linux/drivers/target/target_core_hba.c
Christoph Hellwig 0a06d4309d target: simplify backend driver registration
Rewrite the backend driver registration based on what we did to the fabric
drivers:  introduce a read-only struct target_bakckend_ops that the driver
registers, which is then instanciate as a struct target_backend by the
core.  This allows the ops vector to be smaller and allows us to mark it
const.  At the same time the registration function can set up the
configfs attributes, avoiding the need to add additional boilerplate code
for that to the drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2015-06-01 00:25:34 -07:00

179 lines
4.3 KiB
C

/*******************************************************************************
* 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);
kfree(tb);
break;
}
}
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;
}