_list);
 174         spin_unlock(&se_global->hba_lock);
 175
 176         printk(KERN_INFO "CORE_HBA[%d] - Detached HBA from Generic Target"
 177                         " Core\n", hba->hba_id);
 178
 179         if (hba->transport->owner)
 180                 module_put(hba->transport->owner);
 181
 182         hba->transport = NULL;
 183         kfree(hba);
 184         return 0;
 185 }