1 /*******************************************************************************
2  * Filename:  target_core_rd.c
3  *
4  * This file contains the Storage Engine <-> Ramdisk transport
5  * specific functions.
6  *
7  * (c) Copyright 2003-2013 Datera, Inc.
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/slab.h>
31 #include <linux/spinlock.h>
32 #include <scsi/scsi.h>
33 #include <scsi/scsi_host.h>
34 
35 #include <target/target_core_base.h>
36 #include <target/target_core_backend.h>
37 #include <target/target_core_backend_configfs.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 static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
83 				 u32 sg_table_count)
84 {
85 	struct page *pg;
86 	struct scatterlist *sg;
87 	u32 i, j, page_count = 0, sg_per_table;
88 
89 	for (i = 0; i < sg_table_count; i++) {
90 		sg = sg_table[i].sg_table;
91 		sg_per_table = sg_table[i].rd_sg_count;
92 
93 		for (j = 0; j < sg_per_table; j++) {
94 			pg = sg_page(&sg[j]);
95 			if (pg) {
96 				__free_page(pg);
97 				page_count++;
98 			}
99 		}
100 		kfree(sg);
101 	}
102 
103 	kfree(sg_table);
104 	return page_count;
105 }
106 
107 static void rd_release_device_space(struct rd_dev *rd_dev)
108 {
109 	u32 page_count;
110 
111 	if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
112 		return;
113 
114 	page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array,
115 					  rd_dev->sg_table_count);
116 
117 	pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
118 		" Device ID: %u, pages %u in %u tables total bytes %lu\n",
119 		rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
120 		rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
121 
122 	rd_dev->sg_table_array = NULL;
123 	rd_dev->sg_table_count = 0;
124 }
125 
126 
127 /*	rd_build_device_space():
128  *
129  *
130  */
131 static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
132 				 u32 total_sg_needed, unsigned char init_payload)
133 {
134 	u32 i = 0, j, page_offset = 0, sg_per_table;
135 	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
136 				sizeof(struct scatterlist));
137 	struct page *pg;
138 	struct scatterlist *sg;
139 	unsigned char *p;
140 
141 	while (total_sg_needed) {
142 		unsigned int chain_entry = 0;
143 
144 		sg_per_table = (total_sg_needed > max_sg_per_table) ?
145 			max_sg_per_table : total_sg_needed;
146 
147 #ifdef CONFIG_ARCH_HAS_SG_CHAIN
148 
149 		/*
150 		 * Reserve extra element for chain entry
151 		 */
152 		if (sg_per_table < total_sg_needed)
153 			chain_entry = 1;
154 
155 #endif /* CONFIG_ARCH_HAS_SG_CHAIN */
156 
157 		sg = kcalloc(sg_per_table + chain_entry, sizeof(*sg),
158 				GFP_KERNEL);
159 		if (!sg) {
160 			pr_err("Unable to allocate scatterlist array"
161 				" for struct rd_dev\n");
162 			return -ENOMEM;
163 		}
164 
165 		sg_init_table(sg, sg_per_table + chain_entry);
166 
167 #ifdef CONFIG_ARCH_HAS_SG_CHAIN
168 
169 		if (i > 0) {
170 			sg_chain(sg_table[i - 1].sg_table,
171 				 max_sg_per_table + 1, sg);
172 		}
173 
174 #endif /* CONFIG_ARCH_HAS_SG_CHAIN */
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 			p = kmap(pg);
193 			memset(p, init_payload, PAGE_SIZE);
194 			kunmap(pg);
195 		}
196 
197 		page_offset += sg_per_table;
198 		total_sg_needed -= sg_per_table;
199 	}
200 
201 	return 0;
202 }
203 
204 static int rd_build_device_space(struct rd_dev *rd_dev)
205 {
206 	struct rd_dev_sg_table *sg_table;
207 	u32 sg_tables, total_sg_needed;
208 	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
