| 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(backend_list); |
| 43 | static DEFINE_MUTEX(backend_mutex); |
| 44 | |
| 45 | static u32 hba_id_counter; |
| 46 | |
| 47 | static DEFINE_SPINLOCK(hba_lock); |
| 48 | static LIST_HEAD(hba_list); |
| 49 | |
| 50 | |
| 51 | int 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 | } |
| 77 | EXPORT_SYMBOL(transport_backend_register); |
| 78 | |
| 79 | void 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 | } |
| 101 | EXPORT_SYMBOL(target_backend_unregister); |
| 102 | |
| 103 | static 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; |
| 114 | found: |
| 115 | if (tb->ops->owner && !try_module_get(tb->ops->owner)) |
| 116 | tb = NULL; |
| 117 | mutex_unlock(&backend_mutex); |
| 118 | return tb; |
| 119 | } |
| 120 | |
| 121 | struct se_hba * |
| 122 | core_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 | |
| 159 | out_module_put: |
| 160 | module_put(hba->backend->ops->owner); |
| 161 | hba->backend = NULL; |
| 162 | out_free_hba: |
| 163 | kfree(hba); |
| 164 | return ERR_PTR(ret); |
| 165 | } |
| 166 | |
| 167 | int |
| 168 | core_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 | |
| 188 | bool target_sense_desc_format(struct se_device *dev) |
| 189 | { |
| 190 | return (dev) ? dev->transport->get_blocks(dev) > U32_MAX : false; |
| 191 | } |