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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(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(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[j]);
76 if (pg) {
77 __free_page(pg);
78 page_count++;
79 }
80 }
81 kfree(sg);
82 }
83
84 kfree(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, rd_dev->sg_table_array,
96 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(sg_per_table + chain_entry, 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(sg_table[i - 1].sg_table,
143 max_sg_per_table + 1, 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, 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[j], pg);
160 sg[j].length = PAGE_SIZE;
161
162 p = kmap(pg);
163 memset(p, init_payload, PAGE_SIZE);
164 kunmap(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(sg_tables, 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, 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, rd_dev->sg_prot_array,
222 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(sg_tables, 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, 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(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(rd_dev);
325}
326
327static void rd_free_device(struct se_device *dev)
328{
329 call_rcu(&dev->rcu_head, 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(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(dev, 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(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(dev, 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, false);
456 if (rc)
457 return rc;
458 }
459
460 src_len = PAGE_SIZE - rd_offset;
461 sg_miter_start(&m, sgl, sgl_nents,
462 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(&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(&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(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(dev, rd_page);
511 if (!table) {
512 sg_miter_stop(&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(&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, 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(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, tokens, args);
562 switch (token) {
563 case Opt_rd_pages:
564 match_int(args, &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, &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, &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(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(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
600 rd_dev->rd_dev_id);
601 bl += sprintf(b + bl, " 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, dev->prot_length,
636 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, &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}
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/string.h>
31#include <linux/parser.h>
32#include <linux/timer.h>
33#include <linux/blkdev.h>
34#include <linux/slab.h>
35#include <linux/spinlock.h>
36#include <scsi/scsi.h>
37#include <scsi/scsi_host.h>
38
39#include <target/target_core_base.h>
40#include <target/target_core_backend.h>
41
42#include "target_core_rd.h"
43
44static struct se_subsystem_api rd_mcp_template;
45
46/* rd_attach_hba(): (Part of se_subsystem_api_t template)
47 *
48 *
49 */
50static 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
71static 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/* rd_release_device_space():
83 *
84 *
85 */
86static void rd_release_device_space(struct rd_dev *rd_dev)
87{
88 u32 i, j, page_count = 0, sg_per_table;
89 struct rd_dev_sg_table *sg_table;
90 struct page *pg;
91 struct scatterlist *sg;
92
93 if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
94 return;
95
96 sg_table = rd_dev->sg_table_array;
97
98 for (i = 0; i < rd_dev->sg_table_count; i++) {
99 sg = sg_table[i].sg_table;
100 sg_per_table = sg_table[i].rd_sg_count;
101
102 for (j = 0; j < sg_per_table; j++) {
103 pg = sg_page(&sg[j]);
104 if (pg) {
105 __free_page(pg);
106 page_count++;
107 }
108 }
109
110 kfree(sg);
111 }
112
113 pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
114 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
115 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
116 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
117
118 kfree(sg_table);
119 rd_dev->sg_table_array = NULL;
120 rd_dev->sg_table_count = 0;
121}
122
123
124/* rd_build_device_space():
125 *
126 *
127 */
128static int rd_build_device_space(struct rd_dev *rd_dev)
129{
130 u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed;
131 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
132 sizeof(struct scatterlist));
133 struct rd_dev_sg_table *sg_table;
134 struct page *pg;
135 struct scatterlist *sg;
136
137 if (rd_dev->rd_page_count <= 0) {
138 pr_err("Illegal page count: %u for Ramdisk device\n",
139 rd_dev->rd_page_count);
140 return -EINVAL;
141 }
142 total_sg_needed = rd_dev->rd_page_count;
143
144 sg_tables = (total_sg_needed / max_sg_per_table) + 1;
145
146 sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
147 if (!sg_table) {
148 pr_err("Unable to allocate memory for Ramdisk"
149 " scatterlist tables\n");
150 return -ENOMEM;
151 }
152
153 rd_dev->sg_table_array = sg_table;
154 rd_dev->sg_table_count = sg_tables;
155
156 while (total_sg_needed) {
157 sg_per_table = (total_sg_needed > max_sg_per_table) ?
