1// SPDX-License-Identifier: GPL-2.0-or-later
2/*******************************************************************************
3 * Filename: target_core_rd.c
4 *
5 * This file contains the Storage Engine <-> Ramdisk transport
6 * specific functions.
7 *
8 * (c) Copyright 2003-2013 Datera, Inc.
9 *
10 * Nicholas A. Bellinger <nab@kernel.org>
11 *
12 ******************************************************************************/
13
14#include <linux/string.h>
15#include <linux/parser.h>
16#include <linux/highmem.h>
17#include <linux/timer.h>
18#include <linux/scatterlist.h>
19#include <linux/slab.h>
20#include <linux/spinlock.h>
21#include <scsi/scsi_proto.h>
22
23#include <target/target_core_base.h>
24#include <target/target_core_backend.h>
25
26#include "target_core_rd.h"
27
28static inline struct rd_dev *RD_DEV(struct se_device *dev)
29{
30 return container_of(dev, struct rd_dev, dev);
31}
32
33static int rd_attach_hba(struct se_hba *hba, u32 host_id)
34{
35 struct rd_host *rd_host;
36
37 rd_host = kzalloc(size: sizeof(*rd_host), GFP_KERNEL);
38 if (!rd_host)
39 return -ENOMEM;
40
41 rd_host->rd_host_id = host_id;
42
43 hba->hba_ptr = rd_host;
44
45 pr_debug("CORE_HBA[%d] - TCM Ramdisk HBA Driver %s on"
46 " Generic Target Core Stack %s\n", hba->hba_id,
47 RD_HBA_VERSION, TARGET_CORE_VERSION);
48
49 return 0;
50}
51
52static void rd_detach_hba(struct se_hba *hba)
53{
54 struct rd_host *rd_host = hba->hba_ptr;
55
56 pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
57 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
58
59 kfree(objp: rd_host);
60 hba->hba_ptr = NULL;
61}
62
63static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
64 u32 sg_table_count)
65{
66 struct page *pg;
67 struct scatterlist *sg;
68 u32 i, j, page_count = 0, sg_per_table;
69
70 for (i = 0; i < sg_table_count; i++) {
71 sg = sg_table[i].sg_table;
72 sg_per_table = sg_table[i].rd_sg_count;
73
74 for (j = 0; j < sg_per_table; j++) {
75 pg = sg_page(sg: &sg[j]);
76 if (pg) {
77 __free_page(pg);
78 page_count++;
79 }
80 }
81 kfree(objp: sg);
82 }
83
84 kfree(objp: sg_table);
85 return page_count;
86}
87
88static void rd_release_device_space(struct rd_dev *rd_dev)
89{
90 u32 page_count;
91
92 if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
93 return;
94
95 page_count = rd_release_sgl_table(rd_dev, sg_table: rd_dev->sg_table_array,
96 sg_table_count: rd_dev->sg_table_count);
97
98 pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
99 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
100 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
101 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
102
103 rd_dev->sg_table_array = NULL;
104 rd_dev->sg_table_count = 0;
105}
106
107
108/* rd_build_device_space():
109 *
110 *
111 */
112static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
113 u32 total_sg_needed, unsigned char init_payload)
114{
115 u32 i = 0, j, page_offset = 0, sg_per_table;
116 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
117 sizeof(struct scatterlist));
118 struct page *pg;
119 struct scatterlist *sg;
120 unsigned char *p;
121
122 while (total_sg_needed) {
123 unsigned int chain_entry = 0;
124
125 sg_per_table = (total_sg_needed > max_sg_per_table) ?
