Date:	Mon, 30 Aug 2010 02:22:00 -0700
From:	"Nicholas A. Bellinger" <nab@...ux-iscsi.org>
To:	linux-scsi <linux-scsi@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Cc:	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
	Mike Christie <michaelc@...wisc.edu>,
	Christoph Hellwig <hch@....de>, Hannes Reinecke <hare@...e.de>,
	James Bottomley <James.Bottomley@...e.de>,
	Jens Axboe <axboe@...nel.dk>,
	Boaz Harrosh <bharrosh@...asas.com>,
	Nicholas Bellinger <nab@...ux-iscsi.org>
Subject: [RFC 12/22] tcm: Add Task Management infrastructure

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

This patch adds SPC-3 task management infrastructure and functionality for
LUN_RESET with TASK_ABORTED status (TAS) and in combination with handling
Persistent Reservation PREEMPT_AND_ABORT service action.

Signed-off-by: Nicholas A. Bellinger <nab@...ux-iscsi.org>
---
 drivers/target/target_core_tmr.c |  405 ++++++++++++++++++++++++++++++++++++++
 include/target/target_core_tmr.h |   43 ++++
 2 files changed, 448 insertions(+), 0 deletions(-)
 create mode 100644 drivers/target/target_core_tmr.c
 create mode 100644 include/target/target_core_tmr.h

diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
new file mode 100644
index 0000000..34f53de
--- /dev/null
+++ b/drivers/target/target_core_tmr.c
@@ -0,0 +1,405 @@
+/*******************************************************************************
+ * Filename:  target_core_tmr.c
+ *
+ * This file contains SPC-3 task management infrastructure
+ *
+ * Copyright (c) 2009,2010 Rising Tide Systems
+ * Copyright (c) 2009,2010 Linux-iSCSI.org
+ *
+ * Nicholas A. Bellinger <nab@...nel.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/version.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_device.h>
+#include <target/target_core_tmr.h>
+#include <target/target_core_transport.h>
+#include <target/target_core_fabric_ops.h>
+#include <target/target_core_configfs.h>
+
+#include "target_core_alua.h"
+#include "target_core_pr.h"
+
+#define DEBUG_LUN_RESET
+#ifdef DEBUG_LUN_RESET
+#define DEBUG_LR(x...) printk(KERN_INFO x)
+#else
+#define DEBUG_LR(x...)
+#endif
+
+struct se_tmr_req *core_tmr_alloc_req(
+	struct se_cmd *se_cmd,
+	void *fabric_tmr_ptr,
+	u8 function)
+{
+	struct se_tmr_req *tmr;
+
+	tmr = kmem_cache_zalloc(se_tmr_req_cache, GFP_KERNEL);
+	if (!(tmr)) {
+		printk(KERN_ERR "Unable to allocate struct se_tmr_req\n");
+		return ERR_PTR(-ENOMEM);
+	}
+	tmr->task_cmd = se_cmd;
+	tmr->fabric_tmr_ptr = fabric_tmr_ptr;
+	tmr->function = function;
+	INIT_LIST_HEAD(&tmr->tmr_list);
+
+	return tmr;
+}
+EXPORT_SYMBOL(core_tmr_alloc_req);
+
+/*
+ * Called with struct se_device->se_tmr_lock held.