209 				sizeof(struct scatterlist));
210 	int rc;
211 
212 	if (rd_dev->rd_page_count <= 0) {
213 		pr_err("Illegal page count: %u for Ramdisk device\n",
214 		       rd_dev->rd_page_count);
215 		return -EINVAL;
216 	}
217 
218 	/* Don't need backing pages for NULLIO */
219 	if (rd_dev->rd_flags & RDF_NULLIO)
220 		return 0;
221 
222 	total_sg_needed = rd_dev->rd_page_count;
223 
224 	sg_tables = (total_sg_needed / max_sg_per_table) + 1;
225 
226 	sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
227 	if (!sg_table) {
228 		pr_err("Unable to allocate memory for Ramdisk"
229 		       " scatterlist tables\n");
230 		return -ENOMEM;
231 	}
232 
233 	rd_dev->sg_table_array = sg_table;
234 	rd_dev->sg_table_count = sg_tables;
235 
236 	rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00);
237 	if (rc)
238 		return rc;
239 
240 	pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
241 		 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
242 		 rd_dev->rd_dev_id, rd_dev->rd_page_count,
243 		 rd_dev->sg_table_count);
244 
245 	return 0;
246 }
247 
248 static void rd_release_prot_space(struct rd_dev *rd_dev)
249 {
250 	u32 page_count;
251 
252 	if (!rd_dev->sg_prot_array || !rd_dev->sg_prot_count)
253 		return;
254 
255 	page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_prot_array,
256 					  rd_dev->sg_prot_count);
257 
258 	pr_debug("CORE_RD[%u] - Released protection space for Ramdisk"
259 		 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
260 		 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
261 		 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
262 
263 	rd_dev->sg_prot_array = NULL;
264 	rd_dev->sg_prot_count = 0;
265 }
266 
267 static int rd_build_prot_space(struct rd_dev *rd_dev, int prot_length, int block_size)
268 {
269 	struct rd_dev_sg_table *sg_table;
270 	u32 total_sg_needed, sg_tables;
271 	u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
272 				sizeof(struct scatterlist));
273 	int rc;
274 
275 	if (rd_dev->rd_flags & RDF_NULLIO)
276 		return 0;
277 	/*
278 	 * prot_length=8byte dif data
279 	 * tot sg needed = rd_page_count * (PGSZ/block_size) *
280 	 * 		   (prot_length/block_size) + pad
281 	 * PGSZ canceled each other.
282 	 */
283 	total_sg_needed = (rd_dev->rd_page_count * prot_length / block_size) + 1;
284 
285 	sg_tables = (total_sg_needed / max_sg_per_table) + 1;
286 
287 	sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
288 	if (!sg_table) {
289 		pr_err("Unable to allocate memory for Ramdisk protection"
290 		       " scatterlist tables\n");
291 		return -ENOMEM;
292 	}
293 
294 	rd_dev->sg_prot_array = sg_table;
295 	rd_dev->sg_prot_count = sg_tables;
296 
297 	rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0xff);
298 	if (rc)
299 		return rc;
300 
301 	pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u prot space of"
302 		 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
303 		 rd_dev->rd_dev_id, total_sg_needed, rd_dev->sg_prot_count);
304 
305 	return 0;
306 }
307 
308 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
309 {
310 	struct rd_dev *rd_dev;
311 	struct rd_host *rd_host = hba->hba_ptr;
312 
313 	rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
314 	if (!rd_dev) {
315 		pr_err("Unable to allocate memory for struct rd_dev\n");
316 		return NULL;
317 	}
318 
319 	rd_dev->rd_host = rd_host;
320 
321 	return &rd_dev->dev;
322 }
323 
324 static int rd_configure_device(struct se_device *dev)
325 {
326 	struct rd_dev *rd_dev = RD_DEV(dev);