126 max_sg_per_table : total_sg_needed;
127
128 /*
129 * Reserve extra element for chain entry
130 */
131 if (sg_per_table < total_sg_needed)
132 chain_entry = 1;
133
134 sg = kmalloc_array(n: sg_per_table + chain_entry, size: sizeof(*sg),
135 GFP_KERNEL);
136 if (!sg)
137 return -ENOMEM;
138
139 sg_init_table(sg, sg_per_table + chain_entry);
140
141 if (i > 0) {
142 sg_chain(prv: sg_table[i - 1].sg_table,
143 prv_nents: max_sg_per_table + 1, sgl: sg);
144 }
145
146 sg_table[i].sg_table = sg;
147 sg_table[i].rd_sg_count = sg_per_table;
148 sg_table[i].page_start_offset = page_offset;
149 sg_table[i++].page_end_offset = (page_offset + sg_per_table)
150 - 1;
151
152 for (j = 0; j < sg_per_table; j++) {
153 pg = alloc_pages(GFP_KERNEL, order: 0);
154 if (!pg) {
155 pr_err("Unable to allocate scatterlist"
156 " pages for struct rd_dev_sg_table\n");
157 return -ENOMEM;
158 }
159 sg_assign_page(sg: &sg[j], page: pg);
160 sg[j].length = PAGE_SIZE;
161
162 p = kmap(page: pg);
163 memset(p, init_payload, PAGE_SIZE);
164 kunmap(page: pg);
165 }
166
167 page_offset += sg_per_table;
168 total_sg_needed -= sg_per_table;
169 }
170
171 return 0;
172}
173
174static int rd_build_device_space(struct rd_dev *rd_dev)
175{
176 struct rd_dev_sg_table *sg_table;
177 u32 sg_tables, total_sg_needed;
178 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
179 sizeof(struct scatterlist));
180 int rc;
181
182 if (rd_dev->rd_page_count <= 0) {
183 pr_err("Illegal page count: %u for Ramdisk device\n",
184 rd_dev->rd_page_count);
185 return -EINVAL;
186 }
187
188 /* Don't need backing pages for NULLIO */
189 if (rd_dev->rd_flags & RDF_NULLIO)
190 return 0;
191
192 total_sg_needed = rd_dev->rd_page_count;
193
194 sg_tables = (total_sg_needed / max_sg_per_table) + 1;
195 sg_table = kcalloc(n: sg_tables, size: sizeof(*sg_table), GFP_KERNEL);
196 if (!sg_table)
197 return -ENOMEM;
198
199 rd_dev->sg_table_array = sg_table;
200 rd_dev->sg_table_count = sg_tables;
201
202 rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, init_payload: 0x00);
203 if (rc)
204 return rc;
205
206 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
207 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
208 rd_dev->rd_dev_id, rd_dev->rd_page_count,
209 rd_dev->sg_table_count);
210
211 return 0;
212}
213
214static void rd_release_prot_space(struct rd_dev *rd_dev)
215{
216 u32 page_count;
217
218 if (!rd_dev->sg_prot_array || !rd_dev->sg_prot_count)
219 return;
220
221 page_count = rd_release_sgl_table(rd_dev, sg_table: rd_dev->sg_prot_array,
222 sg_table_count: rd_dev->sg_prot_count);
223
224 pr_debug("CORE_RD[%u] - Released protection space for Ramdisk"
225 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
226 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
227 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
228
229 rd_dev->sg_prot_array = NULL;
230 rd_dev->sg_prot_count = 0;
231}
232
233static int rd_build_prot_space(struct rd_dev *rd_dev, int prot_length, int block_size)
234{
235 struct rd_dev_sg_table *sg_table;
236 u32 total_sg_needed, sg_tables;
237 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
238 sizeof(struct scatterlist));
239 int rc;
240
241 if (rd_dev->rd_flags & RDF_NULLIO)
242 return 0;
243 /*
244 * prot_length=8byte dif data
245 * tot sg needed = rd_page_count * (PGSZ/block_size) *
246 * (prot_length/block_size) + pad
247 * PGSZ canceled each other.
