1 /*******************************************************************************
2  * Filename:  target_core_rd.c
3  *
4  * This file contains the Storage Engine <-> Ramdisk transport
5  * specific functions.
6  *
7  * Copyright (c) 2003, 2004, 2005 PyX Technologies, Inc.
8  * Copyright (c) 2005, 2006, 2007 SBE, Inc.
9  * Copyright (c) 2007-2010 Rising Tide Systems
10  * Copyright (c) 2008-2010 Linux-iSCSI.org
11  *
12  * Nicholas A. Bellinger <nab@kernel.org>
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2 of the License, or
17  * (at your option) any later version.
18  *
19  * This program is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  * GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with this program; if not, write to the Free Software
26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27  *
28  ******************************************************************************/
29 
30 #include <linux/version.h>
31 #include <linux/string.h>
32 #include <linux/parser.h>
33 #include <linux/timer.h>
34 #include <linux/blkdev.h>
35 #include <linux/slab.h>
36 #include <linux/spinlock.h>
37 #include <scsi/scsi.h>
38 #include <scsi/scsi_host.h>
39 
40 #include <target/target_core_base.h>
41 #include <target/target_core_device.h>
42 #include <target/target_core_transport.h>
43 #include <target/target_core_fabric_ops.h>
44 
45 #include "target_core_rd.h"
46 
47 static struct se_subsystem_api rd_mcp_template;
48 
49 /*	rd_attach_hba(): (Part of se_subsystem_api_t template)
50  *
51  *
52  */
53 static int rd_attach_hba(struct se_hba *hba, u32 host_id)
54 {
55 	struct rd_host *rd_host;
56 
57 	rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
58 	if (!rd_host) {
59 		pr_err("Unable to allocate memory for struct rd_host\n");
60 		return -ENOMEM;
61 	}
62 
63 	rd_host->rd_host_id = host_id;
64 
65 	hba->hba_ptr = rd_host;
66 
67 	pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
68 		" Generic Target Core Stack %s\n", hba->hba_id,
69 		RD_HBA_VERSION, TARGET_CORE_MOD_VERSION);
70 	pr_debug("CORE_HBA[%d] - Attached Ramdisk HBA: %u to Generic"
71 		" MaxSectors: %u\n", hba->hba_id,
72 		rd_host->rd_host_id, RD_MAX_SECTORS);
73 
74 	return 0;
75 }
76 
77 static void rd_detach_hba(struct se_hba *hba)
78 {
79 	struct rd_host *rd_host = hba->hba_ptr;
80 
81 	pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
82 		" Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
83 
84 	kfree(rd_host);
85 	hba->hba_ptr = NULL;
86 }
87 
88 /*	rd_release_device_space():
89  *
90  *
91  */
92 static void rd_release_device_space(struct rd_dev *rd_dev)
93 {
94 	u32 i, j, page_count = 0, sg_per_table;
95 	struct rd_dev_sg_table *sg_table;
96 	struct page *pg;
97 	struct scatterlist *sg;
98 
99 	if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
100 		return;
101 
102 	sg_table = rd_dev->sg_table_array;
103 
104 	for (i = 0; i < rd_dev->sg_table_count; i++) {
105 		sg = sg_table[i].sg_table;
106 		sg_per_table = sg_table[i].rd_sg_count;
107 
108 		for (j = 0; j < sg_per_table; j++) {
109 			pg = sg_page(&sg[j]);
110 			if (pg) {
111 				__free_page(pg);
112 				page_count++;
113 			}
114 		}
115 
116 		kfree(sg);
117 	}
118 
119 	pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
120 		" Device ID: %u, pages %u in %u tables total bytes %lu\n",
121 		rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
122 		rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
123 
124 	kfree(sg_table);
125 	rd_dev->sg_table_array = NULL;
126 	rd_dev->sg_table_count = 0;
127 }
128 
129 
130 /*	rd_build_device_space():
131  *
132  *
133  */
134 static int rd_build_device_space(struct rd_dev *rd_dev)
135 {
136 	u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed;
137 	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
138 				sizeof(struct scatterlist));
139 	struct rd_dev_sg_table *sg_table;
140 	struct page *pg;
141 	struct scatterlist *sg;
142 
143 	if (rd_dev->rd_page_count <= 0) {
144 		pr_err("Illegal page count: %u for Ramdisk device\n",
145 			rd_dev->rd_page_count);
146 		return -EINVAL;
147 	}
148 	total_sg_needed = rd_dev->rd_page_count;
149 
150 	sg_tables = (total_sg_needed / max_sg_per_table) + 1;
151 
152 	sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
153 	if (!sg_table) {
154 		pr_err("Unable to allocate memory for Ramdisk"
155 			" scatterlist tables\n");
156 		return -ENOMEM;
157 	}
158 
159 	rd_dev->sg_table_array = sg_table;
160 	rd_dev->sg_table_count = sg_tables;
161 
162 	while (total_sg_needed) {
163 		sg_per_table = (total_sg_needed > max_sg_per_table) ?
