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
42 static LIST_HEAD(subsystem_list);
43 static DEFINE_MUTEX(subsystem_mutex);
44
45 static u32 hba_id_counter;
46
47 static DEFINE_SPINLOCK(hba_lock);
48 static LIST_HEAD(hba_list);
49
transport_subsystem_register(struct se_subsystem_api * sub_api)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 pr_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 pr_debug("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
transport_subsystem_release(struct se_subsystem_api * sub_api)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
core_get_backend(const char * sub_name)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 *
core_alloc_hba(const char * plugin_name,u32 plugin_dep_id,u32 hba_flags)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 pr_err("Unable to allocate struct se_hba\n");
110 return ERR_PTR(-ENOMEM);
111 }
112
113 spin_lock_init(&hba->device_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 hba->transport = core_get_backend(plugin_name);
120 if (!hba->transport) {
121 ret = -EINVAL;
122 goto out_free_hba;
123 }
124
125 ret = hba->transport->attach_hba(hba, plugin_dep_id);
126 if (ret < 0)
127 goto out_module_put;
128
129 spin_lock(&hba_lock);
130 hba->hba_id = hba_id_counter++;
131 list_add_tail(&hba->hba_node, &hba_list);
132 spin_unlock(&hba_lock);
133
134 pr_debug("CORE_HBA[%d] - Attached HBA to Generic Target"
135 " Core\n", hba->hba_id);
136
137 return hba;
138
139 out_module_put:
140 if (hba->transport->owner)
141 module_put(hba->transport->owner);
142 hba->transport = NULL;
143 out_free_hba:
144 kfree(hba);
145 return ERR_PTR(ret);
146 }
147
148 int
core_delete_hba(struct se_hba * hba)149 core_delete_hba(struct se_hba *hba)
150 {
151 WARN_ON(hba->dev_count);
152
153 hba->transport->detach_hba(hba);
154
155 spin_lock(&hba_lock);
156 list_del(&hba->hba_node);
157 spin_unlock(&hba_lock);
158
159 pr_debug("CORE_HBA[%d] - Detached HBA from Generic Target"
160 " Core\n", hba->hba_id);
161
162 if (hba->transport->owner)
163 module_put(hba->transport->owner);
164
165 hba->transport = NULL;
166 kfree(hba);
167 return 0;
168 }
169