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 			if (!dst)
394 				BUG();
395 
396 			src = sg_virt(&sg_s[j]) + src_offset;
397 			if (!src)
398 				BUG();
399 
400 			dst_offset = 0;
401 			src_offset = length;
402 			page_end = 0;
403 		} else {
404 			length = (sg_s[j].length - src_offset);
405 
406 			pr_debug("Step 2 - sg_d[%d]: %p length: %d"
407 				" offset: %u sg_s[%d].length: %u\n", i,
408 				&sg_d[i], sg_d[i].length, sg_d[i].offset,
409 				j, sg_s[j].length);
410 			pr_debug("Step 2 - length: %u dst_offset: %u"
411 				" src_offset: %u\n", length, dst_offset,
412 				src_offset);
413 
414 			if (length > req->rd_size)
415 				length = req->rd_size;
416 
417 			dst = sg_virt(&sg_d[i]) + dst_offset;
418 			if (!dst)
419 				BUG();
420 
421 			if (sg_d[i].length == length) {
422 				i++;
423 				dst_offset = 0;
424 			} else
425 				dst_offset = length;
426 
427 			src = sg_virt(&sg_s[j++]) + src_offset;
428 			if (!src)
429 				BUG();
430 
431 			src_offset = 0;
432 			page_end = 1;
433 		}
434 
435 		memcpy(dst, src, length);
436 
437 		pr_debug("page: %u, remaining size: %u, length: %u,"
438 			" i: %u, j: %u\n", req->rd_page,
439 			(req->rd_size - length), length, i, j);
440 
441 		req->rd_size -= length;
442 		if (!req->rd_size)
443 			return 0;
444 
445 		if (!page_end)
446 			continue;
447 
448 		if (++req->rd_page <= table->page_end_offset) {
449 			pr_debug("page: %u in same page table\n",
450 				req->rd_page);
451 			continue;
452 		}
453 
454 		pr_debug("getting new page table for page: %u\n",
455 				req->rd_page);
456 
457 		table = rd_get_sg_table(dev, req->rd_page);
458 		if (!table)
459 			return -EINVAL;
460 
461 		sg_s = &table->sg_table[j = 0];
462 	}
463 
464 	return 0;
465 }
466 
467 /*	rd_MEMCPY_write():
468  *
469  *
470  */
471 static int rd_MEMCPY_write(struct rd_request *req)
472 {
473 	struct se_task *task = &req->rd_task;
474 	struct rd_dev *dev = req->rd_task.se_dev->dev_ptr;
475 	struct rd_dev_sg_table *table;
476 	struct scatterlist *sg_d, *sg_s;
477 	void *dst, *src;
478 	u32 i = 0, j = 0, dst_offset = 0, src_offset = 0;
479 	u32 length, page_end = 0, table_sg_end;
480 	u32 rd_offset = req->rd_offset;
481 
482 	table = rd_get_sg_table(dev, req->rd_page);
483 	if (!table)
484 		return -EINVAL;
485 
486 	table_sg_end = (table->page_end_offset - req->rd_page);
487 	sg_d = &table->sg_table[req->rd_page - table->page_start_offset];
488 	sg_s = task->task_sg;
489 
490 	pr_debug("RD[%d] Write LBA: %llu, Size: %u, Page: %u,"
491 		" Offset: %u\n", dev->rd_dev_id, task->task_lba, req->rd_size,
492 		req->rd_page, req->rd_offset);
493 
494 	dst_offset = rd_offset;
495 
496 	while (req->rd_size) {
497 		if ((sg_s[i].length - src_offset) <
498 		    (sg_d[j].length - dst_offset)) {
499 			length = (sg_s[i].length - src_offset);
500 
501 			pr_debug("Step 1 - sg_s[%d]: %p length: %d"
502 				" offset: %d sg_d[%d].length: %u\n", i,
503 				&sg_s[i], sg_s[i].length, sg_s[i].offset,
504 				j, sg_d[j].length);
505 			pr_debug("Step 1 - length: %u src_offset: %u"
506 				" dst_offset: %u\n", length, src_offset,
507 				dst_offset);
508 
509 			if (length > req->rd_size)
510 				length = req->rd_size;
511 
512 			src = sg_virt(&sg_s[i++]) + src_offset;
513 			if (!src)
514 				BUG();
515 
