path: root/drivers/target/loopback/tcm_loop.c

/*******************************************************************************
 *
 * This file contains the Linux/SCSI LLD virtual SCSI initiator driver
 * for emulated SAS initiator ports
 *
 * © Copyright 2011-2013 Datera, Inc.
 *
 * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
 *
 * Author: Nicholas A. Bellinger <nab@risingtidesystems.com>
 *
 * 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/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/configfs.h>
#include <scsi/scsi.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>

#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_fabric_configfs.h>
#include <target/target_core_configfs.h>

#include "tcm_loop.h"

#define to_tcm_loop_hba(hba)	container_of(hba, struct tcm_loop_hba, dev)

/* Local pointer to allocated TCM configfs fabric module */
static struct target_fabric_configfs *tcm_loop_fabric_configfs;

static struct workqueue_struct *tcm_loop_workqueue;
static struct kmem_cache *tcm_loop_cmd_cache;

static int tcm_loop_hba_no_cnt;

static int tcm_loop_queue_status(struct se_cmd *se_cmd);

/*
 * Called from struct target_core_fabric_ops->check_stop_free()
 */
static int tcm_loop_check_stop_free(struct se_cmd *se_cmd)
{
	/*
	 * Do not release struct se_cmd's containing a valid TMR
	 * pointer.  These will be released directly in tcm_loop_device_reset()
	 * with transport_generic_free_cmd().
	 */
	if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
		return 0;
	/*
	 * Release the struct se_cmd, which will make a callback to release
	 * struct tcm_loop_cmd * in tcm_loop_deallocate_core_cmd()
	 */
	transport_generic_free_cmd(se_cmd, 0);
	return 1;
}

static void tcm_loop_release_cmd(struct se_cmd *se_cmd)
{
	struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
				struct tcm_loop_cmd, tl_se_cmd);

	kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
}

static int tcm_loop_show_info(struct seq_file *m, struct Scsi_Host *host)
{
	seq_printf(m, "tcm_loop_proc_info()\n");
	return 0;
}

static int tcm_loop_driver_probe(struct device *);
static int tcm_loop_driver_remove(struct device *);

static int pseudo_lld_bus_match(struct device *dev,
				struct device_driver *dev_driver)
{
	return 1;
}

static struct bus_type tcm_loop_lld_bus = {
	.name			= "tcm_loop_bus",
	.match			= pseudo_lld_bus_match,
	.probe			= tcm_loop_driver_probe,
	.remove			= tcm_loop_driver_remove,
};

static struct device_driver tcm_loop_driverfs = {
	.name			= "tcm_loop",
	.bus			= &tcm_loop_lld_bus,
};
/*
 * Used with root_device_register() in tcm_loop_alloc_core_bus() below
 */
struct device *tcm_loop_primary;

/*
 * Copied from drivers/scsi/libfc/fc_fcp.c:fc_change_queue_depth() and
 * drivers/scsi/libiscsi.c:iscsi_change_queue_depth()
 */
static int tcm_loop_change_queue_depth(
	struct scsi_device *sdev,
	int depth,
	int reason)
{
	switch (reason) {
	case SCSI_QDEPTH_DEFAULT:
		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
		break;
	case SCSI_QDEPTH_QFULL:
		scsi_track_queue_full(sdev, depth);
		break;
	case SCSI_QDEPTH_RAMP_UP:
		scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
		break;
	default:
		return -EOPNOTSUPP;
	}
	return sdev->queue_depth;
}

static int tcm_loop_change_queue_type(struct scsi_device *sdev, int tag)
{
	if (sdev->tagged_supported) {
		scsi_set_tag_type(sdev, tag);

		if (tag)
			scsi_activate_tcq(sdev, sdev->queue_depth);
		else
			scsi_deactivate_tcq(sdev, sdev->queue_depth);
	} else
		tag = 0;

	return tag;
}

/*
 * Locate the SAM Task Attr from struct scsi_cmnd *
 */
static int