327 	struct rd_host *rd_host = dev->se_hba->hba_ptr;
328 	int ret;
329 
330 	if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
331 		pr_debug("Missing rd_pages= parameter\n");
332 		return -EINVAL;
333 	}
334 
335 	ret = rd_build_device_space(rd_dev);
336 	if (ret < 0)
337 		goto fail;
338 
339 	dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
340 	dev->dev_attrib.hw_max_sectors = UINT_MAX;
341 	dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
342 
343 	rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
344 
345 	pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
346 		" %u pages in %u tables, %lu total bytes\n",
347 		rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
348 		rd_dev->sg_table_count,
349 		(unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
350 
351 	return 0;
352 
353 fail:
354 	rd_release_device_space(rd_dev);
355 	return ret;
356 }
357 
358 static void rd_free_device(struct se_device *dev)
359 {
360 	struct rd_dev *rd_dev = RD_DEV(dev);
361 
362 	rd_release_device_space(rd_dev);
363 	kfree(rd_dev);
364 }
365 
366 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
367 {
368 	struct rd_dev_sg_table *sg_table;
369 	u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
370 				sizeof(struct scatterlist));
371 
372 	i = page / sg_per_table;
373 	if (i < rd_dev->sg_table_count) {
374 		sg_table = &rd_dev->sg_table_array[i];
375 		if ((sg_table->page_start_offset <= page) &&
376 		    (sg_table->page_end_offset >= page))
377 			return sg_table;
378 	}
379 
380 	pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
381 			page);
382 
383 	return NULL;
384 }
385 
386 static struct rd_dev_sg_table *rd_get_prot_table(struct rd_dev *rd_dev, u32 page)
387 {
388 	struct rd_dev_sg_table *sg_table;
389 	u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
390 				sizeof(struct scatterlist));
391 
392 	i = page / sg_per_table;
393 	if (i < rd_dev->sg_prot_count) {
394 		sg_table = &rd_dev->sg_prot_array[i];
395 		if ((sg_table->page_start_offset <= page) &&
396 		     (sg_table->page_end_offset >= page))
397 			return sg_table;
398 	}
399 
400 	pr_err("Unable to locate struct prot rd_dev_sg_table for page: %u\n",
401 			page);
402 
403 	return NULL;
404 }
405 
406 typedef sense_reason_t (*dif_verify)(struct se_cmd *, sector_t, unsigned int,
407 				     unsigned int, struct scatterlist *, int);
408 
409 static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, dif_verify dif_verify)
410 {
411 	struct se_device *se_dev = cmd->se_dev;
412 	struct rd_dev *dev = RD_DEV(se_dev);
413 	struct rd_dev_sg_table *prot_table;
414 	bool need_to_release = false;
415 	struct scatterlist *prot_sg;
416 	u32 sectors = cmd->data_length / se_dev->dev_attrib.block_size;
417 	u32 prot_offset, prot_page;
418 	u32 prot_npages __maybe_unused;
419 	u64 tmp;
420 	sense_reason_t rc = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
421 
422 	tmp = cmd->t_task_lba * se_dev->prot_length;
423 	prot_offset = do_div(tmp, PAGE_SIZE);
424 	prot_page = tmp;
425 
426 	prot_table = rd_get_prot_table(dev, prot_page);
427 	if (!prot_table)
428 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
429 
430 	prot_sg = &prot_table->sg_table[prot_page -
431 					prot_table->page_start_offset];
432 
433 #ifndef CONFIG_ARCH_HAS_SG_CHAIN
434 
435 	prot_npages = DIV_ROUND_UP(prot_offset + sectors * se_dev->prot_length,
436 				   PAGE_SIZE);
437 
438 	/*
439 	 * Allocate temporaly contiguous scatterlist entries if prot pages
440 	 * straddles multiple scatterlist tables.
