1 /*******************************************************************************
2 * Filename: target_core_rd.c
4 * This file contains the Storage Engine <-> Ramdisk transport
7 * (c) Copyright 2003-2013 Datera, Inc.
9 * Nicholas A. Bellinger <nab@kernel.org>
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.
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.
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.
25 ******************************************************************************/
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_proto.h>
34 #include <target/target_core_base.h>
35 #include <target/target_core_backend.h>
37 #include "target_core_rd.h"
39 static inline struct rd_dev *RD_DEV(struct se_device *dev)
41 return container_of(dev, struct rd_dev, dev);
44 static int rd_attach_hba(struct se_hba *hba, u32 host_id)
46 struct rd_host *rd_host;
48 rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
50 pr_err("Unable to allocate memory for struct rd_host\n");
54 rd_host->rd_host_id = host_id;
56 hba->hba_ptr = rd_host;
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);
65 static void rd_detach_hba(struct se_hba *hba)
67 struct rd_host *rd_host = hba->hba_ptr;
69 pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
70 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
76 static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
80 struct scatterlist *sg;
81 u32 i, j, page_count = 0, sg_per_table;
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;
87 for (j = 0; j < sg_per_table; j++) {
101 static void rd_release_device_space(struct rd_dev *rd_dev)
105 if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
108 page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array,
109 rd_dev->sg_table_count);
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);
116 rd_dev->sg_table_array = NULL;
117 rd_dev->sg_table_count = 0;
121 /* rd_build_device_space():
125 static 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)
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));
132 struct scatterlist *sg;
135 while (total_sg_needed) {
136 unsigned int chain_entry = 0;
138 sg_per_table = (total_sg_needed > max_sg_per_table) ?
139 max_sg_per_table : total_sg_needed;
141 #ifdef CONFIG_ARCH_HAS_SG_CHAIN
144 * Reserve extra element for chain entry
146 if (sg_per_table < total_sg_needed)
149 #endif /* CONFIG_ARCH_HAS_SG_CHAIN */
151 sg = kcalloc(sg_per_table + chain_entry, sizeof(*sg),
154 pr_err("Unable to allocate scatterlist array"
155 " for struct rd_dev\n");
159 sg_init_table(sg, sg_per_table + chain_entry);
161 #ifdef CONFIG_ARCH_HAS_SG_CHAIN
164 sg_chain(sg_table[i - 1].sg_table,
165 max_sg_per_table + 1, sg);
168 #endif /* CONFIG_ARCH_HAS_SG_CHAIN */
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)
176 for (j = 0; j < sg_per_table; j++) {
177 pg = alloc_pages(GFP_KERNEL, 0);
179 pr_err("Unable to allocate scatterlist"
180 " pages for struct rd_dev_sg_table\n");
183 sg_assign_page(&sg[j], pg);
184 sg[j].length = PAGE_SIZE;
187 memset(p, init_payload, PAGE_SIZE);
191 page_offset += sg_per_table;
192 total_sg_needed -= sg_per_table;
198 static int rd_build_device_space(struct rd_dev *rd_dev)
200 struct rd_dev_sg_table *sg_table;
201 u32 sg_tables, total_sg_needed;
202 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
203 sizeof(struct scatterlist));
206 if (rd_dev->rd_page_count <= 0) {
207 pr_err("Illegal page count: %u for Ramdisk device\n",
208 rd_dev->rd_page_count);
212 /* Don't need backing pages for NULLIO */
213 if (rd_dev->rd_flags & RDF_NULLIO)
216 total_sg_needed = rd_dev->rd_page_count;
218 sg_tables = (total_sg_needed / max_sg_per_table) + 1;
220 sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
222 pr_err("Unable to allocate memory for Ramdisk"
223 " scatterlist tables\n");
227 rd_dev->sg_table_array = sg_table;
228 rd_dev->sg_table_count = sg_tables;
230 rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00);
234 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
235 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
236 rd_dev->rd_dev_id, rd_dev->rd_page_count,
237 rd_dev->sg_table_count);
242 static void rd_release_prot_space(struct rd_dev *rd_dev)
246 if (!rd_dev->sg_prot_array || !rd_dev->sg_prot_count)
249 page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_prot_array,
250 rd_dev->sg_prot_count);
252 pr_debug("CORE_RD[%u] - Released protection space for Ramdisk"
253 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
254 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
255 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
257 rd_dev->sg_prot_array = NULL;
258 rd_dev->sg_prot_count = 0;
261 static int rd_build_prot_space(struct rd_dev *rd_dev, int prot_length, int block_size)
263 struct rd_dev_sg_table *sg_table;
264 u32 total_sg_needed, sg_tables;
265 u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
266 sizeof(struct scatterlist));
269 if (rd_dev->rd_flags & RDF_NULLIO)
272 * prot_length=8byte dif data
273 * tot sg needed = rd_page_count * (PGSZ/block_size) *
274 * (prot_length/block_size) + pad
275 * PGSZ canceled each other.
