1/*******************************************************************************
2 * Filename:  target_core_hba.c
3 *
4 * This file contains the TCM 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 <linux/module.h>
36#include <net/sock.h>
37#include <net/tcp.h>
38
39#include <target/target_core_base.h>
40#include <target/target_core_backend.h>
41#include <target/target_core_fabric.h>
42
43#include "target_core_internal.h"
44
45static LIST_HEAD(subsystem_list);
46static DEFINE_MUTEX(subsystem_mutex);
47
48static u32 hba_id_counter;
49
50static DEFINE_SPINLOCK(hba_lock);
51static LIST_HEAD(hba_list);
52
53int transport_subsystem_register(struct se_subsystem_api *sub_api)
54{
55	struct se_subsystem_api *s;
56
57	INIT_LIST_HEAD(&sub_api->sub_api_list);
58
59	mutex_lock(&subsystem_mutex);
60	list_for_each_entry(s, &subsystem_list, sub_api_list) {
61		if (!strcmp(s->name, sub_api->name)) {
62			pr_err("%p is already registered with"
63				" duplicate name %s, unable to process"
64				" request\n", s, s->name);
65			mutex_unlock(&subsystem_mutex);
66			return -EEXIST;
67		}
68	}
69	list_add_tail(&sub_api->sub_api_list, &subsystem_list);
70	mutex_unlock(&subsystem_mutex);
71
72	pr_debug("TCM: Registered subsystem plugin: %s struct module:"
73			" %p\n", sub_api->name, sub_api->owner);
74	return 0;
75}
76EXPORT_SYMBOL(transport_subsystem_register);
77
78void transport_subsystem_release(struct se_subsystem_api *sub_api)
79{
80	mutex_lock(&subsystem_mutex);
81	list_del(&sub_api->sub_api_list);
82	mutex_unlock(&subsystem_mutex);
83}
84EXPORT_SYMBOL(transport_subsystem_release);
85
86static struct se_subsystem_api *core_get_backend(const char *sub_name)
87{
88	struct se_subsystem_api *s;
89
90	mutex_lock(&subsystem_mutex);
91	list_for_each_entry(s, &subsystem_list, sub_api_list) {
92		if (!strcmp(s->name, sub_name))
93			goto found;
94	}
95	mutex_unlock(&subsystem_mutex);
96	return NULL;
97found:
98	if (s->owner && !try_module_get(s->owner))
99		s = NULL;
100	mutex_unlock(&subsystem_mutex);
101	return s;
102}
103
104struct se_hba *
105core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
106{
107	struct se_hba *hba;
108	int ret = 0;
109
110	hba = kzalloc(sizeof(*hba), GFP_KERNEL);
111	if (!hba) {
112		pr_err("Unable to allocate struct se_hba\n");
113		return ERR_PTR(-ENOMEM);
114	}
115
116	INIT_LIST_HEAD(&hba->hba_dev_list);
117	spin_lock_init(&hba->device_lock);
118	mutex_init(&hba->hba_access_mutex);
119
120	hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
121	hba->hba_flags |= hba_flags;
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(&hba_lock);
134	hba->hba_id = hba_id_counter++;
135	list_add_tail(&hba->hba_node, &hba_list);
136	spin_unlock(&hba_lock);
137
138	pr_debug("CORE_HBA[%d] - Attached HBA to Generic Target"
139			" Core\n", hba->hba_id);
140
141	return hba;
142
143out_module_put:
144	if (hba->transport->owner)
145		module_put(hba->transport->owner);
146	hba->transport = NULL;
147out_free_hba:
148	kfree(hba);
149	return ERR_PTR(ret);
150}
151
152int
153core_delete_hba(struct se_hba *hba)
154{
155	if (!list_empty(&hba->hba_dev_list))
156		dump_stack();
157
158	hba->transport->detach_hba(hba);
159
160	spin_lock(&hba_lock);
161	list_del(&hba->hba_node);
162	spin_unlock(&hba_lock);
163
164	pr_debug("CORE_HBA[%d] - Detached HBA from Generic Target"
165			" Core\n", hba->hba_id);
166
167	if (hba->transport->owner)
168		module_put(hba->transport->owner);
169
170	hba->transport = NULL;
171	kfree(hba);
172	return 0;
173}
174