441 	 */
442 	if (prot_table->page_end_offset < prot_page + prot_npages - 1) {
443 		int i;
444 
445 		prot_sg = kcalloc(prot_npages, sizeof(*prot_sg), GFP_KERNEL);
446 		if (!prot_sg)
447 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
448 
449 		need_to_release = true;
450 		sg_init_table(prot_sg, prot_npages);
451 
452 		for (i = 0; i < prot_npages; i++) {
453 			if (prot_page + i > prot_table->page_end_offset) {
454 				prot_table = rd_get_prot_table(dev,
455 								prot_page + i);
456 				if (!prot_table) {
457 					kfree(prot_sg);
458 					return rc;
459 				}
460 				sg_unmark_end(&prot_sg[i - 1]);
461 			}
462 			prot_sg[i] = prot_table->sg_table[prot_page + i -
463 						prot_table->page_start_offset];
464 		}
465 	}
466 
467 #endif /* !CONFIG_ARCH_HAS_SG_CHAIN */
468 
469 	rc = dif_verify(cmd, cmd->t_task_lba, sectors, 0, prot_sg, prot_offset);
470 	if (need_to_release)
471 		kfree(prot_sg);
472 
473 	return rc;
474 }
475 
476 static sense_reason_t
477 rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
478 	      enum dma_data_direction data_direction)
479 {
480 	struct se_device *se_dev = cmd->se_dev;
481 	struct rd_dev *dev = RD_DEV(se_dev);
482 	struct rd_dev_sg_table *table;
483 	struct scatterlist *rd_sg;
484 	struct sg_mapping_iter m;
485 	u32 rd_offset;
486 	u32 rd_size;
487 	u32 rd_page;
488 	u32 src_len;
489 	u64 tmp;
490 	sense_reason_t rc;
491 
492 	if (dev->rd_flags & RDF_NULLIO) {
493 		target_complete_cmd(cmd, SAM_STAT_GOOD);
494 		return 0;
495 	}
496 
497 	tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
498 	rd_offset = do_div(tmp, PAGE_SIZE);
499 	rd_page = tmp;
500 	rd_size = cmd->data_length;
501 
502 	table = rd_get_sg_table(dev, rd_page);
503 	if (!table)
504 		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
505 
506 	rd_sg = &table->sg_table[rd_page - table->page_start_offset];
507 
508 	pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
509 			dev->rd_dev_id,
510 			data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
511 			cmd->t_task_lba, rd_size, rd_page, rd_offset);
512 
513 	if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
514 	    data_direction == DMA_TO_DEVICE) {
515 		rc = rd_do_prot_rw(cmd, sbc_dif_verify_write);
516 		if (rc)
517 			return rc;
518 	}
519 
520 	src_len = PAGE_SIZE - rd_offset;
521 	sg_miter_start(&m, sgl, sgl_nents,
522 			data_direction == DMA_FROM_DEVICE ?
523 				SG_MITER_TO_SG : SG_MITER_FROM_SG);
524 	while (rd_size) {
525 		u32 len;
526 		void *rd_addr;
527 
528 		sg_miter_next(&m);
529 		if (!(u32)m.length) {
530 			pr_debug("RD[%u]: invalid sgl %p len %zu\n",
531 				 dev->rd_dev_id, m.addr, m.length);
532 			sg_miter_stop(&m);
533 			return TCM_INCORRECT_AMOUNT_OF_DATA;
534 		}
535 		len = min((u32)m.length, src_len);
536 		if (len > rd_size) {
537 			pr_debug("RD[%u]: size underrun page %d offset %d "
538 				 "size %d\n", dev->rd_dev_id,
539 				 rd_page, rd_offset, rd_size);
540 			len = rd_size;
541 		}
542 		m.consumed = len;
543 
544 		rd_addr = sg_virt(rd_sg) + rd_offset;
545 
546 		if (data_direction == DMA_FROM_DEVICE)
547 			memcpy(m.addr, rd_addr, len);
548 		else
