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Message-ID: <4C8F8954.3000502@vlnb.net>
Date:	Tue, 14 Sep 2010 18:40:20 +0400
From:	Vladislav Bolkhovitin <vst@...b.net>
To:	linux-scsi@...r.kernel.org
CC:	linux-kernel@...r.kernel.org,
	scst-devel <scst-devel@...ts.sourceforge.net>,
	James Bottomley <James.Bottomley@...senPartnership.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	FUJITA Tomonori <fujita.tomonori@....ntt.co.jp>,
	Mike Christie <michaelc@...wisc.edu>,
	Jeff Garzik <jeff@...zik.org>, Vu Pham <vuhuong@...lanox.com>,
	Bart Van Assche <bart.vanassche@...il.com>,
	James Smart <James.Smart@...lex.Com>,
	Joe Eykholt <jeykholt@...co.com>, Andy Yan <ayan@...vell.com>,
	Chetan Loke <generationgnu@...oo.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Hannes Reinecke <hare@...e.de>,
	Richard Sharpe <realrichardsharpe@...il.com>
Subject: [PATCH 4/17]: SCST main management files and private headers

This patch contains main management files and private headers.

Signed-off-by: Vladislav Bolkhovitin <vst@...b.net>
---
 scst_main.c   | 2096 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 scst_module.c |   63 +
 scst_priv.h   |  609 ++++++++++++++++
 3 files changed, 2768 insertions(+)

diff -uprN orig/linux-2.6.35/drivers/scst/scst_main.c linux-2.6.35/drivers/scst/scst_main.c
--- orig/linux-2.6.35/drivers/scst/scst_main.c
+++ linux-2.6.35/drivers/scst/scst_main.c
@@ -0,0 +1,2096 @@
+/*
+ *  scst_main.c
+ *
+ *  Copyright (C) 2004 - 2010 Vladislav Bolkhovitin <vst@...b.net>
+ *  Copyright (C) 2004 - 2005 Leonid Stoljar
+ *  Copyright (C) 2007 - 2010 ID7 Ltd.
+ *
+ *  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, version 2
+ *  of the License.
+ *
+ *  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/module.h>
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/unistd.h>
+#include <linux/string.h>
+#include <linux/kthread.h>
+#include <linux/delay.h>
+
+#include <scst/scst.h>
+#include "scst_priv.h"
+#include "scst_mem.h"
+#include "scst_pres.h"
+
+#if defined(CONFIG_HIGHMEM4G) || defined(CONFIG_HIGHMEM64G)
+#warning "HIGHMEM kernel configurations are fully supported, but not\
+ recommended for performance reasons. Consider changing VMSPLIT\
+ option or use a 64-bit configuration instead. See README file for\
+ details."
+#endif
+
+/**
+ ** SCST global variables. They are all uninitialized to have their layout in
+ ** memory be exactly as specified. Otherwise compiler puts zero-initialized
+ ** variable separately from nonzero-initialized ones.
+ **/
+
+/*
+ * Main SCST mutex. All targets, devices and dev_types management is done
+ * under this mutex.
+ *
+ * It must NOT be used in any works (schedule_work(), etc.), because
+ * otherwise a deadlock (double lock, actually) is possible, e.g., with
+ * scst_user detach_tgt(), which is called under scst_mutex and calls
+ * flush_scheduled_work().
+ */
+struct mutex scst_mutex;
+EXPORT_SYMBOL_GPL(scst_mutex);
+
+/*
+ * Secondary level main mutex, inner for scst_mutex. Needed for
+ * __scst_pr_register_all_tg_pt(), since we can't use scst_mutex there,
+ * because of the circular locking dependency with dev_pr_mutex.
+ */
+struct mutex scst_mutex2;
+
+/* Both protected by scst_mutex or scst_mutex2 on read and both on write */
+struct list_head scst_template_list;
+struct list_head scst_dev_list;
+
+/* Protected by scst_mutex */
+struct list_head scst_dev_type_list;
+struct list_head scst_virtual_dev_type_list;
+
+spinlock_t scst_main_lock;
+
+static struct kmem_cache *scst_mgmt_cachep;
+mempool_t *scst_mgmt_mempool;
+static struct kmem_cache *scst_mgmt_stub_cachep;
+mempool_t *scst_mgmt_stub_mempool;
+static struct kmem_cache *scst_ua_cachep;
+mempool_t *scst_ua_mempool;
+static struct kmem_cache *scst_sense_cachep;
+mempool_t *scst_sense_mempool;
+static struct kmem_cache *scst_aen_cachep;
+mempool_t *scst_aen_mempool;
+struct kmem_cache *scst_tgtd_cachep;
+struct kmem_cache *scst_sess_cachep;
+struct kmem_cache *scst_acgd_cachep;
+
+unsigned int scst_setup_id;
+
+spinlock_t scst_init_lock;
+wait_queue_head_t scst_init_cmd_list_waitQ;
+struct list_head scst_init_cmd_list;
+unsigned int scst_init_poll_cnt;
+
+struct kmem_cache *scst_cmd_cachep;
+
+#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
+unsigned long scst_trace_flag;
+#endif
+
+unsigned long scst_flags;
+atomic_t scst_cmd_count;
+
+struct scst_cmd_threads scst_main_cmd_threads;
+
+struct scst_tasklet scst_tasklets[NR_CPUS];
+
+spinlock_t scst_mcmd_lock;
+struct list_head scst_active_mgmt_cmd_list;
+struct list_head scst_delayed_mgmt_cmd_list;
+wait_queue_head_t scst_mgmt_cmd_list_waitQ;
+
+wait_queue_head_t scst_mgmt_waitQ;
+spinlock_t scst_mgmt_lock;
+struct list_head scst_sess_init_list;
+struct list_head scst_sess_shut_list;
+
+wait_queue_head_t scst_dev_cmd_waitQ;
+
+static struct mutex scst_suspend_mutex;
+/* protected by scst_suspend_mutex */
+static struct list_head scst_cmd_threads_list;
+
+int scst_threads;
+static struct task_struct *scst_init_cmd_thread;
+static struct task_struct *scst_mgmt_thread;
+static struct task_struct *scst_mgmt_cmd_thread;
+
+static int suspend_count;
+
+static int scst_virt_dev_last_id; /* protected by scst_mutex */
+
+static unsigned int scst_max_cmd_mem;
+unsigned int scst_max_dev_cmd_mem;
+
+module_param_named(scst_threads, scst_threads, int, 0);
+MODULE_PARM_DESC(scst_threads, "SCSI target threads count");
+
+module_param_named(scst_max_cmd_mem, scst_max_cmd_mem, int, S_IRUGO);
+MODULE_PARM_DESC(scst_max_cmd_mem, "Maximum memory allowed to be consumed by "
+	"all SCSI commands of all devices at any given time in MB");
+
+module_param_named(scst_max_dev_cmd_mem, scst_max_dev_cmd_mem, int, S_IRUGO);
+MODULE_PARM_DESC(scst_max_dev_cmd_mem, "Maximum memory allowed to be consumed "
+	"by all SCSI commands of a device at any given time in MB");
+
+struct scst_dev_type scst_null_devtype = {
+	.name = "none",
+	.threads_num = -1,
+};
+
+static void __scst_resume_activity(void);
+
+/**
+ * __scst_register_target_template() - register target template.
+ * @vtt:	target template
+ * @version:	SCST_INTERFACE_VERSION version string to ensure that
+ *		SCST core and the target driver use the same version of
+ *		the SCST interface
+ *
+ * Description:
+ *    Registers a target template and returns 0 on success or appropriate
+ *    error code otherwise.
+ *
+ *    Target drivers supposed to behave sanely and not call register()
+ *    and unregister() randomly sinultaneously.
+ */
+int __scst_register_target_template(struct scst_tgt_template *vtt,
+	const char *version)
+{
+	int res = 0;
+	struct scst_tgt_template *t;
+
+	INIT_LIST_HEAD(&vtt->tgt_list);
+
+	if (strcmp(version, SCST_INTERFACE_VERSION) != 0) {
+		PRINT_ERROR("Incorrect version of target %s", vtt->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (!vtt->detect) {
+		PRINT_ERROR("Target driver %s must have "
+			"detect() method.", vtt->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (!vtt->release) {
+		PRINT_ERROR("Target driver %s must have "
+			"release() method.", vtt->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (!vtt->xmit_response) {
+		PRINT_ERROR("Target driver %s must have "
+			"xmit_response() method.", vtt->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (vtt->get_initiator_port_transport_id == NULL)
+		PRINT_WARNING("Target driver %s doesn't support Persistent "
+			"Reservations", vtt->name);
+
+	if (vtt->threads_num < 0) {
+		PRINT_ERROR("Wrong threads_num value %d for "
+			"target \"%s\"", vtt->threads_num,
+			vtt->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if ((!vtt->enable_target || !vtt->is_target_enabled) &&
+	    !vtt->enabled_attr_not_needed)
+		PRINT_WARNING("Target driver %s doesn't have enable_target() "
+			"and/or is_target_enabled() method(s). This is unsafe "
+			"and can lead that initiators connected on the "
+			"initialization time can see an unexpected set of "
+			"devices or no devices at all!", vtt->name);
+
+	if (((vtt->add_target != NULL) && (vtt->del_target == NULL)) ||
+	    ((vtt->add_target == NULL) && (vtt->del_target != NULL))) {
+		PRINT_ERROR("Target driver %s must either define both "
+			"add_target() and del_target(), or none.", vtt->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (vtt->rdy_to_xfer == NULL)
+		vtt->rdy_to_xfer_atomic = 1;
+
+	if (mutex_lock_interruptible(&scst_mutex) != 0)
+		goto out;
+	list_for_each_entry(t, &scst_template_list, scst_template_list_entry) {
+		if (strcmp(t->name, vtt->name) == 0) {
+			PRINT_ERROR("Target driver %s already registered",
+				vtt->name);
+			mutex_unlock(&scst_mutex);
+			goto out_unlock;
+		}
+	}
+	mutex_unlock(&scst_mutex);
+
+	res = scst_tgtt_sysfs_create(vtt);
+	if (res)
+		goto out;
+
+	mutex_lock(&scst_mutex);
+	mutex_lock(&scst_mutex2);
+	list_add_tail(&vtt->scst_template_list_entry, &scst_template_list);
+	mutex_unlock(&scst_mutex2);
+	mutex_unlock(&scst_mutex);
+
+	TRACE_DBG("%s", "Calling target driver's detect()");
+	res = vtt->detect(vtt);
+	TRACE_DBG("Target driver's detect() returned %d", res);
+	if (res < 0) {
+		PRINT_ERROR("%s", "The detect() routine failed");
+		res = -EINVAL;
+		goto out_del;
+	}
+
+	PRINT_INFO("Target template %s registered successfully", vtt->name);
+
+out:
+	return res;
+
+out_del:
+	scst_tgtt_sysfs_del(vtt);
+
+	mutex_lock(&scst_mutex);
+
+	mutex_lock(&scst_mutex2);
+	list_del(&vtt->scst_template_list_entry);
+	mutex_unlock(&scst_mutex2);
+
+out_unlock:
+	mutex_unlock(&scst_mutex);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(__scst_register_target_template);
+
+static int scst_check_non_gpl_target_template(struct scst_tgt_template *vtt)
+{
+	int res;
+
+	if (vtt->task_mgmt_affected_cmds_done || vtt->threads_num ||
+	    vtt->on_hw_pending_cmd_timeout) {
+		PRINT_ERROR("Not allowed functionality in non-GPL version for "
+			"target template %s", vtt->name);
+		res = -EPERM;
+		goto out;
+	}
+
+	res = 0;
+
+out:
+	return res;
+}
+
+/**
+ * __scst_register_target_template_non_gpl() - register target template,
+ *					      non-GPL version
+ * @vtt:	target template
+ * @version:	SCST_INTERFACE_VERSION version string to ensure that
+ *		SCST core and the target driver use the same version of
+ *		the SCST interface
+ *
+ * Description:
+ *    Registers a target template and returns 0 on success or appropriate
+ *    error code otherwise.
+ *
+ *    Note: *vtt must be static!
+ */
+int __scst_register_target_template_non_gpl(struct scst_tgt_template *vtt,
+	const char *version)
+{
+	int res;
+
+	res = scst_check_non_gpl_target_template(vtt);
+	if (res != 0)
+		goto out;
+
+	res = __scst_register_target_template(vtt, version);
+
+out:
+	return res;
+}
+EXPORT_SYMBOL(__scst_register_target_template_non_gpl);
+
+/**
+ * scst_unregister_target_template() - unregister target template
+ *
+ * Target drivers supposed to behave sanely and not call register()
+ * and unregister() randomly sinultaneously. Also it is supposed that
+ * no attepts to create new targets for this vtt will be done in a race
+ * with this function.