516 			dst = sg_virt(&sg_d[j]) + dst_offset;
517 			if (!dst)
518 				BUG();
519 
520 			src_offset = 0;
521 			dst_offset = length;
522 			page_end = 0;
523 		} else {
524 			length = (sg_d[j].length - dst_offset);
525 
526 			pr_debug("Step 2 - sg_s[%d]: %p length: %d"
527 				" offset: %d sg_d[%d].length: %u\n", i,
528 				&sg_s[i], sg_s[i].length, sg_s[i].offset,
529 				j, sg_d[j].length);
530 			pr_debug("Step 2 - length: %u src_offset: %u"
531 				" dst_offset: %u\n", length, src_offset,
532 				dst_offset);
533 
534 			if (length > req->rd_size)
535 				length = req->rd_size;
536 
537 			src = sg_virt(&sg_s[i]) + src_offset;
538 			if (!src)
539 				BUG();
540 
541 			if (sg_s[i].length == length) {
542 				i++;
543 				src_offset = 0;
544 			} else
545 				src_offset = length;
546 
547 			dst = sg_virt(&sg_d[j++]) + dst_offset;
548 			if (!dst)
549 				BUG();
550 
551 			dst_offset = 0;
552 			page_end = 1;
553 		}
554 
555 		memcpy(dst, src, length);
556 
557 		pr_debug("page: %u, remaining size: %u, length: %u,"
558 			" i: %u, j: %u\n", req->rd_page,
559 			(req->rd_size - length), length, i, j);
560 
561 		req->rd_size -= length;
562 		if (!req->rd_size)
563 			return 0;
564 
565 		if (!page_end)
566 			continue;
567 
568 		if (++req->rd_page <= table->page_end_offset) {
569 			pr_debug("page: %u in same page table\n",
570 				req->rd_page);
571 			continue;
572 		}
573 
574 		pr_debug("getting new page table for page: %u\n",
575 				req->rd_page);
576 
577 		table = rd_get_sg_table(dev, req->rd_page);
578 		if (!table)
579 			return -EINVAL;
580 
581 		sg_d = &table->sg_table[j = 0];
582 	}
583 
584 	return 0;
585 }
586 
587 /*	rd_MEMCPY_do_task(): (Part of se_subsystem_api_t template)
588  *
589  *
590  */
591 static int rd_MEMCPY_do_task(struct se_task *task)
592 {
593 	struct se_device *dev = task->se_dev;
594 	struct rd_request *req = RD_REQ(task);
595 	unsigned long long lba;
596 	int ret;
597 
598 	req->rd_page = (task->task_lba * dev->se_sub_dev->se_dev_attrib.block_size) / PAGE_SIZE;
599 	lba = task->task_lba;
600 	req->rd_offset = (do_div(lba,
601 			  (PAGE_SIZE / dev->se_sub_dev->se_dev_attrib.block_size))) *
602 			   dev->se_sub_dev->se_dev_attrib.block_size;
603 	req->rd_size = task->task_size;
604 
605 	if (task->task_data_direction == DMA_FROM_DEVICE)
606 		ret = rd_MEMCPY_read(req);
607 	else
608 		ret = rd_MEMCPY_write(req);
609 
610 	if (ret != 0)
611 		return ret;
612 
613 	task->task_scsi_status = GOOD;
614 	transport_complete_task(task, 1);
615 
616 	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
617 }
618 
619 /*	rd_free_task(): (Part of se_subsystem_api_t template)
620  *
621  *
622  */
623 static void rd_free_task(struct se_task *task)
624 {
625 	kfree(RD_REQ(task));
626 }
627 
628 enum {
629 	Opt_rd_pages, Opt_err
630 };
631 
632 static match_table_t tokens = {
633 	{Opt_rd_pages, "rd_pages=%d"},
634 	{Opt_err, NULL}
635 };
636 
637 static ssize_t rd_set_configfs_dev_params(
638 	struct se_hba *hba,
639 	struct se_subsystem_dev *se_dev,
640 	const char *page,
641 	ssize_t count)
642 {
643 	struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
644 	char *orig, *ptr, *opts;
645 	substring_t args[MAX_OPT_ARGS];
646 	int ret = 0, arg, token;
647 
648 	opts = kstrdup(page, GFP_KERNEL);
