[PATCH v2 08/11] firewire-sbp-target: Add sbp_login.{c,h}

[Chris Boot <bootc@bootc.net>]

This file contains the implementation of the login, reconnect and logout
management ORBs in SBP-2.

Signed-off-by: Chris Boot <bootc@bootc.net>
Cc: Andy Grover <agrover@redhat.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/target/sbp/sbp_login.c |  665 ++++++++++++++++++++++++++++++++++++++++
 drivers/target/sbp/sbp_login.h |   14 +
 2 files changed, 679 insertions(+), 0 deletions(-)
 create mode 100644 drivers/target/sbp/sbp_login.c
 create mode 100644 drivers/target/sbp/sbp_login.h

diff --git a/drivers/target/sbp/sbp_login.c b/drivers/target/sbp/sbp_login.c
new file mode 100644
index 0000000..74b5eaf
--- /dev/null
+++ b/drivers/target/sbp/sbp_login.c
@@ -0,0 +1,665 @@
+/*
+ * SBP2 target driver (SCSI over IEEE1394 in target mode)
+ *
+ * Copyright (C) 2011  Chris Boot <bootc@bootc.net>
+ *
+ * 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.
+ */
+
+#define KMSG_COMPONENT "sbp_target"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kref.h>
+#include <linux/firewire.h>
+#include <linux/firewire-constants.h>
+#include <linux/slab.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_fabric.h>
+
+#include "sbp_base.h"
+#include "sbp_management_agent.h"
+#include "sbp_login.h"
+#include "sbp_target_agent.h"
+
+#define SESSION_MAINTENANCE_INTERVAL HZ
+
+static atomic_t login_id = ATOMIC_INIT(0);
+
+static void session_maintenance_work(struct work_struct *work);
+
+static int read_peer_guid(u64 *guid, const struct sbp_management_request *req)
+{
+	int ret;
+	__be32 high, low;
+
+	ret = fw_run_transaction(req->card, TCODE_READ_QUADLET_REQUEST,
+			req->node_addr, req->generation, req->speed,
+			(CSR_REGISTER_BASE | CSR_CONFIG_ROM) + 3 * 4,
+			&high, sizeof(high));
+	if (ret != RCODE_COMPLETE)
+		return ret;
+
+	ret = fw_run_transaction(req->card, TCODE_READ_QUADLET_REQUEST,
+			req->node_addr, req->generation, req->speed,
+			(CSR_REGISTER_BASE | CSR_CONFIG_ROM) + 4 * 4,
+			&low, sizeof(low));
+	if (ret != RCODE_COMPLETE)
+		return ret;
+
+	*guid = (u64)be32_to_cpu(high) << 32 | be32_to_cpu(low);
+
+	return RCODE_COMPLETE;
+}
+
+static struct sbp_session *sbp_session_find_by_guid(
+	struct sbp_tpg *tpg, u64 guid)
+{
+	struct se_session *se_sess;
+
+	spin_lock(&tpg->se_tpg.session_lock);
+	list_for_each_entry(se_sess, &tpg->se_tpg.tpg_sess_list, sess_list) {
+		struct sbp_session *sess = se_sess->fabric_sess_ptr;
+		if (sess->guid == guid) {
+			spin_unlock(&tpg->se_tpg.session_lock);
+			return sess;
+		}
+	}
+	spin_unlock(&tpg->se_tpg.session_lock);
+
+	return NULL;
+}
+
+static struct sbp_login_descriptor *sbp_login_find_by_lun(
+		struct sbp_session *session, struct se_lun *lun)
+{
+	struct sbp_login_descriptor *login;
+
+	spin_lock(&session->login_list_lock);
+	list_for_each_entry(login, &session->login_list, link) {
+		if (login->lun == lun) {
+			spin_unlock(&session->login_list_lock);