+ */
+void scst_unregister_target_template(struct scst_tgt_template *vtt)
+{
+	struct scst_tgt *tgt;
+	struct scst_tgt_template *t;
+	int found = 0;
+
+	mutex_lock(&scst_mutex);
+
+	list_for_each_entry(t, &scst_template_list, scst_template_list_entry) {
+		if (strcmp(t->name, vtt->name) == 0) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found) {
+		PRINT_ERROR("Target driver %s isn't registered", vtt->name);
+		goto out_err_up;
+	}
+
+	mutex_lock(&scst_mutex2);
+	list_del(&vtt->scst_template_list_entry);
+	mutex_unlock(&scst_mutex2);
+
+	/* Wait for outstanding sysfs mgmt calls completed */
+	while (vtt->tgtt_active_sysfs_works_count > 0) {
+		mutex_unlock(&scst_mutex);
+		msleep(100);
+		mutex_lock(&scst_mutex);
+	}
+
+restart:
+	list_for_each_entry(tgt, &vtt->tgt_list, tgt_list_entry) {
+		mutex_unlock(&scst_mutex);
+		scst_unregister_target(tgt);
+		mutex_lock(&scst_mutex);
+		goto restart;
+	}
+
+	mutex_unlock(&scst_mutex);
+
+	scst_tgtt_sysfs_del(vtt);
+
+	PRINT_INFO("Target template %s unregistered successfully", vtt->name);
+
+out:
+	return;
+
+out_err_up:
+	mutex_unlock(&scst_mutex);
+	goto out;
+}
+EXPORT_SYMBOL(scst_unregister_target_template);
+
+/**
+ * scst_register_target() - register target
+ *
+ * Registers a target for template vtt and returns new target structure on
+ * success or NULL otherwise.
+ */
+struct scst_tgt *scst_register_target(struct scst_tgt_template *vtt,
+	const char *target_name)
+{
+	struct scst_tgt *tgt;
+	int rc = 0;
+
+	rc = scst_alloc_tgt(vtt, &tgt);
+	if (rc != 0)
+		goto out;
+
+	if (target_name != NULL) {
+
+		tgt->tgt_name = kmalloc(strlen(target_name) + 1, GFP_KERNEL);
+		if (tgt->tgt_name == NULL) {
+			TRACE(TRACE_OUT_OF_MEM, "Allocation of tgt name %s failed",
+				target_name);
+			rc = -ENOMEM;
+			goto out_free_tgt;
+		}
+		strcpy(tgt->tgt_name, target_name);
+	} else {
+		static int tgt_num; /* protected by scst_mutex */
+		int len = strlen(vtt->name) +
+			strlen(SCST_DEFAULT_TGT_NAME_SUFFIX) + 11 + 1;
+
+		tgt->tgt_name = kmalloc(len, GFP_KERNEL);
+		if (tgt->tgt_name == NULL) {
+			TRACE(TRACE_OUT_OF_MEM, "Allocation of tgt name failed "
+				"(template name %s)", vtt->name);
+			rc = -ENOMEM;
+			goto out_free_tgt;
+		}
+		sprintf(tgt->tgt_name, "%s%s%d", vtt->name,
+			SCST_DEFAULT_TGT_NAME_SUFFIX, tgt_num++);
+	}
+
+	if (mutex_lock_interruptible(&scst_mutex) != 0) {
+		rc = -EINTR;
+		goto out_free_tgt;
+	}
+
+	rc = scst_tgt_sysfs_create(tgt);
+	if (rc < 0)
+		goto out_unlock;
+
+	tgt->default_acg = scst_alloc_add_acg(tgt, tgt->tgt_name, false);
+	if (tgt->default_acg == NULL)
+		goto out_sysfs_del;
+
+	mutex_lock(&scst_mutex2);
+	list_add_tail(&tgt->tgt_list_entry, &vtt->tgt_list);
+	mutex_unlock(&scst_mutex2);
+
+	mutex_unlock(&scst_mutex);
+
+	PRINT_INFO("Target %s for template %s registered successfully",
+		tgt->tgt_name, vtt->name);
+
+	TRACE_DBG("tgt %p", tgt);
+
+out:
+	return tgt;
+
+out_sysfs_del:
+	mutex_unlock(&scst_mutex);
+	scst_tgt_sysfs_del(tgt);
+	goto out_free_tgt;
+
+out_unlock:
+	mutex_unlock(&scst_mutex);
+
+out_free_tgt:
+	/* In case of error tgt_name will be freed in scst_free_tgt() */
+	scst_free_tgt(tgt);
+	tgt = NULL;
+	goto out;
+}
+EXPORT_SYMBOL(scst_register_target);
+
+static inline int test_sess_list(struct scst_tgt *tgt)
+{
+	int res;
+	mutex_lock(&scst_mutex);
+	res = list_empty(&tgt->sess_list);
+	mutex_unlock(&scst_mutex);
+	return res;
+}
+
+/**
+ * scst_unregister_target() - unregister target.
+ *
+ * It is supposed that no attepts to create new sessions for this
+ * target will be done in a race with this function.
+ */
+void scst_unregister_target(struct scst_tgt *tgt)
+{
+	struct scst_session *sess;
+	struct scst_tgt_template *vtt = tgt->tgtt;
+	struct scst_acg *acg, *acg_tmp;
+
+	TRACE_DBG("%s", "Calling target driver's release()");
+	tgt->tgtt->release(tgt);
+	TRACE_DBG("%s", "Target driver's release() returned");
+
+	mutex_lock(&scst_mutex);
+again:
+	list_for_each_entry(sess, &tgt->sess_list, sess_list_entry) {
+		if (sess->shut_phase == SCST_SESS_SPH_READY) {
+			/*
+			 * Sometimes it's hard for target driver to track all
+			 * its sessions (see scst_local, eg), so let's help it.
+			 */
+			mutex_unlock(&scst_mutex);
+			scst_unregister_session(sess, 0, NULL);
+			mutex_lock(&scst_mutex);
+			goto again;
+		}
+	}
+	mutex_unlock(&scst_mutex);
+
+	TRACE_DBG("%s", "Waiting for sessions shutdown");
+	wait_event(tgt->unreg_waitQ, test_sess_list(tgt));
+	TRACE_DBG("%s", "wait_event() returned");
+
+	scst_suspend_activity(false);
+	mutex_lock(&scst_mutex);
+
+	mutex_lock(&scst_mutex2);
+	list_del(&tgt->tgt_list_entry);
+	mutex_unlock(&scst_mutex2);
+
+	del_timer_sync(&tgt->retry_timer);
+
+	scst_del_free_acg(tgt->default_acg);
+
+	list_for_each_entry_safe(acg, acg_tmp, &tgt->tgt_acg_list,
+					acg_list_entry) {
+		scst_del_free_acg(acg);
+	}
+
+	mutex_unlock(&scst_mutex);
+	scst_resume_activity();
+
+	scst_tgt_sysfs_del(tgt);
+
+	PRINT_INFO("Target %s for template %s unregistered successfully",
+		tgt->tgt_name, vtt->name);
+
+	scst_free_tgt(tgt);
+
+	TRACE_DBG("Unregistering tgt %p finished", tgt);
+	return;
+}
+EXPORT_SYMBOL(scst_unregister_target);
+
+static int scst_susp_wait(bool interruptible)
+{
+	int res = 0;
+
+	if (interruptible) {
+		res = wait_event_interruptible_timeout(scst_dev_cmd_waitQ,
+			(atomic_read(&scst_cmd_count) == 0),
+			SCST_SUSPENDING_TIMEOUT);
+		if (res <= 0) {
+			__scst_resume_activity();
+			if (res == 0)
+				res = -EBUSY;
+		} else
+			res = 0;
+	} else
+		wait_event(scst_dev_cmd_waitQ,
+			   atomic_read(&scst_cmd_count) == 0);
+
+	TRACE_MGMT_DBG("wait_event() returned %d", res);
+	return res;
+}
+
+/**
+ * scst_suspend_activity() - globally suspend any activity
+ *
+ * Description:
+ *    Globally suspends any activity and doesn't return, until there are any
+ *    active commands (state after SCST_CMD_STATE_INIT). If "interruptible"
+ *    is true, it returns after SCST_SUSPENDING_TIMEOUT or if it was interrupted
+ *    by a signal with the corresponding error status < 0. If "interruptible"
+ *    is false, it will wait virtually forever. On success returns 0.
+ *
+ *    New arriving commands stay in the suspended state until
+ *    scst_resume_activity() is called.
+ */
+int scst_suspend_activity(bool interruptible)
+{
+	int res = 0;
+	bool rep = false;
+
+	if (interruptible) {
+		if (mutex_lock_interruptible(&scst_suspend_mutex) != 0) {
+			res = -EINTR;
+			goto out;
+		}
+	} else
+		mutex_lock(&scst_suspend_mutex);
+
+	TRACE_MGMT_DBG("suspend_count %d", suspend_count);
+	suspend_count++;
+	if (suspend_count > 1)
+		goto out_up;
+
+	set_bit(SCST_FLAG_SUSPENDING, &scst_flags);
+	set_bit(SCST_FLAG_SUSPENDED, &scst_flags);
+	/*
+	 * Assignment of SCST_FLAG_SUSPENDING and SCST_FLAG_SUSPENDED must be
+	 * ordered with scst_cmd_count. Otherwise lockless logic in
+	 * scst_translate_lun() and scst_mgmt_translate_lun() won't work.
+	 */
+	smp_mb__after_set_bit();
+
+	/*
+	 * See comment in scst_user.c::dev_user_task_mgmt_fn() for more
+	 * information about scst_user behavior.
+	 *
+	 * ToDo: make the global suspending unneeded (switch to per-device
+	 * reference counting? That would mean to switch off from lockless
+	 * implementation of scst_translate_lun().. )
+	 */
+
+	if (atomic_read(&scst_cmd_count) != 0) {
+		PRINT_INFO("Waiting for %d active commands to complete... This "
+			"might take few minutes for disks or few hours for "
+			"tapes, if you use long executed commands, like "
+			"REWIND or FORMAT. In case, if you have a hung user "
+			"space device (i.e. made using scst_user module) not "
+			"responding to any commands, if might take virtually "
+			"forever until the corresponding user space "
+			"program recovers and starts responding or gets "
+			"killed.", atomic_read(&scst_cmd_count));
+		rep = true;
+	}
+
+	res = scst_susp_wait(interruptible);
+	if (res != 0)
+		goto out_clear;
+
+	clear_bit(SCST_FLAG_SUSPENDING, &scst_flags);
+	/* See comment about smp_mb() above */
+	smp_mb__after_clear_bit();
+
+	TRACE_MGMT_DBG("Waiting for %d active commands finally to complete",
+		atomic_read(&scst_cmd_count));
+
+	res = scst_susp_wait(interruptible);
+	if (res != 0)
+		goto out_clear;
+
+	if (rep)
+		PRINT_INFO("%s", "All active commands completed");
+
+out_up:
+	mutex_unlock(&scst_suspend_mutex);
+
+out:
+	return res;
+
+out_clear:
+	clear_bit(SCST_FLAG_SUSPENDING, &scst_flags);
+	/* See comment about smp_mb() above */
+	smp_mb__after_clear_bit();
+	goto out_up;
+}
+EXPORT_SYMBOL_GPL(scst_suspend_activity);
+
+static void __scst_resume_activity(void)
+{
+	struct scst_cmd_threads *l;
+
+	suspend_count--;
+	TRACE_MGMT_DBG("suspend_count %d left", suspend_count);
+	if (suspend_count > 0)
+		goto out;
+
+	clear_bit(SCST_FLAG_SUSPENDED, &scst_flags);
+	/*
+	 * The barrier is needed to make sure all woken up threads see the
+	 * cleared flag. Not sure if it's really needed, but let's be safe.
