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_tpg.h>
  41 #include <target/target_core_transport.h>
  42
  43 #include "target_core_hba.h"
  44
  45 static LIST_HEAD(subsystem_list);
  46 static DEFINE_MUTEX(subsystem_mutex);
  47
  48 int transport_subsystem_register(struct se_subsystem_api *sub_api)
  49 {
  50         struct se_subsystem_api *s;
  51
  52         INIT_LIST_HEAD(&sub_api->sub_api_list);
  53
  54         mutex_lock(&subsystem_mutex);
  55         list_for_each_entry(s, &subsystem_list, sub_api_list) {
  56                 if (!(strcmp(s->name, sub_api->name))) {
  57                         printk(KERN_ERR "%p is already registered with"
  58                                 " duplicate name %s, unable to process"
  59                                 " request\n", s, s->name);
  60                         mutex_unlock(&subsystem_mutex);
  61                         return -EEXIST;
  62                 }
  63         }
  64         list_add_tail(&sub_api->sub_api_list, &subsystem_list);
  65         mutex_unlock(&subsystem_mutex);
  66
  67         printk(KERN_INFO "TCM: Registered subsystem plugin: %s struct module:"
  68                         " %p\n", sub_api->name, sub_api->owner);
  69         return 0;
  70 }
  71 EXPORT_SYMBOL(transport_subsystem_register);
  72
  73 void transport_subsystem_release(struct se_subsystem_api *sub_api)
  74 {
  75         mutex_lock(&subsystem_mutex);
  76         list_del(&sub_api->sub_api_list);
  77         mutex_unlock(&subsystem_mutex);
  78 }
  79 EXPORT_SYMBOL(transport_subsystem_release);
  80
  81 static struct se_subsystem_api *core_get_backend(const char *sub_name)
  82 {
  83         struct se_subsystem_api *s;
  84
  85         mutex_lock(&subsystem_mutex);
  86         list_for_each_entry(s, &subsystem_list, sub_api_list) {
  87                 if (!strcmp(s->name, sub_name))
  88                         goto found;
  89         }
  90         mutex_unlock(&subsystem_mutex);
  91         return NULL;
  92 found:
  93         if (s->owner && !try_module_get(s->owner))
  94                 s = NULL;
  95         mutex_unlock(&subsystem_mutex);
  96         return s;
  97 }
  98
  99 struct se_hba *
 100 core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
 101 {
 102         struct se_hba *hba;
 103         int ret = 0;
 104
 105         hba = kzalloc(sizeof(*hba), GFP_KERNEL);
 106         if (!hba) {
 107                 printk(KERN_ERR "Unable to allocate struct se_hba\n");
 108                 return ERR_PTR(-ENOMEM);
 109         }
 110
 111         INIT_LIST_HEAD(&hba->hba_dev_list);
 112         spin_lock_init(&hba->device_lock);
 113         spin_lock_init(&hba->hba_queue_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         atomic_set(&hba->max_queue_depth, 0);
 120         atomic_set(&hba->left_queue_depth, 0);
 121
 122         hba->transport = core_get_backend(plugin_name);
 123         if (!hba->transport) {
 124                 ret = -EINVAL;
 125                 goto out_free_hba;
 126         }
 127
 128         ret = hba->transport->attach_hba(hba, plugin_dep_id);
 129         if (ret < 0)
 130                 goto out_module_put;
 131
 132         spin_lock(&se_global->hba_lock);
 133         hba->hba_id = se_global->g_hba_id_counter++;
 134         list_add_tail(&hba->hba_list, &se_global->g_hba_list);
 135         spin_unlock(&se_global->hba_lock);
 136
 137         printk(KERN_INFO "CORE_HBA[%d] - Attached HBA to Generic Target"
 138                         " Core\n", hba->hba_id);
 139
 140         return hba;
 141
 142 out_module_put:
 143         if (hba->transport->owner)
 144                 module_put(hba->transport->owner);
 145         hba->transport = NULL;
 146 out_free_hba:
 147         kfree(hba);
 148         return ERR_PTR(ret);
 149 }
 150
 151 int
 152 core_delete_hba(struct se_hba *hba)
 153 {
 154         if (!list_empty(&hba->hba_dev_list))
 155                 dump_stack();
 156
 157         hba->transport->detach_hba(hba);
 158
 159         spin_lock(&se_global->hba_lock);
 160         list_del(&hba->hba_list);
 161         spin_unlock(&se_global->hba_lock);
 162
 163         printk(KERN_INFO "CORE_HBA[%d] - Detached HBA from Generic Target"
 164                         " Core\n", hba->hba_id);
 165
 166         if (hba->transport->owner)
 167                 module_put(hba->transport->owner);
 168
 169         hba->transport = NULL;
 170         kfree(hba);
 171         return 0;
 172 }