277 total_sg_needed = (rd_dev->rd_page_count * prot_length / block_size) + 1;
279 sg_tables = (total_sg_needed / max_sg_per_table) + 1;
281 sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
283 pr_err("Unable to allocate memory for Ramdisk protection"
284 " scatterlist tables\n");
288 rd_dev->sg_prot_array = sg_table;
289 rd_dev->sg_prot_count = sg_tables;
291 rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0xff);
295 pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u prot space of"
296 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
297 rd_dev->rd_dev_id, total_sg_needed, rd_dev->sg_prot_count);
302 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
304 struct rd_dev *rd_dev;
305 struct rd_host *rd_host = hba->hba_ptr;
307 rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
309 pr_err("Unable to allocate memory for struct rd_dev\n");
313 rd_dev->rd_host = rd_host;
318 static int rd_configure_device(struct se_device *dev)
320 struct rd_dev *rd_dev = RD_DEV(dev);
321 struct rd_host *rd_host = dev->se_hba->hba_ptr;
324 if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
325 pr_debug("Missing rd_pages= parameter\n");
329 ret = rd_build_device_space(rd_dev);
333 dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
334 dev->dev_attrib.hw_max_sectors = UINT_MAX;
335 dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
336 dev->dev_attrib.is_nonrot = 1;
338 rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
340 pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
341 " %u pages in %u tables, %lu total bytes\n",
342 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
343 rd_dev->sg_table_count,
344 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
349 rd_release_device_space(rd_dev);
353 static void rd_dev_call_rcu(struct rcu_head *p)
355 struct se_device *dev = container_of(p, struct se_device, rcu_head);
356 struct rd_dev *rd_dev = RD_DEV(dev);
361 static void rd_free_device(struct se_device *dev)
363 struct rd_dev *rd_dev = RD_DEV(dev);
365 rd_release_device_space(rd_dev);
366 call_rcu(&dev->rcu_head, rd_dev_call_rcu);
369 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
371 struct rd_dev_sg_table *sg_table;
372 u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
373 sizeof(struct scatterlist));
375 i = page / sg_per_table;
376 if (i < rd_dev->sg_table_count) {
377 sg_table = &rd_dev->sg_table_array[i];
378 if ((sg_table->page_start_offset <= page) &&
379 (sg_table->page_end_offset >= page))
383 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
389 static struct rd_dev_sg_table *rd_get_prot_table(struct rd_dev *rd_dev, u32 page)
391 struct rd_dev_sg_table *sg_table;
392 u32 i, sg_per_table = (RD_MAX_ALLOCATION_SIZE /
393 sizeof(struct scatterlist));
395 i = page / sg_per_table;
396 if (i < rd_dev->sg_prot_count) {
397 sg_table = &rd_dev->sg_prot_array[i];
398 if ((sg_table->page_start_offset <= page) &&
399 (sg_table->page_end_offset >= page))
403 pr_err("Unable to locate struct prot rd_dev_sg_table for page: %u\n",
409 static sense_reason_t rd_do_prot_rw(struct se_cmd *cmd, bool is_read)
411 struct se_device *se_dev = cmd->se_dev;
412 struct rd_dev *dev = RD_DEV(se_dev);
413 struct rd_dev_sg_table *prot_table;
414 bool need_to_release = false;
415 struct scatterlist *prot_sg;
416 u32 sectors = cmd->data_length / se_dev->dev_attrib.block_size;
417 u32 prot_offset, prot_page;
418 u32 prot_npages __maybe_unused;
420 sense_reason_t rc = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
422 tmp = cmd->t_task_lba * se_dev->prot_length;
423 prot_offset = do_div(tmp, PAGE_SIZE);
426 prot_table = rd_get_prot_table(dev, prot_page);
428 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
430 prot_sg = &prot_table->sg_table[prot_page -
431 prot_table->page_start_offset];
433 #ifndef CONFIG_ARCH_HAS_SG_CHAIN
435 prot_npages = DIV_ROUND_UP(prot_offset + sectors * se_dev->prot_length,
439 * Allocate temporaly contiguous scatterlist entries if prot pages
440 * straddles multiple scatterlist tables.
