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