+ */
+void __core_tmr_release_req(
+	struct se_tmr_req *tmr)
+{
+	list_del(&tmr->tmr_list);
+	kmem_cache_free(se_tmr_req_cache, tmr);
+}
+
+void core_tmr_release_req(
+	struct se_tmr_req *tmr)
+{
+	struct se_device *dev = tmr->tmr_dev;
+
+	spin_lock(&dev->se_tmr_lock);
+	__core_tmr_release_req(tmr);
+	spin_unlock(&dev->se_tmr_lock);
+}
+
+static void core_tmr_handle_tas_abort(
+	struct se_node_acl *tmr_nacl,
+	struct se_cmd *cmd,
+	int tas,
+	int fe_count)
+{
+	if (!(fe_count)) {
+		transport_cmd_finish_abort(cmd, 1);
+		return;
+	}
+	/*
+	 * TASK ABORTED status (TAS) bit support
+	*/
+	if (((tmr_nacl != NULL) &&
+	     (tmr_nacl == cmd->se_sess->se_node_acl)) || tas)
+		transport_send_task_abort(cmd);
+
+	transport_cmd_finish_abort(cmd, 0);
+}
+
+int core_tmr_lun_reset(
+	struct se_device *dev,
+	struct se_tmr_req *tmr,
+	struct list_head *preempt_and_abort_list,
+	struct se_cmd *prout_cmd)
+{
+	struct se_cmd *cmd;
+	struct se_queue_req *qr, *qr_tmp;
+	struct se_node_acl *tmr_nacl = NULL;
+	struct se_portal_group *tmr_tpg = NULL;
+	struct se_queue_obj *qobj = dev->dev_queue_obj;
+	struct se_tmr_req *tmr_p, *tmr_pp;
+	struct se_task *task, *task_tmp;
+	unsigned long flags;
+	int fe_count, state, tas;
+	/*
+	 * TASK_ABORTED status bit, this is configurable via ConfigFS
+	 * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
+	 *
+	 * A task aborted status (TAS) bit set to zero specifies that aborted
+	 * tasks shall be terminated by the device server without any response
+	 * to the application client. A TAS bit set to one specifies that tasks
+	 * aborted by the actions of an I_T nexus other than the I_T nexus on
+	 * which the command was received shall be completed with TASK ABORTED
+	 * status (see SAM-4).
+	 */
+	tas = DEV_ATTRIB(dev)->emulate_tas;
+	/*
+	 * Determine if this se_tmr is coming from a $FABRIC_MOD
+	 * or struct se_device passthrough..
+	 */
+	if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
+		tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
+		tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
+		if (tmr_nacl && tmr_tpg) {
+			DEBUG_LR("LUN_RESET: TMR caller fabric: %s"
+				" initiator port %s\n",
+				TPG_TFO(tmr_tpg)->get_fabric_name(),
+				tmr_nacl->initiatorname);
+		}
+	}
+	DEBUG_LR("LUN_RESET: %s starting for [%s], tas: %d\n",
+		(preempt_and_abort_list) ? "Preempt" : "TMR",
+		TRANSPORT(dev)->name, tas);
+	/*
+	 * Release all pending and outgoing TMRs aside from the received
+	 * LUN_RESET tmr..
+	 */
+	spin_lock(&dev->se_tmr_lock);
+	list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
+		/*
+		 * Allow the received TMR to return with FUNCTION_COMPLETE.
+		 */
+		if (tmr && (tmr_p == tmr))
+			continue;
+
+		cmd = tmr_p->task_cmd;
+		if (!(cmd)) {
+			printk(KERN_ERR "Unable to locate struct se_cmd for TMR\n");
+			continue;
+		}
+		/*
+		 * If this function was called with a valid pr_res_key
+		 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
+		 * skip non regisration key matching TMRs.
+		 */
+		if ((preempt_and_abort_list != NULL) &&
+		    (core_scsi3_check_cdb_abort_and_preempt(
+					preempt_and_abort_list, cmd) != 0))
+			continue;
+		spin_unlock(&dev->se_tmr_lock);
+
+		spin_lock_irqsave(&T_TASK(cmd)->t_state_lock, flags);
+		if (!(atomic_read(&T_TASK(cmd)->t_transport_active))) {
+			spin_unlock_irqrestore(&T_TASK(cmd)->t_state_lock, flags);
+			spin_lock(&dev->se_tmr_lock);
+			continue;
+		}
+		if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
+			spin_unlock_irqrestore(&T_TASK(cmd)->t_state_lock, flags);
+			spin_lock(&dev->se_tmr_lock);
+			continue;
+		}
+		DEBUG_LR("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
+			" Response: 0x%02x, t_state: %d\n",
+			(preempt_and_abort_list) ? "Preempt" : "", tmr_p,
+			tmr_p->function, tmr_p->response, cmd->t_state);
+		spin_unlock_irqrestore(&T_TASK(cmd)->t_state_lock, flags);
+
+		transport_cmd_finish_abort_tmr(cmd);
+		spin_lock(&dev->se_tmr_lock);
+	}
+	spin_unlock(&dev->se_tmr_lock);
+	/*
+	 * Complete outstanding struct se_task CDBs with TASK_ABORTED SAM status.