+	 */
+	smp_mb__after_clear_bit();
+
+	list_for_each_entry(l, &scst_cmd_threads_list, lists_list_entry) {
+		wake_up_all(&l->cmd_list_waitQ);
+	}
+	wake_up_all(&scst_init_cmd_list_waitQ);
+
+	spin_lock_irq(&scst_mcmd_lock);
+	if (!list_empty(&scst_delayed_mgmt_cmd_list)) {
+		struct scst_mgmt_cmd *m;
+		m = list_entry(scst_delayed_mgmt_cmd_list.next, typeof(*m),
+				mgmt_cmd_list_entry);
+		TRACE_MGMT_DBG("Moving delayed mgmt cmd %p to head of active "
+			"mgmt cmd list", m);
+		list_move(&m->mgmt_cmd_list_entry, &scst_active_mgmt_cmd_list);
+	}
+	spin_unlock_irq(&scst_mcmd_lock);
+	wake_up_all(&scst_mgmt_cmd_list_waitQ);
+
+out:
+	return;
+}
+
+/**
+ * scst_resume_activity() - globally resume all activities
+ *
+ * Resumes suspended by scst_suspend_activity() activities.
+ */
+void scst_resume_activity(void)
+{
+
+	mutex_lock(&scst_suspend_mutex);
+	__scst_resume_activity();
+	mutex_unlock(&scst_suspend_mutex);
+	return;
+}
+EXPORT_SYMBOL_GPL(scst_resume_activity);
+
+static int scst_register_device(struct scsi_device *scsidp)
+{
+	int res = 0;
+	struct scst_device *dev, *d;
+
+	if (mutex_lock_interruptible(&scst_mutex) != 0) {
+		res = -EINTR;
+		goto out;
+	}
+
+	res = scst_alloc_device(GFP_KERNEL, &dev);
+	if (res != 0)
+		goto out_unlock;
+
+	dev->type = scsidp->type;
+
+	dev->virt_name = kmalloc(50, GFP_KERNEL);
+	if (dev->virt_name == NULL) {
+		PRINT_ERROR("%s", "Unable to alloc device name");
+		res = -ENOMEM;
+		goto out_free_dev;
+	}
+	snprintf(dev->virt_name, 50, "%d:%d:%d:%d", scsidp->host->host_no,
+		scsidp->channel, scsidp->id, scsidp->lun);
+
+	list_for_each_entry(d, &scst_dev_list, dev_list_entry) {
+		if (strcmp(d->virt_name, dev->virt_name) == 0) {
+			PRINT_ERROR("Device %s already exists", dev->virt_name);
+			res = -EEXIST;
+			goto out_free_dev;
+		}
+	}
+
+	dev->scsi_dev = scsidp;
+
+	list_add_tail(&dev->dev_list_entry, &scst_dev_list);
+
+	mutex_unlock(&scst_mutex);
+
+	res = scst_dev_sysfs_create(dev);
+	if (res != 0)
+		goto out_del;
+
+	PRINT_INFO("Attached to scsi%d, channel %d, id %d, lun %d, "
+		"type %d", scsidp->host->host_no, scsidp->channel,
+		scsidp->id, scsidp->lun, scsidp->type);
+
+out:
+	return res;
+
+out_del:
+	list_del(&dev->dev_list_entry);
+
+out_free_dev:
+	scst_free_device(dev);
+
+out_unlock:
+	mutex_unlock(&scst_mutex);
+	goto out;
+}
+
+static void scst_unregister_device(struct scsi_device *scsidp)
+{
+	struct scst_device *d, *dev = NULL;
+	struct scst_acg_dev *acg_dev, *aa;
+
+	scst_suspend_activity(false);
+	mutex_lock(&scst_mutex);
+
+	list_for_each_entry(d, &scst_dev_list, dev_list_entry) {
+		if (d->scsi_dev == scsidp) {
+			dev = d;
+			TRACE_DBG("Device %p found", dev);
+			break;
+		}
+	}
+	if (dev == NULL) {
+		PRINT_ERROR("SCST device for SCSI device %d:%d:%d:%d not found",
+			scsidp->host->host_no, scsidp->channel, scsidp->id,
+			scsidp->lun);
+		goto out_unlock;
+	}
+
+	list_del(&dev->dev_list_entry);
+
+	scst_assign_dev_handler(dev, &scst_null_devtype);
+
+	list_for_each_entry_safe(acg_dev, aa, &dev->dev_acg_dev_list,
+				 dev_acg_dev_list_entry) {
+		scst_acg_del_lun(acg_dev->acg, acg_dev->lun, true);
+	}
+
+	mutex_unlock(&scst_mutex);
+
+	scst_resume_activity();
+
+	scst_dev_sysfs_del(dev);
+
+	PRINT_INFO("Detached from scsi%d, channel %d, id %d, lun %d, type %d",
+		scsidp->host->host_no, scsidp->channel, scsidp->id,
+		scsidp->lun, scsidp->type);
+
+	scst_free_device(dev);
+
+out:
+	return;
+
+out_unlock:
+	mutex_unlock(&scst_mutex);
+	scst_resume_activity();
+	goto out;
+}
+
+static int scst_dev_handler_check(struct scst_dev_type *dev_handler)
+{
+	int res = 0;
+
+	if (dev_handler->parse == NULL) {
+		PRINT_ERROR("scst dev handler %s must have "
+			"parse() method.", dev_handler->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (((dev_handler->add_device != NULL) &&
+	     (dev_handler->del_device == NULL)) ||
+	    ((dev_handler->add_device == NULL) &&
+	     (dev_handler->del_device != NULL))) {
+		PRINT_ERROR("Dev handler %s must either define both "
+			"add_device() and del_device(), or none.",
+			dev_handler->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (dev_handler->alloc_data_buf == NULL)
+		dev_handler->alloc_data_buf_atomic = 1;
+
+	if (dev_handler->dev_done == NULL)
+		dev_handler->dev_done_atomic = 1;
+
+out:
+	return res;
+}
+
+static int scst_check_device_name(const char *dev_name)
+{
+	int res = 0;
+
+	if (strchr(dev_name, '/') != NULL) {
+		PRINT_ERROR("Dev name %s contains illegal character '/'",
+			dev_name);
+		res = -EINVAL;
+	}
+	return res;
+}
+
+/**
+ * scst_register_virtual_device() - register a virtual device.
+ * @dev_handler: the device's device handler
+ * @dev_name:	the new device name, NULL-terminated string. Must be uniq
+ *              among all virtual devices in the system.
+ *
+ * Registers a virtual device and returns assinged to the device ID on
+ * success, or negative value otherwise
+ */
+int scst_register_virtual_device(struct scst_dev_type *dev_handler,
+	const char *dev_name)
+{
+	int res, rc;
+	struct scst_device *dev, *d;
+	bool sysfs_del = false;
+
+	if (dev_handler == NULL) {
+		PRINT_ERROR("%s: valid device handler must be supplied",
+			    __func__);
+		res = -EINVAL;
+		goto out;
+	}
+
+	if (dev_name == NULL) {
+		PRINT_ERROR("%s: device name must be non-NULL", __func__);
+		res = -EINVAL;
+		goto out;
+	}
+
+	res = scst_check_device_name(dev_name);
+	if (res != 0)
+		goto out;
+
+	res = scst_dev_handler_check(dev_handler);
+	if (res != 0)
+		goto out;
+
+	res = scst_suspend_activity(true);
+	if (res != 0)
+		goto out;
+
+	if (mutex_lock_interruptible(&scst_mutex) != 0) {
+		res = -EINTR;
+		goto out_resume;
+	}
+
+	res = scst_alloc_device(GFP_KERNEL, &dev);
+	if (res != 0)
+		goto out_unlock;
+
+	dev->type = dev_handler->type;
+	dev->scsi_dev = NULL;
+	dev->virt_name = kstrdup(dev_name, GFP_KERNEL);
+	if (dev->virt_name == NULL) {
+		PRINT_ERROR("Unable to allocate virt_name for dev %s",
+			dev_name);
+		res = -ENOMEM;
+		goto out_free_dev;
+	}
+
+	while (1) {
+		dev->virt_id = scst_virt_dev_last_id++;
+		if (dev->virt_id > 0)
+			break;
+		scst_virt_dev_last_id = 1;
+	}
+
+	res = dev->virt_id;
+
+	rc = scst_pr_init_dev(dev);
+	if (rc != 0) {
+		res = rc;
+		goto out_free_dev;
+	}
+
+	/*
+	 * We can drop scst_mutex, because we have not yet added the dev in
+	 * scst_dev_list, so it "doesn't exist" yet.
+	 */
+	mutex_unlock(&scst_mutex);
+
+	res = scst_dev_sysfs_create(dev);
+	if (res != 0)
+		goto out_lock_pr_clear_dev;
+
+	mutex_lock(&scst_mutex);
+
+	list_for_each_entry(d, &scst_dev_list, dev_list_entry) {
+		if (strcmp(d->virt_name, dev_name) == 0) {
+			PRINT_ERROR("Device %s already exists", dev_name);
+			res = -EEXIST;
+			sysfs_del = true;
+			goto out_pr_clear_dev;
+		}
+	}
+
+	rc = scst_assign_dev_handler(dev, dev_handler);
+	if (rc != 0) {
+		res = rc;
+		sysfs_del = true;
+		goto out_pr_clear_dev;
+	}
+
+	list_add_tail(&dev->dev_list_entry, &scst_dev_list);
+
+	mutex_unlock(&scst_mutex);
+	scst_resume_activity();
+
+	res = dev->virt_id;
+
+	PRINT_INFO("Attached to virtual device %s (id %d)",
+		dev_name, res);
+
+out:
+	return res;
+
+out_lock_pr_clear_dev:
+	mutex_lock(&scst_mutex);
+
+out_pr_clear_dev:
+	scst_pr_clear_dev(dev);
+
+out_free_dev:
+	mutex_unlock(&scst_mutex);
+	if (sysfs_del)
+		scst_dev_sysfs_del(dev);
+	scst_free_device(dev);
+	goto out_resume;
+
+out_unlock:
+	mutex_unlock(&scst_mutex);
+
+out_resume:
+	scst_resume_activity();
+	goto out;
+}
+EXPORT_SYMBOL_GPL(scst_register_virtual_device);
+
+/**
+ * scst_unregister_virtual_device() - unegister a virtual device.
+ * @id:		the device's ID, returned by the registration function
+ */
+void scst_unregister_virtual_device(int id)
+{
+	struct scst_device *d, *dev = NULL;
+	struct scst_acg_dev *acg_dev, *aa;
+
+	scst_suspend_activity(false);
+	mutex_lock(&scst_mutex);
+
+	list_for_each_entry(d, &scst_dev_list, dev_list_entry) {
+		if (d->virt_id == id) {
+			dev = d;
+			TRACE_DBG("Virtual device %p (id %d) found", dev, id);
+			break;
+		}
+	}
+	if (dev == NULL) {
+		PRINT_ERROR("Virtual device (id %d) not found", id);
+		goto out_unlock;
+	}
+
+	list_del(&dev->dev_list_entry);
+
+	scst_pr_clear_dev(dev);
+
+	scst_assign_dev_handler(dev, &scst_null_devtype);
+
+	list_for_each_entry_safe(acg_dev, aa, &dev->dev_acg_dev_list,
+				 dev_acg_dev_list_entry) {
+		scst_acg_del_lun(acg_dev->acg, acg_dev->lun, true);
+	}
+
+	mutex_unlock(&scst_mutex);
+	scst_resume_activity();
+
+	scst_dev_sysfs_del(dev);
+
+	PRINT_INFO("Detached from virtual device %s (id %d)",
+		dev->virt_name, dev->virt_id);
+
+	scst_free_device(dev);
+
+out:
+	return;
+
+out_unlock:
+	mutex_unlock(&scst_mutex);
+	scst_resume_activity();
+	goto out;
+}
+EXPORT_SYMBOL_GPL(scst_unregister_virtual_device);
+
+/**
+ * __scst_register_dev_driver() - register pass-through dev handler driver
+ * @dev_type:	dev handler template
+ * @version:	SCST_INTERFACE_VERSION version string to ensure that
+ *		SCST core and the dev handler use the same version of
+ *		the SCST interface
+ *
+ * Description:
+ *    Registers a pass-through dev handler driver. Returns 0 on success
+ *    or appropriate error code otherwise.