+			return login;
+		}
+	}
+	spin_unlock(&session->login_list_lock);
+
+	return NULL;
+}
+
+static int sbp_login_count_all_by_lun(
+		struct sbp_tpg *tpg,
+		struct se_lun *lun,
+		int exclusive)
+{
+	struct se_session *se_sess;
+	int count = 0;
+
+	spin_lock(&tpg->se_tpg.session_lock);
+	list_for_each_entry(se_sess, &tpg->se_tpg.tpg_sess_list, sess_list) {
+		struct sbp_session *sess = se_sess->fabric_sess_ptr;
+		struct sbp_login_descriptor *login;
+
+		spin_lock(&sess->login_list_lock);
+		list_for_each_entry(login, &sess->login_list, link) {
+			if (login->lun != lun)
+				continue;
+
+			if (!exclusive) {
+				count++;
+				continue;
+			}
+
+			if (login->exclusive)
+				count++;
+		}
+		spin_unlock(&sess->login_list_lock);
+	}
+	spin_unlock(&tpg->se_tpg.session_lock);
+
+	return count;
+}
+
+static struct sbp_login_descriptor *sbp_login_find_by_id(
+	struct sbp_tpg *tpg, int login_id)
+{
+	struct se_session *se_sess;
+
+	spin_lock(&tpg->se_tpg.session_lock);
+	list_for_each_entry(se_sess, &tpg->se_tpg.tpg_sess_list, sess_list) {
+		struct sbp_session *sess = se_sess->fabric_sess_ptr;
+		struct sbp_login_descriptor *login;
+
+		spin_lock(&sess->login_list_lock);
+		list_for_each_entry(login, &sess->login_list, link) {
+			if (login->login_id == login_id) {
+				spin_unlock(&sess->login_list_lock);
+				spin_unlock(&tpg->se_tpg.session_lock);
+				return login;
+			}
+		}
+		spin_unlock(&sess->login_list_lock);
+	}
+	spin_unlock(&tpg->se_tpg.session_lock);
+
+	return NULL;
+}
+
+static struct se_lun *sbp_get_lun_from_tpg(struct sbp_tpg *tpg, int lun)
+{
+	struct se_portal_group *se_tpg = &tpg->se_tpg;
+	struct se_lun *se_lun;
+
+	if (lun >= TRANSPORT_MAX_LUNS_PER_TPG)
+		return ERR_PTR(-ENODEV);
+
+	spin_lock(&se_tpg->tpg_lun_lock);
+	se_lun = &se_tpg->tpg_lun_list[lun];
+
+	if (se_lun->lun_status != TRANSPORT_LUN_STATUS_ACTIVE)
+		se_lun = ERR_PTR(-EINVAL);
+
+	spin_unlock(&se_tpg->tpg_lun_lock);
+
+	return se_lun;
+}
+
+static struct sbp_session *sbp_session_create(
+		struct sbp_tpg *tpg,
+		u64 guid)
+{
+	struct sbp_session *sess;
+	int ret;
+	char guid_str[17];
+	struct se_node_acl *se_nacl;
+
+	sess = kmalloc(sizeof(*sess), GFP_KERNEL);
+	if (!sess) {
+		pr_err("failed to allocate session descriptor\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	sess->se_sess = transport_init_session();
+	if (IS_ERR(sess->se_sess)) {
+		pr_err("failed to init se_session\n");
+
+		ret = PTR_ERR(sess->se_sess);
+		kfree(sess);
+		return ERR_PTR(ret);
+	}
+
+	snprintf(guid_str, sizeof(guid_str), "%016llx", guid);
+
+	se_nacl = core_tpg_check_initiator_node_acl(&tpg->se_tpg, guid_str);
+	if (!se_nacl) {
+		pr_warn("Node ACL not found for %s\n", guid_str);
+
+		transport_free_session(sess->se_sess);
+		kfree(sess);
+
+		return ERR_PTR(-EPERM);
+	}
+
+	sess->se_sess->se_node_acl = se_nacl;
+
+	INIT_LIST_HEAD(&sess->login_list);
+	spin_lock_init(&sess->login_list_lock);