248 */
249 total_sg_needed = (rd_dev->rd_page_count * prot_length / block_size) + 1;
250
251 sg_tables = (total_sg_needed / max_sg_per_table) + 1;
252 sg_table = kcalloc(n: sg_tables, size: sizeof(*sg_table), GFP_KERNEL);
253 if (!sg_table)
254 return -ENOMEM;
255
256 rd_dev->sg_prot_array = sg_table;
257 rd_dev->sg_prot_count = sg_tables;
258
259 rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, init_payload: 0xff);
260 if (rc)
261 return rc;
262
263 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u prot space of"
264 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
265 rd_dev->rd_dev_id, total_sg_needed, rd_dev->sg_prot_count);
266
267 return 0;
268}
269
270static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
271{
272 struct rd_dev *rd_dev;
273 struct rd_host *rd_host = hba->hba_ptr;
274
275 rd_dev = kzalloc(size: sizeof(*rd_dev), GFP_KERNEL);
276 if (!rd_dev)
277 return NULL;
278
279 rd_dev->rd_host = rd_host;
280
281 return &rd_dev->dev;
282}
283
284static int rd_configure_device(struct se_device *dev)
285{
286 struct rd_dev *rd_dev = RD_DEV(dev);
287 struct rd_host *rd_host = dev->se_hba->hba_ptr;
288 int ret;
289
290 if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
291 pr_debug("Missing rd_pages= parameter\n");
292 return -EINVAL;
293 }
294
295 ret = rd_build_device_space(rd_dev);
296 if (ret < 0)
297 goto fail;
298
299 dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
300 dev->dev_attrib.hw_max_sectors = UINT_MAX;
301 dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
302 dev->dev_attrib.is_nonrot = 1;
303
304 rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
305
306 pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
307 " %u pages in %u tables, %lu total bytes\n",
308 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
309 rd_dev->sg_table_count,
310 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
311
312 return 0;
313
314fail:
315 rd_release_device_space(rd_dev);
316 return ret;
317}
318
319static void rd_dev_call_rcu(struct rcu_head *p)
320{
321 struct se_device *dev = container_of(p, struct se_device, rcu_head);
322 struct rd_dev *rd_dev = RD_DEV(dev);
323
324 kfree(objp: rd_dev);
325}
326
327static void rd_free_device(struct se_device *dev)
328{
329 call_rcu(head: &dev->rcu_head, func: rd_dev_call_rcu);
330}
331
332static void rd_destroy_device(struct se_device *dev)
333{
334 struct rd_dev *rd_dev = RD_DEV(dev);
335
336 rd_release_device_space(rd_dev);
337}
338
339static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
340{
341 struct rd_dev_sg_table *sg_table;
342 u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
343 sizeof(struct scatterlist));
344
345 i = page / sg_per_table;
346 if (i < rd_dev->sg_table_count) {
347 sg_table = &rd_dev->sg_table_array[i];
348 if ((sg_table->page_start_offset <= page) &&
349 (sg_table->page_end_offset >= page))
350 return sg_table;
351 }
352
353 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
354 page);
355
356 return NULL;
357}
358
359static struct rd_dev_sg_table *rd_get_prot_table(struct rd_dev *rd_dev, u32 page)
360{
361 struct rd_dev_sg_table *sg_table;
362 u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
363 sizeof(struct scatterlist));
364
365 i = page / sg_per_table;
366 if (i < rd_dev->sg_prot_count) {
367 sg_table = &rd_dev->sg_prot_array[i];
368 if ((sg_table->page_start_offset <= page) &&
369 (sg_table->page_end_offset >= page))
370 return sg_table;
371 }
372
373 pr_err("Unable to locate struct prot rd_dev_sg_table for page: %u\n",
374 page);
375
376 return NULL;
377}
378
379static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, bool is_read)
380{
381 struct se_device *se_dev = cmd->se_dev;
382 struct rd_dev *dev = RD_DEV(dev: se_dev);
383 struct rd_dev_sg_table *prot_table;
384 struct scatterlist *prot_sg;
385 u32 sectors = cmd->data_length / se_dev->dev_attrib.block_size;
386 u32 prot_offset, prot_page;
