linux/drivers/target/target_core_hba.c
Fubo Chen 05aea6e7e4 [SCSI] target: Remove unnecessary hba_dev_list walk and se_clear_dev_ports legacy code
This patch removes a legacy struct se_hba->hba_dev_list -> se_release_device_for_hba()
list walk in core_delete_hba(), which is no longer required while using configfs
VFS level parent/child struct config_group dependency referencing.  The reason
is because any struct se_hba->hba_dev_list-> struct se_device members are going
to have to be released via:

	rmdir /sys/kernel/config/target/core/$HBA/*

before rmdir release of struct se_hba via target_core_configfs.c:
target_core_call_delhbafromtarget() -> core_delete_hba()

	rmdir /sys/kernel/config/target/core/$HBA

to release struct se_hba in core_delete_hba().

This patch also removes the legacy se_clear_dev_ports() function, which is
left-over pre-configfs shutdown logic for when se_free_virtual_device()
was responsible for walking struct se_device->dev_sep_list and calling
core_dev_del_lun() for each individual active struct se_port->se_lun.

The reason this can be removed is because all struct se_device->dev_sep_list
-> struct se_port communication is done via configfs symlinks, which
means that an target fabric module's endpoints containg active struct
se_port(s) will have to be released via target_core_fabric_configfs.c:
target_fabric_port_unlink() via:

	unlink /sys/kernel/config/target/$FABRIC_MOD/$ENDPOINT/tpgt_$TPGT/lun/lun_$LUN_ID/<symlink>

before rmdir release of struct se_device in target_core_configfs.c:
target_core_drop_subdev() -> se_free_virtual_device() can happen via:

	rmdir /sys/kernel/config/target/core/$HBA/*

to release struct se_subsystem_dev in target_core_drop_subdev()

Reported-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Reported-by: Fubo Chen <fubo.chen@gmail.com>
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2011-03-23 11:36:27 -05:00

173 lines
4.6 KiB
C

/*******************************************************************************
* Filename: target_core_hba.c
*
* This file copntains the iSCSI HBA Transport related functions.
*
* Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
* Copyright (c) 2005, 2006, 2007 SBE, Inc.
* Copyright (c) 2007-2010 Rising Tide Systems
* Copyright (c) 2008-2010 Linux-iSCSI.org
*
* 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 <net/sock.h>
#include <net/tcp.h>
#include <target/target_core_base.h>
#include <target/target_core_device.h>
#include <target/target_core_tpg.h>
#include <target/target_core_transport.h>
#include "target_core_hba.h"
static LIST_HEAD(subsystem_list);
static DEFINE_MUTEX(subsystem_mutex);
int transport_subsystem_register(struct se_subsystem_api *sub_api)
{
struct se_subsystem_api *s;
INIT_LIST_HEAD(&sub_api->sub_api_list);
mutex_lock(&subsystem_mutex);
list_for_each_entry(s, &subsystem_list, sub_api_list) {
if (!(strcmp(s->name, sub_api->name))) {
printk(KERN_ERR "%p is already registered with"
" duplicate name %s, unable to process"
" request\n", s, s->name);
mutex_unlock(&subsystem_mutex);
return -EEXIST;
}
}
list_add_tail(&sub_api->sub_api_list, &subsystem_list);
mutex_unlock(&subsystem_mutex);
printk(KERN_INFO "TCM: Registered subsystem plugin: %s struct module:"
" %p\n", sub_api->name, sub_api->owner);
return 0;
}
EXPORT_SYMBOL(transport_subsystem_register);
void transport_subsystem_release(struct se_subsystem_api *sub_api)
{
mutex_lock(&subsystem_mutex);
list_del(&sub_api->sub_api_list);
mutex_unlock(&subsystem_mutex);
}
EXPORT_SYMBOL(transport_subsystem_release);
static struct se_subsystem_api *core_get_backend(const char *sub_name)
{
struct se_subsystem_api *s;
mutex_lock(&subsystem_mutex);
list_for_each_entry(s, &subsystem_list, sub_api_list) {
if (!strcmp(s->name, sub_name))
goto found;
}
mutex_unlock(&subsystem_mutex);
return NULL;
found:
if (s->owner && !try_module_get(s->owner))
s = NULL;
mutex_unlock(&subsystem_mutex);
return s;
}
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) {
printk(KERN_ERR "Unable to allocate struct se_hba\n");
return ERR_PTR(-ENOMEM);
}
INIT_LIST_HEAD(&hba->hba_dev_list);
spin_lock_init(&hba->device_lock);
spin_lock_init(&hba->hba_queue_lock);
mutex_init(&hba->hba_access_mutex);
hba->hba_index = scsi_get_new_index(SCSI_INST_INDEX);
hba->hba_flags |= hba_flags;
atomic_set(&hba->max_queue_depth, 0);
atomic_set(&hba->left_queue_depth, 0);
hba->transport = core_get_backend(plugin_name);
if (!hba->transport) {
ret = -EINVAL;
goto out_free_hba;
}
ret = hba->transport->attach_hba(hba, plugin_dep_id);
if (ret < 0)
goto out_module_put;
spin_lock(&se_global->hba_lock);
hba->hba_id = se_global->g_hba_id_counter++;
list_add_tail(&hba->hba_list, &se_global->g_hba_list);
spin_unlock(&se_global->hba_lock);
printk(KERN_INFO "CORE_HBA[%d] - Attached HBA to Generic Target"
" Core\n", hba->hba_id);
return hba;
out_module_put:
if (hba->transport->owner)
module_put(hba->transport->owner);
hba->transport = NULL;
out_free_hba:
kfree(hba);
return ERR_PTR(ret);
}
int
core_delete_hba(struct se_hba *hba)
{
if (!list_empty(&hba->hba_dev_list))
dump_stack();
hba->transport->detach_hba(hba);
spin_lock(&se_global->hba_lock);
list_del(&hba->hba_list);
spin_unlock(&se_global->hba_lock);
printk(KERN_INFO "CORE_HBA[%d] - Detached HBA from Generic Target"
" Core\n", hba->hba_id);
if (hba->transport->owner)
module_put(hba->transport->owner);
hba->transport = NULL;
kfree(hba);
return 0;
}