442 if (prot_table->page_end_offset < prot_page + prot_npages - 1) {
445 prot_sg = kcalloc(prot_npages, sizeof(*prot_sg), GFP_KERNEL);
447 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
449 need_to_release = true;
450 sg_init_table(prot_sg, prot_npages);
452 for (i = 0; i < prot_npages; i++) {
453 if (prot_page + i > prot_table->page_end_offset) {
454 prot_table = rd_get_prot_table(dev,
460 sg_unmark_end(&prot_sg[i - 1]);
462 prot_sg[i] = prot_table->sg_table[prot_page + i -
463 prot_table->page_start_offset];
467 #endif /* !CONFIG_ARCH_HAS_SG_CHAIN */
470 rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
471 prot_sg, prot_offset);
473 rc = sbc_dif_verify(cmd, cmd->t_task_lba, sectors, 0,
477 sbc_dif_copy_prot(cmd, sectors, is_read, prot_sg, prot_offset);
485 static sense_reason_t
486 rd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
487 enum dma_data_direction data_direction)
489 struct se_device *se_dev = cmd->se_dev;
490 struct rd_dev *dev = RD_DEV(se_dev);
491 struct rd_dev_sg_table *table;
492 struct scatterlist *rd_sg;
493 struct sg_mapping_iter m;
501 if (dev->rd_flags & RDF_NULLIO) {
502 target_complete_cmd(cmd, SAM_STAT_GOOD);
506 tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
507 rd_offset = do_div(tmp, PAGE_SIZE);
509 rd_size = cmd->data_length;
511 table = rd_get_sg_table(dev, rd_page);
513 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
515 rd_sg = &table->sg_table[rd_page - table->page_start_offset];
517 pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
519 data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
520 cmd->t_task_lba, rd_size, rd_page, rd_offset);
522 if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
523 data_direction == DMA_TO_DEVICE) {
524 rc = rd_do_prot_rw(cmd, false);
529 src_len = PAGE_SIZE - rd_offset;
530 sg_miter_start(&m, sgl, sgl_nents,
531 data_direction == DMA_FROM_DEVICE ?