+ */
+int __scst_register_dev_driver(struct scst_dev_type *dev_type,
+	const char *version)
+{
+	int res, exist;
+	struct scst_dev_type *dt;
+
+	if (strcmp(version, SCST_INTERFACE_VERSION) != 0) {
+		PRINT_ERROR("Incorrect version of dev handler %s",
+			dev_type->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	res = scst_dev_handler_check(dev_type);
+	if (res != 0)
+		goto out;
+
+	if (mutex_lock_interruptible(&scst_mutex) != 0) {
+		res = -EINTR;
+		goto out;
+	}
+
+	exist = 0;
+	list_for_each_entry(dt, &scst_dev_type_list, dev_type_list_entry) {
+		if (strcmp(dt->name, dev_type->name) == 0) {
+			PRINT_ERROR("Device type handler \"%s\" already "
+				"exist", dt->name);
+			exist = 1;
+			break;
+		}
+	}
+	if (exist)
+		goto out_unlock;
+
+	list_add_tail(&dev_type->dev_type_list_entry, &scst_dev_type_list);
+
+	mutex_unlock(&scst_mutex);
+
+	res = scst_devt_sysfs_create(dev_type);
+	if (res < 0)
+		goto out;
+
+	PRINT_INFO("Device handler \"%s\" for type %d registered "
+		"successfully", dev_type->name, dev_type->type);
+
+out:
+	return res;
+
+out_unlock:
+	mutex_unlock(&scst_mutex);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(__scst_register_dev_driver);
+
+/**
+ * scst_unregister_dev_driver() - unregister pass-through dev handler driver
+ */
+void scst_unregister_dev_driver(struct scst_dev_type *dev_type)
+{
+	struct scst_device *dev;
+	struct scst_dev_type *dt;
+	int found = 0;
+
+	scst_suspend_activity(false);
+	mutex_lock(&scst_mutex);
+
+	list_for_each_entry(dt, &scst_dev_type_list, dev_type_list_entry) {
+		if (strcmp(dt->name, dev_type->name) == 0) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found) {
+		PRINT_ERROR("Dev handler \"%s\" isn't registered",
+			dev_type->name);
+		goto out_up;
+	}
+
+	list_for_each_entry(dev, &scst_dev_list, dev_list_entry) {
+		if (dev->handler == dev_type) {
+			scst_assign_dev_handler(dev, &scst_null_devtype);
+			TRACE_DBG("Dev handler removed from device %p", dev);
+		}
+	}
+
+	list_del(&dev_type->dev_type_list_entry);
+
+	mutex_unlock(&scst_mutex);
+	scst_resume_activity();
+
+	scst_devt_sysfs_del(dev_type);
+
+	PRINT_INFO("Device handler \"%s\" for type %d unloaded",
+		   dev_type->name, dev_type->type);
+
+out:
+	return;
+
+out_up:
+	mutex_unlock(&scst_mutex);
+	scst_resume_activity();
+	goto out;
+}
+EXPORT_SYMBOL_GPL(scst_unregister_dev_driver);
+
+/**
+ * __scst_register_virtual_dev_driver() - register virtual dev handler driver
+ * @dev_type:	dev handler template
+ * @version:	SCST_INTERFACE_VERSION version string to ensure that
+ *		SCST core and the dev handler use the same version of
+ *		the SCST interface
+ *
+ * Description:
+ *    Registers a virtual dev handler driver. Returns 0 on success or
+ *    appropriate error code otherwise.
+ */
+int __scst_register_virtual_dev_driver(struct scst_dev_type *dev_type,
+	const char *version)
+{
+	int res;
+
+	if (strcmp(version, SCST_INTERFACE_VERSION) != 0) {
+		PRINT_ERROR("Incorrect version of virtual dev handler %s",
+			dev_type->name);
+		res = -EINVAL;
+		goto out;
+	}
+
+	res = scst_dev_handler_check(dev_type);
+	if (res != 0)
+		goto out;
+
+	mutex_lock(&scst_mutex);
+	list_add_tail(&dev_type->dev_type_list_entry, &scst_virtual_dev_type_list);
+	mutex_unlock(&scst_mutex);
+
+	res = scst_devt_sysfs_create(dev_type);
+	if (res < 0)
+		goto out;
+
+	if (dev_type->type != -1) {
+		PRINT_INFO("Virtual device handler %s for type %d "
+			"registered successfully", dev_type->name,
+			dev_type->type);
+	} else {
+		PRINT_INFO("Virtual device handler \"%s\" registered "
+			"successfully", dev_type->name);
+	}
+
+out:
+	return res;
+}
+EXPORT_SYMBOL_GPL(__scst_register_virtual_dev_driver);
+
+/**
+ * scst_unregister_virtual_dev_driver() - unregister virtual dev driver
+ */
+void scst_unregister_virtual_dev_driver(struct scst_dev_type *dev_type)
+{
+
+	mutex_lock(&scst_mutex);
+
+	/* Disable sysfs mgmt calls (e.g. addition of new devices) */
+	list_del(&dev_type->dev_type_list_entry);
+
+	/* Wait for outstanding sysfs mgmt calls completed */
+	while (dev_type->devt_active_sysfs_works_count > 0) {
+		mutex_unlock(&scst_mutex);
+		msleep(100);
+		mutex_lock(&scst_mutex);
+	}
+
+	mutex_unlock(&scst_mutex);
+
+	scst_devt_sysfs_del(dev_type);
+
+	PRINT_INFO("Device handler \"%s\" unloaded", dev_type->name);
+	return;
+}
+EXPORT_SYMBOL_GPL(scst_unregister_virtual_dev_driver);
+
+/* scst_mutex supposed to be held */
+int scst_add_threads(struct scst_cmd_threads *cmd_threads,
+	struct scst_device *dev, struct scst_tgt_dev *tgt_dev, int num)
+{
+	int res = 0, i;
+	struct scst_cmd_thread_t *thr;
+	int n = 0, tgt_dev_num = 0;
+
+	if (num == 0) {
+		res = 0;
+		goto out;
+	}
+
+	list_for_each_entry(thr, &cmd_threads->threads_list, thread_list_entry) {
+		n++;
+	}
+
+	TRACE_DBG("cmd_threads %p, dev %p, tgt_dev %p, num %d, n %d",
+		cmd_threads, dev, tgt_dev, num, n);
+
+	if (tgt_dev != NULL) {
+		struct scst_tgt_dev *t;
+		list_for_each_entry(t, &tgt_dev->dev->dev_tgt_dev_list,
+				dev_tgt_dev_list_entry) {
+			if (t == tgt_dev)
+				break;
+			tgt_dev_num++;
+		}
+	}
+
+	for (i = 0; i < num; i++) {
+		thr = kmalloc(sizeof(*thr), GFP_KERNEL);
+		if (!thr) {
+			res = -ENOMEM;
+			PRINT_ERROR("Fail to allocate thr %d", res);
+			goto out_wait;
+		}
+
+		if (dev != NULL) {
+			char nm[14]; /* to limit the name's len */
+			strlcpy(nm, dev->virt_name, ARRAY_SIZE(nm));
+			thr->cmd_thread = kthread_create(scst_cmd_thread,
+				cmd_threads, "%s%d", nm, n++);
+		} else if (tgt_dev != NULL) {
+			char nm[11]; /* to limit the name's len */
+			strlcpy(nm, tgt_dev->dev->virt_name, ARRAY_SIZE(nm));
+			thr->cmd_thread = kthread_create(scst_cmd_thread,
+				cmd_threads, "%s%d_%d", nm, tgt_dev_num, n++);
+		} else
+			thr->cmd_thread = kthread_create(scst_cmd_thread,
+				cmd_threads, "scstd%d", n++);
+
+		if (IS_ERR(thr->cmd_thread)) {
+			res = PTR_ERR(thr->cmd_thread);
+			PRINT_ERROR("kthread_create() failed: %d", res);
+			kfree(thr);
+			goto out_wait;
+		}
+
+		list_add(&thr->thread_list_entry, &cmd_threads->threads_list);
+		cmd_threads->nr_threads++;
+
+		TRACE_DBG("Added thr %p to threads list (nr_threads %d, n %d)",
+			thr, cmd_threads->nr_threads, n);
+
+		wake_up_process(thr->cmd_thread);
+	}
+
+out_wait:
+	if (cmd_threads != &scst_main_cmd_threads) {
+		/*
+		 * Wait for io_context gets initialized to avoid possible races
+		 * for it from the sharing it tgt_devs.
+		 */
+		while (!*(volatile bool*)&cmd_threads->io_context_ready) {
+			TRACE_DBG("Waiting for io_context for cmd_threads %p "
+				"initialized", cmd_threads);
+			msleep(50);
+		}
+	}
+
+	if (res != 0)
+		scst_del_threads(cmd_threads, i);
+
+out:
+	return res;
+}
+
+/* scst_mutex supposed to be held */
+void scst_del_threads(struct scst_cmd_threads *cmd_threads, int num)
+{
+	struct scst_cmd_thread_t *ct, *tmp;
+
+	if (num == 0)
+		goto out;
+
+	list_for_each_entry_safe_reverse(ct, tmp, &cmd_threads->threads_list,
+				thread_list_entry) {
+		int rc;
+		struct scst_device *dev;
+
+		rc = kthread_stop(ct->cmd_thread);
+		if (rc < 0)
+			TRACE_MGMT_DBG("kthread_stop() failed: %d", rc);
+
+		list_del(&ct->thread_list_entry);
+
+		list_for_each_entry(dev, &scst_dev_list, dev_list_entry) {
+			struct scst_tgt_dev *tgt_dev;
+			list_for_each_entry(tgt_dev, &dev->dev_tgt_dev_list,
+					dev_tgt_dev_list_entry) {
+				scst_del_thr_data(tgt_dev, ct->cmd_thread);
+			}
+		}
+
+		kfree(ct);
+
+		cmd_threads->nr_threads--;
+
+		--num;
+		if (num == 0)
+			break;
+	}
+
+	EXTRACHECKS_BUG_ON((cmd_threads->nr_threads == 0) &&
+		(cmd_threads->io_context != NULL));
+
+out:
+	return;
+}
+
+/* The activity supposed to be suspended and scst_mutex held */
+void scst_stop_dev_threads(struct scst_device *dev)
+{
+	struct scst_tgt_dev *tgt_dev;
+
+	list_for_each_entry(tgt_dev, &dev->dev_tgt_dev_list,
+				dev_tgt_dev_list_entry) {
+		scst_tgt_dev_stop_threads(tgt_dev);
+	}
+
+	if ((dev->threads_num > 0) &&
+	    (dev->threads_pool_type == SCST_THREADS_POOL_SHARED))
+		scst_del_threads(&dev->dev_cmd_threads, -1);
+	return;
+}
+
+/* The activity supposed to be suspended and scst_mutex held */
+int scst_create_dev_threads(struct scst_device *dev)
+{
+	int res = 0;
+	struct scst_tgt_dev *tgt_dev;
+
+	list_for_each_entry(tgt_dev, &dev->dev_tgt_dev_list,
+			dev_tgt_dev_list_entry) {
+		res = scst_tgt_dev_setup_threads(tgt_dev);
+		if (res != 0)
+			goto out_err;
+	}
+
+	if ((dev->threads_num > 0) &&
+	    (dev->threads_pool_type == SCST_THREADS_POOL_SHARED)) {
+		res = scst_add_threads(&dev->dev_cmd_threads, dev, NULL,
+			dev->threads_num);
+		if (res != 0)
+			goto out_err;
+	}
+
+out:
+	return res;
+
+out_err:
+	scst_stop_dev_threads(dev);
+	goto out;
+}
+
+/* The activity supposed to be suspended and scst_mutex held */
+int scst_assign_dev_handler(struct scst_device *dev,
+	struct scst_dev_type *handler)
+{
+	int res = 0;
+	struct scst_tgt_dev *tgt_dev;
+	LIST_HEAD(attached_tgt_devs);
+
+	BUG_ON(handler == NULL);
+
+	if (dev->handler == handler)
+		goto out;
+
+	if (dev->handler == NULL)
+		goto assign;
+
+	if (dev->handler->detach_tgt) {
+		list_for_each_entry(tgt_dev, &dev->dev_tgt_dev_list,
+				dev_tgt_dev_list_entry) {
+			TRACE_DBG("Calling dev handler's detach_tgt(%p)",
+				tgt_dev);
+			dev->handler->detach_tgt(tgt_dev);
+			TRACE_DBG("%s", "Dev handler's detach_tgt() returned");
+		}
+	}
+
+	/*
+	 * devt_dev sysfs must be created AFTER attach() and deleted BEFORE
+	 * detach() to avoid calls from sysfs for not yet ready or already dead
+	 * objects.