158 max_sg_per_table : total_sg_needed;
159
160 sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
161 GFP_KERNEL);
162 if (!sg) {
163 pr_err("Unable to allocate scatterlist array"
164 " for struct rd_dev\n");
165 return -ENOMEM;
166 }
167
168 sg_init_table(sg, sg_per_table);
169
170 sg_table[i].sg_table = sg;
171 sg_table[i].rd_sg_count = sg_per_table;
172 sg_table[i].page_start_offset = page_offset;
173 sg_table[i++].page_end_offset = (page_offset + sg_per_table)
174 - 1;
175
176 for (j = 0; j < sg_per_table; j++) {
177 pg = alloc_pages(GFP_KERNEL, 0);
178 if (!pg) {
179 pr_err("Unable to allocate scatterlist"
180 " pages for struct rd_dev_sg_table\n");
181 return -ENOMEM;
182 }
183 sg_assign_page(&sg[j], pg);
184 sg[j].length = PAGE_SIZE;
185 }
186
187 page_offset += sg_per_table;
188 total_sg_needed -= sg_per_table;
189 }
190
191 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
192 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
193 rd_dev->rd_dev_id, rd_dev->rd_page_count,
194 rd_dev->sg_table_count);
195
196 return 0;
197}
198
199static void *rd_allocate_virtdevice(struct se_hba *hba, const char *name)
200{
201 struct rd_dev *rd_dev;
202 struct rd_host *rd_host = hba->hba_ptr;
203
204 rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
205 if (!rd_dev) {
206 pr_err("Unable to allocate memory for struct rd_dev\n");
207 return NULL;
208 }
209
210 rd_dev->rd_host = rd_host;
211
212 return rd_dev;
213}
214
215static struct se_device *rd_create_virtdevice(struct se_hba *hba,
216 struct se_subsystem_dev *se_dev, void *p)
217{
218 struct se_device *dev;
219 struct se_dev_limits dev_limits;
220 struct rd_dev *rd_dev = p;
221 struct rd_host *rd_host = hba->hba_ptr;
222 int dev_flags = 0, ret;
223 char prod[16], rev[4];
224
225 memset(&dev_limits, 0, sizeof(struct se_dev_limits));
226
227 ret = rd_build_device_space(rd_dev);
228 if (ret < 0)
229 goto fail;
230
231 snprintf(prod, 16, "RAMDISK-MCP");
232 snprintf(rev, 4, "%s", RD_MCP_VERSION);
233
234 dev_limits.limits.logical_block_size = RD_BLOCKSIZE;
235 dev_limits.limits.max_hw_sectors = UINT_MAX;
236 dev_limits.limits.max_sectors = UINT_MAX;
237 dev_limits.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
238 dev_limits.queue_depth = RD_DEVICE_QUEUE_DEPTH;
239
240 dev = transport_add_device_to_core_hba(hba,
241 &rd_mcp_template, se_dev, dev_flags, rd_dev,
242 &dev_limits, prod, rev);
243 if (!dev)
244 goto fail;
245
246 rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
247
248 pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
249 " %u pages in %u tables, %lu total bytes\n",
250 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
251 rd_dev->sg_table_count,
252 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
253
254 return dev;
255
256fail:
257 rd_release_device_space(rd_dev);
258 return ERR_PTR(ret);
259}
260
261static void rd_free_device(void *p)
262{
263 struct rd_dev *rd_dev = p;
264
265 rd_release_device_space(rd_dev);
266 kfree(rd_dev);
267}
268
269static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
270{
271 u32 i;
272 struct rd_dev_sg_table *sg_table;
273
274 for (i = 0; i < rd_dev->sg_table_count; i++) {
275 sg_table = &rd_dev->sg_table_array[i];
276 if ((sg_table->page_start_offset <= page) &&
277 (sg_table->page_end_offset >= page))
278 return sg_table;
279 }
280
281 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
282 page);
283
284 return NULL;
285}
286
287static int rd_execute_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
288 u32 sgl_nents, enum dma_data_direction data_direction)
289{
290 struct se_device *se_dev = cmd->se_dev;
291 struct rd_dev *dev = se_dev->dev_ptr;
292 struct rd_dev_sg_table *table;
293 struct scatterlist *rd_sg;
294 struct sg_mapping_iter m;
295 u32 rd_offset;
296 u32 rd_size;
297 u32 rd_page;
298 u32 src_len;
299 u64 tmp;
300
301 tmp = cmd->t_task_lba * se_dev->se_sub_dev->se_dev_attrib.block_size;
302 rd_offset = do_div(tmp, PAGE_SIZE);
303 rd_page = tmp;
304 rd_size = cmd->data_length;
305
306 table = rd_get_sg_table(dev, rd_page);
307 if (!table)
308 return -EINVAL;
309
310 rd_sg = &table->sg_table[rd_page - table->page_start_offset];
311
312 pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
313 dev->rd_dev_id,
314 data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
315 cmd->t_task_lba, rd_size, rd_page, rd_offset);
316
317 src_len = PAGE_SIZE - rd_offset;
318 sg_miter_start(&m, sgl, sgl_nents,
319 data_direction == DMA_FROM_DEVICE ?