387 u32 prot_npages __maybe_unused;
388 u64 tmp;
389 sense_reason_t rc = 0;
390
391 tmp = cmd->t_task_lba * se_dev->prot_length;
392 prot_offset = do_div(tmp, PAGE_SIZE);
393 prot_page = tmp;
394
395 prot_table = rd_get_prot_table(rd_dev: dev, page: prot_page);
396 if (!prot_table)
397 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
398
399 prot_sg = &prot_table->sg_table[prot_page -
400 prot_table->page_start_offset];
401
402 if (se_dev->dev_attrib.pi_prot_verify) {
403 if (is_read)
404 rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
405 prot_sg, prot_offset);
406 else
407 rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
408 cmd->t_prot_sg, 0);
409 }
410 if (!rc)
411 sbc_dif_copy_prot(cmd, sectors, is_read, prot_sg, prot_offset);
412
413 return rc;
414}
415
416static sense_reason_t
417rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
418 enum dma_data_direction data_direction)
419{
420 struct se_device *se_dev = cmd->se_dev;
421 struct rd_dev *dev = RD_DEV(dev: se_dev);
422 struct rd_dev_sg_table *table;
423 struct scatterlist *rd_sg;
424 struct sg_mapping_iter m;
425 u32 rd_offset;
426 u32 rd_size;
427 u32 rd_page;
428 u32 src_len;
429 u64 tmp;
430 sense_reason_t rc;
431
432 if (dev->rd_flags & RDF_NULLIO) {
433 target_complete_cmd(cmd, SAM_STAT_GOOD);
434 return 0;
435 }
436
437 tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
438 rd_offset = do_div(tmp, PAGE_SIZE);
439 rd_page = tmp;
440 rd_size = cmd->data_length;
441
442 table = rd_get_sg_table(rd_dev: dev, page: rd_page);
443 if (!table)
444 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
445
446 rd_sg = &table->sg_table[rd_page - table->page_start_offset];
447
448 pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
449 dev->rd_dev_id,
450 data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
451 cmd->t_task_lba, rd_size, rd_page, rd_offset);
452
453 if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
454 data_direction == DMA_TO_DEVICE) {
455 rc = rd_do_prot_rw(cmd, is_read: false);
456 if (rc)
457 return rc;
458 }
459
460 src_len = PAGE_SIZE - rd_offset;
461 sg_miter_start(miter: &m, sgl, nents: sgl_nents,
462 flags: data_direction == DMA_FROM_DEVICE ?
463 SG_MITER_TO_SG : SG_MITER_FROM_SG);
464 while (rd_size) {
465 u32 len;
466 void *rd_addr;
467
468 sg_miter_next(miter: &m);
469 if (!(u32)m.length) {
470 pr_debug("RD[%u]: invalid sgl %p len %zu\n",
471 dev->rd_dev_id, m.addr, m.length);
472 sg_miter_stop(miter: &m);
473 return TCM_INCORRECT_AMOUNT_OF_DATA;
474 }
475 len = min((u32)m.length, src_len);
476 if (len > rd_size) {
477 pr_debug("RD[%u]: size underrun page %d offset %d "
478 "size %d\n", dev->rd_dev_id,
479 rd_page, rd_offset, rd_size);
480 len = rd_size;
481 }
482 m.consumed = len;
483
484 rd_addr = sg_virt(sg: rd_sg) + rd_offset;
485
486 if (data_direction == DMA_FROM_DEVICE)
487 memcpy(m.addr, rd_addr, len);
488 else
489 memcpy(rd_addr, m.addr, len);
490
491 rd_size -= len;
492 if (!rd_size)
493 continue;
494
495 src_len -= len;
496 if (src_len) {
497 rd_offset += len;
498 continue;
499 }
500
501 /* rd page completed, next one please */
502 rd_page++;
503 rd_offset = 0;
504 src_len = PAGE_SIZE;
505 if (rd_page <= table->page_end_offset) {
506 rd_sg++;
507 continue;
508 }
509
510 table = rd_get_sg_table(rd_dev: dev, page: rd_page);
511 if (!table) {
512 sg_miter_stop(miter: &m);
513 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
514 }
515
516 /* since we increment, the first sg entry is correct */
517 rd_sg = table->sg_table;
518 }
519 sg_miter_stop(miter: &m);
520
521 if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
522 data_direction == DMA_FROM_DEVICE) {
523 rc = rd_do_prot_rw(cmd, is_read: true);
524 if (rc)
525 return rc;
526 }
527
528 target_complete_cmd(cmd, SAM_STAT_GOOD);
529 return 0;
530}
531
532enum {
533 Opt_rd_pages, Opt_rd_nullio, Opt_rd_dummy, Opt_err
534};
535
536static match_table_t tokens = {
