drivers/target/iscsi/iscsi_target_tq.c - maze/linux - Git at Google

 /*******************************************************************************
  * This file contains the iSCSI Login Thread and Thread Queue functions.
  *
  * \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
  *
  * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
  *
  * Author: Nicholas A. Bellinger <nab@linux-iscsi.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.
  ******************************************************************************/

 #include <linux/kthread.h>
 #include <linux/list.h>
 #include <linux/bitmap.h>

 #include "iscsi_target_core.h"
 #include "iscsi_target_tq.h"
 #include "iscsi_target.h"

 static LIST_HEAD(active_ts_list);
 static LIST_HEAD(inactive_ts_list);
 static DEFINE_SPINLOCK(active_ts_lock);
 static DEFINE_SPINLOCK(inactive_ts_lock);
 static DEFINE_SPINLOCK(ts_bitmap_lock);

 static void iscsi_add_ts_to_active_list(struct iscsi_thread_set *ts)
 {
 	spin_lock(&active_ts_lock);
 	list_add_tail(&ts->ts_list, &active_ts_list);
 	iscsit_global->active_ts++;
 	spin_unlock(&active_ts_lock);
 }

 extern void iscsi_add_ts_to_inactive_list(struct iscsi_thread_set *ts)
 {
 	spin_lock(&inactive_ts_lock);
 	list_add_tail(&ts->ts_list, &inactive_ts_list);
 	iscsit_global->inactive_ts++;
 	spin_unlock(&inactive_ts_lock);
 }

 static void iscsi_del_ts_from_active_list(struct iscsi_thread_set *ts)
 {
 	spin_lock(&active_ts_lock);
 	list_del(&ts->ts_list);
 	iscsit_global->active_ts--;
 	spin_unlock(&active_ts_lock);
 }

 static struct iscsi_thread_set *iscsi_get_ts_from_inactive_list(void)
 {
 	struct iscsi_thread_set *ts;

 	spin_lock(&inactive_ts_lock);
 	if (list_empty(&inactive_ts_list)) {
 		spin_unlock(&inactive_ts_lock);
 		return NULL;
 	}

 	list_for_each_entry(ts, &inactive_ts_list, ts_list)
 		break;

 	list_del(&ts->ts_list);
 	iscsit_global->inactive_ts--;
 	spin_unlock(&inactive_ts_lock);

 	return ts;
 }

 extern int iscsi_allocate_thread_sets(u32 thread_pair_count)
 {
 	int allocated_thread_pair_count = 0, i, thread_id;
 	struct iscsi_thread_set *ts = NULL;

 	for (i = 0; i < thread_pair_count; i++) {
 		ts = kzalloc(sizeof(struct iscsi_thread_set), GFP_KERNEL);
 		if (!ts) {
 			pr_err("Unable to allocate memory for"
 					" thread set.\n");
 			return allocated_thread_pair_count;
 		}
 		/*
 		 * Locate the next available regision in the thread_set_bitmap
 		 */
 		spin_lock(&ts_bitmap_lock);
 		thread_id = bitmap_find_free_region(iscsit_global->ts_bitmap,
 				iscsit_global->ts_bitmap_count, get_order(1));
 		spin_unlock(&ts_bitmap_lock);
 		if (thread_id < 0) {
 			pr_err("bitmap_find_free_region() failed for"
 				" thread_set_bitmap\n");
 			kfree(ts);
 			return allocated_thread_pair_count;
 		}

 		ts->thread_id = thread_id;
 		ts->status = ISCSI_THREAD_SET_FREE;
 		INIT_LIST_HEAD(&ts->ts_list);
 		spin_lock_init(&ts->ts_state_lock);
 		init_completion(&ts->rx_post_start_comp);
 		init_completion(&ts->tx_post_start_comp);
 		init_completion(&ts->rx_restart_comp);
 		init_completion(&ts->tx_restart_comp);
 		init_completion(&ts->rx_start_comp);
 		init_completion(&ts->tx_start_comp);

 		ts->create_threads = 1;
 		ts->tx_thread = kthread_run(iscsi_target_tx_thread, ts, "%s",
 					ISCSI_TX_THREAD_NAME);
 		if (IS_ERR(ts->tx_thread)) {
 			dump_stack();
 			pr_err("Unable to start iscsi_target_tx_thread\n");
 			break;
 		}

 		ts->rx_thread = kthread_run(iscsi_target_rx_thread, ts, "%s",
 					ISCSI_RX_THREAD_NAME);
 		if (IS_ERR(ts->rx_thread)) {
 			kthread_stop(ts->tx_thread);
 			pr_err("Unable to start iscsi_target_rx_thread\n");
 			break;
 		}
 		ts->create_threads = 0;

 		iscsi_add_ts_to_inactive_list(ts);
 		allocated_thread_pair_count++;
 	}

 	pr_debug("Spawned %d thread set(s) (%d total threads).\n",
 		allocated_thread_pair_count, allocated_thread_pair_count * 2);
 	return allocated_thread_pair_count;
 }