+	INIT_DELAYED_WORK(&sess->maint_work, session_maintenance_work);
+
+	sess->guid = guid;
+
+	transport_register_session(&tpg->se_tpg, se_nacl, sess->se_sess, sess);
+
+	return sess;
+}
+
+static void sbp_session_release(struct sbp_session *sess, bool cancel_work)
+{
+	spin_lock(&sess->login_list_lock);
+	if (!list_empty(&sess->login_list)) {
+		spin_unlock(&sess->login_list_lock);
+		return;
+	}
+	spin_unlock(&sess->login_list_lock);
+
+	transport_deregister_session_configfs(sess->se_sess);
+	transport_deregister_session(sess->se_sess);
+
+	if (sess->card)
+		fw_card_put(sess->card);
+
+	if (cancel_work)
+		cancel_delayed_work_sync(&sess->maint_work);
+
+	kfree(sess);
+}
+
+static void sbp_login_release(struct sbp_login_descriptor *login,
+	bool cancel_work)
+{
+	struct sbp_session *sess = login->sess;
+
+	/* FIXME: abort/wait on tasks */
+
+	spin_lock(&sess->login_list_lock);
+	list_del(&login->link);
+	spin_unlock(&sess->login_list_lock);
+
+	sbp_target_agent_unregister(login->tgt_agt);
+	sbp_session_release(sess, cancel_work);
+	kfree(login);
+}
+
+void sbp_management_request_login(
+	struct sbp_management_agent *agent, struct sbp_management_request *req,
+	int *status_data_size)
+{
+	struct sbp_tport *tport = agent->tport;
+	struct sbp_tpg *tpg = tport->tpg;
+	struct se_lun *se_lun;
+	int ret;
+	u64 guid;
+	struct sbp_session *sess;
+	struct sbp_login_descriptor *login;
+	struct sbp_login_response_block *response;
+	int login_response_len;
+
+	se_lun = sbp_get_lun_from_tpg(tpg,
+			LOGIN_ORB_LUN(be32_to_cpu(req->orb.misc)));
+	if (IS_ERR(se_lun)) {
+		pr_notice("login to unknown LUN: %d\n",
+			LOGIN_ORB_LUN(be32_to_cpu(req->orb.misc)));
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_LUN_NOTSUPP));
+		return;
+	}
+
+	ret = read_peer_guid(&guid, req);
+	if (ret != RCODE_COMPLETE) {
+		pr_warn("failed to read peer GUID: %d\n", ret);
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_TRANSPORT_FAILURE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_UNSPECIFIED_ERROR));
+		return;
+	}
+
+	pr_notice("mgt_agent LOGIN to LUN %d from %016llx\n",
+		se_lun->unpacked_lun, guid);
+
+	sess = sbp_session_find_by_guid(tpg, guid);
+	if (sess) {
+		login = sbp_login_find_by_lun(sess, se_lun);
+		if (login) {
+			pr_notice("initiator already logged-in\n");
+
+			/*
+			 * SBP-2 R4 says we should return access denied, but
+			 * that can confuse initiators. Instead we need to
+			 * treat this like a reconnect, but send the login
+			 * response block like a fresh login.
+			 *
+			 * This is required particularly in the case of Apple
+			 * devices booting off the FireWire target, where
+			 * the firmware has an active login to the target. When
+			 * the OS takes control of the session it issues its own
+			 * LOGIN rather than a RECONNECT. To avoid the machine
+			 * waiting until the reconnect_hold expires, we can skip
+			 * the ACCESS_DENIED errors to speed things up.