164 			max_sg_per_table : total_sg_needed;
165 
166 		sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
167 				GFP_KERNEL);
168 		if (!sg) {
169 			pr_err("Unable to allocate scatterlist array"
170 				" for struct rd_dev\n");
171 			return -ENOMEM;
172 		}
173 
174 		sg_init_table(sg, sg_per_table);
175 
176 		sg_table[i].sg_table = sg;
177 		sg_table[i].rd_sg_count = sg_per_table;
178 		sg_table[i].page_start_offset = page_offset;
179 		sg_table[i++].page_end_offset = (page_offset + sg_per_table)
180 						- 1;
181 
182 		for (j = 0; j < sg_per_table; j++) {
183 			pg = alloc_pages(GFP_KERNEL, 0);
184 			if (!pg) {
185 				pr_err("Unable to allocate scatterlist"
186 					" pages for struct rd_dev_sg_table\n");
187 				return -ENOMEM;
188 			}
189 			sg_assign_page(&sg[j], pg);
190 			sg[j].length = PAGE_SIZE;
191 		}
192 
193 		page_offset += sg_per_table;
194 		total_sg_needed -= sg_per_table;
195 	}
196 
197 	pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
198 		" %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
199 		rd_dev->rd_dev_id, rd_dev->rd_page_count,
200 		rd_dev->sg_table_count);
201 
202 	return 0;
203 }
204 
205 static void *rd_allocate_virtdevice(
206 	struct se_hba *hba,
207 	const char *name,
208 	int rd_direct)
209 {
210 	struct rd_dev *rd_dev;
211 	struct rd_host *rd_host = hba->hba_ptr;
212 
213 	rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
214 	if (!rd_dev) {
215 		pr_err("Unable to allocate memory for struct rd_dev\n");
216 		return NULL;
217 	}
218 
219 	rd_dev->rd_host = rd_host;
220 	rd_dev->rd_direct = rd_direct;
221 
222 	return rd_dev;
223 }
224 
225 static void *rd_MEMCPY_allocate_virtdevice(struct se_hba *hba, const char *name)
226 {
227 	return rd_allocate_virtdevice(hba, name, 0);
228 }
229 
230 /*	rd_create_virtdevice():
231  *
232  *
233  */
234 static struct se_device *rd_create_virtdevice(
235 	struct se_hba *hba,
236 	struct se_subsystem_dev *se_dev,
237 	void *p,
238 	int rd_direct)
239 {
240 	struct se_device *dev;
241 	struct se_dev_limits dev_limits;
242 	struct rd_dev *rd_dev = p;
243 	struct rd_host *rd_host = hba->hba_ptr;
244 	int dev_flags = 0, ret;
245 	char prod[16], rev[4];
246 
247 	memset(&dev_limits, 0, sizeof(struct se_dev_limits));
248 
249 	ret = rd_build_device_space(rd_dev);
250 	if (ret < 0)
251 		goto fail;
252 
253 	snprintf(prod, 16, "RAMDISK-%s", (rd_dev->rd_direct) ? "DR" : "MCP");
254 	snprintf(rev, 4, "%s", (rd_dev->rd_direct) ? RD_DR_VERSION :
255 						RD_MCP_VERSION);
256 
257 	dev_limits.limits.logical_block_size = RD_BLOCKSIZE;
258 	dev_limits.limits.max_hw_sectors = RD_MAX_SECTORS;
259 	dev_limits.limits.max_sectors = RD_MAX_SECTORS;
260 	dev_limits.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
261 	dev_limits.queue_depth = RD_DEVICE_QUEUE_DEPTH;
262 
263 	dev = transport_add_device_to_core_hba(hba,
264 			&rd_mcp_template, se_dev, dev_flags, rd_dev,
265 			&dev_limits, prod, rev);
266 	if (!dev)
267 		goto fail;
268 
269 	rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
270 	rd_dev->rd_queue_depth = dev->queue_depth;
271 
272 	pr_debug("CORE_RD[%u] - Added TCM %s Ramdisk Device ID: %u of"
273 		" %u pages in %u tables, %lu total bytes\n",