+	 */
+	scst_devt_dev_sysfs_del(dev);
+
+	if (dev->handler->detach) {
+		TRACE_DBG("%s", "Calling dev handler's detach()");
+		dev->handler->detach(dev);
+		TRACE_DBG("%s", "Old handler's detach() returned");
+	}
+
+	scst_stop_dev_threads(dev);
+
+assign:
+	dev->handler = handler;
+
+	if (handler == NULL)
+		goto out;
+
+	dev->threads_num = handler->threads_num;
+	dev->threads_pool_type = handler->threads_pool_type;
+
+	if (handler->attach) {
+		TRACE_DBG("Calling new dev handler's attach(%p)", dev);
+		res = handler->attach(dev);
+		TRACE_DBG("New dev handler's attach() returned %d", res);
+		if (res != 0) {
+			PRINT_ERROR("New device handler's %s attach() "
+				"failed: %d", handler->name, res);
+			goto out;
+		}
+	}
+
+	res = scst_devt_dev_sysfs_create(dev);
+	if (res != 0)
+		goto out_detach;
+
+	if (handler->attach_tgt) {
+		list_for_each_entry(tgt_dev, &dev->dev_tgt_dev_list,
+				dev_tgt_dev_list_entry) {
+			TRACE_DBG("Calling dev handler's attach_tgt(%p)",
+				tgt_dev);
+			res = handler->attach_tgt(tgt_dev);
+			TRACE_DBG("%s", "Dev handler's attach_tgt() returned");
+			if (res != 0) {
+				PRINT_ERROR("Device handler's %s attach_tgt() "
+				    "failed: %d", handler->name, res);
+				goto out_err_remove_sysfs;
+			}
+			list_add_tail(&tgt_dev->extra_tgt_dev_list_entry,
+				&attached_tgt_devs);
+		}
+	}
+
+	res = scst_create_dev_threads(dev);
+	if (res != 0)
+		goto out_err_detach_tgt;
+
+out:
+	return res;
+
+out_err_detach_tgt:
+	if (handler && handler->detach_tgt) {
+		list_for_each_entry(tgt_dev, &attached_tgt_devs,
+				 extra_tgt_dev_list_entry) {
+			TRACE_DBG("Calling handler's detach_tgt(%p)",
+				tgt_dev);
+			handler->detach_tgt(tgt_dev);
+			TRACE_DBG("%s", "Handler's detach_tgt() returned");
+		}
+	}
+
+out_err_remove_sysfs:
+	scst_devt_dev_sysfs_del(dev);
+
+out_detach:
+	if (handler && handler->detach) {
+		TRACE_DBG("%s", "Calling handler's detach()");
+		handler->detach(dev);
+		TRACE_DBG("%s", "Handler's detach() returned");
+	}
+
+	dev->handler = &scst_null_devtype;
+	dev->threads_num = scst_null_devtype.threads_num;
+	dev->threads_pool_type = scst_null_devtype.threads_pool_type;
+	goto out;
+}
+
+/**
+ * scst_init_threads() - initialize SCST processing threads pool
+ *
+ * Initializes scst_cmd_threads structure
+ */
+void scst_init_threads(struct scst_cmd_threads *cmd_threads)
+{
+
+	spin_lock_init(&cmd_threads->cmd_list_lock);
+	INIT_LIST_HEAD(&cmd_threads->active_cmd_list);
+	init_waitqueue_head(&cmd_threads->cmd_list_waitQ);
+	INIT_LIST_HEAD(&cmd_threads->threads_list);
+
+	mutex_lock(&scst_suspend_mutex);
+	list_add_tail(&cmd_threads->lists_list_entry,
+		&scst_cmd_threads_list);
+	mutex_unlock(&scst_suspend_mutex);
+	return;
+}
+EXPORT_SYMBOL_GPL(scst_init_threads);
+
+/**
+ * scst_deinit_threads() - deinitialize SCST processing threads pool
+ *
+ * Deinitializes scst_cmd_threads structure
+ */
+void scst_deinit_threads(struct scst_cmd_threads *cmd_threads)
+{
+
+	mutex_lock(&scst_suspend_mutex);
+	list_del(&cmd_threads->lists_list_entry);
+	mutex_unlock(&scst_suspend_mutex);
+
+	BUG_ON(cmd_threads->io_context);
+	return;
+}
+EXPORT_SYMBOL_GPL(scst_deinit_threads);
+
+static void scst_stop_global_threads(void)
+{
+
+	mutex_lock(&scst_mutex);
+
+	scst_del_threads(&scst_main_cmd_threads, -1);
+
+	if (scst_mgmt_cmd_thread)
+		kthread_stop(scst_mgmt_cmd_thread);
+	if (scst_mgmt_thread)
+		kthread_stop(scst_mgmt_thread);
+	if (scst_init_cmd_thread)
+		kthread_stop(scst_init_cmd_thread);
+
+	mutex_unlock(&scst_mutex);
+	return;
+}
+
+/* It does NOT stop ran threads on error! */
+static int scst_start_global_threads(int num)
+{
+	int res;
+
+	mutex_lock(&scst_mutex);
+
+	res = scst_add_threads(&scst_main_cmd_threads, NULL, NULL, num);
+	if (res < 0)
+		goto out_unlock;
+
+	scst_init_cmd_thread = kthread_run(scst_init_thread,
+		NULL, "scst_initd");
+	if (IS_ERR(scst_init_cmd_thread)) {
+		res = PTR_ERR(scst_init_cmd_thread);
+		PRINT_ERROR("kthread_create() for init cmd failed: %d", res);
+		scst_init_cmd_thread = NULL;
+		goto out_unlock;
+	}
+
+	scst_mgmt_cmd_thread = kthread_run(scst_tm_thread,
+		NULL, "scsi_tm");
+	if (IS_ERR(scst_mgmt_cmd_thread)) {
+		res = PTR_ERR(scst_mgmt_cmd_thread);
+		PRINT_ERROR("kthread_create() for TM failed: %d", res);
+		scst_mgmt_cmd_thread = NULL;
+		goto out_unlock;
+	}
+
+	scst_mgmt_thread = kthread_run(scst_global_mgmt_thread,
+		NULL, "scst_mgmtd");
+	if (IS_ERR(scst_mgmt_thread)) {
+		res = PTR_ERR(scst_mgmt_thread);
+		PRINT_ERROR("kthread_create() for mgmt failed: %d", res);
+		scst_mgmt_thread = NULL;
+		goto out_unlock;
+	}
+
+out_unlock:
+	mutex_unlock(&scst_mutex);
+	return res;
+}
+
+/**
+ * scst_get() - increase global SCST ref counter
+ *
+ * Increases global SCST ref counter that prevents from entering into suspended
+ * activities stage, so protects from any global management operations.
+ */
+void scst_get(void)
+{
+	__scst_get(0);
+}
+EXPORT_SYMBOL(scst_get);
+
+/**
+ * scst_put() - decrease global SCST ref counter
+ *
+ * Decreses global SCST ref counter that prevents from entering into suspended
+ * activities stage, so protects from any global management operations. On
+ * zero, if suspending activities is waiting, they will be suspended.
+ */
+void scst_put(void)
+{
+	__scst_put();
+}
+EXPORT_SYMBOL(scst_put);
+
+/**
+ * scst_get_setup_id() - return SCST setup ID
+ *
+ * Returns SCST setup ID. This ID can be used for multiple
+ * setups with the same configuration.
+ */
+unsigned int scst_get_setup_id(void)
+{
+	return scst_setup_id;
+}
+EXPORT_SYMBOL_GPL(scst_get_setup_id);
+
+static int scst_add(struct device *cdev, struct class_interface *intf)
+{
+	struct scsi_device *scsidp;
+	int res = 0;
+
+	scsidp = to_scsi_device(cdev->parent);
+
+	if ((scsidp->host->hostt->name == NULL) ||
+	    (strcmp(scsidp->host->hostt->name, SCST_LOCAL_NAME) != 0))
+		res = scst_register_device(scsidp);
+	return res;
+}
+
+static void scst_remove(struct device *cdev, struct class_interface *intf)
+{
+	struct scsi_device *scsidp;
+
+	scsidp = to_scsi_device(cdev->parent);
+
+	if ((scsidp->host->hostt->name == NULL) ||
+	    (strcmp(scsidp->host->hostt->name, SCST_LOCAL_NAME) != 0))
+		scst_unregister_device(scsidp);
+	return;
+}
+
+static struct class_interface scst_interface = {
+	.add_dev = scst_add,
+	.remove_dev = scst_remove,
+};
+
+static void __init scst_print_config(void)
+{
+	char buf[128];
+	int i, j;
+
+	i = snprintf(buf, sizeof(buf), "Enabled features: ");
+	j = i;
+
+#ifdef CONFIG_SCST_STRICT_SERIALIZING
+	i += snprintf(&buf[i], sizeof(buf) - i, "STRICT_SERIALIZING");
+#endif
+
+#ifdef CONFIG_SCST_EXTRACHECKS
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sEXTRACHECKS",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_TRACING
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sTRACING",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_DEBUG
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sDEBUG",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_DEBUG_TM
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sDEBUG_TM",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_DEBUG_RETRY
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sDEBUG_RETRY",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_DEBUG_OOM
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sDEBUG_OOM",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_DEBUG_SN
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sDEBUG_SN",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_USE_EXPECTED_VALUES
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sUSE_EXPECTED_VALUES",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_TEST_IO_IN_SIRQ
+	i += snprintf(&buf[i], sizeof(buf) - i,
+		"%sTEST_IO_IN_SIRQ",
+		(j == i) ? "" : ", ");
+#endif
+
+#ifdef CONFIG_SCST_STRICT_SECURITY
+	i += snprintf(&buf[i], sizeof(buf) - i, "%sSTRICT_SECURITY",
+		(j == i) ? "" : ", ");
+#endif
+
+	if (j != i)
+		PRINT_INFO("%s", buf);
+}
+
+static int __init init_scst(void)
+{
+	int res, i;
+	int scst_num_cpus;
+
+	{
+		struct scsi_sense_hdr *shdr;
+		BUILD_BUG_ON(SCST_SENSE_BUFFERSIZE < sizeof(*shdr));
+	}
+	{
+		struct scst_tgt_dev *t;
+		struct scst_cmd *c;
+		BUILD_BUG_ON(sizeof(t->curr_sn) != sizeof(t->expected_sn));
+		BUILD_BUG_ON(sizeof(c->sn) != sizeof(t->expected_sn));
+	}
+
+	mutex_init(&scst_mutex);
+	mutex_init(&scst_mutex2);
+	INIT_LIST_HEAD(&scst_template_list);
+	INIT_LIST_HEAD(&scst_dev_list);
+	INIT_LIST_HEAD(&scst_dev_type_list);
+	INIT_LIST_HEAD(&scst_virtual_dev_type_list);
+	spin_lock_init(&scst_main_lock);
+	spin_lock_init(&scst_init_lock);
+	init_waitqueue_head(&scst_init_cmd_list_waitQ);
+	INIT_LIST_HEAD(&scst_init_cmd_list);
+#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
+	scst_trace_flag = SCST_DEFAULT_LOG_FLAGS;
+#endif
+	atomic_set(&scst_cmd_count, 0);
+	spin_lock_init(&scst_mcmd_lock);
+	INIT_LIST_HEAD(&scst_active_mgmt_cmd_list);
+	INIT_LIST_HEAD(&scst_delayed_mgmt_cmd_list);
+	init_waitqueue_head(&scst_mgmt_cmd_list_waitQ);
+	init_waitqueue_head(&scst_mgmt_waitQ);
+	spin_lock_init(&scst_mgmt_lock);
+	INIT_LIST_HEAD(&scst_sess_init_list);
+	INIT_LIST_HEAD(&scst_sess_shut_list);
+	init_waitqueue_head(&scst_dev_cmd_waitQ);
+	mutex_init(&scst_suspend_mutex);
+	INIT_LIST_HEAD(&scst_cmd_threads_list);
+
+	scst_init_threads(&scst_main_cmd_threads);
+
+	res = scst_lib_init();
+	if (res != 0)
+		goto out_deinit_threads;
+
+	scst_num_cpus = num_online_cpus();
+
+	/* ToDo: register_cpu_notifier() */
+
+	if (scst_threads == 0)
+		scst_threads = scst_num_cpus;
+
+	if (scst_threads < 1) {
+		PRINT_ERROR("%s", "scst_threads can not be less than 1");
+		scst_threads = scst_num_cpus;
+	}
+
+#define INIT_CACHEP(p, s, o) do {					\
+		p = KMEM_CACHE(s, SCST_SLAB_FLAGS);			\
+		TRACE_MEM("Slab create: %s at %p size %zd", #s, p,	\
+			  sizeof(struct s));				\
+		if (p == NULL) {					\
+			res = -ENOMEM;					\
+			goto o;						\
+		}							\
+	} while (0)
+
+	INIT_CACHEP(scst_mgmt_cachep, scst_mgmt_cmd, out_lib_exit);
+	INIT_CACHEP(scst_mgmt_stub_cachep, scst_mgmt_cmd_stub,
+			out_destroy_mgmt_cache);
+	INIT_CACHEP(scst_ua_cachep, scst_tgt_dev_UA,
+			out_destroy_mgmt_stub_cache);
+	{
+		struct scst_sense { uint8_t s[SCST_SENSE_BUFFERSIZE]; };
+		INIT_CACHEP(scst_sense_cachep, scst_sense,
+			    out_destroy_ua_cache);
+	}
+	INIT_CACHEP(scst_aen_cachep, scst_aen, out_destroy_sense_cache);
+	INIT_CACHEP(scst_cmd_cachep, scst_cmd, out_destroy_aen_cache);
+	INIT_CACHEP(scst_sess_cachep, scst_session, out_destroy_cmd_cache);
+	INIT_CACHEP(scst_tgtd_cachep, scst_tgt_dev, out_destroy_sess_cache);
+	INIT_CACHEP(scst_acgd_cachep, scst_acg_dev, out_destroy_tgt_cache);
+
+	scst_mgmt_mempool = mempool_create(64, mempool_alloc_slab,
+		mempool_free_slab, scst_mgmt_cachep);
+	if (scst_mgmt_mempool == NULL) {
+		res = -ENOMEM;
+		goto out_destroy_acg_cache;
+	}
+
+	/*
+	 * All mgmt stubs, UAs and sense buffers are bursty and loosing them
+	 * may have fatal consequences, so let's have big pools for them.