320 SG_MITER_TO_SG : SG_MITER_FROM_SG);
321 while (rd_size) {
322 u32 len;
323 void *rd_addr;
324
325 sg_miter_next(&m);
326 len = min((u32)m.length, src_len);
327 m.consumed = len;
328
329 rd_addr = sg_virt(rd_sg) + rd_offset;
330
331 if (data_direction == DMA_FROM_DEVICE)
332 memcpy(m.addr, rd_addr, len);
333 else
334 memcpy(rd_addr, m.addr, len);
335
336 rd_size -= len;
337 if (!rd_size)
338 continue;
339
340 src_len -= len;
341 if (src_len) {
342 rd_offset += len;
343 continue;
344 }
345
346 /* rd page completed, next one please */
347 rd_page++;
348 rd_offset = 0;
349 src_len = PAGE_SIZE;
350 if (rd_page <= table->page_end_offset) {
351 rd_sg++;
352 continue;
353 }
354
355 table = rd_get_sg_table(dev, rd_page);
356 if (!table) {
357 sg_miter_stop(&m);
358 return -EINVAL;
359 }
360
361 /* since we increment, the first sg entry is correct */
362 rd_sg = table->sg_table;
363 }
364 sg_miter_stop(&m);
365
366 target_complete_cmd(cmd, SAM_STAT_GOOD);
367 return 0;
368}
369
370enum {
371 Opt_rd_pages, Opt_err
372};
373
374static match_table_t tokens = {
375 {Opt_rd_pages, "rd_pages=%d"},
376 {Opt_err, NULL}
377};
378
379static ssize_t rd_set_configfs_dev_params(
380 struct se_hba *hba,
381 struct se_subsystem_dev *se_dev,
382 const char *page,
383 ssize_t count)
384{
385 struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
386 char *orig, *ptr, *opts;
387 substring_t args[MAX_OPT_ARGS];
388 int ret = 0, arg, token;
389
390 opts = kstrdup(page, GFP_KERNEL);
391 if (!opts)
392 return -ENOMEM;
393
394 orig = opts;
395
396 while ((ptr = strsep(&opts, ",\n")) != NULL) {
397 if (!*ptr)
398 continue;
399
400 token = match_token(ptr, tokens, args);
401 switch (token) {
402 case Opt_rd_pages:
403 match_int(args, &arg);
404 rd_dev->rd_page_count = arg;
405 pr_debug("RAMDISK: Referencing Page"
406 " Count: %u\n", rd_dev->rd_page_count);
407 rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
408 break;
409 default:
410 break;
411 }
412 }
413
414 kfree(orig);
415 return (!ret) ? count : ret;
416}
417
418static ssize_t rd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
419{
420 struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
421
422 if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
423 pr_debug("Missing rd_pages= parameter\n");
424 return -EINVAL;
425 }
426
427 return 0;
428}
429
430static ssize_t rd_show_configfs_dev_params(
431 struct se_hba *hba,
432 struct se_subsystem_dev *se_dev,
433 char *b)
434{
435 struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
436 ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
437 rd_dev->rd_dev_id);
438 bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu"
439 " SG_table_count: %u\n", rd_dev->rd_page_count,
440 PAGE_SIZE, rd_dev->sg_table_count);
441 return bl;
442}
443
444static u32 rd_get_device_rev(struct se_device *dev)
445{
446 return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
447}
448
449static u32 rd_get_device_type(struct se_device *dev)
450{
451 return TYPE_DISK;
452}
453
454static sector_t rd_get_blocks(struct se_device *dev)
455{
456 struct rd_dev *rd_dev = dev->dev_ptr;
457 unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
458 dev->se_sub_dev->se_dev_attrib.block_size) - 1;
459
460 return blocks_long;
461}
462
463static struct se_subsystem_api rd_mcp_template = {
464 .name = "rd_mcp",
465 .transport_type = TRANSPORT_PLUGIN_VHBA_VDEV,
466 .attach_hba = rd_attach_hba,
467 .detach_hba = rd_detach_hba,
468 .allocate_virtdevice = rd_allocate_virtdevice,
469 .create_virtdevice = rd_create_virtdevice,
470 .free_device = rd_free_device,
471 .execute_cmd = rd_execute_cmd,
472 .check_configfs_dev_params = rd_check_configfs_dev_params,
473 .set_configfs_dev_params = rd_set_configfs_dev_params,
474 .show_configfs_dev_params = rd_show_configfs_dev_params,
475 .get_device_rev = rd_get_device_rev,
476 .get_device_type = rd_get_device_type,
477 .get_blocks = rd_get_blocks,
478};
479
480int __init rd_module_init(void)
481{
482 int ret;
483
484 ret = transport_subsystem_register(&rd_mcp_template);
485 if (ret < 0) {
486 return ret;
487 }
488
489 return 0;
490}
491
492void rd_module_exit(void)
493{
494 transport_subsystem_release(&rd_mcp_template);
495}