537 {Opt_rd_pages, "rd_pages=%d"},
538 {Opt_rd_nullio, "rd_nullio=%d"},
539 {Opt_rd_dummy, "rd_dummy=%d"},
540 {Opt_err, NULL}
541};
542
543static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
544 const char *page, ssize_t count)
545{
546 struct rd_dev *rd_dev = RD_DEV(dev);
547 char *orig, *ptr, *opts;
548 substring_t args[MAX_OPT_ARGS];
549 int arg, token;
550
551 opts = kstrdup(s: page, GFP_KERNEL);
552 if (!opts)
553 return -ENOMEM;
554
555 orig = opts;
556
557 while ((ptr = strsep(&opts, ",\n")) != NULL) {
558 if (!*ptr)
559 continue;
560
561 token = match_token(ptr, table: tokens, args);
562 switch (token) {
563 case Opt_rd_pages:
564 match_int(args, result: &arg);
565 rd_dev->rd_page_count = arg;
566 pr_debug("RAMDISK: Referencing Page"
567 " Count: %u\n", rd_dev->rd_page_count);
568 rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
569 break;
570 case Opt_rd_nullio:
571 match_int(args, result: &arg);
572 if (arg != 1)
573 break;
574
575 pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
576 rd_dev->rd_flags |= RDF_NULLIO;
577 break;
578 case Opt_rd_dummy:
579 match_int(args, result: &arg);
580 if (arg != 1)
581 break;
582
583 pr_debug("RAMDISK: Setting DUMMY flag: %d\n", arg);
584 rd_dev->rd_flags |= RDF_DUMMY;
585 break;
586 default:
587 break;
588 }
589 }
590
591 kfree(objp: orig);
592 return count;
593}
594
595static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
596{
597 struct rd_dev *rd_dev = RD_DEV(dev);
598
599 ssize_t bl = sprintf(buf: b, fmt: "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
600 rd_dev->rd_dev_id);
601 bl += sprintf(buf: b + bl, fmt: " PAGES/PAGE_SIZE: %u*%lu"
602 " SG_table_count: %u nullio: %d dummy: %d\n",
603 rd_dev->rd_page_count,
604 PAGE_SIZE, rd_dev->sg_table_count,
605 !!(rd_dev->rd_flags & RDF_NULLIO),
606 !!(rd_dev->rd_flags & RDF_DUMMY));
607 return bl;
608}
609
610static u32 rd_get_device_type(struct se_device *dev)
611{
612 if (RD_DEV(dev)->rd_flags & RDF_DUMMY)
613 return 0x3f; /* Unknown device type, not connected */
614 else
615 return sbc_get_device_type(dev);
616}
617
618static sector_t rd_get_blocks(struct se_device *dev)
619{
620 struct rd_dev *rd_dev = RD_DEV(dev);
621
622 unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
623 dev->dev_attrib.block_size) - 1;
624
625 return blocks_long;
626}
627
628static int rd_init_prot(struct se_device *dev)
629{
630 struct rd_dev *rd_dev = RD_DEV(dev);
631
632 if (!dev->dev_attrib.pi_prot_type)
633 return 0;
634
635 return rd_build_prot_space(rd_dev, prot_length: dev->prot_length,
636 block_size: dev->dev_attrib.block_size);
637}
638
639static void rd_free_prot(struct se_device *dev)
640{
641 struct rd_dev *rd_dev = RD_DEV(dev);
642
643 rd_release_prot_space(rd_dev);
644}
645
646static struct exec_cmd_ops rd_exec_cmd_ops = {
647 .execute_rw = rd_execute_rw,
648};
649
650static sense_reason_t
651rd_parse_cdb(struct se_cmd *cmd)
652{
653 return sbc_parse_cdb(cmd, ops: &rd_exec_cmd_ops);
654}
655
656static const struct target_backend_ops rd_mcp_ops = {
657 .name = "rd_mcp",
658 .inquiry_prod = "RAMDISK-MCP",
659 .inquiry_rev = RD_MCP_VERSION,
660 .attach_hba = rd_attach_hba,
661 .detach_hba = rd_detach_hba,
662 .alloc_device = rd_alloc_device,
663 .configure_device = rd_configure_device,
664 .destroy_device = rd_destroy_device,
665 .free_device = rd_free_device,
666 .parse_cdb = rd_parse_cdb,
667 .set_configfs_dev_params = rd_set_configfs_dev_params,
668 .show_configfs_dev_params = rd_show_configfs_dev_params,
669 .get_device_type = rd_get_device_type,
670 .get_blocks = rd_get_blocks,
671 .init_prot = rd_init_prot,
672 .free_prot = rd_free_prot,
673 .tb_dev_attrib_attrs = sbc_attrib_attrs,
674};
675
676int __init rd_module_init(void)
677{
678 return transport_backend_register(&rd_mcp_ops);
679}
680
681void rd_module_exit(void)
682{
683 target_backend_unregister(&rd_mcp_ops);
684}
685

source code of linux/drivers/target/target_core_rd.c