+			 */
+
+			goto already_logged_in;
+		}
+	}
+
+	/*
+	 * check exclusive bit in login request
+	 * reject with access_denied if any logins present
+	 */
+	if (LOGIN_ORB_EXCLUSIVE(be32_to_cpu(req->orb.misc)) &&
+			sbp_login_count_all_by_lun(tpg, se_lun, 0)) {
+		pr_warn("refusing exclusive login with other active logins\n");
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_ACCESS_DENIED));
+		return;
+	}
+
+	/*
+	 * check exclusive bit in any existing login descriptor
+	 * reject with access_denied if any exclusive logins present
+	 */
+	if (sbp_login_count_all_by_lun(tpg, se_lun, 1)) {
+		pr_warn("refusing login while another exclusive login present\n");
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_ACCESS_DENIED));
+		return;
+	}
+
+	/*
+	 * check we haven't exceeded the number of allowed logins
+	 * reject with resources_unavailable if we have
+	 */
+	if (sbp_login_count_all_by_lun(tpg, se_lun, 0) >=
+			tport->max_logins_per_lun) {
+		pr_warn("max number of logins reached\n");
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_RESOURCES_UNAVAIL));
+		return;
+	}
+
+	if (!sess) {
+		sess = sbp_session_create(tpg, guid);
+		if (IS_ERR(sess)) {
+			switch (PTR_ERR(sess)) {
+			case -EPERM:
+				ret = SBP_STATUS_ACCESS_DENIED;
+				break;
+			default:
+				ret = SBP_STATUS_RESOURCES_UNAVAIL;
+				break;
+			}
+
+			req->status.status = cpu_to_be32(
+				STATUS_BLOCK_RESP(
+					STATUS_RESP_REQUEST_COMPLETE) |
+				STATUS_BLOCK_SBP_STATUS(ret));
+			return;
+		}
+
+		sess->node_id = req->node_addr;
+		sess->card = fw_card_get(req->card);
+		sess->generation = req->generation;
+		sess->speed = req->speed;
+
+		queue_delayed_work(sbp_workqueue, &sess->maint_work,
+			SESSION_MAINTENANCE_INTERVAL);
+	}
+
+	/* only take the latest reconnect_hold into account */
+	sess->reconnect_hold = min(
+		1 << LOGIN_ORB_RECONNECT(be32_to_cpu(req->orb.misc)),
+		tport->max_reconnect_timeout) - 1;
+
+	login = kmalloc(sizeof(*login), GFP_KERNEL);
+	if (!login) {
+		pr_err("failed to allocate login descriptor\n");
+
+		sbp_session_release(sess, true);
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_RESOURCES_UNAVAIL));
+		return;
+	}
+
+	login->sess = sess;
+	login->lun = se_lun;
+	login->status_fifo_addr = sbp2_pointer_to_addr(&req->orb.status_fifo);
+	login->exclusive = LOGIN_ORB_EXCLUSIVE(be32_to_cpu(req->orb.misc));
+	login->login_id = atomic_inc_return(&login_id);
+	atomic_set(&login->unsolicited_status_enable, 0);
+
+	login->tgt_agt = sbp_target_agent_register(login);
+	if (IS_ERR(login->tgt_agt)) {
+		ret = PTR_ERR(login->tgt_agt);
+		pr_err("failed to map command block handler: %d\n", ret);
+
+		sbp_session_release(sess, true);
+		kfree(login);
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_RESOURCES_UNAVAIL));
+		return;
+	}
+
+	spin_lock(&sess->login_list_lock);
+	list_add_tail(&login->link, &sess->login_list);
+	spin_unlock(&sess->login_list_lock);
+
+already_logged_in:
+	response = kzalloc(sizeof(*response), GFP_KERNEL);
+	if (!response) {
+		pr_err("failed to allocate login response block\n");
+
+		sbp_login_release(login, true);
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_RESOURCES_UNAVAIL));
+		return;
+	}
+
+	login_response_len = clamp_val(
+			LOGIN_ORB_RESPONSE_LENGTH(be32_to_cpu(req->orb.length)),
+			12, sizeof(*response));
