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