 extern void iscsi_deallocate_thread_sets(void)
 {
 	u32 released_count = 0;
 	struct iscsi_thread_set *ts = NULL;

 	while ((ts = iscsi_get_ts_from_inactive_list())) {

 		spin_lock_bh(&ts->ts_state_lock);
 		ts->status = ISCSI_THREAD_SET_DIE;
 		spin_unlock_bh(&ts->ts_state_lock);

 		if (ts->rx_thread) {
 			send_sig(SIGINT, ts->rx_thread, 1);
 			kthread_stop(ts->rx_thread);
 		}
 		if (ts->tx_thread) {
 			send_sig(SIGINT, ts->tx_thread, 1);
 			kthread_stop(ts->tx_thread);
 		}
 		/*
 		 * Release this thread_id in the thread_set_bitmap
 		 */
 		spin_lock(&ts_bitmap_lock);
 		bitmap_release_region(iscsit_global->ts_bitmap,
 				ts->thread_id, get_order(1));
 		spin_unlock(&ts_bitmap_lock);

 		released_count++;
 		kfree(ts);
 	}

 	if (released_count)
 		pr_debug("Stopped %d thread set(s) (%d total threads)."
 			"\n", released_count, released_count * 2);
 }

 static void iscsi_deallocate_extra_thread_sets(void)
 {
 	u32 orig_count, released_count = 0;
 	struct iscsi_thread_set *ts = NULL;

 	orig_count = TARGET_THREAD_SET_COUNT;

 	while ((iscsit_global->inactive_ts + 1) > orig_count) {
 		ts = iscsi_get_ts_from_inactive_list();
 		if (!ts)
 			break;

 		spin_lock_bh(&ts->ts_state_lock);
 		ts->status = ISCSI_THREAD_SET_DIE;
 		spin_unlock_bh(&ts->ts_state_lock);

 		if (ts->rx_thread) {
 			send_sig(SIGINT, ts->rx_thread, 1);
 			kthread_stop(ts->rx_thread);
 		}
 		if (ts->tx_thread) {
 			send_sig(SIGINT, ts->tx_thread, 1);
 			kthread_stop(ts->tx_thread);
 		}
 		/*
 		 * Release this thread_id in the thread_set_bitmap
 		 */
 		spin_lock(&ts_bitmap_lock);
 		bitmap_release_region(iscsit_global->ts_bitmap,
 				ts->thread_id, get_order(1));
 		spin_unlock(&ts_bitmap_lock);

 		released_count++;
 		kfree(ts);
 	}

 	if (released_count) {
 		pr_debug("Stopped %d thread set(s) (%d total threads)."
 			"\n", released_count, released_count * 2);
 	}
 }

 void iscsi_activate_thread_set(struct iscsi_conn *conn, struct iscsi_thread_set *ts)
 {
 	iscsi_add_ts_to_active_list(ts);

 	spin_lock_bh(&ts->ts_state_lock);
 	conn->thread_set = ts;
 	ts->conn = conn;
 	spin_unlock_bh(&ts->ts_state_lock);
 	/*
 	 * Start up the RX thread and wait on rx_post_start_comp.  The RX
 	 * Thread will then do the same for the TX Thread in
 	 * iscsi_rx_thread_pre_handler().
 	 */
 	complete(&ts->rx_start_comp);
 	wait_for_completion(&ts->rx_post_start_comp);
 }

 struct iscsi_thread_set *iscsi_get_thread_set(void)
 {
 	int allocate_ts = 0;
 	struct completion comp;
 	struct iscsi_thread_set *ts = NULL;
 	/*
 	 * If no inactive thread set is available on the first call to
 	 * iscsi_get_ts_from_inactive_list(), sleep for a second and
 	 * try again.  If still none are available after two attempts,
 	 * allocate a set ourselves.
 	 */
 get_set:
 	ts = iscsi_get_ts_from_inactive_list();
 	if (!ts) {
 		if (allocate_ts == 2)
 			iscsi_allocate_thread_sets(1);

 		init_completion(&comp);
 		wait_for_completion_timeout(&comp, 1 * HZ);

 		allocate_ts++;
 		goto get_set;
 	}

 	ts->delay_inactive = 1;
 	ts->signal_sent = 0;
 	ts->thread_count = 2;
 	init_completion(&ts->rx_restart_comp);
 	init_completion(&ts->tx_restart_comp);

 	return ts;
 }

 void iscsi_set_thread_clear(struct iscsi_conn *conn, u8 thread_clear)
 {
 	struct iscsi_thread_set *ts = NULL;

 	if (!conn->thread_set) {
 		pr_err("struct iscsi_conn->thread_set is NULL\n");
 		return;
 	}
 	ts = conn->thread_set;

 	spin_lock_bh(&ts->ts_state_lock);
 	ts->thread_clear &= ~thread_clear;

 	if ((thread_clear & ISCSI_CLEAR_RX_THREAD) &&
 	    (ts->blocked_threads & ISCSI_BLOCK_RX_THREAD))
 		complete(&ts->rx_restart_comp);
 	else if ((thread_clear & ISCSI_CLEAR_TX_THREAD) &&
 		 (ts->blocked_threads & ISCSI_BLOCK_TX_THREAD))
 		complete(&ts->tx_restart_comp);
 	spin_unlock_bh(&ts->ts_state_lock);
 }