274 		rd_host->rd_host_id, (!rd_dev->rd_direct) ? "MEMCPY" :
275 		"DIRECT", rd_dev->rd_dev_id, rd_dev->rd_page_count,
276 		rd_dev->sg_table_count,
277 		(unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
278 
279 	return dev;
280 
281 fail:
282 	rd_release_device_space(rd_dev);
283 	return ERR_PTR(ret);
284 }
285 
286 static struct se_device *rd_MEMCPY_create_virtdevice(
287 	struct se_hba *hba,
288 	struct se_subsystem_dev *se_dev,
289 	void *p)
290 {
291 	return rd_create_virtdevice(hba, se_dev, p, 0);
292 }
293 
294 /*	rd_free_device(): (Part of se_subsystem_api_t template)
295  *
296  *
297  */
298 static void rd_free_device(void *p)
299 {
300 	struct rd_dev *rd_dev = p;
301 
302 	rd_release_device_space(rd_dev);
303 	kfree(rd_dev);
304 }
305 
306 static inline struct rd_request *RD_REQ(struct se_task *task)
307 {
308 	return container_of(task, struct rd_request, rd_task);
309 }
310 
311 static struct se_task *
312 rd_alloc_task(unsigned char *cdb)
313 {
314 	struct rd_request *rd_req;
315 
316 	rd_req = kzalloc(sizeof(struct rd_request), GFP_KERNEL);
317 	if (!rd_req) {
318 		pr_err("Unable to allocate struct rd_request\n");
319 		return NULL;
320 	}
321 
322 	return &rd_req->rd_task;
323 }
324 
325 /*	rd_get_sg_table():
326  *
327  *
328  */
329 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
330 {
331 	u32 i;
332 	struct rd_dev_sg_table *sg_table;
333 
334 	for (i = 0; i < rd_dev->sg_table_count; i++) {
335 		sg_table = &rd_dev->sg_table_array[i];
336 		if ((sg_table->page_start_offset <= page) &&
337 		    (sg_table->page_end_offset >= page))
338 			return sg_table;
339 	}
340 
341 	pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
342 			page);
343 
344 	return NULL;
345 }
346 
347 /*	rd_MEMCPY_read():
348  *
349  *
350  */
351 static int rd_MEMCPY_read(struct rd_request *req)
352 {
353 	struct se_task *task = &req->rd_task;
354 	struct rd_dev *dev = req->rd_task.se_dev->dev_ptr;
355 	struct rd_dev_sg_table *table;
356 	struct scatterlist *sg_d, *sg_s;
357 	void *dst, *src;
358 	u32 i = 0, j = 0, dst_offset = 0, src_offset = 0;
359 	u32 length, page_end = 0, table_sg_end;
360 	u32 rd_offset = req->rd_offset;
361 
362 	table = rd_get_sg_table(dev, req->rd_page);
363 	if (!table)
364 		return -EINVAL;
365 
366 	table_sg_end = (table->page_end_offset - req->rd_page);
367 	sg_d = task->task_sg;
368 	sg_s = &table->sg_table[req->rd_page - table->page_start_offset];
369 
370 	pr_debug("RD[%u]: Read LBA: %llu, Size: %u Page: %u, Offset:"
371 		" %u\n", dev->rd_dev_id, task->task_lba, req->rd_size,
372 		req->rd_page, req->rd_offset);
373 
374 	src_offset = rd_offset;
375 
376 	while (req->rd_size) {
377 		if ((sg_d[i].length - dst_offset) <
378 		    (sg_s[j].length - src_offset)) {
379 			length = (sg_d[i].length - dst_offset);
380 
381 			pr_debug("Step 1 - sg_d[%d]: %p length: %d"
382 				" offset: %u sg_s[%d].length: %u\n", i,
383 				&sg_d[i], sg_d[i].length, sg_d[i].offset, j,
384 				sg_s[j].length);
385 			pr_debug("Step 1 - length: %u dst_offset: %u"
386 				" src_offset: %u\n", length, dst_offset,
387 				src_offset);
388 
389 			if (length > req->rd_size)
390 				length = req->rd_size;
391 
392 			dst = sg_virt(&sg_d[i++]) + dst_offset;
393 			BUG_ON(!dst);
