[linux-2.6-block.git] / drivers / target / target_core_rd.c

/*******************************************************************************
 * Filename:  target_core_rd.c
 *
 * This file contains the Storage Engine <-> Ramdisk transport
 * specific functions.
 *
 * (c) Copyright 2003-2012 RisingTide Systems LLC.
 *
 * 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/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_backend.h>

#include "target_core_rd.h"

static inline struct rd_dev *RD_DEV(struct se_device *dev)
{
	return container_of(dev, struct rd_dev, dev);
}

/*	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) {
		pr_err("Unable to allocate memory for struct rd_host\n");
		return -ENOMEM;
	}

	rd_host->rd_host_id = host_id;

	hba->hba_ptr = rd_host;

	pr_debug("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);

	return 0;
}

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

	pr_debug("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);
	}

	pr_debug("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));
	struct rd_dev_sg_table *sg_table;
	struct page *pg;
	struct scatterlist *sg;

	if (rd_dev->rd_page_count <= 0) {
		pr_err("Illegal page count: %u for Ramdisk device\n",
			rd_dev->rd_page_count);
		return -EINVAL;
	}
	total_sg_needed = rd_dev->rd_page_count;

	sg_tables = (total_sg_needed / max_sg_per_table) + 1;

	sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
	if (!sg_table) {
		pr_err("Unable to allocate memory for Ramdisk"
			" scatterlist tables\n");
		return -ENOMEM;
	}

	rd_dev->sg_table_array = sg_table;
	rd_dev->sg_table_count = sg_tables;

	while (total_sg_needed) {
		sg_per_table = (total_sg_needed > max_sg_per_table) ?
			max_sg_per_table : total_sg_needed;

		sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
				GFP_KERNEL);
		if (!sg) {
			pr_err("Unable to allocate scatterlist array"
				" for struct rd_dev\n");
			return -ENOMEM;
		}

		sg_init_table(sg, sg_per_table);

		sg_table[i].sg_table = sg;
		sg_table[i].rd_sg_count = sg_per_table;
		sg_table[i].page_start_offset = page_offset;
		sg_table[i++].page_end_offset = (page_offset + sg_per_table)
						- 1;

		for (j = 0; j < sg_per_table; j++) {
			pg = alloc_pages(GFP_KERNEL, 0);
			if (!pg) {
				pr_err("Unable to allocate scatterlist"
					" pages for struct rd_dev_sg_table\n");
				return -ENOMEM;
			}
			sg_assign_page(&sg[j], pg);
			sg[j].length = PAGE_SIZE;
		}

		page_offset += sg_per_table;
		total_sg_needed -= sg_per_table;
	}

	pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
		" %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
		rd_dev->rd_dev_id, rd_dev->rd_page_count,
		rd_dev->sg_table_count);

	return 0;
}

static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
{
	struct rd_dev *rd_dev;
	struct rd_host *rd_host = hba->hba_ptr;

	rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
	if (!rd_dev) {
		pr_err("Unable to allocate memory for struct rd_dev\n");
		return NULL;
	}

	rd_dev->rd_host = rd_host;

	return &rd_dev->dev;
}

static int rd_configure_device(struct se_device *dev)
{
	struct rd_dev *rd_dev = RD_DEV(dev);
	struct rd_host *rd_host = dev->se_hba->hba_ptr;
	int ret;

	if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
		pr_debug("Missing rd_pages= parameter\n");
		return -EINVAL;
	}

	ret = rd_build_device_space(rd_dev);
	if (ret < 0)
		goto fail;

	dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
	dev->dev_attrib.hw_max_sectors = UINT_MAX;
	dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;

	rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;

	pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
		" %u pages in %u tables, %lu total bytes\n",
		rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
		rd_dev->sg_table_count,
		(unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));

	return 0;

fail:
	rd_release_device_space(rd_dev);
	return ret;
}

static void rd_free_device(struct se_device *dev)
{
	struct rd_dev *rd_dev = RD_DEV(dev);

	rd_release_device_space(rd_dev);
	kfree(rd_dev);
}

static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
{
	struct rd_dev_sg_table *sg_table;
	u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
				sizeof(struct scatterlist));

	i = page / sg_per_table;
	if (i < rd_dev->sg_table_count) {
		sg_table = &rd_dev->sg_table_array[i];
		if ((sg_table->page_start_offset <= page) &&
		    (sg_table->page_end_offset >= page))
			return sg_table;
	}

	pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
			page);

	return NULL;
}

static sense_reason_t
rd_execute_rw(struct se_cmd *cmd)
{
	struct scatterlist *sgl = cmd->t_data_sg;
	u32 sgl_nents = cmd->t_data_nents;
	enum dma_data_direction data_direction = cmd->data_direction;
	struct se_device *se_dev = cmd->se_dev;
	struct rd_dev *dev = RD_DEV(se_dev);
	struct rd_dev_sg_table *table;
	struct scatterlist *rd_sg;
	struct sg_mapping_iter m;
	u32 rd_offset;
	u32 rd_size;
	u32 rd_page;
	u32 src_len;
	u64 tmp;

	tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
	rd_offset = do_div(tmp, PAGE_SIZE);
	rd_page = tmp;
	rd_size = cmd->data_length;

	table = rd_get_sg_table(dev, rd_page);
	if (!table)
		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

	rd_sg = &table->sg_table[rd_page - table->page_start_offset];

	pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
			dev->rd_dev_id,
			data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
			cmd->t_task_lba, rd_size, rd_page, rd_offset);

	src_len = PAGE_SIZE - rd_offset;
	sg_miter_start(&m, sgl, sgl_nents,
			data_direction == DMA_FROM_DEVICE ?
				SG_MITER_TO_SG : SG_MITER_FROM_SG);
	while (rd_size) {
		u32 len;
		void *rd_addr;

		sg_miter_next(&m);
		if (!(u32)m.length) {
			pr_debug("RD[%u]: invalid sgl %p len %zu\n",
				 dev->rd_dev_id, m.addr, m.length);
			sg_miter_stop(&m);
			return TCM_INCORRECT_AMOUNT_OF_DATA;
		}
		len = min((u32)m.length, src_len);
		if (len > rd_size) {
			pr_debug("RD[%u]: size underrun page %d offset %d "
				 "size %d\n", dev->rd_dev_id,
				 rd_page, rd_offset, rd_size);
			len = rd_size;
		}
		m.consumed = len;

		rd_addr = sg_virt(rd_sg) + rd_offset;

		if (data_direction == DMA_FROM_DEVICE)
			memcpy(m.addr, rd_addr, len);
		else
			memcpy(rd_addr, m.addr, len);

		rd_size -= len;
		if (!rd_size)
			continue;

		src_len -= len;
		if (src_len) {
			rd_offset += len;
			continue;
		}

		/* rd page completed, next one please */
		rd_page++;
		rd_offset = 0;
		src_len = PAGE_SIZE;
		if (rd_page <= table->page_end_offset) {
			rd_sg++;
			continue;
		}

		table = rd_get_sg_table(dev, rd_page);
		if (!table) {
			sg_miter_stop(&m);
			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
		}

		/* since we increment, the first sg entry is correct */
		rd_sg = table->sg_table;
	}
	sg_miter_stop(&m);

	target_complete_cmd(cmd, SAM_STAT_GOOD);
	return 0;
}

enum {
	Opt_rd_pages, Opt_err
};

static match_table_t tokens = {
	{Opt_rd_pages, "rd_pages=%d"},
	{Opt_err, NULL}
};

static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
		const char *page, ssize_t count)
{
	struct rd_dev *rd_dev = RD_DEV(dev);
	char *orig, *ptr, *opts;
	substring_t args[MAX_OPT_ARGS];
	int ret = 0, arg, token;

	opts = kstrdup(page, GFP_KERNEL);
	if (!opts)
		return -ENOMEM;

	orig = opts;

	while ((ptr = strsep(&opts, ",\n")) != NULL) {
		if (!*ptr)
			continue;

		token = match_token(ptr, tokens, args);
		switch (token) {
		case Opt_rd_pages:
			match_int(args, &arg);
			rd_dev->rd_page_count = arg;
			pr_debug("RAMDISK: Referencing Page"
				" Count: %u\n", rd_dev->rd_page_count);
			rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
			break;
		default:
			break;
		}
	}

	kfree(orig);
	return (!ret) ? count : ret;
}

static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
{
	struct rd_dev *rd_dev = RD_DEV(dev);

	ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
			rd_dev->rd_dev_id);
	bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
			"  SG_table_count: %u\n", rd_dev->rd_page_count,
			PAGE_SIZE, rd_dev->sg_table_count);
	return bl;
}

static sector_t rd_get_blocks(struct se_device *dev)
{
	struct rd_dev *rd_dev = RD_DEV(dev);

	unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
			dev->dev_attrib.block_size) - 1;

	return blocks_long;
}

static struct sbc_ops rd_sbc_ops = {
	.execute_rw		= rd_execute_rw,
};

static sense_reason_t
rd_parse_cdb(struct se_cmd *cmd)
{
	return sbc_parse_cdb(cmd, &rd_sbc_ops);
}

static struct se_subsystem_api rd_mcp_template = {
	.name			= "rd_mcp",
	.inquiry_prod		= "RAMDISK-MCP",
	.inquiry_rev		= RD_MCP_VERSION,
	.transport_type		= TRANSPORT_PLUGIN_VHBA_VDEV,
	.attach_hba		= rd_attach_hba,
	.detach_hba		= rd_detach_hba,
	.alloc_device		= rd_alloc_device,
	.configure_device	= rd_configure_device,
	.free_device		= rd_free_device,
	.parse_cdb		= rd_parse_cdb,
	.set_configfs_dev_params = rd_set_configfs_dev_params,
	.show_configfs_dev_params = rd_show_configfs_dev_params,
	.get_device_type	= sbc_get_device_type,
	.get_blocks		= rd_get_blocks,
};

int __init rd_module_init(void)
{
	int ret;

	ret = transport_subsystem_register(&rd_mcp_template);
	if (ret < 0) {
		return ret;
	}