 void iscsi_set_thread_set_signal(struct iscsi_conn *conn, u8 signal_sent)
 {
 	struct iscsi_thread_set *ts = NULL;

 	if (!conn->thread_set) {
 		pr_err("struct iscsi_conn->thread_set is NULL\n");
 		return;
 	}
 	ts = conn->thread_set;

 	spin_lock_bh(&ts->ts_state_lock);
 	ts->signal_sent |= signal_sent;
 	spin_unlock_bh(&ts->ts_state_lock);
 }

 int iscsi_release_thread_set(struct iscsi_conn *conn)
 {
 	int thread_called = 0;
 	struct iscsi_thread_set *ts = NULL;

 	if (!conn || !conn->thread_set) {
 		pr_err("connection or thread set pointer is NULL\n");
 		BUG();
 	}
 	ts = conn->thread_set;

 	spin_lock_bh(&ts->ts_state_lock);
 	ts->status = ISCSI_THREAD_SET_RESET;

 	if (!strncmp(current->comm, ISCSI_RX_THREAD_NAME,
 			strlen(ISCSI_RX_THREAD_NAME)))
 		thread_called = ISCSI_RX_THREAD;
 	else if (!strncmp(current->comm, ISCSI_TX_THREAD_NAME,
 			strlen(ISCSI_TX_THREAD_NAME)))
 		thread_called = ISCSI_TX_THREAD;

 	if (ts->rx_thread && (thread_called == ISCSI_TX_THREAD) &&
 	   (ts->thread_clear & ISCSI_CLEAR_RX_THREAD)) {

 		if (!(ts->signal_sent & ISCSI_SIGNAL_RX_THREAD)) {
 			send_sig(SIGINT, ts->rx_thread, 1);
 			ts->signal_sent |= ISCSI_SIGNAL_RX_THREAD;
 		}
 		ts->blocked_threads |= ISCSI_BLOCK_RX_THREAD;
 		spin_unlock_bh(&ts->ts_state_lock);
 		wait_for_completion(&ts->rx_restart_comp);
 		spin_lock_bh(&ts->ts_state_lock);
 		ts->blocked_threads &= ~ISCSI_BLOCK_RX_THREAD;
 	}
 	if (ts->tx_thread && (thread_called == ISCSI_RX_THREAD) &&
 	   (ts->thread_clear & ISCSI_CLEAR_TX_THREAD)) {

 		if (!(ts->signal_sent & ISCSI_SIGNAL_TX_THREAD)) {
 			send_sig(SIGINT, ts->tx_thread, 1);
 			ts->signal_sent |= ISCSI_SIGNAL_TX_THREAD;
 		}
 		ts->blocked_threads |= ISCSI_BLOCK_TX_THREAD;
 		spin_unlock_bh(&ts->ts_state_lock);
 		wait_for_completion(&ts->tx_restart_comp);
 		spin_lock_bh(&ts->ts_state_lock);
 		ts->blocked_threads &= ~ISCSI_BLOCK_TX_THREAD;
 	}

 	ts->conn = NULL;
 	ts->status = ISCSI_THREAD_SET_FREE;
 	spin_unlock_bh(&ts->ts_state_lock);

 	return 0;
 }

 int iscsi_thread_set_force_reinstatement(struct iscsi_conn *conn)
 {
 	struct iscsi_thread_set *ts;

 	if (!conn->thread_set)
 		return -1;
 	ts = conn->thread_set;

 	spin_lock_bh(&ts->ts_state_lock);
 	if (ts->status != ISCSI_THREAD_SET_ACTIVE) {
 		spin_unlock_bh(&ts->ts_state_lock);
 		return -1;
 	}

 	if (ts->tx_thread && (!(ts->signal_sent & ISCSI_SIGNAL_TX_THREAD))) {
 		send_sig(SIGINT, ts->tx_thread, 1);
 		ts->signal_sent |= ISCSI_SIGNAL_TX_THREAD;
 	}
 	if (ts->rx_thread && (!(ts->signal_sent & ISCSI_SIGNAL_RX_THREAD))) {
 		send_sig(SIGINT, ts->rx_thread, 1);
 		ts->signal_sent |= ISCSI_SIGNAL_RX_THREAD;
 	}
 	spin_unlock_bh(&ts->ts_state_lock);

 	return 0;
 }

 static void iscsi_check_to_add_additional_sets(void)
 {
 	int thread_sets_add;

 	spin_lock(&inactive_ts_lock);
 	thread_sets_add = iscsit_global->inactive_ts;
 	spin_unlock(&inactive_ts_lock);
 	if (thread_sets_add == 1)
 		iscsi_allocate_thread_sets(1);
 }

