[PATCH v2 02f/03] target: Add HBA core infrastructure

["Nicholas A. Bellinger" <nab@linux-iscsi.org>]

From: Nicholas Bellinger <nab@linux-iscsi.org>

This patch adds the core struct se_hba functionality that is used internally by
target_core_mod to group the same subsystem storage objects types until a single
/sys/kernel/config/target/core/$HBA directory.  The HBA code supports boths
physical storage objects (from Linux/SCSI) and virtual storage objects (from Linux/BLOCK,
Linux/VFS, RAMDISK)

Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
---
 drivers/target/target_core_hba.c |  185 ++++++++++++++++++++++++++++++++++++++
 drivers/target/target_core_hba.h |    7 ++
 2 files changed, 192 insertions(+), 0 deletions(-)
 create mode 100644 drivers/target/target_core_hba.c
 create mode 100644 drivers/target/target_core_hba.h

diff --git a/drivers/target/target_core_hba.c b/drivers/target/target_core_hba.c
new file mode 100644
index 0000000..4bbe820
--- /dev/null
+++ b/drivers/target/target_core_hba.c
@@ -0,0 +1,185 @@
+/*******************************************************************************
+ * 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/smp_lock.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_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)
+{
+	struct se_device *dev, *dev_tmp;
+
+	spin_lock(&hba->device_lock);
+	list_for_each_entry_safe(dev, dev_tmp, &hba->hba_dev_list, dev_list) {
+
+		se_clear_dev_ports(dev);
+		spin_unlock(&hba->device_lock);
+
+		se_release_device_for_hba(dev);
+
+		spin_lock(&hba->device_lock);
+	}
+	spin_unlock(&hba->device_lock);
+
+	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;
+}
diff --git a/drivers/target/target_core_hba.h b/drivers/target/target_core_hba.h
new file mode 100644
index 0000000..bb0fea5
--- /dev/null
+++ b/drivers/target/target_core_hba.h
@@ -0,0 +1,7 @@
+#ifndef TARGET_CORE_HBA_H
+#define TARGET_CORE_HBA_H
+
+extern struct se_hba *core_alloc_hba(const char *, u32, u32);
+extern int core_delete_hba(struct se_hba *);
+
+#endif /* TARGET_CORE_HBA_H */
-- 
1.7.3.4