1 /*******************************************************************************
2 * Filename: target_core_rd.c
4 * This file contains the Storage Engine <-> Ramdisk transport
7 * (c) Copyright 2003-2012 RisingTide Systems LLC.
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/blkdev.h>
31 #include <linux/slab.h>
32 #include <linux/spinlock.h>
33 #include <scsi/scsi.h>
34 #include <scsi/scsi_host.h>
36 #include <target/target_core_base.h>
37 #include <target/target_core_backend.h>
39 #include "target_core_rd.h"
41 static inline struct rd_dev *RD_DEV(struct se_device *dev)
43 return container_of(dev, struct rd_dev, dev);
46 /* rd_attach_hba(): (Part of se_subsystem_api_t template)
50 static int rd_attach_hba(struct se_hba *hba, u32 host_id)
52 struct rd_host *rd_host;
54 rd_host = kzalloc(sizeof(struct rd_host), GFP_KERNEL);
56 pr_err("Unable to allocate memory for struct rd_host\n");
60 rd_host->rd_host_id = host_id;
62 hba->hba_ptr = rd_host;
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);
71 static void rd_detach_hba(struct se_hba *hba)
73 struct rd_host *rd_host = hba->hba_ptr;
75 pr_debug("CORE_HBA[%d] - Detached Ramdisk HBA: %u from"
76 " Generic Target Core\n", hba->hba_id, rd_host->rd_host_id);
82 /* rd_release_device_space():
86 static void rd_release_device_space(struct rd_dev *rd_dev)
88 u32 i, j, page_count = 0, sg_per_table;
89 struct rd_dev_sg_table *sg_table;
91 struct scatterlist *sg;
93 if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
96 sg_table = rd_dev->sg_table_array;
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;
102 for (j = 0; j < sg_per_table; j++) {
103 pg = sg_page(&sg[j]);
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);
119 rd_dev->sg_table_array = NULL;
120 rd_dev->sg_table_count = 0;
124 /* rd_build_device_space():
128 static int rd_build_device_space(struct rd_dev *rd_dev)
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;
135 struct scatterlist *sg;
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);
142 total_sg_needed = rd_dev->rd_page_count;
144 sg_tables = (total_sg_needed / max_sg_per_table) + 1;
146 sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
148 pr_err("Unable to allocate memory for Ramdisk"
149 " scatterlist tables\n");
153 rd_dev->sg_table_array = sg_table;
154 rd_dev->sg_table_count = sg_tables;
156 while (total_sg_needed) {
157 sg_per_table = (total_sg_needed > max_sg_per_table) ?
158 max_sg_per_table : total_sg_needed;
160 sg = kzalloc(sg_per_table * sizeof(struct scatterlist),
163 pr_err("Unable to allocate scatterlist array"
164 " for struct rd_dev\n");
168 sg_init_table(sg, sg_per_table);
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 page_offset += sg_per_table;
188 total_sg_needed -= sg_per_table;
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);
199 static struct se_device *rd_alloc_device(struct se_hba *hba, const char *name)
201 struct rd_dev *rd_dev;
202 struct rd_host *rd_host = hba->hba_ptr;
204 rd_dev = kzalloc(sizeof(struct rd_dev), GFP_KERNEL);
206 pr_err("Unable to allocate memory for struct rd_dev\n");
210 rd_dev->rd_host = rd_host;
215 static int rd_configure_device(struct se_device *dev)
217 struct rd_dev *rd_dev = RD_DEV(dev);
218 struct rd_host *rd_host = dev->se_hba->hba_ptr;
221 if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
222 pr_debug("Missing rd_pages= parameter\n");
226 ret = rd_build_device_space(rd_dev);
230 dev->dev_attrib.hw_block_size = RD_BLOCKSIZE;
231 dev->dev_attrib.hw_max_sectors = UINT_MAX;
232 dev->dev_attrib.hw_queue_depth = RD_MAX_DEVICE_QUEUE_DEPTH;
234 rd_dev->rd_dev_id = rd_host->rd_host_dev_id_count++;
236 pr_debug("CORE_RD[%u] - Added TCM MEMCPY Ramdisk Device ID: %u of"
237 " %u pages in %u tables, %lu total bytes\n",
238 rd_host->rd_host_id, rd_dev->rd_dev_id, rd_dev->rd_page_count,
239 rd_dev->sg_table_count,
240 (unsigned long)(rd_dev->rd_page_count * PAGE_SIZE));
245 rd_release_device_space(rd_dev);
249 static void rd_free_device(struct se_device *dev)
251 struct rd_dev *rd_dev = RD_DEV(dev);
253 rd_release_device_space(rd_dev);
257 static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page)
260 struct rd_dev_sg_table *sg_table;
262 for (i = 0; i < rd_dev->sg_table_count; i++) {
263 sg_table = &rd_dev->sg_table_array[i];
264 if ((sg_table->page_start_offset <= page) &&
265 (sg_table->page_end_offset >= page))
269 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
275 static sense_reason_t
276 rd_execute_rw(struct se_cmd *cmd)
278 struct scatterlist *sgl = cmd->t_data_sg;
279 u32 sgl_nents = cmd->t_data_nents;
280 enum dma_data_direction data_direction = cmd->data_direction;
281 struct se_device *se_dev = cmd->se_dev;
282 struct rd_dev *dev = RD_DEV(se_dev);
283 struct rd_dev_sg_table *table;
284 struct scatterlist *rd_sg;
285 struct sg_mapping_iter m;
292 tmp = cmd->t_task_lba * se_dev->dev_attrib.block_size;
293 rd_offset = do_div(tmp, PAGE_SIZE);
295 rd_size = cmd->data_length;
297 table = rd_get_sg_table(dev, rd_page);
299 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
301 rd_sg = &table->sg_table[rd_page - table->page_start_offset];
303 pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
305 data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
306 cmd->t_task_lba, rd_size, rd_page, rd_offset);
308 src_len = PAGE_SIZE - rd_offset;
309 sg_miter_start(&m, sgl, sgl_nents,
310 data_direction == DMA_FROM_DEVICE ?