+	 * This is following sam4r17, section 5.6 Aborting commands, Table 38
+	 * for TMR LUN_RESET:
+	 *
+	 * a) "Yes" indicates that each command that is aborted on an I_T nexus
+	 * other than the one that caused the SCSI device condition is
+	 * completed with TASK ABORTED status, if the TAS bit is set to one in
+	 * the Control mode page (see SPC-4). "No" indicates that no status is
+	 * returned for aborted commands.
+	 *
+	 * d) If the logical unit reset is caused by a particular I_T nexus
+	 * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
+	 * (TASK_ABORTED status) applies.
+	 *
+	 * Otherwise (e.g., if triggered by a hard reset), "no"
+	 * (no TASK_ABORTED SAM status) applies.
+	 *
+	 * Note that this seems to be independent of TAS (Task Aborted Status)
+	 * in the Control Mode Page.
+	 */
+	spin_lock_irqsave(&dev->execute_task_lock, flags);
+	list_for_each_entry_safe(task, task_tmp, &dev->state_task_list,
+				t_state_list) {
+		if (!(TASK_CMD(task))) {
+			printk(KERN_ERR "TASK_CMD(task) is NULL!\n");
+			continue;
+		}
+		cmd = TASK_CMD(task);
+
+		if (!T_TASK(cmd)) {
+			printk(KERN_ERR "T_TASK(cmd) is NULL for task: %p cmd:"
+				" %p ITT: 0x%08x\n", task, cmd,
+				CMD_TFO(cmd)->get_task_tag(cmd));
+			continue;
+		}
+		/*
+		 * For PREEMPT_AND_ABORT usage, only process commands
+		 * with a matching reservation key.
+		 */
+		if ((preempt_and_abort_list != NULL) &&
+		    (core_scsi3_check_cdb_abort_and_preempt(
+					preempt_and_abort_list, cmd) != 0))
+			continue;
+		/*
+		 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
+		 */
+		if (prout_cmd == cmd)
+			continue;
+
+		list_del(&task->t_state_list);
+		atomic_set(&task->task_state_active, 0);
+		spin_unlock_irqrestore(&dev->execute_task_lock, flags);
+
+		spin_lock_irqsave(&T_TASK(cmd)->t_state_lock, flags);
+		DEBUG_LR("LUN_RESET: %s cmd: %p se_fabric_cmd_ptr: %p task: %p"
+			" ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state/"
+			"def_t_state: %d/%d cdb: 0x%02x\n",
+			(preempt_and_abort_list) ? "Preempt" : "", cmd,
+			cmd->se_fabric_cmd_ptr, task,
+			CMD_TFO(cmd)->get_task_tag(cmd), 0,
+			CMD_TFO(cmd)->get_cmd_state(cmd), cmd->t_state,
+			cmd->deferred_t_state, T_TASK(cmd)->t_task_cdb[0]);
+		DEBUG_LR("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
+			" t_task_cdbs: %d t_task_cdbs_left: %d"
+			" t_task_cdbs_sent: %d -- t_transport_active: %d"
+			" t_transport_stop: %d t_transport_sent: %d\n",
+			CMD_TFO(cmd)->get_task_tag(cmd), cmd->pr_res_key,
+			T_TASK(cmd)->t_task_cdbs,
+			atomic_read(&T_TASK(cmd)->t_task_cdbs_left),
+			atomic_read(&T_TASK(cmd)->t_task_cdbs_sent),
+			atomic_read(&T_TASK(cmd)->t_transport_active),
+			atomic_read(&T_TASK(cmd)->t_transport_stop),
+			atomic_read(&T_TASK(cmd)->t_transport_sent));
+
+		if (atomic_read(&task->task_active)) {
+			atomic_set(&task->task_stop, 1);
+			spin_unlock_irqrestore(
+				&T_TASK(cmd)->t_state_lock, flags);
+
+			DEBUG_LR("LUN_RESET: Waiting for task: %p to shutdown"
+				" for dev: %p\n", task, dev);