549 			memcpy(rd_addr, m.addr, len);
550 
551 		rd_size -= len;
552 		if (!rd_size)
553 			continue;
554 
555 		src_len -= len;
556 		if (src_len) {
557 			rd_offset += len;
558 			continue;
559 		}
560 
561 		/* rd page completed, next one please */
562 		rd_page++;
563 		rd_offset = 0;
564 		src_len = PAGE_SIZE;
565 		if (rd_page <= table->page_end_offset) {
566 			rd_sg++;
567 			continue;
568 		}
569 
570 		table = rd_get_sg_table(dev, rd_page);
571 		if (!table) {
572 			sg_miter_stop(&m);
573 			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
574 		}
575 
576 		/* since we increment, the first sg entry is correct */
577 		rd_sg = table->sg_table;
578 	}
579 	sg_miter_stop(&m);
580 
581 	if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
582 	    data_direction == DMA_FROM_DEVICE) {
583 		rc = rd_do_prot_rw(cmd, sbc_dif_verify_read);
584 		if (rc)
585 			return rc;
586 	}
587 
588 	target_complete_cmd(cmd, SAM_STAT_GOOD);
589 	return 0;
590 }
591 
592 enum {
593 	Opt_rd_pages, Opt_rd_nullio, Opt_err
594 };
595 
596 static match_table_t tokens = {
597 	{Opt_rd_pages, "rd_pages=%d"},
598 	{Opt_rd_nullio, "rd_nullio=%d"},
599 	{Opt_err, NULL}
600 };
601 
602 static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
603 		const char *page, ssize_t count)
604 {
605 	struct rd_dev *rd_dev = RD_DEV(dev);
606 	char *orig, *ptr, *opts;
607 	substring_t args[MAX_OPT_ARGS];
608 	int ret = 0, arg, token;
609 
610 	opts = kstrdup(page, GFP_KERNEL);
611 	if (!opts)
612 		return -ENOMEM;
613 
614 	orig = opts;
615 
616 	while ((ptr = strsep(&opts, ",\n")) != NULL) {
617 		if (!*ptr)
618 			continue;
619 
620 		token = match_token(ptr, tokens, args);
621 		switch (token) {
622 		case Opt_rd_pages:
623 			match_int(args, &arg);
624 			rd_dev->rd_page_count = arg;
625 			pr_debug("RAMDISK: Referencing Page"
626 				" Count: %u\n", rd_dev->rd_page_count);
627 			rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
628 			break;
629 		case Opt_rd_nullio:
630 			match_int(args, &arg);
631 			if (arg != 1)
632 				break;
633 
634 			pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
635 			rd_dev->rd_flags |= RDF_NULLIO;
636 			break;
637 		default:
638 			break;
639 		}
640 	}
641 
642 	kfree(orig);
643 	return (!ret) ? count : ret;
644 }
645 
646 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
647 {
648 	struct rd_dev *rd_dev = RD_DEV(dev);
649 
650 	ssize_t bl = sprintf(b, "TCM RamDisk ID: %u  RamDisk Makeup: rd_mcp\n",
651 			rd_dev->rd_dev_id);
652 	bl += sprintf(b + bl, "        PAGES/PAGE_SIZE: %u*%lu"
653 			"  SG_table_count: %u  nullio: %d\n", rd_dev->rd_page_count,
654 			PAGE_SIZE, rd_dev->sg_table_count,
655 			!!(rd_dev->rd_flags & RDF_NULLIO));
656 	return bl;
657 }
658 
659 static sector_t rd_get_blocks(struct se_device *dev)
660 {
661 	struct rd_dev *rd_dev = RD_DEV(dev);
662 
663 	unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
664 			dev->dev_attrib.block_size) - 1;
665 
666 	return blocks_long;
667 }
668 
669 static int rd_init_prot(struct se_device *dev)
670 {
671 	struct rd_dev *rd_dev = RD_DEV(dev);
672 
673         if (!dev->dev_attrib.pi_prot_type)
674 		return 0;