	return 0;
}

void rd_module_exit(void)
{
	transport_subsystem_release(&rd_mcp_template);
}
Commit	Line	Data
	1	/*******************************************************************************
	2	* Filename: target_core_rd.c
	3	*
	4	* This file contains the Storage Engine <-> Ramdisk transport
	5	* specific functions.
	6	*
	7	* (c) Copyright 2003-2012 RisingTide Systems LLC.
	8	*
	9	* Nicholas A. Bellinger <nab@kernel.org>
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License as published by
	13	* the Free Software Foundation; either version 2 of the License, or
	14	* (at your option) any later version.
	15	*
	16	* This program is distributed in the hope that it will be useful,
	17	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	* GNU General Public License for more details.
	20	*
	21	* You should have received a copy of the GNU General Public License
	22	* along with this program; if not, write to the Free Software
	23	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	24	*
	25	******************************************************************************/
	26
	27	#include <linux/string.h>
	28	#include <linux/parser.h>
	29	#include <linux/timer.h>
	30	#include <linux/blkdev.h>
	31	#include <linux/slab.h>
	32	#include <linux/spinlock.h>
	33	#include <scsi/scsi.h>
	34	#include <scsi/scsi_host.h>
	35
	36	#include <target/target_core_base.h>
	37	#include <target/target_core_backend.h>
	38
	39	#include "target_core_rd.h"
	40
	41	static inline struct rd_dev RD_DEV(struct se_device dev)
	42	{
	43	return container_of(dev, struct rd_dev, dev);
	44	}
	45
	46	/* rd_attach_hba(): (Part of se_subsystem_api_t template)
	47	*
	48	*
	49	*/
	50	static int rd_attach_hba(struct se_hba *hba, u32 host_id)
	51	{
	52	struct rd_host *rd_host;
	53
	54	rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
	55	if (!rd_host) {
	56	pr_err("Unable to allocate memory for struct rd_host\n");
	57	return -ENOMEM;
	58	}
	59
	60	rd_host->rd_host_id = host_id;
	61
	62	hba->hba_ptr = rd_host;
	63
	64	pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
	65	" Generic Target Core Stack %s\n", hba->hba_id,
	66	RD_HBA_VERSION, TARGET_CORE_MOD_VERSION);
	67
	68	return 0;
	69	}
	70
	71	static void rd_detach_hba(struct se_hba *hba)
	72	{
	73	struct rd_host *rd_host = hba->hba_ptr;
	74
	75	pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
	76	" Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
	77
	78	kfree(rd_host);
	79	hba->hba_ptr = NULL;
	80	}
	81
	82	/* rd_release_device_space():
	83	*
	84	*
	85	*/
	86	static void rd_release_device_space(struct rd_dev *rd_dev)
	87	{
	88	u32 i, j, page_count = 0, sg_per_table;
	89	struct rd_dev_sg_table *sg_table;
	90	struct page *pg;
	91	struct scatterlist *sg;
	92
	93	if (!rd_dev->sg_table_array \|\| !rd_dev->sg_table_count)
	94	return;
	95
	96	sg_table = rd_dev->sg_table_array;
	97
	98	for (i = 0; i < rd_dev->sg_table_count; i++) {
	99	sg = sg_table[i].sg_table;
	100	sg_per_table = sg_table[i].rd_sg_count;
	101
	102	for (j = 0; j < sg_per_table; j++) {
	103	pg = sg_page(&sg[j]);
	104	if (pg) {
	105	__free_page(pg);
	106	page_count++;
	107	}
	108	}
	109
	110	kfree(sg);
	111	}
	112
	113	pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
	114	" Device ID: %u, pages %u in %u tables total bytes %lu\n",
	115	rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
	116	rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
	117
	118	kfree(sg_table);
	119	rd_dev->sg_table_array = NULL;
	120	rd_dev->sg_table_count = 0;
	121	}
	122
	123
	124	/* rd_build_device_space():
	125	*
	126	*
	127	*/
	128	static int rd_build_device_space(struct rd_dev *rd_dev)
	129	{
	130	u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed;
	131	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
	132	sizeof(struct scatterlist));
	133	struct rd_dev_sg_table *sg_table;
	134	struct page *pg;
	135	struct scatterlist *sg;
	136
	137	if (rd_dev->rd_page_count <= 0) {
	138	pr_err("Illegal page count: %u for Ramdisk device\n",
	139	rd_dev->rd_page_count);
	140	return -EINVAL;
	141	}
	142	total_sg_needed = rd_dev->rd_page_count;
	143
	144	sg_tables = (total_sg_needed / max_sg_per_table) + 1;
	145
	146	sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
	147	if (!sg_table) {
	148	pr_err("Unable to allocate memory for Ramdisk"
	149	" scatterlist tables\n");
	150	return -ENOMEM;
	151	}
	152
	153	rd_dev->sg_table_array = sg_table;