 static int iscsi_signal_thread_pre_handler(struct iscsi_thread_set *ts)
 {
 	spin_lock_bh(&ts->ts_state_lock);
 	if ((ts->status == ISCSI_THREAD_SET_DIE) || signal_pending(current)) {
 		spin_unlock_bh(&ts->ts_state_lock);
 		return -1;
 	}
 	spin_unlock_bh(&ts->ts_state_lock);

 	return 0;
 }

 struct iscsi_conn *iscsi_rx_thread_pre_handler(struct iscsi_thread_set *ts)
 {
 	int ret;

 	spin_lock_bh(&ts->ts_state_lock);
 	if (ts->create_threads) {
 		spin_unlock_bh(&ts->ts_state_lock);
 		goto sleep;
 	}

 	flush_signals(current);

 	if (ts->delay_inactive && (--ts->thread_count == 0)) {
 		spin_unlock_bh(&ts->ts_state_lock);
 		iscsi_del_ts_from_active_list(ts);

 		if (!iscsit_global->in_shutdown)
 			iscsi_deallocate_extra_thread_sets();

 		iscsi_add_ts_to_inactive_list(ts);
 		spin_lock_bh(&ts->ts_state_lock);
 	}

 	if ((ts->status == ISCSI_THREAD_SET_RESET) &&
 	    (ts->thread_clear & ISCSI_CLEAR_RX_THREAD))
 		complete(&ts->rx_restart_comp);

 	ts->thread_clear &= ~ISCSI_CLEAR_RX_THREAD;
 	spin_unlock_bh(&ts->ts_state_lock);
 sleep:
 	ret = wait_for_completion_interruptible(&ts->rx_start_comp);
 	if (ret != 0)
 		return NULL;

 	if (iscsi_signal_thread_pre_handler(ts) < 0)
 		return NULL;

 	if (!ts->conn) {
 		pr_err("struct iscsi_thread_set->conn is NULL for"
 			" thread_id: %d, going back to sleep\n", ts->thread_id);
 		goto sleep;
 	}
 	iscsi_check_to_add_additional_sets();
 	/*
 	 * The RX Thread starts up the TX Thread and sleeps.
 	 */
 	ts->thread_clear |= ISCSI_CLEAR_RX_THREAD;
 	complete(&ts->tx_start_comp);
 	wait_for_completion(&ts->tx_post_start_comp);

 	return ts->conn;
 }

 struct iscsi_conn *iscsi_tx_thread_pre_handler(struct iscsi_thread_set *ts)
 {
 	int ret;

 	spin_lock_bh(&ts->ts_state_lock);
 	if (ts->create_threads) {
 		spin_unlock_bh(&ts->ts_state_lock);
 		goto sleep;
 	}

 	flush_signals(current);

 	if (ts->delay_inactive && (--ts->thread_count == 0)) {
 		spin_unlock_bh(&ts->ts_state_lock);
 		iscsi_del_ts_from_active_list(ts);

 		if (!iscsit_global->in_shutdown)
 			iscsi_deallocate_extra_thread_sets();

 		iscsi_add_ts_to_inactive_list(ts);
 		spin_lock_bh(&ts->ts_state_lock);
 	}
 	if ((ts->status == ISCSI_THREAD_SET_RESET) &&
 	    (ts->thread_clear & ISCSI_CLEAR_TX_THREAD))
 		complete(&ts->tx_restart_comp);

 	ts->thread_clear &= ~ISCSI_CLEAR_TX_THREAD;
 	spin_unlock_bh(&ts->ts_state_lock);
 sleep:
 	ret = wait_for_completion_interruptible(&ts->tx_start_comp);
 	if (ret != 0)
 		return NULL;

 	if (iscsi_signal_thread_pre_handler(ts) < 0)
 		return NULL;

 	if (!ts->conn) {
 		pr_err("struct iscsi_thread_set->conn is NULL for "
 			" thread_id: %d, going back to sleep\n",
 			ts->thread_id);
 		goto sleep;
 	}

 	iscsi_check_to_add_additional_sets();
 	/*
 	 * From the TX thread, up the tx_post_start_comp that the RX Thread is
 	 * sleeping on in iscsi_rx_thread_pre_handler(), then up the
 	 * rx_post_start_comp that iscsi_activate_thread_set() is sleeping on.
 	 */
 	ts->thread_clear |= ISCSI_CLEAR_TX_THREAD;
 	complete(&ts->tx_post_start_comp);
 	complete(&ts->rx_post_start_comp);

 	spin_lock_bh(&ts->ts_state_lock);
 	ts->status = ISCSI_THREAD_SET_ACTIVE;
 	spin_unlock_bh(&ts->ts_state_lock);

 	return ts->conn;
 }

 int iscsi_thread_set_init(void)
 {
 	int size;

 	iscsit_global->ts_bitmap_count = ISCSI_TS_BITMAP_BITS;

 	size = BITS_TO_LONGS(iscsit_global->ts_bitmap_count) * sizeof(long);
 	iscsit_global->ts_bitmap = kzalloc(size, GFP_KERNEL);
 	if (!iscsit_global->ts_bitmap) {
 		pr_err("Unable to allocate iscsit_global->ts_bitmap\n");
 		return -ENOMEM;
 	}

