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/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>
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 static int rd_attach_hba(struct se_hba
*hba
, u32 host_id
)
48 struct rd_host
*rd_host
;
50 rd_host
= kzalloc(sizeof(*rd_host
), GFP_KERNEL
);
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
;
142 * Reserve extra element for chain entry
144 if (sg_per_table
< total_sg_needed
)
147 sg
= kcalloc(sg_per_table
+ chain_entry
, sizeof(*sg
),
152 sg_init_table(sg
, sg_per_table
+ chain_entry
);
155 sg_chain(sg_table
[i
- 1].sg_table
,
156 max_sg_per_table
+ 1, sg
);
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
)
165 for (j
= 0; j
< sg_per_table
; j
++) {
166 pg
= alloc_pages(GFP_KERNEL
, 0);
168 pr_err("Unable to allocate scatterlist"
169 " pages for struct rd_dev_sg_table\n");
172 sg_assign_page(&sg
[j
], pg
);
173 sg
[j
].length
= PAGE_SIZE
;
176 memset(p
, init_payload
, PAGE_SIZE
);
180 page_offset
+= sg_per_table
;
181 total_sg_needed
-= sg_per_table
;
187 static int rd_build_device_space(struct rd_dev
*rd_dev
)
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
));
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
);
201 /* Don't need backing pages for NULLIO */
202 if (rd_dev
->rd_flags
& RDF_NULLIO
)
205 total_sg_needed
= rd_dev
->rd_page_count
;
207 sg_tables
= (total_sg_needed
/ max_sg_per_table
) + 1;
208 sg_table
= kcalloc(sg_tables
, sizeof(*sg_table
), GFP_KERNEL
);
212 rd_dev
->sg_table_array
= sg_table
;
213 rd_dev
->sg_table_count
= sg_tables
;
215 rc
= rd_allocate_sgl_table(rd_dev
, sg_table
, total_sg_needed
, 0x00);
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
);
227 static void rd_release_prot_space(struct rd_dev
*rd_dev
)
231 if (!rd_dev
->sg_prot_array
|| !rd_dev
->sg_prot_count
)
234 page_count
= rd_release_sgl_table(rd_dev
, rd_dev
->sg_prot_array
,
235 rd_dev
->sg_prot_count
);
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
);
242 rd_dev
->sg_prot_array
= NULL
;
243 rd_dev
->sg_prot_count
= 0;
246 static int rd_build_prot_space(struct rd_dev
*rd_dev
, int prot_length
, int block_size
)
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
));
254 if (rd_dev
->rd_flags
& RDF_NULLIO
)
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.
262 total_sg_needed
= (rd_dev
->rd_page_count
* prot_length
/ block_size
) + 1;
264 sg_tables
= (total_sg_needed
/ max_sg_per_table
) + 1;
265 sg_table
= kcalloc(sg_tables
, sizeof(*sg_table
), GFP_KERNEL
);
269 rd_dev
->sg_prot_array
= sg_table
;
270 rd_dev
->sg_prot_count
= sg_tables
;
272 rc
= rd_allocate_sgl_table(rd_dev
, sg_table
, total_sg_needed
, 0xff);
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
);
283 static struct se_device
*rd_alloc_device(struct se_hba
*hba
, const char *name
)
285 struct rd_dev
*rd_dev
;
286 struct rd_host
*rd_host
= hba
->hba_ptr
;
288 rd_dev
= kzalloc(sizeof(*rd_dev
), GFP_KERNEL
);
292 rd_dev
->rd_host
= rd_host
;
297 static int rd_configure_device(struct se_device
*dev
)
299 struct rd_dev
*rd_dev
= RD_DEV(dev
);
300 struct rd_host
*rd_host
= dev
->se_hba
->hba_ptr
;
303 if (!(rd_dev
->rd_flags
& RDF_HAS_PAGE_COUNT
)) {
304 pr_debug("Missing rd_pages= parameter\n");
308 ret
= rd_build_device_space(rd_dev
);
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;
317 rd_dev
->rd_dev_id
= rd_host
->rd_host_dev_id_count
++;
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
));
328 rd_release_device_space(rd_dev
);