	154	rd_dev->sg_table_count = sg_tables;
	155
	156	while (total_sg_needed) {
	157	sg_per_table = (total_sg_needed > max_sg_per_table) ?
	158	max_sg_per_table : total_sg_needed;
	159
	160	sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
	161	GFP_KERNEL);
	162	if (!sg) {
	163	pr_err("Unable to allocate scatterlist array"
	164	" for struct rd_dev\n");
	165	return -ENOMEM;
	166	}
	167
	168	sg_init_table(sg, sg_per_table);
	169
	170	sg_table[i].sg_table = sg;
	171	sg_table[i].rd_sg_count = sg_per_table;
	172	sg_table[i].page_start_offset = page_offset;
	173	sg_table[i++].page_end_offset = (page_offset + sg_per_table)
	174	- 1;
	175
	176	for (j = 0; j < sg_per_table; j++) {
	177	pg = alloc_pages(GFP_KERNEL, 0);
	178	if (!pg) {
	179	pr_err("Unable to allocate scatterlist"
	180	" pages for struct rd_dev_sg_table\n");
	181	return -ENOMEM;
	182	}
	183	sg_assign_page(&sg[j], pg);
	184	sg[j].length = PAGE_SIZE;
	185	}
	186
	187	page_offset += sg_per_table;
	188	total_sg_needed -= sg_per_table;
	189	}
	190
	191	pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
	192	" %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
	193	rd_dev->rd_dev_id, rd_dev->rd_page_count,
	194	rd_dev->sg_table_count);
	195
	196	return 0;
	197	}
	198
	199	static struct se_device rd_alloc_device(struct se_hba hba, const char *name)
	200	{
	201	struct rd_dev *rd_dev;
	202	struct rd_host *rd_host = hba->hba_ptr;
	203
	204	rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
	205	if (!rd_dev) {
	206	pr_err("Unable to allocate memory for struct rd_dev\n");
	207	return NULL;
	208	}
	209
	210	rd_dev->rd_host = rd_host;
	211
	212	return &rd_dev->dev;
	213	}
	214
	215	static int rd_configure_device(struct se_device *dev)
	216	{
	217	struct rd_dev *rd_dev = RD_DEV(dev);
	218	struct rd_host *rd_host = dev->se_hba->hba_ptr;
	219	int ret;
	220
	221	if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
	222	pr_debug("Missing rd_pages= parameter\n");
	223	return -EINVAL;
	224	}
	225
	226	ret = rd_build_device_space(rd_dev);
	227	if (ret < 0)
	228	goto fail;
	229
	230	dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
	231	dev->dev_attrib.hw_max_sectors = UINT_MAX;
	232	dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
	233
	234	rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
	235
	236	pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
	237	" %u pages in %u tables, %lu total bytes\n",
	238	rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
	239	rd_dev->sg_table_count,
	240	(unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
	241
	242	return 0;
	243
	244	fail:
	245	rd_release_device_space(rd_dev);
	246	return ret;
	247	}
	248
	249	static void rd_free_device(struct se_device *dev)
	250	{
	251	struct rd_dev *rd_dev = RD_DEV(dev);
	252
	253	rd_release_device_space(rd_dev);
	254	kfree(rd_dev);
	255	}
	256
	257	static struct rd_dev_sg_table rd_get_sg_table(struct rd_dev rd_dev, u32 page)
	258	{
	259	struct rd_dev_sg_table *sg_table;
	260	u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
	261	sizeof(struct scatterlist));
	262
	263	i = page / sg_per_table;
	264	if (i < rd_dev->sg_table_count) {
	265	sg_table = &rd_dev->sg_table_array[i];
	266	if ((sg_table->page_start_offset <= page) &&
	267	(sg_table->page_end_offset >= page))
	268	return sg_table;
	269	}
	270
	271	pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
	272	page);
	273
	274	return NULL;
	275	}
	276
	277	static sense_reason_t
	278	rd_execute_rw(struct se_cmd *cmd)
	279	{
	280	struct scatterlist *sgl = cmd->t_data_sg;
	281	u32 sgl_nents = cmd->t_data_nents;
	282	enum dma_data_direction data_direction = cmd->data_direction;
	283	struct se_device *se_dev = cmd->se_dev;
	284	struct rd_dev *dev = RD_DEV(se_dev);
	285	struct rd_dev_sg_table *table;
	286	struct scatterlist *rd_sg;
	287	struct sg_mapping_iter m;
	288	u32 rd_offset;
	289	u32 rd_size;
	290	u32 rd_page;
	291	u32 src_len;
	292	u64 tmp;
	293
	294	tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
	295	rd_offset = do_div(tmp, PAGE_SIZE);
	296	rd_page = tmp;
	297	rd_size = cmd->data_length;
	298
	299	table = rd_get_sg_table(dev, rd_page);
	300	if (!table)
	301	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
	302
	303	rd_sg = &table->sg_table[rd_page - table->page_start_offset];
	304
	305	pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
	306	dev->rd_dev_id,
	307	data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