 	spin_lock_init(&active_ts_lock);
 	spin_lock_init(&inactive_ts_lock);
 	spin_lock_init(&ts_bitmap_lock);
 	INIT_LIST_HEAD(&active_ts_list);
 	INIT_LIST_HEAD(&inactive_ts_list);

 	return 0;
 }

 void iscsi_thread_set_free(void)
 {
 	kfree(iscsit_global->ts_bitmap);
 }
	/*******************************************************************************
	* This file contains the iSCSI Login Thread and Thread Queue functions.
	*
	* \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
	*
	* Licensed to the Linux Foundation under the General Public License (GPL) version 2.
	*
	* Author: Nicholas A. Bellinger <nab@linux-iscsi.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.
	******************************************************************************/

	#include <linux/kthread.h>
	#include <linux/list.h>
	#include <linux/bitmap.h>

	#include "iscsi_target_core.h"
	#include "iscsi_target_tq.h"
	#include "iscsi_target.h"

	static LIST_HEAD(active_ts_list);
	static LIST_HEAD(inactive_ts_list);
	static DEFINE_SPINLOCK(active_ts_lock);
	static DEFINE_SPINLOCK(inactive_ts_lock);
	static DEFINE_SPINLOCK(ts_bitmap_lock);

	static void iscsi_add_ts_to_active_list(struct iscsi_thread_set *ts)
	{
	spin_lock(&active_ts_lock);
	list_add_tail(&ts->ts_list, &active_ts_list);
	iscsit_global->active_ts++;
	spin_unlock(&active_ts_lock);
	}

	extern void iscsi_add_ts_to_inactive_list(struct iscsi_thread_set *ts)
	{
	spin_lock(&inactive_ts_lock);
	list_add_tail(&ts->ts_list, &inactive_ts_list);
	iscsit_global->inactive_ts++;
	spin_unlock(&inactive_ts_lock);
	}

	static void iscsi_del_ts_from_active_list(struct iscsi_thread_set *ts)
	{
	spin_lock(&active_ts_lock);
	list_del(&ts->ts_list);
	iscsit_global->active_ts--;
	spin_unlock(&active_ts_lock);
	}

	static struct iscsi_thread_set *iscsi_get_ts_from_inactive_list(void)
	{
	struct iscsi_thread_set *ts;

	spin_lock(&inactive_ts_lock);
	if (list_empty(&inactive_ts_list)) {
	spin_unlock(&inactive_ts_lock);
	return NULL;
	}

	list_for_each_entry(ts, &inactive_ts_list, ts_list)
	break;

	list_del(&ts->ts_list);
	iscsit_global->inactive_ts--;
	spin_unlock(&inactive_ts_lock);

	return ts;
	}

	extern int iscsi_allocate_thread_sets(u32 thread_pair_count)
	{
	int allocated_thread_pair_count = 0, i, thread_id;
	struct iscsi_thread_set *ts = NULL;

	for (i = 0; i < thread_pair_count; i++) {
	ts = kzalloc(sizeof(struct iscsi_thread_set), GFP_KERNEL);
	if (!ts) {
	pr_err("Unable to allocate memory for"
	" thread set.\n");
	return allocated_thread_pair_count;
	}
	/*
	* Locate the next available regision in the thread_set_bitmap
	*/
	spin_lock(&ts_bitmap_lock);
	thread_id = bitmap_find_free_region(iscsit_global->ts_bitmap,
	iscsit_global->ts_bitmap_count, get_order(1));
	spin_unlock(&ts_bitmap_lock);
	if (thread_id < 0) {
	pr_err("bitmap_find_free_region() failed for"
	" thread_set_bitmap\n");
	kfree(ts);
	return allocated_thread_pair_count;
	}

	ts->thread_id = thread_id;
	ts->status = ISCSI_THREAD_SET_FREE;
	INIT_LIST_HEAD(&ts->ts_list);
	spin_lock_init(&ts->ts_state_lock);
	init_completion(&ts->rx_post_start_comp);
	init_completion(&ts->tx_post_start_comp);
	init_completion(&ts->rx_restart_comp);
	init_completion(&ts->tx_restart_comp);
	init_completion(&ts->rx_start_comp);
	init_completion(&ts->tx_start_comp);

	ts->create_threads = 1;
	ts->tx_thread = kthread_run(iscsi_target_tx_thread, ts, "%s",
	ISCSI_TX_THREAD_NAME);
	if (IS_ERR(ts->tx_thread)) {
	dump_stack();
	pr_err("Unable to start iscsi_target_tx_thread\n");
	break;
	}

	ts->rx_thread = kthread_run(iscsi_target_rx_thread, ts, "%s",
	ISCSI_RX_THREAD_NAME);
	if (IS_ERR(ts->rx_thread)) {
	kthread_stop(ts->tx_thread);
	pr_err("Unable to start iscsi_target_rx_thread\n");
	break;
	}
	ts->create_threads = 0;