332 static void rd_dev_call_rcu(struct rcu_head
*p
)
334 struct se_device
*dev
= container_of(p
, struct se_device
, rcu_head
);
335 struct rd_dev
*rd_dev
= RD_DEV(dev
);
340 static void rd_free_device(struct se_device
*dev
)
342 struct rd_dev
*rd_dev
= RD_DEV(dev
);
344 rd_release_device_space(rd_dev
);
345 call_rcu(&dev
->rcu_head
, rd_dev_call_rcu
);
348 static struct rd_dev_sg_table
*rd_get_sg_table(struct rd_dev
*rd_dev
, u32 page
)
350 struct rd_dev_sg_table
*sg_table
;
351 u32 i
, sg_per_table
= (RD_MAX_ALLOCATION_SIZE
/
352 sizeof(struct scatterlist
));
354 i
= page
/ sg_per_table
;
355 if (i
< rd_dev
->sg_table_count
) {
356 sg_table
= &rd_dev
->sg_table_array
[i
];
357 if ((sg_table
->page_start_offset
<= page
) &&
358 (sg_table
->page_end_offset
>= page
))
362 pr_err("Unable to locate struct rd_dev_sg_table for page: %u\n",
368 static struct rd_dev_sg_table
*rd_get_prot_table(struct rd_dev
*rd_dev
, u32 page
)
370 struct rd_dev_sg_table
*sg_table
;
371 u32 i
, sg_per_table
= (RD_MAX_ALLOCATION_SIZE
/
372 sizeof(struct scatterlist
));
374 i
= page
/ sg_per_table
;
375 if (i
< rd_dev
->sg_prot_count
) {
376 sg_table
= &rd_dev
->sg_prot_array
[i
];
377 if ((sg_table
->page_start_offset
<= page
) &&
378 (sg_table
->page_end_offset
>= page
))
382 pr_err("Unable to locate struct prot rd_dev_sg_table for page: %u\n",
388 static sense_reason_t
rd_do_prot_rw(struct se_cmd
*cmd
, bool is_read
)
390 struct se_device
*se_dev
= cmd
->se_dev
;
391 struct rd_dev
*dev
= RD_DEV(se_dev
);
392 struct rd_dev_sg_table
*prot_table
;
393 struct scatterlist
*prot_sg
;
394 u32 sectors
= cmd
->data_length
/ se_dev
->dev_attrib
.block_size
;
395 u32 prot_offset
, prot_page
;
396 u32 prot_npages __maybe_unused
;
398 sense_reason_t rc
= 0;
400 tmp
= cmd
->t_task_lba
* se_dev
->prot_length
;
401 prot_offset
= do_div(tmp
, PAGE_SIZE
);
404 prot_table
= rd_get_prot_table(dev
, prot_page
);
406 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE
;
408 prot_sg
= &prot_table
->sg_table
[prot_page
-
409 prot_table
->page_start_offset
];
411 if (se_dev
->dev_attrib
.pi_prot_verify
) {
413 rc
= sbc_dif_verify(cmd
, cmd
->t_task_lba
, sectors
, 0,
414 prot_sg
, prot_offset
);
416 rc
= sbc_dif_verify(cmd
, cmd
->t_task_lba
, sectors
, 0,
420 sbc_dif_copy_prot(cmd
, sectors
, is_read
, prot_sg
, prot_offset
);
425 static sense_reason_t
426 rd_execute_rw(struct se_cmd
*cmd
, struct scatterlist
*sgl
, u32 sgl_nents
,
427 enum dma_data_direction data_direction
)
429 struct se_device
*se_dev
= cmd
->se_dev
;
430 struct rd_dev
*dev
= RD_DEV(se_dev
);
431 struct rd_dev_sg_table
*table
;
432 struct scatterlist
*rd_sg
;
433 struct sg_mapping_iter m
;
441 if (dev
->rd_flags
& RDF_NULLIO
) {
442 target_complete_cmd(cmd
, SAM_STAT_GOOD
);
446 tmp
= cmd
->t_task_lba
* se_dev
->dev_attrib
.block_size
;
447 rd_offset
= do_div(tmp
, PAGE_SIZE
);
449 rd_size
= cmd
->data_length
;
451 table
= rd_get_sg_table(dev
, rd_page
);
453 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE
;
455 rd_sg
= &table
->sg_table
[rd_page
- table
->page_start_offset
];
457 pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
459 data_direction
== DMA_FROM_DEVICE
? "Read" : "Write",
460 cmd
->t_task_lba
, rd_size
, rd_page
, rd_offset
);
462 if (cmd
->prot_type
&& se_dev
->dev_attrib
.pi_prot_type
&&
463 data_direction
== DMA_TO_DEVICE
) {
464 rc
= rd_do_prot_rw(cmd
, false);
469 src_len
= PAGE_SIZE
- rd_offset
;
470 sg_miter_start(&m
, sgl
, sgl_nents
,
471 data_direction
== DMA_FROM_DEVICE
?