394 
395 			src = sg_virt(&sg_s[j]) + src_offset;
396 			BUG_ON(!src);
397 
398 			dst_offset = 0;
399 			src_offset = length;
400 			page_end = 0;
401 		} else {
402 			length = (sg_s[j].length - src_offset);
403 
404 			pr_debug("Step 2 - sg_d[%d]: %p length: %d"
405 				" offset: %u sg_s[%d].length: %u\n", i,
406 				&sg_d[i], sg_d[i].length, sg_d[i].offset,
407 				j, sg_s[j].length);
408 			pr_debug("Step 2 - length: %u dst_offset: %u"
409 				" src_offset: %u\n", length, dst_offset,
410 				src_offset);
411 
412 			if (length > req->rd_size)
413 				length = req->rd_size;
414 
415 			dst = sg_virt(&sg_d[i]) + dst_offset;
416 			BUG_ON(!dst);
417 
418 			if (sg_d[i].length == length) {
419 				i++;
420 				dst_offset = 0;
421 			} else
422 				dst_offset = length;
423 
424 			src = sg_virt(&sg_s[j++]) + src_offset;
425 			BUG_ON(!src);
426 
427 			src_offset = 0;
428 			page_end = 1;
429 		}
430 
431 		memcpy(dst, src, length);
432 
433 		pr_debug("page: %u, remaining size: %u, length: %u,"
434 			" i: %u, j: %u\n", req->rd_page,
435 			(req->rd_size - length), length, i, j);
436 
437 		req->rd_size -= length;
438 		if (!req->rd_size)
439 			return 0;
440 
441 		if (!page_end)
442 			continue;
443 
444 		if (++req->rd_page <= table->page_end_offset) {
445 			pr_debug("page: %u in same page table\n",
446 				req->rd_page);
447 			continue;
448 		}
449 
450 		pr_debug("getting new page table for page: %u\n",
451 				req->rd_page);
452 
453 		table = rd_get_sg_table(dev, req->rd_page);
454 		if (!table)
455 			return -EINVAL;
456 
457 		sg_s = &table->sg_table[j = 0];
458 	}
459 
460 	return 0;
461 }
462 
463 /*	rd_MEMCPY_write():
464  *
465  *
466  */
467 static int rd_MEMCPY_write(struct rd_request *req)
468 {
469 	struct se_task *task = &req->rd_task;
470 	struct rd_dev *dev = req->rd_task.se_dev->dev_ptr;
471 	struct rd_dev_sg_table *table;
472 	struct scatterlist *sg_d, *sg_s;
473 	void *dst, *src;
474 	u32 i = 0, j = 0, dst_offset = 0, src_offset = 0;
475 	u32 length, page_end = 0, table_sg_end;
476 	u32 rd_offset = req->rd_offset;
477 
478 	table = rd_get_sg_table(dev, req->rd_page);
479 	if (!table)
480 		return -EINVAL;
481 
482 	table_sg_end = (table->page_end_offset - req->rd_page);
483 	sg_d = &table->sg_table[req->rd_page - table->page_start_offset];
484 	sg_s = task->task_sg;
485 
486 	pr_debug("RD[%d] Write LBA: %llu, Size: %u, Page: %u,"
487 		" Offset: %u\n", dev->rd_dev_id, task->task_lba, req->rd_size,
488 		req->rd_page, req->rd_offset);
489 
490 	dst_offset = rd_offset;
491 
492 	while (req->rd_size) {
493 		if ((sg_s[i].length - src_offset) <
494 		    (sg_d[j].length - dst_offset)) {
495 			length = (sg_s[i].length - src_offset);
496 
497 			pr_debug("Step 1 - sg_s[%d]: %p length: %d"
498 				" offset: %d sg_d[%d].length: %u\n", i,
499 				&sg_s[i], sg_s[i].length, sg_s[i].offset,
500 				j, sg_d[j].length);
501 			pr_debug("Step 1 - length: %u src_offset: %u"
502 				" dst_offset: %u\n", length, src_offset,
503 				dst_offset);
504 
505 			if (length > req->rd_size)
506 				length = req->rd_size;
507 
508 			src = sg_virt(&sg_s[i++]) + src_offset;
509 			BUG_ON(!src);
510 
511 			dst = sg_virt(&sg_d[j]) + dst_offset;
512 			BUG_ON(!dst);
513 