	iscsi_add_ts_to_inactive_list(ts);
	allocated_thread_pair_count++;
	}

	pr_debug("Spawned %d thread set(s) (%d total threads).\n",
	allocated_thread_pair_count, allocated_thread_pair_count * 2);
	return allocated_thread_pair_count;
	}

	extern void iscsi_deallocate_thread_sets(void)
	{
	u32 released_count = 0;
	struct iscsi_thread_set *ts = NULL;

	while ((ts = iscsi_get_ts_from_inactive_list())) {

	spin_lock_bh(&ts->ts_state_lock);
	ts->status = ISCSI_THREAD_SET_DIE;
	spin_unlock_bh(&ts->ts_state_lock);

	if (ts->rx_thread) {
	send_sig(SIGINT, ts->rx_thread, 1);
	kthread_stop(ts->rx_thread);
	}
	if (ts->tx_thread) {
	send_sig(SIGINT, ts->tx_thread, 1);
	kthread_stop(ts->tx_thread);
	}
	/*
	* Release this thread_id in the thread_set_bitmap
	*/
	spin_lock(&ts_bitmap_lock);
	bitmap_release_region(iscsit_global->ts_bitmap,
	ts->thread_id, get_order(1));
	spin_unlock(&ts_bitmap_lock);

	released_count++;
	kfree(ts);
	}

	if (released_count)
	pr_debug("Stopped %d thread set(s) (%d total threads)."
	"\n", released_count, released_count * 2);
	}

	static void iscsi_deallocate_extra_thread_sets(void)
	{
	u32 orig_count, released_count = 0;
	struct iscsi_thread_set *ts = NULL;

	orig_count = TARGET_THREAD_SET_COUNT;

	while ((iscsit_global->inactive_ts + 1) > orig_count) {
	ts = iscsi_get_ts_from_inactive_list();
	if (!ts)
	break;

	spin_lock_bh(&ts->ts_state_lock);
	ts->status = ISCSI_THREAD_SET_DIE;
	spin_unlock_bh(&ts->ts_state_lock);

	if (ts->rx_thread) {
	send_sig(SIGINT, ts->rx_thread, 1);
	kthread_stop(ts->rx_thread);
	}
	if (ts->tx_thread) {
	send_sig(SIGINT, ts->tx_thread, 1);
	kthread_stop(ts->tx_thread);
	}
	/*
	* Release this thread_id in the thread_set_bitmap
	*/
	spin_lock(&ts_bitmap_lock);
	bitmap_release_region(iscsit_global->ts_bitmap,
	ts->thread_id, get_order(1));
	spin_unlock(&ts_bitmap_lock);

	released_count++;
	kfree(ts);
	}

	if (released_count) {
	pr_debug("Stopped %d thread set(s) (%d total threads)."
	"\n", released_count, released_count * 2);
	}
	}

	void iscsi_activate_thread_set(struct iscsi_conn conn, struct iscsi_thread_set ts)
	{
	iscsi_add_ts_to_active_list(ts);

	spin_lock_bh(&ts->ts_state_lock);
	conn->thread_set = ts;
	ts->conn = conn;
	spin_unlock_bh(&ts->ts_state_lock);
	/*
	* Start up the RX thread and wait on rx_post_start_comp. The RX
	* Thread will then do the same for the TX Thread in
	* iscsi_rx_thread_pre_handler().
	*/
	complete(&ts->rx_start_comp);
	wait_for_completion(&ts->rx_post_start_comp);
	}

	struct iscsi_thread_set *iscsi_get_thread_set(void)
	{
	int allocate_ts = 0;
	struct completion comp;
	struct iscsi_thread_set *ts = NULL;
	/*
	* If no inactive thread set is available on the first call to
	* iscsi_get_ts_from_inactive_list(), sleep for a second and
	* try again. If still none are available after two attempts,
	* allocate a set ourselves.
	*/
	get_set:
	ts = iscsi_get_ts_from_inactive_list();
	if (!ts) {
	if (allocate_ts == 2)
	iscsi_allocate_thread_sets(1);

	init_completion(&comp);
	wait_for_completion_timeout(&comp, 1 * HZ);

	allocate_ts++;
	goto get_set;
	}

	ts->delay_inactive = 1;
	ts->signal_sent = 0;
	ts->thread_count = 2;
	init_completion(&ts->rx_restart_comp);
	init_completion(&ts->tx_restart_comp);

	return ts;
	}

	void iscsi_set_thread_clear(struct iscsi_conn *conn, u8 thread_clear)
	{
	struct iscsi_thread_set *ts = NULL;

	if (!conn->thread_set) {
	pr_err("struct iscsi_conn->thread_set is NULL\n");
	return;
	}
	ts = conn->thread_set;

	spin_lock_bh(&ts->ts_state_lock);
	ts->thread_clear &= ~thread_clear;

	if ((thread_clear & ISCSI_CLEAR_RX_THREAD) &&
	(ts->blocked_threads & ISCSI_BLOCK_RX_THREAD))
	complete(&ts->rx_restart_comp);
	else if ((thread_clear & ISCSI_CLEAR_TX_THREAD) &&
	(ts->blocked_threads & ISCSI_BLOCK_TX_THREAD))
	complete(&ts->tx_restart_comp);
	spin_unlock_bh(&ts->ts_state_lock);
	}