+			wait_for_completion(&task->task_stop_comp);
+			DEBUG_LR("LUN_RESET Completed task: %p shutdown for"
+				" dev: %p\n", task, dev);
+			spin_lock_irqsave(&T_TASK(cmd)->t_state_lock, flags);
+			atomic_dec(&T_TASK(cmd)->t_task_cdbs_left);
+
+			atomic_set(&task->task_active, 0);
+			atomic_set(&task->task_stop, 0);
+		}
+		__transport_stop_task_timer(task, &flags);
+
+		if (!(atomic_dec_and_test(&T_TASK(cmd)->t_task_cdbs_ex_left))) {
+			spin_unlock_irqrestore(
+					&T_TASK(cmd)->t_state_lock, flags);
+			DEBUG_LR("LUN_RESET: Skipping task: %p, dev: %p for"
+				" t_task_cdbs_ex_left: %d\n", task, dev,
+				atomic_read(&T_TASK(cmd)->t_task_cdbs_ex_left));
+
+			spin_lock_irqsave(&dev->execute_task_lock, flags);
+			continue;
+		}
+		fe_count = atomic_read(&T_TASK(cmd)->t_fe_count);
+
+		if (atomic_read(&T_TASK(cmd)->t_transport_active)) {
+			DEBUG_LR("LUN_RESET: got t_transport_active = 1 for"
+				" task: %p, t_fe_count: %d dev: %p\n", task,
+				fe_count, dev);
+			spin_unlock_irqrestore(&T_TASK(cmd)->t_state_lock,
+						flags);
+			core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
+
+			spin_lock_irqsave(&dev->execute_task_lock, flags);
+			continue;
+		}
+		DEBUG_LR("LUN_RESET: Got t_transport_active = 0 for task: %p,"
+			" t_fe_count: %d dev: %p\n", task, fe_count, dev);
+		spin_unlock_irqrestore(&T_TASK(cmd)->t_state_lock, flags);
+		core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
+
+		spin_lock_irqsave(&dev->execute_task_lock, flags);
+	}
+	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
+	/*
+	 * Release all commands remaining in the struct se_device cmd queue.
+	 *
+	 * This follows the same logic as above for the struct se_device
+	 * struct se_task state list, where commands are returned with
+	 * TASK_ABORTED status, if there is an outstanding $FABRIC_MOD
+	 * reference, otherwise the struct se_cmd is released.
+	 */
+	spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
+	list_for_each_entry_safe(qr, qr_tmp, &qobj->qobj_list, qr_list) {
+		cmd = (struct se_cmd *)qr->cmd;
+		if (!(cmd)) {
+			/*
+			 * Skip these for non PREEMPT_AND_ABORT usage..
+			 */
+			if (preempt_and_abort_list != NULL)
+				continue;
+
+			atomic_dec(&qobj->queue_cnt);
+			list_del(&qr->qr_list);
+			kfree(qr);
+			continue;
+		}
+		/*
+		 * For PREEMPT_AND_ABORT usage, only process commands
+		 * with a matching reservation key.
+		 */
+		if ((preempt_and_abort_list != NULL) &&
+		    (core_scsi3_check_cdb_abort_and_preempt(
+					preempt_and_abort_list, cmd) != 0))
+			continue;
+		/*
+		 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
+		 */
+		if (prout_cmd == cmd)
+			continue;
+
+		atomic_dec(&T_TASK(cmd)->t_transport_queue_active);
+		atomic_dec(&qobj->queue_cnt);
+		list_del(&qr->qr_list);
+		spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
+
+		state = qr->state;
+		kfree(qr);
+
+		DEBUG_LR("LUN_RESET: %s from Device Queue: cmd: %p t_state:"
+			" %d t_fe_count: %d\n", (preempt_and_abort_list) ?