514 			src_offset = 0;
515 			dst_offset = length;
516 			page_end = 0;
517 		} else {
518 			length = (sg_d[j].length - dst_offset);
519 
520 			pr_debug("Step 2 - sg_s[%d]: %p length: %d"
521 				" offset: %d sg_d[%d].length: %u\n", i,
522 				&sg_s[i], sg_s[i].length, sg_s[i].offset,
523 				j, sg_d[j].length);
524 			pr_debug("Step 2 - length: %u src_offset: %u"
525 				" dst_offset: %u\n", length, src_offset,
526 				dst_offset);
527 
528 			if (length > req->rd_size)
529 				length = req->rd_size;
530 
531 			src = sg_virt(&sg_s[i]) + src_offset;
532 			BUG_ON(!src);
533 
534 			if (sg_s[i].length == length) {
535 				i++;
536 				src_offset = 0;
537 			} else
538 				src_offset = length;
539 
540 			dst = sg_virt(&sg_d[j++]) + dst_offset;
541 			BUG_ON(!dst);
542 
543 			dst_offset = 0;
544 			page_end = 1;
545 		}
546 
547 		memcpy(dst, src, length);
548 
549 		pr_debug("page: %u, remaining size: %u, length: %u,"
550 			" i: %u, j: %u\n", req->rd_page,
551 			(req->rd_size - length), length, i, j);
552 
553 		req->rd_size -= length;
554 		if (!req->rd_size)
555 			return 0;
556 
557 		if (!page_end)
558 			continue;
559 
560 		if (++req->rd_page <= table->page_end_offset) {
561 			pr_debug("page: %u in same page table\n",
562 				req->rd_page);
563 			continue;
564 		}
565 
566 		pr_debug("getting new page table for page: %u\n",
567 				req->rd_page);
568 
569 		table = rd_get_sg_table(dev, req->rd_page);
570 		if (!table)
571 			return -EINVAL;
572 
573 		sg_d = &table->sg_table[j = 0];
574 	}
575 
576 	return 0;
577 }
578 
579 /*	rd_MEMCPY_do_task(): (Part of se_subsystem_api_t template)
580  *
581  *
582  */
583 static int rd_MEMCPY_do_task(struct se_task *task)
584 {
585 	struct se_device *dev = task->se_dev;
586 	struct rd_request *req = RD_REQ(task);
587 	unsigned long long lba;
588 	int ret;
589 
590 	req->rd_page = (task->task_lba * dev->se_sub_dev->se_dev_attrib.block_size) / PAGE_SIZE;
591 	lba = task->task_lba;
592 	req->rd_offset = (do_div(lba,
593 			  (PAGE_SIZE / dev->se_sub_dev->se_dev_attrib.block_size))) *
594 			   dev->se_sub_dev->se_dev_attrib.block_size;
595 	req->rd_size = task->task_size;
596 
597 	if (task->task_data_direction == DMA_FROM_DEVICE)
598 		ret = rd_MEMCPY_read(req);
599 	else
600 		ret = rd_MEMCPY_write(req);
601 
602 	if (ret != 0)
603 		return ret;
604 
605 	task->task_scsi_status = GOOD;
606 	transport_complete_task(task, 1);
607 
608 	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
609 }
610 
611 /*	rd_free_task(): (Part of se_subsystem_api_t template)
612  *
613  *
614  */
615 static void rd_free_task(struct se_task *task)
616 {
617 	kfree(RD_REQ(task));
618 }
619 
620 enum {
621 	Opt_rd_pages, Opt_err
622 };
623 
624 static match_table_t tokens = {
625 	{Opt_rd_pages, "rd_pages=%d"},
626 	{Opt_err, NULL}
627 };
628 
629 static ssize_t rd_set_configfs_dev_params(
630 	struct se_hba *hba,
631 	struct se_subsystem_dev *se_dev,
632 	const char *page,
633 	ssize_t count)
634 {
635 	struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
636 	char *orig, *ptr, *opts;
637 	substring_t args[MAX_OPT_ARGS];
638 	int ret = 0, arg, token;
639 
640 	opts = kstrdup(page, GFP_KERNEL);
641 	if (!opts)
642 		return -ENOMEM;
643 