+	 */
+
+	scst_mgmt_stub_mempool = mempool_create(1024, mempool_alloc_slab,
+		mempool_free_slab, scst_mgmt_stub_cachep);
+	if (scst_mgmt_stub_mempool == NULL) {
+		res = -ENOMEM;
+		goto out_destroy_mgmt_mempool;
+	}
+
+	scst_ua_mempool = mempool_create(512, mempool_alloc_slab,
+		mempool_free_slab, scst_ua_cachep);
+	if (scst_ua_mempool == NULL) {
+		res = -ENOMEM;
+		goto out_destroy_mgmt_stub_mempool;
+	}
+
+	scst_sense_mempool = mempool_create(1024, mempool_alloc_slab,
+		mempool_free_slab, scst_sense_cachep);
+	if (scst_sense_mempool == NULL) {
+		res = -ENOMEM;
+		goto out_destroy_ua_mempool;
+	}
+
+	scst_aen_mempool = mempool_create(100, mempool_alloc_slab,
+		mempool_free_slab, scst_aen_cachep);
+	if (scst_aen_mempool == NULL) {
+		res = -ENOMEM;
+		goto out_destroy_sense_mempool;
+	}
+
+	res = scst_sysfs_init();
+	if (res != 0)
+		goto out_destroy_aen_mempool;
+
+	if (scst_max_cmd_mem == 0) {
+		struct sysinfo si;
+		si_meminfo(&si);
+#if BITS_PER_LONG == 32
+		scst_max_cmd_mem = min(
+			(((uint64_t)(si.totalram - si.totalhigh) << PAGE_SHIFT)
+				>> 20) >> 2, (uint64_t)1 << 30);
+#else
+		scst_max_cmd_mem = (((si.totalram - si.totalhigh) << PAGE_SHIFT)
+					>> 20) >> 2;
+#endif
+	}
+
+	if (scst_max_dev_cmd_mem != 0) {
+		if (scst_max_dev_cmd_mem > scst_max_cmd_mem) {
+			PRINT_ERROR("scst_max_dev_cmd_mem (%d) > "
+				"scst_max_cmd_mem (%d)",
+				scst_max_dev_cmd_mem,
+				scst_max_cmd_mem);
+			scst_max_dev_cmd_mem = scst_max_cmd_mem;
+		}
+	} else
+		scst_max_dev_cmd_mem = scst_max_cmd_mem * 2 / 5;
+
+	res = scst_sgv_pools_init(
+		((uint64_t)scst_max_cmd_mem << 10) >> (PAGE_SHIFT - 10), 0);
+	if (res != 0)
+		goto out_sysfs_cleanup;
+
+	res = scsi_register_interface(&scst_interface);
+	if (res != 0)
+		goto out_destroy_sgv_pool;
+
+	for (i = 0; i < (int)ARRAY_SIZE(scst_tasklets); i++) {
+		spin_lock_init(&scst_tasklets[i].tasklet_lock);
+		INIT_LIST_HEAD(&scst_tasklets[i].tasklet_cmd_list);
+		tasklet_init(&scst_tasklets[i].tasklet,
+			     (void *)scst_cmd_tasklet,
+			     (unsigned long)&scst_tasklets[i]);
+	}
+
+	TRACE_DBG("%d CPUs found, starting %d threads", scst_num_cpus,
+		scst_threads);
+
+	res = scst_start_global_threads(scst_threads);
+	if (res < 0)
+		goto out_thread_free;
+
+	res = scst_pr_check_pr_path();
+	if (res != 0)
+		goto out_thread_free;
+
+	PRINT_INFO("SCST version %s loaded successfully (max mem for "
+		"commands %dMB, per device %dMB)", SCST_VERSION_STRING,
+		scst_max_cmd_mem, scst_max_dev_cmd_mem);
+
+	scst_print_config();
+
+out:
+	return res;
+
+out_thread_free:
+	scst_stop_global_threads();
+
+	scsi_unregister_interface(&scst_interface);
+
+out_destroy_sgv_pool:
+	scst_sgv_pools_deinit();
+
+out_sysfs_cleanup:
+	scst_sysfs_cleanup();
+
+out_destroy_aen_mempool:
+	mempool_destroy(scst_aen_mempool);
+
+out_destroy_sense_mempool:
+	mempool_destroy(scst_sense_mempool);
+
+out_destroy_ua_mempool:
+	mempool_destroy(scst_ua_mempool);
+
+out_destroy_mgmt_stub_mempool:
+	mempool_destroy(scst_mgmt_stub_mempool);
+
+out_destroy_mgmt_mempool:
+	mempool_destroy(scst_mgmt_mempool);
+
+out_destroy_acg_cache:
+	kmem_cache_destroy(scst_acgd_cachep);
+
+out_destroy_tgt_cache:
+	kmem_cache_destroy(scst_tgtd_cachep);
+
+out_destroy_sess_cache:
+	kmem_cache_destroy(scst_sess_cachep);
+
+out_destroy_cmd_cache:
+	kmem_cache_destroy(scst_cmd_cachep);
+
+out_destroy_aen_cache:
+	kmem_cache_destroy(scst_aen_cachep);
+
+out_destroy_sense_cache:
+	kmem_cache_destroy(scst_sense_cachep);
+
+out_destroy_ua_cache:
+	kmem_cache_destroy(scst_ua_cachep);
+
+out_destroy_mgmt_stub_cache:
+	kmem_cache_destroy(scst_mgmt_stub_cachep);
+
+out_destroy_mgmt_cache:
+	kmem_cache_destroy(scst_mgmt_cachep);
+
+out_lib_exit:
+	scst_lib_exit();
+
+out_deinit_threads:
+	scst_deinit_threads(&scst_main_cmd_threads);
+	goto out;
+}
+
+static void __exit exit_scst(void)
+{
+
+	/* ToDo: unregister_cpu_notifier() */
+
+	scst_stop_global_threads();
+
+	scst_deinit_threads(&scst_main_cmd_threads);
+
+	scsi_unregister_interface(&scst_interface);
+
+	scst_sgv_pools_deinit();
+
+	scst_sysfs_cleanup();
+
+#define DEINIT_CACHEP(p) do {		\
+		kmem_cache_destroy(p);	\
+		p = NULL;		\
+	} while (0)
+
+	mempool_destroy(scst_mgmt_mempool);
+	mempool_destroy(scst_mgmt_stub_mempool);
+	mempool_destroy(scst_ua_mempool);
+	mempool_destroy(scst_sense_mempool);
+	mempool_destroy(scst_aen_mempool);
+
+	DEINIT_CACHEP(scst_mgmt_cachep);
+	DEINIT_CACHEP(scst_mgmt_stub_cachep);
+	DEINIT_CACHEP(scst_ua_cachep);
+	DEINIT_CACHEP(scst_sense_cachep);
+	DEINIT_CACHEP(scst_aen_cachep);
+	DEINIT_CACHEP(scst_cmd_cachep);
+	DEINIT_CACHEP(scst_sess_cachep);
+	DEINIT_CACHEP(scst_tgtd_cachep);
+	DEINIT_CACHEP(scst_acgd_cachep);
+
+	scst_lib_exit();
+
+	PRINT_INFO("%s", "SCST unloaded");
+	return;
+}
+
+module_init(init_scst);
+module_exit(exit_scst);
+
+MODULE_AUTHOR("Vladislav Bolkhovitin");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SCSI target core");
+MODULE_VERSION(SCST_VERSION_STRING);
diff -uprN orig/linux-2.6.35/drivers/scst/scst_module.c linux-2.6.35/drivers/scst/scst_module.c
--- orig/linux-2.6.35/drivers/scst/scst_module.c
+++ linux-2.6.35/drivers/scst/scst_module.c
@@ -0,0 +1,63 @@
+/*
+ *  scst_module.c
+ *
+ *  Copyright (C) 2004 - 2010 Vladislav Bolkhovitin <vst@...b.net>
+ *  Copyright (C) 2004 - 2005 Leonid Stoljar
+ *  Copyright (C) 2007 - 2010 ID7 Ltd.
+ *
+ *  Support for loading target modules. The usage is similar to scsi_module.c
+ *
+ *  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, version 2
+ *  of the License.
+ *
+ *  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/module.h>
+#include <linux/init.h>
+
+#include <scst.h>
+
+static int __init init_this_scst_driver(void)
+{
+	int res;
+
+	res = scst_register_target_template(&driver_target_template);
+	TRACE_DBG("scst_register_target_template() returned %d", res);
+	if (res < 0)
+		goto out;
+
+#ifdef SCST_REGISTER_INITIATOR_DRIVER
+	driver_template.module = THIS_MODULE;
+	scsi_register_module(MODULE_SCSI_HA, &driver_template);
+	TRACE_DBG("driver_template.present=%d",
+	      driver_template.present);
+	if (driver_template.present == 0) {
+		res = -ENODEV;
+		MOD_DEC_USE_COUNT;
+		goto out;
+	}
+#endif
+
+out:
+	return res;
+}
+
+static void __exit exit_this_scst_driver(void)
+{
+
+#ifdef SCST_REGISTER_INITIATOR_DRIVER
+	scsi_unregister_module(MODULE_SCSI_HA, &driver_template);
+#endif
+
+	scst_unregister_target_template(&driver_target_template);
+	return;
+}
+
+module_init(init_this_scst_driver);
+module_exit(exit_this_scst_driver);
diff -uprN orig/linux-2.6.35/drivers/scst/scst_priv.h linux-2.6.35/drivers/scst/scst_priv.h
--- orig/linux-2.6.35/drivers/scst/scst_priv.h
+++ linux-2.6.35/drivers/scst/scst_priv.h
@@ -0,0 +1,609 @@
+/*
+ *  scst_priv.h
+ *
+ *  Copyright (C) 2004 - 2010 Vladislav Bolkhovitin <vst@...b.net>
+ *  Copyright (C) 2004 - 2005 Leonid Stoljar
+ *  Copyright (C) 2007 - 2010 ID7 Ltd.
+ *
+ *  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, version 2
+ *  of the License.
+ *
+ *  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.
