1 files changed, 551 insertions, 0 deletions

diff --git a/drivers/target/iscsi/iscsi_target_tq.c b/drivers/target/iscsi/iscsi_target_tq.c
new file mode 100644
index 0000000..0baac5b
--- /dev/null
+++ b/drivers/target/iscsi/iscsi_target_tq.c
@@ -0,0 +1,551 @@
+/*******************************************************************************
+ * 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);
+}