target: More core cleanups from AGrover (round 2)
[linux-2.6.git] / drivers / target / target_core_hba.c
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 <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 static u32 hba_id_counter;
49
50 static DEFINE_SPINLOCK(hba_lock);
51 static LIST_HEAD(hba_list);
52
53 int 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                         printk(KERN_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         printk(KERN_INFO "TCM: Registered subsystem plugin: %s struct module:"
73                         " %p\n", sub_api->name, sub_api->owner);
74         return 0;
75 }
76 EXPORT_SYMBOL(transport_subsystem_register);
77
78 void 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 }
84 EXPORT_SYMBOL(transport_subsystem_release);
85
86 static 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;
97 found:
98         if (s->owner && !try_module_get(s->owner))
99                 s = NULL;
100         mutex_unlock(&subsystem_mutex);
101         return s;
102 }
103
104 struct se_hba *
105 core_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                 printk(KERN_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         printk(KERN_INFO "CORE_HBA[%d] - Attached HBA to Generic Target"
139                         " Core\n", hba->hba_id);
140
141         return hba;
142
143 out_module_put:
144         if (hba->transport->owner)
145                 module_put(hba->transport->owner);
146         hba->transport = NULL;
147 out_free_hba:
148         kfree(hba);
149         return ERR_PTR(ret);
150 }
151
152 int
153 core_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         printk(KERN_INFO "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 }