	void iscsi_set_thread_set_signal(struct iscsi_conn *conn, u8 signal_sent)
	{
	struct iscsi_thread_set *ts = NULL;

	if (!conn->thread_set) {
	pr_err("struct iscsi_conn->thread_set is NULL\n");
	return;
	}
	ts = conn->thread_set;

	spin_lock_bh(&ts->ts_state_lock);
	ts->signal_sent \|= signal_sent;
	spin_unlock_bh(&ts->ts_state_lock);
	}

	int iscsi_release_thread_set(struct iscsi_conn *conn)
	{
	int thread_called = 0;
	struct iscsi_thread_set *ts = NULL;

	if (!conn \|\| !conn->thread_set) {
	pr_err("connection or thread set pointer is NULL\n");
	BUG();
	}
	ts = conn->thread_set;

	spin_lock_bh(&ts->ts_state_lock);
	ts->status = ISCSI_THREAD_SET_RESET;

	if (!strncmp(current->comm, ISCSI_RX_THREAD_NAME,
	strlen(ISCSI_RX_THREAD_NAME)))
	thread_called = ISCSI_RX_THREAD;
	else if (!strncmp(current->comm, ISCSI_TX_THREAD_NAME,
	strlen(ISCSI_TX_THREAD_NAME)))
	thread_called = ISCSI_TX_THREAD;

	if (ts->rx_thread && (thread_called == ISCSI_TX_THREAD) &&
	(ts->thread_clear & ISCSI_CLEAR_RX_THREAD)) {

	if (!(ts->signal_sent & ISCSI_SIGNAL_RX_THREAD)) {
	send_sig(SIGINT, ts->rx_thread, 1);
	ts->signal_sent \|= ISCSI_SIGNAL_RX_THREAD;
	}
	ts->blocked_threads \|= ISCSI_BLOCK_RX_THREAD;
	spin_unlock_bh(&ts->ts_state_lock);
	wait_for_completion(&ts->rx_restart_comp);
	spin_lock_bh(&ts->ts_state_lock);
	ts->blocked_threads &= ~ISCSI_BLOCK_RX_THREAD;
	}
	if (ts->tx_thread && (thread_called == ISCSI_RX_THREAD) &&
	(ts->thread_clear & ISCSI_CLEAR_TX_THREAD)) {

	if (!(ts->signal_sent & ISCSI_SIGNAL_TX_THREAD)) {
	send_sig(SIGINT, ts->tx_thread, 1);
	ts->signal_sent \|= ISCSI_SIGNAL_TX_THREAD;
	}
	ts->blocked_threads \|= ISCSI_BLOCK_TX_THREAD;
	spin_unlock_bh(&ts->ts_state_lock);
	wait_for_completion(&ts->tx_restart_comp);
	spin_lock_bh(&ts->ts_state_lock);
	ts->blocked_threads &= ~ISCSI_BLOCK_TX_THREAD;
	}

	ts->conn = NULL;
	ts->status = ISCSI_THREAD_SET_FREE;
	spin_unlock_bh(&ts->ts_state_lock);

	return 0;
	}

	int iscsi_thread_set_force_reinstatement(struct iscsi_conn *conn)
	{
	struct iscsi_thread_set *ts;

	if (!conn->thread_set)
	return -1;
	ts = conn->thread_set;

	spin_lock_bh(&ts->ts_state_lock);
	if (ts->status != ISCSI_THREAD_SET_ACTIVE) {
	spin_unlock_bh(&ts->ts_state_lock);
	return -1;
	}

	if (ts->tx_thread && (!(ts->signal_sent & ISCSI_SIGNAL_TX_THREAD))) {
	send_sig(SIGINT, ts->tx_thread, 1);
	ts->signal_sent \|= ISCSI_SIGNAL_TX_THREAD;
	}
	if (ts->rx_thread && (!(ts->signal_sent & ISCSI_SIGNAL_RX_THREAD))) {
	send_sig(SIGINT, ts->rx_thread, 1);
	ts->signal_sent \|= ISCSI_SIGNAL_RX_THREAD;
	}
	spin_unlock_bh(&ts->ts_state_lock);

	return 0;
	}

	static void iscsi_check_to_add_additional_sets(void)
	{
	int thread_sets_add;

	spin_lock(&inactive_ts_lock);
	thread_sets_add = iscsit_global->inactive_ts;
	spin_unlock(&inactive_ts_lock);
	if (thread_sets_add == 1)
	iscsi_allocate_thread_sets(1);
	}

	static int iscsi_signal_thread_pre_handler(struct iscsi_thread_set *ts)
	{
	spin_lock_bh(&ts->ts_state_lock);
	if ((ts->status == ISCSI_THREAD_SET_DIE) \|\| signal_pending(current)) {
	spin_unlock_bh(&ts->ts_state_lock);
	return -1;
	}
	spin_unlock_bh(&ts->ts_state_lock);