311 SG_MITER_TO_SG : SG_MITER_FROM_SG);
317 len = min((u32)m.length, src_len);
320 rd_addr = sg_virt(rd_sg) + rd_offset;
322 if (data_direction == DMA_FROM_DEVICE)
323 memcpy(m.addr, rd_addr, len);
325 memcpy(rd_addr, m.addr, len);
337 /* rd page completed, next one please */
341 if (rd_page <= table->page_end_offset) {
346 table = rd_get_sg_table(dev, rd_page);
349 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
352 /* since we increment, the first sg entry is correct */
353 rd_sg = table->sg_table;
357 target_complete_cmd(cmd, SAM_STAT_GOOD);
362 Opt_rd_pages, Opt_err
365 static match_table_t tokens = {
366 {Opt_rd_pages, "rd_pages=%d"},
370 static ssize_t rd_set_configfs_dev_params(struct se_device *dev,
371 const char *page, ssize_t count)
373 struct rd_dev *rd_dev = RD_DEV(dev);
374 char *orig, *ptr, *opts;
375 substring_t args[MAX_OPT_ARGS];
376 int ret = 0, arg, token;
378 opts = kstrdup(page, GFP_KERNEL);
384 while ((ptr = strsep(&opts, ",\n")) != NULL) {
388 token = match_token(ptr, tokens, args);
391 match_int(args, &arg);
392 rd_dev->rd_page_count = arg;
393 pr_debug("RAMDISK: Referencing Page"
394 " Count: %u\n", rd_dev->rd_page_count);
395 rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
403 return (!ret) ? count : ret;
406 static ssize_t rd_show_configfs_dev_params(struct se_device *dev, char *b)
408 struct rd_dev *rd_dev = RD_DEV(dev);
410 ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
412 bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu"
413 " SG_table_count: %u\n", rd_dev->rd_page_count,
414 PAGE_SIZE, rd_dev->sg_table_count);
418 static sector_t rd_get_blocks(struct se_device *dev)
420 struct rd_dev *rd_dev = RD_DEV(dev);
422 unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
423 dev->dev_attrib.block_size) - 1;
428 static struct sbc_ops rd_sbc_ops = {
429 .execute_rw = rd_execute_rw,
432 static sense_reason_t
433 rd_parse_cdb(struct se_cmd *cmd)
435 return sbc_parse_cdb(cmd, &rd_sbc_ops);
438 static struct se_subsystem_api rd_mcp_template = {
440 .inquiry_prod = "RAMDISK-MCP",
441 .inquiry_rev = RD_MCP_VERSION,
442 .transport_type = TRANSPORT_PLUGIN_VHBA_VDEV,
443 .attach_hba = rd_attach_hba,
444 .detach_hba = rd_detach_hba,
445 .alloc_device = rd_alloc_device,
446 .configure_device = rd_configure_device,
447 .free_device = rd_free_device,
448 .parse_cdb = rd_parse_cdb,
449 .set_configfs_dev_params = rd_set_configfs_dev_params,
450 .show_configfs_dev_params = rd_show_configfs_dev_params,
451 .get_device_type = sbc_get_device_type,
452 .get_blocks = rd_get_blocks,
455 int __init rd_module_init(void)
459 ret = transport_subsystem_register(&rd_mcp_template);
467 void rd_module_exit(void)
469 transport_subsystem_release(&rd_mcp_template);