472 SG_MITER_TO_SG
: SG_MITER_FROM_SG
);
478 if (!(u32
)m
.length
) {
479 pr_debug("RD[%u]: invalid sgl %p len %zu\n",
480 dev
->rd_dev_id
, m
.addr
, m
.length
);
482 return TCM_INCORRECT_AMOUNT_OF_DATA
;
484 len
= min((u32
)m
.length
, src_len
);
486 pr_debug("RD[%u]: size underrun page %d offset %d "
487 "size %d\n", dev
->rd_dev_id
,
488 rd_page
, rd_offset
, rd_size
);
493 rd_addr
= sg_virt(rd_sg
) + rd_offset
;
495 if (data_direction
== DMA_FROM_DEVICE
)
496 memcpy(m
.addr
, rd_addr
, len
);
498 memcpy(rd_addr
, m
.addr
, len
);
510 /* rd page completed, next one please */
514 if (rd_page
<= table
->page_end_offset
) {
519 table
= rd_get_sg_table(dev
, rd_page
);
522 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE
;
525 /* since we increment, the first sg entry is correct */
526 rd_sg
= table
->sg_table
;
530 if (cmd
->prot_type
&& se_dev
->dev_attrib
.pi_prot_type
&&
531 data_direction
== DMA_FROM_DEVICE
) {
532 rc
= rd_do_prot_rw(cmd
, true);
537 target_complete_cmd(cmd
, SAM_STAT_GOOD
);
542 Opt_rd_pages
, Opt_rd_nullio
, Opt_err
545 static match_table_t tokens
= {
546 {Opt_rd_pages
, "rd_pages=%d"},
547 {Opt_rd_nullio
, "rd_nullio=%d"},
551 static ssize_t
rd_set_configfs_dev_params(struct se_device
*dev
,
552 const char *page
, ssize_t count
)
554 struct rd_dev
*rd_dev
= RD_DEV(dev
);
555 char *orig
, *ptr
, *opts
;
556 substring_t args
[MAX_OPT_ARGS
];
557 int ret
= 0, arg
, token
;
559 opts
= kstrdup(page
, GFP_KERNEL
);
565 while ((ptr
= strsep(&opts
, ",\n")) != NULL
) {
569 token
= match_token(ptr
, tokens
, args
);
572 match_int(args
, &arg
);
573 rd_dev
->rd_page_count
= arg
;
574 pr_debug("RAMDISK: Referencing Page"
575 " Count: %u\n", rd_dev
->rd_page_count
);
576 rd_dev
->rd_flags
|= RDF_HAS_PAGE_COUNT
;
579 match_int(args
, &arg
);
583 pr_debug("RAMDISK: Setting NULLIO flag: %d\n", arg
);
584 rd_dev
->rd_flags
|= RDF_NULLIO
;
592 return (!ret
) ? count
: ret
;
595 static ssize_t
rd_show_configfs_dev_params(struct se_device
*dev
, char *b
)
597 struct rd_dev
*rd_dev
= RD_DEV(dev
);
599 ssize_t bl
= sprintf(b
, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
601 bl
+= sprintf(b
+ bl
, " PAGES/PAGE_SIZE: %u*%lu"
602 " SG_table_count: %u nullio: %d\n", rd_dev
->rd_page_count
,
603 PAGE_SIZE
, rd_dev
->sg_table_count
,
604 !!(rd_dev
->rd_flags
& RDF_NULLIO
));
608 static sector_t
rd_get_blocks(struct se_device
*dev
)
610 struct rd_dev
*rd_dev
= RD_DEV(dev
);
612 unsigned long long blocks_long
= ((rd_dev
->rd_page_count
* PAGE_SIZE
) /
613 dev
->dev_attrib
.block_size
) - 1;
618 static int rd_init_prot(struct se_device
*dev
)
620 struct rd_dev
*rd_dev
= RD_DEV(dev
);
622 if (!dev
->dev_attrib
.pi_prot_type
)
625 return rd_build_prot_space(rd_dev
, dev
->prot_length
,
626 dev
->dev_attrib
.block_size
);
629 static void rd_free_prot(struct se_device
*dev
)
631 struct rd_dev
*rd_dev
= RD_DEV(dev
);
633 rd_release_prot_space(rd_dev
);
636 static struct sbc_ops rd_sbc_ops
= {
637 .execute_rw
= rd_execute_rw
,
640 static sense_reason_t
641 rd_parse_cdb(struct se_cmd
*cmd
)
643 return sbc_parse_cdb(cmd
, &rd_sbc_ops
);
646 static const struct target_backend_ops rd_mcp_ops
= {
648 .inquiry_prod
= "RAMDISK-MCP",
649 .inquiry_rev
= RD_MCP_VERSION
,
650 .attach_hba
= rd_attach_hba
,
651 .detach_hba
= rd_detach_hba
,
652 .alloc_device
= rd_alloc_device
,
653 .configure_device
= rd_configure_device
,
654 .free_device
= rd_free_device
,
655 .parse_cdb
= rd_parse_cdb
,
656 .set_configfs_dev_params
= rd_set_configfs_dev_params
,
657 .show_configfs_dev_params
= rd_show_configfs_dev_params
,
658 .get_device_type
= sbc_get_device_type
,
659 .get_blocks
= rd_get_blocks
,
660 .init_prot
= rd_init_prot
,
661 .free_prot
= rd_free_prot
,
662 .tb_dev_attrib_attrs
= sbc_attrib_attrs
,
665 int __init
rd_module_init(void)
667 return transport_backend_register(&rd_mcp_ops
);
670 void rd_module_exit(void)
672 target_backend_unregister(&rd_mcp_ops
);