+ */
+
+#ifndef __SCST_PRIV_H
+#define __SCST_PRIV_H
+
+#include <linux/types.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_host.h>
+
+#define LOG_PREFIX "scst"
+
+#include <scst/scst_debug.h>
+
+#define TRACE_RTRY              0x80000000
+#define TRACE_SCSI_SERIALIZING  0x40000000
+/** top being the edge away from the interupt */
+#define TRACE_SND_TOP		0x20000000
+#define TRACE_RCV_TOP		0x01000000
+/** bottom being the edge toward the interupt */
+#define TRACE_SND_BOT		0x08000000
+#define TRACE_RCV_BOT		0x04000000
+
+#if defined(CONFIG_SCST_DEBUG) || defined(CONFIG_SCST_TRACING)
+#define trace_flag scst_trace_flag
+extern unsigned long scst_trace_flag;
+#endif
+
+#ifdef CONFIG_SCST_DEBUG
+
+#define SCST_DEFAULT_LOG_FLAGS (TRACE_OUT_OF_MEM | TRACE_MINOR | TRACE_PID | \
+	TRACE_LINE | TRACE_FUNCTION | TRACE_SPECIAL | TRACE_MGMT | \
+	TRACE_MGMT_DEBUG | TRACE_RTRY)
+
+#define TRACE_RETRY(args...)	TRACE_DBG_FLAG(TRACE_RTRY, args)
+#define TRACE_SN(args...)	TRACE_DBG_FLAG(TRACE_SCSI_SERIALIZING, args)
+#define TRACE_SEND_TOP(args...)	TRACE_DBG_FLAG(TRACE_SND_TOP, args)
+#define TRACE_RECV_TOP(args...)	TRACE_DBG_FLAG(TRACE_RCV_TOP, args)
+#define TRACE_SEND_BOT(args...)	TRACE_DBG_FLAG(TRACE_SND_BOT, args)
+#define TRACE_RECV_BOT(args...)	TRACE_DBG_FLAG(TRACE_RCV_BOT, args)
+
+#else /* CONFIG_SCST_DEBUG */
+
+# ifdef CONFIG_SCST_TRACING
+#define SCST_DEFAULT_LOG_FLAGS (TRACE_OUT_OF_MEM | TRACE_MGMT | \
+	TRACE_SPECIAL)
+# else
+#define SCST_DEFAULT_LOG_FLAGS 0
+# endif
+
+#define TRACE_RETRY(args...)
+#define TRACE_SN(args...)
+#define TRACE_SEND_TOP(args...)
+#define TRACE_RECV_TOP(args...)
+#define TRACE_SEND_BOT(args...)
+#define TRACE_RECV_BOT(args...)
+
+#endif
+
+/**
+ ** Bits for scst_flags
+ **/
+
+/*
+ * Set if new commands initialization is being suspended for a while.
+ * Used to let TM commands execute while preparing the suspend, since
+ * RESET or ABORT could be necessary to free SCSI commands.
+ */
+#define SCST_FLAG_SUSPENDING		     0
+
+/* Set if new commands initialization is suspended for a while */
+#define SCST_FLAG_SUSPENDED		     1
+
+/**
+ ** Return codes for cmd state process functions. Codes are the same as
+ ** for SCST_EXEC_* to avoid translation to them and, hence, have better code.
+ **/
+#define SCST_CMD_STATE_RES_CONT_NEXT         SCST_EXEC_COMPLETED
+#define SCST_CMD_STATE_RES_CONT_SAME         SCST_EXEC_NOT_COMPLETED
+#define SCST_CMD_STATE_RES_NEED_THREAD       (SCST_EXEC_NOT_COMPLETED+1)
+
+/**
+ ** Maximum count of uncompleted commands that an initiator could
+ ** queue on any device. Then it will start getting TASK QUEUE FULL status.
+ **/
+#define SCST_MAX_TGT_DEV_COMMANDS            48
+
+/**
+ ** Maximum count of uncompleted commands that could be queued on any device.
+ ** Then initiators sending commands to this device will start getting
+ ** TASK QUEUE FULL status.
+ **/
+#define SCST_MAX_DEV_COMMANDS                256
+
+#define SCST_TGT_RETRY_TIMEOUT               (3/2*HZ)
+
+/* Definitions of symbolic constants for LUN addressing method */
+#define SCST_LUN_ADDR_METHOD_PERIPHERAL	0
+#define SCST_LUN_ADDR_METHOD_FLAT	1
+
+/* Activities suspending timeout */
+#define SCST_SUSPENDING_TIMEOUT			(90 * HZ)
+
+extern struct mutex scst_mutex2;
+
+extern int scst_threads;
+
+extern unsigned int scst_max_dev_cmd_mem;
+
+extern mempool_t *scst_mgmt_mempool;
+extern mempool_t *scst_mgmt_stub_mempool;
+extern mempool_t *scst_ua_mempool;
+extern mempool_t *scst_sense_mempool;
+extern mempool_t *scst_aen_mempool;
+
+extern struct kmem_cache *scst_cmd_cachep;
+extern struct kmem_cache *scst_sess_cachep;
+extern struct kmem_cache *scst_tgtd_cachep;
+extern struct kmem_cache *scst_acgd_cachep;
+
+extern spinlock_t scst_main_lock;
+
+extern struct scst_sgv_pools scst_sgv;
+
+extern unsigned long scst_flags;
+extern atomic_t scst_cmd_count;
+extern struct list_head scst_template_list;
+extern struct list_head scst_dev_list;
+extern struct list_head scst_dev_type_list;
+extern struct list_head scst_virtual_dev_type_list;
+extern wait_queue_head_t scst_dev_cmd_waitQ;
+
+extern unsigned int scst_setup_id;
+
+extern spinlock_t scst_init_lock;
+extern struct list_head scst_init_cmd_list;
+extern wait_queue_head_t scst_init_cmd_list_waitQ;
+extern unsigned int scst_init_poll_cnt;
+
+extern struct scst_cmd_threads scst_main_cmd_threads;
+
+extern spinlock_t scst_mcmd_lock;
+/* The following lists protected by scst_mcmd_lock */
+extern struct list_head scst_active_mgmt_cmd_list;
+extern struct list_head scst_delayed_mgmt_cmd_list;
+extern wait_queue_head_t scst_mgmt_cmd_list_waitQ;
+
+struct scst_tasklet {
+	spinlock_t tasklet_lock;
+	struct list_head tasklet_cmd_list;
+	struct tasklet_struct tasklet;
+};
+extern struct scst_tasklet scst_tasklets[NR_CPUS];
+
+extern wait_queue_head_t scst_mgmt_waitQ;
+extern spinlock_t scst_mgmt_lock;
+extern struct list_head scst_sess_init_list;
+extern struct list_head scst_sess_shut_list;
+
+struct scst_cmd_thread_t {
+	struct task_struct *cmd_thread;
+	struct list_head thread_list_entry;
+};
+
+static inline bool scst_set_io_context(struct scst_cmd *cmd,
+	struct io_context **old)
+{
+	bool res;
+
+#ifdef CONFIG_SCST_TEST_IO_IN_SIRQ
+	return false;
+#endif
+
+	if (cmd->cmd_threads == &scst_main_cmd_threads) {
+		EXTRACHECKS_BUG_ON(in_interrupt());
+		/*
+		 * No need for any ref counting action, because io_context
+		 * supposed to be cleared in the end of the caller function.
+		 */
+		current->io_context = cmd->tgt_dev->async_io_context;
+		res = true;
+		TRACE_DBG("io_context %p (tgt_dev %p)", current->io_context,
+			cmd->tgt_dev);
+		EXTRACHECKS_BUG_ON(current->io_context == NULL);
+	} else
+		res = false;
+
+	return res;
+}
+
+static inline void scst_reset_io_context(struct scst_tgt_dev *tgt_dev,
+	struct io_context *old)
+{
+	current->io_context = old;
+	TRACE_DBG("io_context %p reset", current->io_context);
+	return;
+}
+
+/*
+ * Converts string presentation of threads pool type to enum.
+ * Returns SCST_THREADS_POOL_TYPE_INVALID if the string is invalid.
+ */
+extern enum scst_dev_type_threads_pool_type scst_parse_threads_pool_type(
+	const char *p, int len);
+
+extern int scst_add_threads(struct scst_cmd_threads *cmd_threads,
+	struct scst_device *dev, struct scst_tgt_dev *tgt_dev, int num);
+extern void scst_del_threads(struct scst_cmd_threads *cmd_threads, int num);
+
+extern int scst_create_dev_threads(struct scst_device *dev);
+extern void scst_stop_dev_threads(struct scst_device *dev);
+
+extern int scst_tgt_dev_setup_threads(struct scst_tgt_dev *tgt_dev);
+extern void scst_tgt_dev_stop_threads(struct scst_tgt_dev *tgt_dev);
+
+extern bool scst_del_thr_data(struct scst_tgt_dev *tgt_dev,
+	struct task_struct *tsk);
+
+extern struct scst_dev_type scst_null_devtype;
+
+extern struct scst_cmd *__scst_check_deferred_commands(
+	struct scst_tgt_dev *tgt_dev);
+
+/* Used to save the function call on the fast path */
+static inline struct scst_cmd *scst_check_deferred_commands(
+	struct scst_tgt_dev *tgt_dev)
+{
+	if (tgt_dev->def_cmd_count == 0)
+		return NULL;
+	else
+		return __scst_check_deferred_commands(tgt_dev);
+}
+
+static inline void scst_make_deferred_commands_active(
+	struct scst_tgt_dev *tgt_dev)
+{
+	struct scst_cmd *c;
+
+	c = __scst_check_deferred_commands(tgt_dev);
+	if (c != NULL) {
+		TRACE_SN("Adding cmd %p to active cmd list", c);
+		spin_lock_irq(&c->cmd_threads->cmd_list_lock);
+		list_add_tail(&c->cmd_list_entry,
+			&c->cmd_threads->active_cmd_list);
+		wake_up(&c->cmd_threads->cmd_list_waitQ);
+		spin_unlock_irq(&c->cmd_threads->cmd_list_lock);
+	}
+
+	return;
+}
+
+void scst_inc_expected_sn(struct scst_tgt_dev *tgt_dev, atomic_t *slot);
+int scst_check_hq_cmd(struct scst_cmd *cmd);
+
+void scst_unblock_deferred(struct scst_tgt_dev *tgt_dev,
+	struct scst_cmd *cmd_sn);
+
+void scst_on_hq_cmd_response(struct scst_cmd *cmd);
+void scst_xmit_process_aborted_cmd(struct scst_cmd *cmd);
+
+int scst_cmd_thread(void *arg);
+void scst_cmd_tasklet(long p);
+int scst_init_thread(void *arg);
+int scst_tm_thread(void *arg);
+int scst_global_mgmt_thread(void *arg);
+
+void scst_zero_write_rest(struct scst_cmd *cmd);
+void scst_limit_sg_write_len(struct scst_cmd *cmd);
+void scst_adjust_resp_data_len(struct scst_cmd *cmd);
+
+int scst_queue_retry_cmd(struct scst_cmd *cmd, int finished_cmds);
+
+int scst_alloc_tgt(struct scst_tgt_template *tgtt, struct scst_tgt **tgt);
+void scst_free_tgt(struct scst_tgt *tgt);
+
+int scst_alloc_device(gfp_t gfp_mask, struct scst_device **out_dev);
+void scst_free_device(struct scst_device *dev);
+
+struct scst_acg *scst_alloc_add_acg(struct scst_tgt *tgt,
+	const char *acg_name, bool tgt_acg);
+void scst_del_free_acg(struct scst_acg *acg);
+
+struct scst_acg *scst_tgt_find_acg(struct scst_tgt *tgt, const char *name);
+struct scst_acg *scst_find_acg(const struct scst_session *sess);
+
+void scst_check_reassign_sessions(void);
+
+int scst_sess_alloc_tgt_devs(struct scst_session *sess);
+void scst_sess_free_tgt_devs(struct scst_session *sess);
+void scst_nexus_loss(struct scst_tgt_dev *tgt_dev, bool queue_UA);
+
+int scst_acg_add_lun(struct scst_acg *acg, struct kobject *parent,
+	struct scst_device *dev, uint64_t lun, int read_only,
+	bool gen_scst_report_luns_changed, struct scst_acg_dev **out_acg_dev);
+int scst_acg_del_lun(struct scst_acg *acg, uint64_t lun,
+	bool gen_scst_report_luns_changed);
+
+int scst_acg_add_acn(struct scst_acg *acg, const char *name);
+void scst_del_free_acn(struct scst_acn *acn, bool reassign);
+struct scst_acn *scst_find_acn(struct scst_acg *acg, const char *name);
+
+/* The activity supposed to be suspended and scst_mutex held */
+static inline bool scst_acg_sess_is_empty(struct scst_acg *acg)
+{
+	return list_empty(&acg->acg_sess_list);
+}
+
+int scst_prepare_request_sense(struct scst_cmd *orig_cmd);
+int scst_finish_internal_cmd(struct scst_cmd *cmd);