532 SG_MITER_TO_SG : SG_MITER_FROM_SG);
538 if (!(u32)m.length) {
539 pr_debug("RD[%u]: invalid sgl %p len %zu\n",
540 dev->rd_dev_id, m.addr, m.length);
542 return TCM_INCORRECT_AMOUNT_OF_DATA;
544 len = min((u32)m.length, src_len);
546 pr_debug("RD[%u]: size underrun page %d offset %d "
547 "size %d\n", dev->rd_dev_id,
548 rd_page, rd_offset, rd_size);
553 rd_addr = sg_virt(rd_sg) + rd_offset;
555 if (data_direction == DMA_FROM_DEVICE)
556 memcpy(m.addr, rd_addr, len);
558 memcpy(rd_addr, m.addr, len);
570 /* rd page completed, next one please */
574 if (rd_page <= table->page_end_offset) {
579 table = rd_get_sg_table(dev, rd_page);
582 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
585 /* since we increment, the first sg entry is correct */
586 rd_sg = table->sg_table;
590 if (cmd->prot_type && se_dev->dev_attrib.pi_prot_type &&
591 data_direction == DMA_FROM_DEVICE) {
592 rc = rd_do_prot_rw(cmd, true);
597 target_complete_cmd(cmd, SAM_STAT_GOOD);
602 Opt_rd_pages, Opt_rd_nullio, Opt_err
605 static match_table_t tokens = {
606 {Opt_rd_pages, "rd_pages=%d"},
607 {Opt_rd_nullio, "rd_nullio=%d"},
611 static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
612 const char *page, ssize_t count)
614 struct rd_dev *rd_dev = RD_DEV(dev);
615 char *orig, *ptr, *opts;
616 substring_t args[MAX_OPT_ARGS];
617 int ret = 0, arg, token;
619 opts = kstrdup(page, GFP_KERNEL);
625 while ((ptr = strsep(&opts, ",\n")) != NULL) {
629 token = match_token(ptr, tokens, args);
632 match_int(args, &arg);
633 rd_dev->rd_page_count = arg;
634 pr_debug("RAMDISK: Referencing Page"
635 " Count: %u\n", rd_dev->rd_page_count);
636 rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
639 match_int(args, &arg);
643 pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg);
644 rd_dev->rd_flags |= RDF_NULLIO;
652 return (!ret) ? count : ret;
655 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
657 struct rd_dev *rd_dev = RD_DEV(dev);
659 ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
661 bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu"
662 " SG_table_count: %u nullio: %d\n", rd_dev->rd_page_count,
663 PAGE_SIZE, rd_dev->sg_table_count,
664 !!(rd_dev->rd_flags & RDF_NULLIO));
668 static sector_t rd_get_blocks(struct se_device *dev)
670 struct rd_dev *rd_dev = RD_DEV(dev);
672 unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
673 dev->dev_attrib.block_size) - 1;
678 static int rd_init_prot(struct se_device *dev)
680 struct rd_dev *rd_dev = RD_DEV(dev);
682 if (!dev->dev_attrib.pi_prot_type)
685 return rd_build_prot_space(rd_dev, dev->prot_length,
686 dev->dev_attrib.block_size);
689 static void rd_free_prot(struct se_device *dev)
691 struct rd_dev *rd_dev = RD_DEV(dev);
693 rd_release_prot_space(rd_dev);
696 static struct sbc_ops rd_sbc_ops = {
697 .execute_rw = rd_execute_rw,
700 static sense_reason_t
701 rd_parse_cdb(struct se_cmd *cmd)
703 return sbc_parse_cdb(cmd, &rd_sbc_ops);
706 static const struct target_backend_ops rd_mcp_ops = {
708 .inquiry_prod = "RAMDISK-MCP",
709 .inquiry_rev = RD_MCP_VERSION,
710 .attach_hba = rd_attach_hba,
711 .detach_hba = rd_detach_hba,
712 .alloc_device = rd_alloc_device,
713 .configure_device = rd_configure_device,
714 .free_device = rd_free_device,
715 .parse_cdb = rd_parse_cdb,
716 .set_configfs_dev_params = rd_set_configfs_dev_params,
717 .show_configfs_dev_params = rd_show_configfs_dev_params,
718 .get_device_type = sbc_get_device_type,
719 .get_blocks = rd_get_blocks,
720 .init_prot = rd_init_prot,
721 .free_prot = rd_free_prot,
722 .tb_dev_attrib_attrs = sbc_attrib_attrs,
725 int __init rd_module_init(void)
727 return transport_backend_register(&rd_mcp_ops);
730 void rd_module_exit(void)
732 target_backend_unregister(&rd_mcp_ops);