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/*******************************************************************************
* Filename: target_core_hba.c
*
* This file contains the TCM HBA Transport related functions.
*
* (c) Copyright 2003-2013 Datera, Inc.
*
* Nicholas A. Bellinger <nab@kernel.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
******************************************************************************/
#include <linux/net.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/in.h>
#include <linux/module.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <target/target_core_base.h>
#include <target/target_core_backend.h>
#include <target/target_core_fabric.h>
#include "target_core_internal.h"
static LIST_HEAD(backend_list);
static DEFINE_MUTEX(backend_mutex);
static u32 hba_id_counter;
static DEFINE_SPINLOCK(hba_lock);
static LIST_HEAD(hba_list);
int transport_backend_register(const struct target_backend_ops *ops)
{
struct target_backend *tb, *old;
tb = kzalloc(sizeof(*tb), GFP_KERNEL);
if (!tb)
return -ENOMEM;
tb->ops = ops;
mutex_lock(&backend_mutex);
list_for_each_entry(old, &backend_list, list) {
if (!strcmp(old->ops->name, ops->name)) {
pr_err("backend %s already registered.\n", ops->name);
mutex_unlock(&backend_mutex);
kfree(tb);
return -EEXIST;
}
}
target_setup_backend_cits(tb);
list_add_tail(&tb->list, &backend_list);
mutex_unlock(&backend_mutex);
pr_debug("TCM: Registered subsystem plugin: %s struct module: %p\n",
ops->name, ops->owner);
return 0;
}
EXPORT_SYMBOL(transport_backend_register);
void target_backend_unregister(const struct target_backend_ops *ops)
{
struct target_backend *tb;
mutex_lock(&backend_mutex);
list_for_each_entry(tb, &backend_list, list) {
if (tb->ops == ops) {
list_del(&tb->list);
mutex_unlock(&backend_mutex);
/*
* Wait for any outstanding backend driver ->rcu_head
* callbacks to complete post TBO->free_device() ->
* call_rcu(), before allowing backend driver module
* unload of target_backend_ops->owner to proceed.
*/
rcu_barrier();
kfree(tb);
return;
}
}
mutex_unlock(&backend_mutex);
}
EXPORT_SYMBOL(target_backend_unregister);
static struct target_backend *core_get_backend(const char *name)
{
struct target_backend *tb;
mutex_lock(&backend_mutex);
list_for_each_entry(tb, &backend_list, list) {
if (!strcmp(tb->ops->name, name))
goto found;
}
mutex_unlock(&backend_mutex);
return NULL;
found:
if (tb->ops->owner && !try_module_get(tb->ops->owner))
tb = NULL;
mutex_unlock(&backend_mutex);
return tb;
}
struct se_hba *
core_alloc_hba(const char *plugin_name, u32 plugin_dep_id, u32 hba_flags)
{
struct se_hba *hba;
int ret = 0;
hba = kzalloc(sizeof(*hba), GFP_KERNEL);
if (!hba) {
pr_err("Unable to allocate struct se_hba\n");
return ERR_PTR(-ENOMEM);
}
spin_lock_init(&hba->device_lock);
mutex_init(&hba->hba_access_mutex);
hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
hba->hba_flags |= hba_flags;
hba->backend = core_get_backend(plugin_name);
if (!hba->backend) {
ret = -EINVAL;
goto out_free_hba;
}
ret = hba->backend->ops->attach_hba(hba, plugin_dep_id);
if (ret < 0)
goto out_module_put;
spin_lock(&hba_lock);
hba->hba_id = hba_id_counter++;
list_add_tail(&hba->hba_node, &hba_list);
spin_unlock(&hba_lock);
pr_debug("CORE_HBA[%d] - Attached HBA to Generic Target"
" Core\n", hba->hba_id);
return hba;
out_module_put:
module_put(hba->backend->ops->owner);
hba->backend = NULL;
out_free_hba:
kfree(hba);
return ERR_PTR(ret);
}
int
core_delete_hba(struct se_hba *hba)
{
WARN_ON(hba->dev_count);
hba->backend->ops->detach_hba(hba);
spin_lock(&hba_lock);
list_del(&hba->hba_node);
spin_unlock(&hba_lock);
pr_debug("CORE_HBA[%d] - Detached HBA from Generic Target"
" Core\n", hba->hba_id);
module_put(hba->backend->ops->owner);
hba->backend = NULL;
kfree(hba);
return 0;
}
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