+
+void scst_store_sense(struct scst_cmd *cmd);
+
+int scst_assign_dev_handler(struct scst_device *dev,
+	struct scst_dev_type *handler);
+
+struct scst_session *scst_alloc_session(struct scst_tgt *tgt, gfp_t gfp_mask,
+	const char *initiator_name);
+void scst_free_session(struct scst_session *sess);
+void scst_free_session_callback(struct scst_session *sess);
+
+struct scst_cmd *scst_alloc_cmd(gfp_t gfp_mask);
+void scst_free_cmd(struct scst_cmd *cmd);
+static inline void scst_destroy_cmd(struct scst_cmd *cmd)
+{
+	kmem_cache_free(scst_cmd_cachep, cmd);
+	return;
+}
+
+void scst_check_retries(struct scst_tgt *tgt);
+
+int scst_alloc_space(struct scst_cmd *cmd);
+
+int scst_lib_init(void);
+void scst_lib_exit(void);
+
+int scst_get_full_buf(struct scst_cmd *cmd, uint8_t **buf);
+void scst_put_full_buf(struct scst_cmd *cmd, uint8_t *buf);
+
+__be64 scst_pack_lun(const uint64_t lun, unsigned int addr_method);
+uint64_t scst_unpack_lun(const uint8_t *lun, int len);
+
+struct scst_mgmt_cmd *scst_alloc_mgmt_cmd(gfp_t gfp_mask);
+void scst_free_mgmt_cmd(struct scst_mgmt_cmd *mcmd);
+void scst_done_cmd_mgmt(struct scst_cmd *cmd);
+
+static inline void scst_devt_cleanup(struct scst_dev_type *devt) { }
+
+int scst_sysfs_init(void);
+void scst_sysfs_cleanup(void);
+int scst_tgtt_sysfs_create(struct scst_tgt_template *tgtt);
+void scst_tgtt_sysfs_del(struct scst_tgt_template *tgtt);
+int scst_tgt_sysfs_create(struct scst_tgt *tgt);
+void scst_tgt_sysfs_prepare_put(struct scst_tgt *tgt);
+void scst_tgt_sysfs_del(struct scst_tgt *tgt);
+int scst_sess_sysfs_create(struct scst_session *sess);
+void scst_sess_sysfs_del(struct scst_session *sess);
+int scst_recreate_sess_luns_link(struct scst_session *sess);
+int scst_sgv_sysfs_create(struct sgv_pool *pool);
+void scst_sgv_sysfs_del(struct sgv_pool *pool);
+int scst_devt_sysfs_create(struct scst_dev_type *devt);
+void scst_devt_sysfs_del(struct scst_dev_type *devt);
+int scst_dev_sysfs_create(struct scst_device *dev);
+void scst_dev_sysfs_del(struct scst_device *dev);
+int scst_tgt_dev_sysfs_create(struct scst_tgt_dev *tgt_dev);
+void scst_tgt_dev_sysfs_del(struct scst_tgt_dev *tgt_dev);
+int scst_devt_dev_sysfs_create(struct scst_device *dev);
+void scst_devt_dev_sysfs_del(struct scst_device *dev);
+int scst_acg_sysfs_create(struct scst_tgt *tgt,
+	struct scst_acg *acg);
+void scst_acg_sysfs_del(struct scst_acg *acg);
+int scst_acg_dev_sysfs_create(struct scst_acg_dev *acg_dev,
+	struct kobject *parent);
+void scst_acg_dev_sysfs_del(struct scst_acg_dev *acg_dev);
+int scst_acn_sysfs_create(struct scst_acn *acn);
+void scst_acn_sysfs_del(struct scst_acn *acn);
+
+void __scst_dev_check_set_UA(struct scst_device *dev, struct scst_cmd *exclude,
+	const uint8_t *sense, int sense_len);
+static inline void scst_dev_check_set_UA(struct scst_device *dev,
+	struct scst_cmd *exclude, const uint8_t *sense, int sense_len)
+{
+	spin_lock_bh(&dev->dev_lock);
+	__scst_dev_check_set_UA(dev, exclude, sense, sense_len);
+	spin_unlock_bh(&dev->dev_lock);
+	return;
+}
+void scst_dev_check_set_local_UA(struct scst_device *dev,
+	struct scst_cmd *exclude, const uint8_t *sense, int sense_len);
+
+#define SCST_SET_UA_FLAG_AT_HEAD	1
+#define SCST_SET_UA_FLAG_GLOBAL		2
+
+void scst_check_set_UA(struct scst_tgt_dev *tgt_dev,
+	const uint8_t *sense, int sense_len, int flags);
+int scst_set_pending_UA(struct scst_cmd *cmd);
+
+void scst_report_luns_changed(struct scst_acg *acg);
+
+void scst_abort_cmd(struct scst_cmd *cmd, struct scst_mgmt_cmd *mcmd,
+	bool other_ini, bool call_dev_task_mgmt_fn);
+void scst_process_reset(struct scst_device *dev,
+	struct scst_session *originator, struct scst_cmd *exclude_cmd,
+	struct scst_mgmt_cmd *mcmd, bool setUA);
+
+bool scst_is_ua_global(const uint8_t *sense, int len);
+void scst_requeue_ua(struct scst_cmd *cmd);
+
+void scst_gen_aen_or_ua(struct scst_tgt_dev *tgt_dev,
+	int key, int asc, int ascq);
+
+static inline bool scst_is_implicit_hq(struct scst_cmd *cmd)
+{
+	return (cmd->op_flags & SCST_IMPLICIT_HQ) != 0;
+}
+
+/*
+ * Some notes on devices "blocking". Blocking means that no
+ * commands will go from SCST to underlying SCSI device until it
+ * is unblocked. But we don't care about all commands that
+ * already on the device.
+ */
+
+extern int scst_inc_on_dev_cmd(struct scst_cmd *cmd);
+
+extern void __scst_block_dev(struct scst_device *dev);
+extern void scst_block_dev_cmd(struct scst_cmd *cmd, int outstanding);
+extern void scst_unblock_dev(struct scst_device *dev);
+extern void scst_unblock_dev_cmd(struct scst_cmd *cmd);
+
+/* No locks */
+static inline void scst_dec_on_dev_cmd(struct scst_cmd *cmd)
+{
+	struct scst_device *dev = cmd->dev;
+	bool unblock_dev = cmd->inc_blocking;
+
+	if (cmd->inc_blocking) {
+		TRACE_MGMT_DBG("cmd %p (tag %llu): unblocking dev %p", cmd,
+			       (long long unsigned int)cmd->tag, cmd->dev);
+		cmd->inc_blocking = 0;
+	}
+	cmd->dec_on_dev_needed = 0;
+
+	if (unblock_dev)
+		scst_unblock_dev(dev);
+
+	atomic_dec(&dev->on_dev_count);
+	/* See comment in scst_block_dev() */
+	smp_mb__after_atomic_dec();
+
+	TRACE_DBG("New on_dev_count %d", atomic_read(&dev->on_dev_count));
+
+	BUG_ON(atomic_read(&dev->on_dev_count) < 0);
+
+	if (unlikely(dev->block_count != 0))
+		wake_up_all(&dev->on_dev_waitQ);
+
+	return;
+}
+
+static inline void __scst_get(int barrier)
+{
+	atomic_inc(&scst_cmd_count);
+	TRACE_DBG("Incrementing scst_cmd_count(new value %d)",
+		atomic_read(&scst_cmd_count));
+
+	/* See comment about smp_mb() in scst_suspend_activity() */
+	if (barrier)
+		smp_mb__after_atomic_inc();
+}
+
+static inline void __scst_put(void)
+{
+	int f;
+	f = atomic_dec_and_test(&scst_cmd_count);
+	/* See comment about smp_mb() in scst_suspend_activity() */
+	if (f && unlikely(test_bit(SCST_FLAG_SUSPENDED, &scst_flags))) {
+		TRACE_MGMT_DBG("%s", "Waking up scst_dev_cmd_waitQ");
+		wake_up_all(&scst_dev_cmd_waitQ);
+	}
+	TRACE_DBG("Decrementing scst_cmd_count(new value %d)",
+	      atomic_read(&scst_cmd_count));
+}
+
+void scst_sched_session_free(struct scst_session *sess);
+
+static inline void scst_sess_get(struct scst_session *sess)
+{
+	atomic_inc(&sess->refcnt);
+	TRACE_DBG("Incrementing sess %p refcnt (new value %d)",
+		sess, atomic_read(&sess->refcnt));
+}
+
+static inline void scst_sess_put(struct scst_session *sess)
+{
+	TRACE_DBG("Decrementing sess %p refcnt (new value %d)",
+		sess, atomic_read(&sess->refcnt)-1);
+	if (atomic_dec_and_test(&sess->refcnt))
+		scst_sched_session_free(sess);
+}
+
+static inline void __scst_cmd_get(struct scst_cmd *cmd)
+{
+	atomic_inc(&cmd->cmd_ref);
+	TRACE_DBG("Incrementing cmd %p ref (new value %d)",
+		cmd, atomic_read(&cmd->cmd_ref));
+}
+
+static inline void __scst_cmd_put(struct scst_cmd *cmd)
+{
+	TRACE_DBG("Decrementing cmd %p ref (new value %d)",
+		cmd, atomic_read(&cmd->cmd_ref)-1);
+	if (atomic_dec_and_test(&cmd->cmd_ref))
+		scst_free_cmd(cmd);
+}
+
+extern void scst_throttle_cmd(struct scst_cmd *cmd);
+extern void scst_unthrottle_cmd(struct scst_cmd *cmd);
+
+#ifdef CONFIG_SCST_DEBUG_TM
+extern void tm_dbg_check_released_cmds(void);
+extern int tm_dbg_check_cmd(struct scst_cmd *cmd);
+extern void tm_dbg_release_cmd(struct scst_cmd *cmd);
+extern void tm_dbg_task_mgmt(struct scst_device *dev, const char *fn,
+	int force);
+extern int tm_dbg_is_release(void);
+#else
+static inline void tm_dbg_check_released_cmds(void) {}
+static inline int tm_dbg_check_cmd(struct scst_cmd *cmd)
+{
+	return 0;
+}
+static inline void tm_dbg_release_cmd(struct scst_cmd *cmd) {}
+static inline void tm_dbg_task_mgmt(struct scst_device *dev, const char *fn,
+	int force) {}
+static inline int tm_dbg_is_release(void)
+{
+	return 0;
+}
+#endif /* CONFIG_SCST_DEBUG_TM */
+
+#ifdef CONFIG_SCST_DEBUG_SN
+void scst_check_debug_sn(struct scst_cmd *cmd);
+#else
+static inline void scst_check_debug_sn(struct scst_cmd *cmd) {}
+#endif
+
+static inline int scst_sn_before(uint32_t seq1, uint32_t seq2)
+{
+	return (int32_t)(seq1-seq2) < 0;
+}
+
+int gen_relative_target_port_id(uint16_t *id);
+bool scst_is_relative_target_port_id_unique(uint16_t id,
+	const struct scst_tgt *t);
+
+#ifdef CONFIG_SCST_MEASURE_LATENCY
+
+void scst_set_start_time(struct scst_cmd *cmd);
+void scst_set_cur_start(struct scst_cmd *cmd);
+void scst_set_parse_time(struct scst_cmd *cmd);
+void scst_set_alloc_buf_time(struct scst_cmd *cmd);
+void scst_set_restart_waiting_time(struct scst_cmd *cmd);
+void scst_set_rdy_to_xfer_time(struct scst_cmd *cmd);
+void scst_set_pre_exec_time(struct scst_cmd *cmd);
+void scst_set_exec_time(struct scst_cmd *cmd);
+void scst_set_dev_done_time(struct scst_cmd *cmd);
+void scst_set_xmit_time(struct scst_cmd *cmd);
+void scst_set_tgt_on_free_time(struct scst_cmd *cmd);
+void scst_set_dev_on_free_time(struct scst_cmd *cmd);
+void scst_update_lat_stats(struct scst_cmd *cmd);
+
+#else
+
+static inline void scst_set_start_time(struct scst_cmd *cmd) {}
+static inline void scst_set_cur_start(struct scst_cmd *cmd) {}
+static inline void scst_set_parse_time(struct scst_cmd *cmd) {}
+static inline void scst_set_alloc_buf_time(struct scst_cmd *cmd) {}
+static inline void scst_set_restart_waiting_time(struct scst_cmd *cmd) {}
+static inline void scst_set_rdy_to_xfer_time(struct scst_cmd *cmd) {}
+static inline void scst_set_pre_exec_time(struct scst_cmd *cmd) {}
+static inline void scst_set_exec_time(struct scst_cmd *cmd) {}
+static inline void scst_set_dev_done_time(struct scst_cmd *cmd) {}
+static inline void scst_set_xmit_time(struct scst_cmd *cmd) {}
+static inline void scst_set_tgt_on_free_time(struct scst_cmd *cmd) {}
+static inline void scst_set_dev_on_free_time(struct scst_cmd *cmd) {}
+static inline void scst_update_lat_stats(struct scst_cmd *cmd) {}
+
+#endif /* CONFIG_SCST_MEASURE_LATENCY */
+
+#endif /* __SCST_PRIV_H */


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