649 	if (!opts)
650 		return -ENOMEM;
651 
652 	orig = opts;
653 
654 	while ((ptr = strsep(&opts, ",")) != NULL) {
655 		if (!*ptr)
656 			continue;
657 
658 		token = match_token(ptr, tokens, args);
659 		switch (token) {
660 		case Opt_rd_pages:
661 			match_int(args, &arg);
662 			rd_dev->rd_page_count = arg;
663 			pr_debug("RAMDISK: Referencing Page"
664 				" Count: %u\n", rd_dev->rd_page_count);
665 			rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
666 			break;
667 		default:
668 			break;
669 		}
670 	}
671 
672 	kfree(orig);
673 	return (!ret) ? count : ret;
674 }
675 
676 static ssize_t rd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
677 {
678 	struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
679 
680 	if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
681 		pr_debug("Missing rd_pages= parameter\n");
682 		return -EINVAL;
683 	}
684 
685 	return 0;
686 }
687 
688 static ssize_t rd_show_configfs_dev_params(
689 	struct se_hba *hba,
690 	struct se_subsystem_dev *se_dev,
691 	char *b)
692 {
693 	struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
694 	ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: %s\n",
695 			rd_dev->rd_dev_id, (rd_dev->rd_direct) ?
696 			"rd_direct" : "rd_mcp");
697 	bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
698 			"  SG_table_count: %u\n", rd_dev->rd_page_count,
699 			PAGE_SIZE, rd_dev->sg_table_count);
700 	return bl;
701 }
702 
703 /*	rd_get_cdb(): (Part of se_subsystem_api_t template)
704  *
705  *
706  */
707 static unsigned char *rd_get_cdb(struct se_task *task)
708 {
709 	struct rd_request *req = RD_REQ(task);
710 
711 	return req->rd_scsi_cdb;
712 }
713 
714 static u32 rd_get_device_rev(struct se_device *dev)
715 {
716 	return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
717 }
718 
719 static u32 rd_get_device_type(struct se_device *dev)
720 {
721 	return TYPE_DISK;
722 }
723 
724 static sector_t rd_get_blocks(struct se_device *dev)
725 {
726 	struct rd_dev *rd_dev = dev->dev_ptr;
727 	unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
728 			dev->se_sub_dev->se_dev_attrib.block_size) - 1;
729 
730 	return blocks_long;
731 }
732 
733 static struct se_subsystem_api rd_mcp_template = {
734 	.name			= "rd_mcp",
735 	.transport_type		= TRANSPORT_PLUGIN_VHBA_VDEV,
736 	.attach_hba		= rd_attach_hba,
737 	.detach_hba		= rd_detach_hba,
738 	.allocate_virtdevice	= rd_MEMCPY_allocate_virtdevice,
739 	.create_virtdevice	= rd_MEMCPY_create_virtdevice,
740 	.free_device		= rd_free_device,
741 	.alloc_task		= rd_alloc_task,
742 	.do_task		= rd_MEMCPY_do_task,
743 	.free_task		= rd_free_task,
744 	.check_configfs_dev_params = rd_check_configfs_dev_params,
745 	.set_configfs_dev_params = rd_set_configfs_dev_params,
746 	.show_configfs_dev_params = rd_show_configfs_dev_params,
747 	.get_cdb		= rd_get_cdb,
748 	.get_device_rev		= rd_get_device_rev,
749 	.get_device_type	= rd_get_device_type,
750 	.get_blocks		= rd_get_blocks,
751 };
752 
753 int __init rd_module_init(void)
754 {
755 	int ret;
756 
757 	ret = transport_subsystem_register(&rd_mcp_template);
758 	if (ret < 0) {
759 		return ret;
760 	}
761 
762 	return 0;
763 }
764 
765 void rd_module_exit(void)
766 {
767 	transport_subsystem_release(&rd_mcp_template);
768 }
769