+	response->misc = cpu_to_be32(
+		((login_response_len & 0xffff) << 16) |
+		(login->login_id & 0xffff));
+	response->reconnect_hold = cpu_to_be32(sess->reconnect_hold & 0xffff);
+	addr_to_sbp2_pointer(login->tgt_agt->handler.offset,
+		&response->command_block_agent);
+
+	ret = fw_run_transaction(sess->card, TCODE_WRITE_BLOCK_REQUEST,
+		sess->node_id, sess->generation, sess->speed,
+		sbp2_pointer_to_addr(&req->orb.ptr2), response,
+		login_response_len);
+	if (ret != RCODE_COMPLETE) {
+		pr_debug("failed to write login response block: %x\n", ret);
+
+		kfree(response);
+		sbp_login_release(login, true);
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_TRANSPORT_FAILURE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_UNSPECIFIED_ERROR));
+		return;
+	}
+
+	kfree(response);
+
+	req->status.status = cpu_to_be32(
+		STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+		STATUS_BLOCK_SBP_STATUS(SBP_STATUS_OK));
+}
+
+void sbp_management_request_query_logins(
+	struct sbp_management_agent *agent, struct sbp_management_request *req,
+	int *status_data_size)
+{
+	pr_notice("QUERY LOGINS not implemented\n");
+	/* FIXME: implement */
+
+	req->status.status = cpu_to_be32(
+		STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+		STATUS_BLOCK_SBP_STATUS(SBP_STATUS_REQ_TYPE_NOTSUPP));
+}
+
+void sbp_management_request_reconnect(
+	struct sbp_management_agent *agent, struct sbp_management_request *req,
+	int *status_data_size)
+{
+	struct sbp_tport *tport = agent->tport;
+	struct sbp_tpg *tpg = tport->tpg;
+	int ret;
+	u64 guid;
+	struct sbp_login_descriptor *login;
+
+	ret = read_peer_guid(&guid, req);
+	if (ret != RCODE_COMPLETE) {
+		pr_warn("failed to read peer GUID: %d\n", ret);
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_TRANSPORT_FAILURE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_UNSPECIFIED_ERROR));
+		return;
+	}
+
+	pr_notice("mgt_agent RECONNECT from %016llx\n", guid);
+
+	login = sbp_login_find_by_id(tpg,
+		RECONNECT_ORB_LOGIN_ID(be32_to_cpu(req->orb.misc)));
+
+	if (!login) {
+		pr_err("mgt_agent RECONNECT unknown login ID\n");
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_ACCESS_DENIED));
+		return;
+	}
+
+	if (login->sess->guid != guid) {
+		pr_err("mgt_agent RECONNECT login GUID doesn't match\n");
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_ACCESS_DENIED));
+		return;
+	}
+
+	if (login->sess->card)
+		fw_card_put(login->sess->card);
+
+	/* update the node details */
+	login->sess->generation = req->generation;
+	login->sess->node_id = req->node_addr;
+	login->sess->card = fw_card_get(req->card);
+	login->sess->speed = req->speed;
+
+	req->status.status = cpu_to_be32(
+		STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+		STATUS_BLOCK_SBP_STATUS(SBP_STATUS_OK));
+}
+
+void sbp_management_request_logout(
+	struct sbp_management_agent *agent, struct sbp_management_request *req,
+	int *status_data_size)
+{
+	struct sbp_tport *tport = agent->tport;
+	struct sbp_tpg *tpg = tport->tpg;
+	int login_id;
+	struct sbp_login_descriptor *login;
+
+	login_id = LOGOUT_ORB_LOGIN_ID(be32_to_cpu(req->orb.misc));
+
+	login = sbp_login_find_by_id(tpg, login_id);
+	if (!login) {
+		pr_warn("cannot find login: %d\n", login_id);
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_LOGIN_ID_UNKNOWN));
+		return;
+	}
+