	308	cmd->t_task_lba, rd_size, rd_page, rd_offset);
	309
	310	src_len = PAGE_SIZE - rd_offset;
	311	sg_miter_start(&m, sgl, sgl_nents,
	312	data_direction == DMA_FROM_DEVICE ?
	313	SG_MITER_TO_SG : SG_MITER_FROM_SG);
	314	while (rd_size) {
	315	u32 len;
	316	void *rd_addr;
	317
	318	sg_miter_next(&m);
	319	if (!(u32)m.length) {
	320	pr_debug("RD[%u]: invalid sgl %p len %zu\n",
	321	dev->rd_dev_id, m.addr, m.length);
	322	sg_miter_stop(&m);
	323	return TCM_INCORRECT_AMOUNT_OF_DATA;
	324	}
	325	len = min((u32)m.length, src_len);
	326	if (len > rd_size) {
	327	pr_debug("RD[%u]: size underrun page %d offset %d "
	328	"size %d\n", dev->rd_dev_id,
	329	rd_page, rd_offset, rd_size);
	330	len = rd_size;
	331	}
	332	m.consumed = len;
	333
	334	rd_addr = sg_virt(rd_sg) + rd_offset;
	335
	336	if (data_direction == DMA_FROM_DEVICE)
	337	memcpy(m.addr, rd_addr, len);
	338	else
	339	memcpy(rd_addr, m.addr, len);
	340
	341	rd_size -= len;
	342	if (!rd_size)
	343	continue;
	344
	345	src_len -= len;
	346	if (src_len) {
	347	rd_offset += len;
	348	continue;
	349	}
	350
	351	/* rd page completed, next one please */
	352	rd_page++;
	353	rd_offset = 0;
	354	src_len = PAGE_SIZE;
	355	if (rd_page <= table->page_end_offset) {
	356	rd_sg++;
	357	continue;
	358	}
	359
	360	table = rd_get_sg_table(dev, rd_page);
	361	if (!table) {
	362	sg_miter_stop(&m);
	363	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
	364	}
	365
	366	/* since we increment, the first sg entry is correct */
	367	rd_sg = table->sg_table;
	368	}
	369	sg_miter_stop(&m);
	370
	371	target_complete_cmd(cmd, SAM_STAT_GOOD);
	372	return 0;
	373	}
	374
	375	enum {
	376	Opt_rd_pages, Opt_err
	377	};
	378
	379	static match_table_t tokens = {
	380	{Opt_rd_pages, "rd_pages=%d"},
	381	{Opt_err, NULL}
	382	};
	383
	384	static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
	385	const char *page, ssize_t count)
	386	{
	387	struct rd_dev *rd_dev = RD_DEV(dev);
	388	char orig, ptr, *opts;
	389	substring_t args[MAX_OPT_ARGS];
	390	int ret = 0, arg, token;
	391
	392	opts = kstrdup(page, GFP_KERNEL);
	393	if (!opts)
	394	return -ENOMEM;
	395
	396	orig = opts;
	397
	398	while ((ptr = strsep(&opts, ",\n")) != NULL) {
	399	if (!*ptr)
	400	continue;
	401
	402	token = match_token(ptr, tokens, args);
	403	switch (token) {
	404	case Opt_rd_pages:
	405	match_int(args, &arg);
	406	rd_dev->rd_page_count = arg;
	407	pr_debug("RAMDISK: Referencing Page"
	408	" Count: %u\n", rd_dev->rd_page_count);
	409	rd_dev->rd_flags \|= RDF_HAS_PAGE_COUNT;
	410	break;
	411	default:
	412	break;
	413	}
	414	}
	415
	416	kfree(orig);
	417	return (!ret) ? count : ret;
	418	}
	419
	420	static ssize_t rd_show_configfs_dev_params(struct se_device dev, char b)
	421	{
	422	struct rd_dev *rd_dev = RD_DEV(dev);
	423
	424	ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
	425	rd_dev->rd_dev_id);
	426	bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu"
	427	" SG_table_count: %u\n", rd_dev->rd_page_count,
	428	PAGE_SIZE, rd_dev->sg_table_count);
	429	return bl;
	430	}
	431
	432	static sector_t rd_get_blocks(struct se_device *dev)
	433	{
	434	struct rd_dev *rd_dev = RD_DEV(dev);
	435
	436	unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
	437	dev->dev_attrib.block_size) - 1;
	438
	439	return blocks_long;
	440	}
	441
	442	static struct sbc_ops rd_sbc_ops = {
	443	.execute_rw = rd_execute_rw,
	444	};
	445
	446	static sense_reason_t
	447	rd_parse_cdb(struct se_cmd *cmd)
	448	{
	449	return sbc_parse_cdb(cmd, &rd_sbc_ops);
	450	}
	451
	452	static struct se_subsystem_api rd_mcp_template = {
	453	.name = "rd_mcp",
	454	.inquiry_prod = "RAMDISK-MCP",
	455	.inquiry_rev = RD_MCP_VERSION,
	456	.transport_type = TRANSPORT_PLUGIN_VHBA_VDEV,
	457	.attach_hba = rd_attach_hba,
	458	.detach_hba = rd_detach_hba,
	459	.alloc_device = rd_alloc_device,
	460	.configure_device = rd_configure_device,
	461	.free_device = rd_free_device,
	462	.parse_cdb = rd_parse_cdb,
	463	.set_configfs_dev_params = rd_set_configfs_dev_params,
	464	.show_configfs_dev_params = rd_show_configfs_dev_params,
	465	.get_device_type = sbc_get_device_type,
	466	.get_blocks = rd_get_blocks,
	467	};
	468
	469	int __init rd_module_init(void)
	470	{
	471	int ret;
	472
	473	ret = transport_subsystem_register(&rd_mcp_template);
	474	if (ret < 0) {
	475	return ret;
	476	}
	477
	478	return 0;
	479	}
	480
	481	void rd_module_exit(void)
	482	{
	483	transport_subsystem_release(&rd_mcp_template);
	484	}