644 	orig = opts;
645 
646 	while ((ptr = strsep(&opts, ",")) != NULL) {
647 		if (!*ptr)
648 			continue;
649 
650 		token = match_token(ptr, tokens, args);
651 		switch (token) {
652 		case Opt_rd_pages:
653 			match_int(args, &arg);
654 			rd_dev->rd_page_count = arg;
655 			pr_debug("RAMDISK: Referencing Page"
656 				" Count: %u\n", rd_dev->rd_page_count);
657 			rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
658 			break;
659 		default:
660 			break;
661 		}
662 	}
663 
664 	kfree(orig);
665 	return (!ret) ? count : ret;
666 }
667 
668 static ssize_t rd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
669 {
670 	struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
671 
672 	if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
673 		pr_debug("Missing rd_pages= parameter\n");
674 		return -EINVAL;
675 	}
676 
677 	return 0;
678 }
679 
680 static ssize_t rd_show_configfs_dev_params(
681 	struct se_hba *hba,
682 	struct se_subsystem_dev *se_dev,
683 	char *b)
684 {
685 	struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
686 	ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: %s\n",
687 			rd_dev->rd_dev_id, (rd_dev->rd_direct) ?
688 			"rd_direct" : "rd_mcp");
689 	bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
690 			"  SG_table_count: %u\n", rd_dev->rd_page_count,
691 			PAGE_SIZE, rd_dev->sg_table_count);
692 	return bl;
693 }
694 
695 /*	rd_get_cdb(): (Part of se_subsystem_api_t template)
696  *
697  *
698  */
699 static unsigned char *rd_get_cdb(struct se_task *task)
700 {
701 	struct rd_request *req = RD_REQ(task);
702 
703 	return req->rd_scsi_cdb;
704 }
705 
706 static u32 rd_get_device_rev(struct se_device *dev)
707 {
708 	return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
709 }
710 
711 static u32 rd_get_device_type(struct se_device *dev)
712 {
713 	return TYPE_DISK;
714 }
715 
716 static sector_t rd_get_blocks(struct se_device *dev)
717 {
718 	struct rd_dev *rd_dev = dev->dev_ptr;
719 	unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
720 			dev->se_sub_dev->se_dev_attrib.block_size) - 1;
721 
722 	return blocks_long;
723 }
724 
725 static struct se_subsystem_api rd_mcp_template = {
726 	.name			= "rd_mcp",
727 	.transport_type		= TRANSPORT_PLUGIN_VHBA_VDEV,
728 	.attach_hba		= rd_attach_hba,
729 	.detach_hba		= rd_detach_hba,
730 	.allocate_virtdevice	= rd_MEMCPY_allocate_virtdevice,
731 	.create_virtdevice	= rd_MEMCPY_create_virtdevice,
732 	.free_device		= rd_free_device,
733 	.alloc_task		= rd_alloc_task,
734 	.do_task		= rd_MEMCPY_do_task,
735 	.free_task		= rd_free_task,
736 	.check_configfs_dev_params = rd_check_configfs_dev_params,
737 	.set_configfs_dev_params = rd_set_configfs_dev_params,
738 	.show_configfs_dev_params = rd_show_configfs_dev_params,
739 	.get_cdb		= rd_get_cdb,
740 	.get_device_rev		= rd_get_device_rev,
741 	.get_device_type	= rd_get_device_type,
742 	.get_blocks		= rd_get_blocks,
743 };
744 
745 int __init rd_module_init(void)
746 {
747 	int ret;
748 
749 	ret = transport_subsystem_register(&rd_mcp_template);
750 	if (ret < 0) {
751 		return ret;
752 	}
753 
754 	return 0;
755 }
756 
757 void rd_module_exit(void)
758 {
759 	transport_subsystem_release(&rd_mcp_template);
760 }
761