	return 0;
	}

	struct iscsi_conn iscsi_rx_thread_pre_handler(struct iscsi_thread_set ts)
	{
	int ret;

	spin_lock_bh(&ts->ts_state_lock);
	if (ts->create_threads) {
	spin_unlock_bh(&ts->ts_state_lock);
	goto sleep;
	}

	flush_signals(current);

	if (ts->delay_inactive && (--ts->thread_count == 0)) {
	spin_unlock_bh(&ts->ts_state_lock);
	iscsi_del_ts_from_active_list(ts);

	if (!iscsit_global->in_shutdown)
	iscsi_deallocate_extra_thread_sets();

	iscsi_add_ts_to_inactive_list(ts);
	spin_lock_bh(&ts->ts_state_lock);
	}

	if ((ts->status == ISCSI_THREAD_SET_RESET) &&
	(ts->thread_clear & ISCSI_CLEAR_RX_THREAD))
	complete(&ts->rx_restart_comp);

	ts->thread_clear &= ~ISCSI_CLEAR_RX_THREAD;
	spin_unlock_bh(&ts->ts_state_lock);
	sleep:
	ret = wait_for_completion_interruptible(&ts->rx_start_comp);
	if (ret != 0)
	return NULL;

	if (iscsi_signal_thread_pre_handler(ts) < 0)
	return NULL;

	if (!ts->conn) {
	pr_err("struct iscsi_thread_set->conn is NULL for"
	" thread_id: %d, going back to sleep\n", ts->thread_id);
	goto sleep;
	}
	iscsi_check_to_add_additional_sets();
	/*
	* The RX Thread starts up the TX Thread and sleeps.
	*/
	ts->thread_clear \|= ISCSI_CLEAR_RX_THREAD;
	complete(&ts->tx_start_comp);
	wait_for_completion(&ts->tx_post_start_comp);

	return ts->conn;
	}

	struct iscsi_conn iscsi_tx_thread_pre_handler(struct iscsi_thread_set ts)
	{
	int ret;

	spin_lock_bh(&ts->ts_state_lock);
	if (ts->create_threads) {
	spin_unlock_bh(&ts->ts_state_lock);
	goto sleep;
	}

	flush_signals(current);

	if (ts->delay_inactive && (--ts->thread_count == 0)) {
	spin_unlock_bh(&ts->ts_state_lock);
	iscsi_del_ts_from_active_list(ts);

	if (!iscsit_global->in_shutdown)
	iscsi_deallocate_extra_thread_sets();

	iscsi_add_ts_to_inactive_list(ts);
	spin_lock_bh(&ts->ts_state_lock);
	}
	if ((ts->status == ISCSI_THREAD_SET_RESET) &&
	(ts->thread_clear & ISCSI_CLEAR_TX_THREAD))
	complete(&ts->tx_restart_comp);

	ts->thread_clear &= ~ISCSI_CLEAR_TX_THREAD;
	spin_unlock_bh(&ts->ts_state_lock);
	sleep:
	ret = wait_for_completion_interruptible(&ts->tx_start_comp);
	if (ret != 0)
	return NULL;

	if (iscsi_signal_thread_pre_handler(ts) < 0)
	return NULL;

	if (!ts->conn) {
	pr_err("struct iscsi_thread_set->conn is NULL for "
	" thread_id: %d, going back to sleep\n",
	ts->thread_id);
	goto sleep;
	}

	iscsi_check_to_add_additional_sets();
	/*
	* From the TX thread, up the tx_post_start_comp that the RX Thread is
	* sleeping on in iscsi_rx_thread_pre_handler(), then up the
	* rx_post_start_comp that iscsi_activate_thread_set() is sleeping on.
	*/
	ts->thread_clear \|= ISCSI_CLEAR_TX_THREAD;
	complete(&ts->tx_post_start_comp);
	complete(&ts->rx_post_start_comp);

	spin_lock_bh(&ts->ts_state_lock);
	ts->status = ISCSI_THREAD_SET_ACTIVE;
	spin_unlock_bh(&ts->ts_state_lock);

	return ts->conn;
	}

	int iscsi_thread_set_init(void)
	{
	int size;

	iscsit_global->ts_bitmap_count = ISCSI_TS_BITMAP_BITS;

	size = BITS_TO_LONGS(iscsit_global->ts_bitmap_count) * sizeof(long);
	iscsit_global->ts_bitmap = kzalloc(size, GFP_KERNEL);
	if (!iscsit_global->ts_bitmap) {
	pr_err("Unable to allocate iscsit_global->ts_bitmap\n");
	return -ENOMEM;
	}

	spin_lock_init(&active_ts_lock);
	spin_lock_init(&inactive_ts_lock);
	spin_lock_init(&ts_bitmap_lock);
	INIT_LIST_HEAD(&active_ts_list);
	INIT_LIST_HEAD(&inactive_ts_list);

	return 0;
	}

	void iscsi_thread_set_free(void)
	{
	kfree(iscsit_global->ts_bitmap);
	}