1/*******************************************************************************
2 * Filename: target_core_hba.c
3 *
4 * This file contains the TCM HBA Transport related functions.
5 *
6 * (c) Copyright 2003-2013 Datera, Inc.
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
42static LIST_HEAD(backend_list);
43static DEFINE_MUTEX(backend_mutex);
44
45static u32 hba_id_counter;
46
47static DEFINE_SPINLOCK(hba_lock);
48static LIST_HEAD(hba_list);
49
50
51int transport_backend_register(const struct target_backend_ops *ops)
52{
53 struct target_backend *tb, *old;
54
55 tb = kzalloc(sizeof(*tb), GFP_KERNEL);
56 if (!tb)
57 return -ENOMEM;
58 tb->ops = ops;
59
60 mutex_lock(&backend_mutex);
61 list_for_each_entry(old, &backend_list, list) {
62 if (!strcmp(old->ops->name, ops->name)) {
63 pr_err("backend %s already registered.\n", ops->name);
64 mutex_unlock(&backend_mutex);
65 kfree(tb);
66 return -EEXIST;
67 }
68 }
69 target_setup_backend_cits(tb);
70 list_add_tail(&tb->list, &backend_list);
71 mutex_unlock(&backend_mutex);
72
73 pr_debug("TCM: Registered subsystem plugin: %s struct module: %p\n",
74 ops->name, ops->owner);
75 return 0;
76}
77EXPORT_SYMBOL(transport_backend_register);
78
79void target_backend_unregister(const struct target_backend_ops *ops)
80{
81 struct target_backend *tb;
82
83 mutex_lock(&backend_mutex);
84 list_for_each_entry(tb, &backend_list, list) {
85 if (tb->ops == ops) {
86 list_del(&tb->list);
87 mutex_unlock(&backend_mutex);
88 /*
89 * Wait for any outstanding backend driver ->rcu_head
90 * callbacks to complete post TBO->free_device() ->
91 * call_rcu(), before allowing backend driver module
92 * unload of target_backend_ops->owner to proceed.
93 */
94 rcu_barrier();
95 kfree(tb);
96 return;
97 }
98 }
99 mutex_unlock(&backend_mutex);
100}
101EXPORT_SYMBOL(target_backend_unregister);
102
103static struct target_backend *core_get_backend(const char *name)
104{
105 struct target_backend *tb;
106
107 mutex_lock(&backend_mutex);
108 list_for_each_entry(tb, &backend_list, list) {
109 if (!strcmp(tb->ops->name, name))
110 goto found;
111 }
112 mutex_unlock(&backend_mutex);
113 return NULL;
114found:
115 if (tb->ops->owner && !try_module_get(tb->ops->owner))
116 tb = NULL;
117 mutex_unlock(&backend_mutex);
118 return tb;
119}
120
121struct se_hba *
122core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
123{
124 struct se_hba *hba;
125 int ret = 0;
126
127 hba = kzalloc(sizeof(*hba), GFP_KERNEL);
128 if (!hba) {
129 pr_err("Unable to allocate struct se_hba\n");
130 return ERR_PTR(-ENOMEM);
131 }
132
133 spin_lock_init(&hba->device_lock);
134 mutex_init(&hba->hba_access_mutex);
135
136 hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
137 hba->hba_flags |= hba_flags;
138
139 hba->backend = core_get_backend(plugin_name);
140 if (!hba->backend) {
141 ret = -EINVAL;
142 goto out_free_hba;
143 }
144
145 ret = hba->backend->ops->attach_hba(hba, plugin_dep_id);
146 if (ret < 0)
147 goto out_module_put;
148
149 spin_lock(&hba_lock);
150 hba->hba_id = hba_id_counter++;
151 list_add_tail(&hba->hba_node, &hba_list);
152 spin_unlock(&hba_lock);
153
154 pr_debug("CORE_HBA[%d] - Attached HBA to Generic Target"
155 " Core\n", hba->hba_id);
156
157 return hba;
158
159out_module_put:
160 module_put(hba->backend->ops->owner);
161 hba->backend = NULL;
162out_free_hba:
163 kfree(hba);
164 return ERR_PTR(ret);
165}
166
167int
168core_delete_hba(struct se_hba *hba)
169{
170 WARN_ON(hba->dev_count);
171
172 hba->backend->ops->detach_hba(hba);
173
174 spin_lock(&hba_lock);
175 list_del(&hba->hba_node);
176 spin_unlock(&hba_lock);
177
178 pr_debug("CORE_HBA[%d] - Detached HBA from Generic Target"
179 " Core\n", hba->hba_id);
180
181 module_put(hba->backend->ops->owner);
182
183 hba->backend = NULL;
184 kfree(hba);
185 return 0;
186}
187
188bool target_sense_desc_format(struct se_device *dev)
189{
190 return (dev) ? dev->transport->get_blocks(dev) > U32_MAX : false;
191}
192