path: root/drivers/target/target_core_rd.c

/*******************************************************************************
 * Filename:  target_core_rd.c
 *
 * This file contains the Storage Engine <-> Ramdisk transport
 * specific functions.
 *
 * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
 * Copyright (c) 2005, 2006, 2007 SBE, Inc.
 * Copyright (c) 2007-2010 Rising Tide Systems
 * Copyright (c) 2008-2010 Linux-iSCSI.org
 *
 * Nicholas A. Bellinger <nab@kernel.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/version.h>
#include <linux/string.h>
#include <linux/parser.h>
#include <linux/timer.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>

#include <target/target_core_base.h>
#include <target/target_core_device.h>
#include <target/target_core_transport.h>
#include <target/target_core_fabric_ops.h>

#include "target_core_rd.h"

static struct se_subsystem_api rd_dr_template;
static struct se_subsystem_api rd_mcp_template;

/* #define DEBUG_RAMDISK_MCP */
/* #define DEBUG_RAMDISK_DR */

/*	rd_attach_hba(): (Part of se_subsystem_api_t template)
 *
 *
 */
static int rd_attach_hba(struct se_hba *hba, u32 host_id)
{
	struct rd_host *rd_host;

	rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
	if (!(rd_host)) {
		printk(KERN_ERR "Unable to allocate memory for struct rd_host\n");
		return -ENOMEM;
	}

	rd_host->rd_host_id = host_id;

	atomic_set(&hba->left_queue_depth, RD_HBA_QUEUE_DEPTH);
	atomic_set(&hba->max_queue_depth, RD_HBA_QUEUE_DEPTH);
	hba->hba_ptr = (void *) rd_host;

	printk(KERN_INFO "CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
		" Generic Target Core Stack %s\n", hba->hba_id,
		RD_HBA_VERSION, TARGET_CORE_MOD_VERSION);
	printk(KERN_INFO "CORE_HBA[%d] - Attached Ramdisk HBA: %u to Generic"
		" Target Core TCQ Depth: %d MaxSectors: %u\n", hba->hba_id,
		rd_host->rd_host_id, atomic_read(&hba->max_queue_depth),
		RD_MAX_SECTORS);

	return 0;
}

static void rd_detach_hba(struct se_hba *hba)
{
	struct rd_host *rd_host = hba->hba_ptr;

	printk(KERN_INFO "CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
		" Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);

	kfree(rd_host);
	hba->hba_ptr = NULL;
}

/*	rd_release_device_space():
 *
 *
 */
static void rd_release_device_space(struct rd_dev *rd_dev)
{
	u32 i, j, page_count = 0, sg_per_table;
	struct rd_dev_sg_table *sg_table;
	struct page *pg;
	struct scatterlist *sg;

	if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
		return;

	sg_table = rd_dev->sg_table_array;

	for (i = 0; i < rd_dev->sg_table_count; i++) {
		sg = sg_table[i].sg_table;
		sg_per_table = sg_table[i].rd_sg_count;

		for (j = 0; j < sg_per_table; j++) {
			pg = sg_page(&sg[j]);
			if ((pg)) {
				__free_page(pg);
				page_count++;
			}
		}

		kfree(sg);
	}

	printk(KERN_INFO "CORE_RD[%u] - Released device space for Ramdisk"
		" Device ID: %u, pages %u in %u tables total bytes %lu\n",
		rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
		rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);

	kfree(sg_table);
	rd_dev->sg_table_array = NULL;
	rd_dev->sg_table_count = 0;
}


/*	rd_build_device_space():
 *
 *
 */
static int rd_build_device_space(struct rd_dev *rd_dev)
{
	u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed;
	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
				sizeof(struct scatterlist));