+			"Preempt" : "", cmd, state,
+			atomic_read(&T_TASK(cmd)->t_fe_count));
+
+		core_tmr_handle_tas_abort(tmr_nacl, cmd, tas,
+				atomic_read(&T_TASK(cmd)->t_fe_count));
+		spin_lock_irqsave(&qobj->cmd_queue_lock, flags);
+	}
+	spin_unlock_irqrestore(&qobj->cmd_queue_lock, flags);
+	/*
+	 * Clear any legacy SPC-2 reservation when called during
+	 * LOGICAL UNIT RESET
+	 */
+	if (!(preempt_and_abort_list) &&
+	     (dev->dev_flags & DF_SPC2_RESERVATIONS)) {
+		spin_lock(&dev->dev_reservation_lock);
+		dev->dev_reserved_node_acl = NULL;
+		dev->dev_flags &= ~DF_SPC2_RESERVATIONS;
+		spin_unlock(&dev->dev_reservation_lock);
+		printk(KERN_INFO "LUN_RESET: SCSI-2 Released reservation\n");	
+	}	
+
+	spin_lock(&dev->stats_lock);
+	dev->num_resets++;
+	spin_unlock(&dev->stats_lock);
+
+	DEBUG_LR("LUN_RESET: %s for [%s] Complete\n",
+			(preempt_and_abort_list) ? "Preempt" : "TMR",
+			TRANSPORT(dev)->name);
+	return 0;
+}
diff --git a/include/target/target_core_tmr.h b/include/target/target_core_tmr.h
new file mode 100644
index 0000000..6c8248b
--- /dev/null
+++ b/include/target/target_core_tmr.h
@@ -0,0 +1,43 @@
+#ifndef TARGET_CORE_TMR_H
+#define TARGET_CORE_TMR_H
+
+/* task management function values */
+#ifdef ABORT_TASK
+#undef ABORT_TASK
+#endif /* ABORT_TASK */
+#define ABORT_TASK				1
+#ifdef ABORT_TASK_SET
+#undef ABORT_TASK_SET
+#endif /* ABORT_TASK_SET */
+#define ABORT_TASK_SET				2
+#ifdef CLEAR_ACA
+#undef CLEAR_ACA
+#endif /* CLEAR_ACA */
+#define CLEAR_ACA				3
+#ifdef CLEAR_TASK_SET
+#undef CLEAR_TASK_SET
+#endif /* CLEAR_TASK_SET */
+#define CLEAR_TASK_SET				4
+#define LUN_RESET				5
+#define TARGET_WARM_RESET			6
+#define TARGET_COLD_RESET			7
+#define TASK_REASSIGN				8
+
+/* task management response values */
+#define TMR_FUNCTION_COMPLETE			0
+#define TMR_TASK_DOES_NOT_EXIST			1
+#define TMR_LUN_DOES_NOT_EXIST			2
+#define TMR_TASK_STILL_ALLEGIANT		3
+#define TMR_TASK_FAILOVER_NOT_SUPPORTED		4
+#define TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED	5
+#define TMR_FUNCTION_AUTHORIZATION_FAILED	6
+#define TMR_FUNCTION_REJECTED			255
+
+extern struct kmem_cache *se_tmr_req_cache;
+
+extern struct se_tmr_req *core_tmr_alloc_req(struct se_cmd *, void *, u8);
+extern void core_tmr_release_req(struct se_tmr_req *);
+extern int core_tmr_lun_reset(struct se_device *, struct se_tmr_req *,
+				struct list_head *, struct se_cmd *);
+
+#endif /* TARGET_CORE_TMR_H */
-- 
1.7.2.2

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