+	pr_info("mgt_agent LOGOUT from LUN %d session %d\n",
+		login->lun->unpacked_lun, login->login_id);
+
+	if (req->node_addr != login->sess->node_id) {
+		pr_warn("logout from different node ID\n");
+
+		req->status.status = cpu_to_be32(
+			STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+			STATUS_BLOCK_SBP_STATUS(SBP_STATUS_ACCESS_DENIED));
+		return;
+	}
+
+	sbp_login_release(login, true);
+
+	req->status.status = cpu_to_be32(
+		STATUS_BLOCK_RESP(STATUS_RESP_REQUEST_COMPLETE) |
+		STATUS_BLOCK_SBP_STATUS(SBP_STATUS_OK));
+}
+
+static void session_check_for_reset(struct sbp_session *sess)
+{
+	bool card_valid = false;
+
+	if (sess->card) {
+		spin_lock_irq(&sess->card->lock);
+		card_valid = (sess->card->local_node != NULL);
+		spin_unlock_irq(&sess->card->lock);
+
+		if (!card_valid) {
+			fw_card_put(sess->card);
+			sess->card = NULL;
+		}
+	}
+
+	if (!card_valid || (sess->generation != sess->card->generation)) {
+		pr_info("Waiting for reconnect from node: %016llx\n",
+			sess->guid);
+
+		sess->node_id = -1;
+		sess->reconnect_expires = get_jiffies_64() +
+			((sess->reconnect_hold + 1) * HZ);
+	}
+}
+
+static void session_reconnect_expired(struct sbp_session *sess)
+{
+	struct sbp_login_descriptor *login, *temp;
+
+	pr_info("Reconnect timer expired for node: %016llx\n", sess->guid);
+
+	spin_lock(&sess->login_list_lock);
+	list_for_each_entry_safe(login, temp, &sess->login_list, link) {
+		spin_unlock(&sess->login_list_lock);
+		sbp_login_release(login, false);
+		spin_lock(&sess->login_list_lock);
+	}
+	spin_unlock(&sess->login_list_lock);
+
+	/* sbp_login_release() calls sbp_session_release() */
+}
+
+static void session_maintenance_work(struct work_struct *work)
+{
+	struct sbp_session *sess = container_of(work, struct sbp_session,
+		maint_work.work);
+
+	/* could be called while tearing down the session */
+	spin_lock(&sess->login_list_lock);
+	if (list_empty(&sess->login_list)) {
+		spin_unlock(&sess->login_list_lock);
+		return;
+	}
+	spin_unlock(&sess->login_list_lock);
+
+	if (sess->node_id != -1) {
+		/* check for bus reset and make node_id invalid */
+		session_check_for_reset(sess);
+
+		queue_delayed_work(sbp_workqueue, &sess->maint_work,
+			SESSION_MAINTENANCE_INTERVAL);
+	} else if (!time_after64(get_jiffies_64(), sess->reconnect_expires)) {
+		/* still waiting for reconnect */
+		queue_delayed_work(sbp_workqueue, &sess->maint_work,
+			SESSION_MAINTENANCE_INTERVAL);
+	} else {
+		/* reconnect timeout has expired */
+		session_reconnect_expired(sess);
+	}
+}
+
diff --git a/drivers/target/sbp/sbp_login.h b/drivers/target/sbp/sbp_login.h
new file mode 100644
index 0000000..4c86dcb
--- /dev/null
+++ b/drivers/target/sbp/sbp_login.h
@@ -0,0 +1,14 @@
+
+extern void sbp_management_request_login(
+	struct sbp_management_agent *agent, struct sbp_management_request *req,
+	int *status_data_size);
+extern void sbp_management_request_query_logins(
+	struct sbp_management_agent *agent, struct sbp_management_request *req,
+	int *status_data_size);
+extern void sbp_management_request_reconnect(
+	struct sbp_management_agent *agent, struct sbp_management_request *req,
+	int *status_data_size);
+extern void sbp_management_request_logout(
+	struct sbp_management_agent *agent, struct sbp_management_request *req,
+	int *status_data_size);
+
-- 
1.7.9