675 
676 	return rd_build_prot_space(rd_dev, dev->prot_length,
677 				   dev->dev_attrib.block_size);
678 }
679 
680 static void rd_free_prot(struct se_device *dev)
681 {
682 	struct rd_dev *rd_dev = RD_DEV(dev);
683 
684 	rd_release_prot_space(rd_dev);
685 }
686 
687 static struct sbc_ops rd_sbc_ops = {
688 	.execute_rw		= rd_execute_rw,
689 };
690 
691 static sense_reason_t
692 rd_parse_cdb(struct se_cmd *cmd)
693 {
694 	return sbc_parse_cdb(cmd, &rd_sbc_ops);
695 }
696 
697 DEF_TB_DEFAULT_ATTRIBS(rd_mcp);
698 
699 static struct configfs_attribute *rd_mcp_backend_dev_attrs[] = {
700 	&rd_mcp_dev_attrib_emulate_model_alias.attr,
701 	&rd_mcp_dev_attrib_emulate_dpo.attr,
702 	&rd_mcp_dev_attrib_emulate_fua_write.attr,
703 	&rd_mcp_dev_attrib_emulate_fua_read.attr,
704 	&rd_mcp_dev_attrib_emulate_write_cache.attr,
705 	&rd_mcp_dev_attrib_emulate_ua_intlck_ctrl.attr,
706 	&rd_mcp_dev_attrib_emulate_tas.attr,
707 	&rd_mcp_dev_attrib_emulate_tpu.attr,
708 	&rd_mcp_dev_attrib_emulate_tpws.attr,
709 	&rd_mcp_dev_attrib_emulate_caw.attr,
710 	&rd_mcp_dev_attrib_emulate_3pc.attr,
711 	&rd_mcp_dev_attrib_pi_prot_type.attr,
712 	&rd_mcp_dev_attrib_hw_pi_prot_type.attr,
713 	&rd_mcp_dev_attrib_pi_prot_format.attr,
714 	&rd_mcp_dev_attrib_enforce_pr_isids.attr,
715 	&rd_mcp_dev_attrib_is_nonrot.attr,
716 	&rd_mcp_dev_attrib_emulate_rest_reord.attr,
717 	&rd_mcp_dev_attrib_force_pr_aptpl.attr,
718 	&rd_mcp_dev_attrib_hw_block_size.attr,
719 	&rd_mcp_dev_attrib_block_size.attr,
720 	&rd_mcp_dev_attrib_hw_max_sectors.attr,
721 	&rd_mcp_dev_attrib_optimal_sectors.attr,
722 	&rd_mcp_dev_attrib_hw_queue_depth.attr,
723 	&rd_mcp_dev_attrib_queue_depth.attr,
724 	&rd_mcp_dev_attrib_max_unmap_lba_count.attr,
725 	&rd_mcp_dev_attrib_max_unmap_block_desc_count.attr,
726 	&rd_mcp_dev_attrib_unmap_granularity.attr,
727 	&rd_mcp_dev_attrib_unmap_granularity_alignment.attr,
728 	&rd_mcp_dev_attrib_max_write_same_len.attr,
729 	NULL,
730 };
731 
732 static struct se_subsystem_api rd_mcp_template = {
733 	.name			= "rd_mcp",
734 	.inquiry_prod		= "RAMDISK-MCP",
735 	.inquiry_rev		= RD_MCP_VERSION,
736 	.transport_type		= TRANSPORT_PLUGIN_VHBA_VDEV,
737 	.attach_hba		= rd_attach_hba,
738 	.detach_hba		= rd_detach_hba,
739 	.alloc_device		= rd_alloc_device,
740 	.configure_device	= rd_configure_device,
741 	.free_device		= rd_free_device,
742 	.parse_cdb		= rd_parse_cdb,
743 	.set_configfs_dev_params = rd_set_configfs_dev_params,
744 	.show_configfs_dev_params = rd_show_configfs_dev_params,
745 	.get_device_type	= sbc_get_device_type,
746 	.get_blocks		= rd_get_blocks,
747 	.init_prot		= rd_init_prot,
748 	.free_prot		= rd_free_prot,
749 };
750 
751 int __init rd_module_init(void)
752 {
753 	struct target_backend_cits *tbc = &rd_mcp_template.tb_cits;
754 	int ret;
755 
756 	target_core_setup_sub_cits(&rd_mcp_template);
757 	tbc->tb_dev_attrib_cit.ct_attrs = rd_mcp_backend_dev_attrs;
758 
759 	ret = transport_subsystem_register(&rd_mcp_template);
760 	if (ret < 0) {
761 		return ret;
762 	}
763 
764 	return 0;
765 }
766 
767 void rd_module_exit(void)
768 {
769 	transport_subsystem_release(&rd_mcp_template);
770 }
771