Root/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 * 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_rw(struct se_cmd *cmd)
288{
289    struct scatterlist *sgl = cmd->t_data_sg;
290    u32 sgl_nents = cmd->t_data_nents;
291    enum dma_data_direction data_direction = cmd->data_direction;
292    struct se_device *se_dev = cmd->se_dev;
293    struct rd_dev *dev = se_dev->dev_ptr;
294    struct rd_dev_sg_table *table;
295    struct scatterlist *rd_sg;
296    struct sg_mapping_iter m;
297    u32 rd_offset;
298    u32 rd_size;
299    u32 rd_page;
300    u32 src_len;
301    u64 tmp;
302
303    tmp = cmd->t_task_lba * se_dev->se_sub_dev->se_dev_attrib.block_size;
304    rd_offset = do_div(tmp, PAGE_SIZE);
305    rd_page = tmp;
306    rd_size = cmd->data_length;
307
308    table = rd_get_sg_table(dev, rd_page);
309    if (!table)
310        return -EINVAL;
311
312    rd_sg = &table->sg_table[rd_page - table->page_start_offset];
313
314    pr_debug("RD[%u]: %s LBA: %llu, Size: %u Page: %u, Offset: %u\n",
315            dev->rd_dev_id,
316            data_direction == DMA_FROM_DEVICE ? "Read" : "Write",
317            cmd->t_task_lba, rd_size, rd_page, rd_offset);
318
319    src_len = PAGE_SIZE - rd_offset;
320    sg_miter_start(&m, sgl, sgl_nents,
321            data_direction == DMA_FROM_DEVICE ?
322                SG_MITER_TO_SG : SG_MITER_FROM_SG);
323    while (rd_size) {
324        u32 len;
325        void *rd_addr;
326
327        sg_miter_next(&m);
328        len = min((u32)m.length, src_len);
329        m.consumed = len;
330
331        rd_addr = sg_virt(rd_sg) + rd_offset;
332
333        if (data_direction == DMA_FROM_DEVICE)
334            memcpy(m.addr, rd_addr, len);
335        else
336            memcpy(rd_addr, m.addr, len);
337
338        rd_size -= len;
339        if (!rd_size)
340            continue;
341
342        src_len -= len;
343        if (src_len) {
344            rd_offset += len;
345            continue;
346        }
347
348        /* rd page completed, next one please */
349        rd_page++;
350        rd_offset = 0;
351        src_len = PAGE_SIZE;
352        if (rd_page <= table->page_end_offset) {
353            rd_sg++;
354            continue;
355        }
356
357        table = rd_get_sg_table(dev, rd_page);
358        if (!table) {
359            sg_miter_stop(&m);
360            return -EINVAL;
361        }
362
363        /* since we increment, the first sg entry is correct */
364        rd_sg = table->sg_table;
365    }
366    sg_miter_stop(&m);
367
368    target_complete_cmd(cmd, SAM_STAT_GOOD);
369    return 0;
370}
371
372enum {
373    Opt_rd_pages, Opt_err
374};
375
376static match_table_t tokens = {
377    {Opt_rd_pages, "rd_pages=%d"},
378    {Opt_err, NULL}
379};
380
381static ssize_t rd_set_configfs_dev_params(
382    struct se_hba *hba,
383    struct se_subsystem_dev *se_dev,
384    const char *page,
385    ssize_t count)
386{
387    struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
388    char *orig, *ptr, *opts;
389    substring_t args[MAX_OPT_ARGS];
390    int ret = 0, arg, token;
391
392    opts = kstrdup(page, GFP_KERNEL);
393    if (!opts)
394        return -ENOMEM;
395
396    orig = opts;
397
398    while ((ptr = strsep(&opts, ",\n")) != NULL) {
399        if (!*ptr)
400            continue;
401
402        token = match_token(ptr, tokens, args);
403        switch (token) {
404        case Opt_rd_pages:
405            match_int(args, &arg);
406            rd_dev->rd_page_count = arg;
407            pr_debug("RAMDISK: Referencing Page"
408                " Count: %u\n", rd_dev->rd_page_count);
409            rd_dev->rd_flags |= RDF_HAS_PAGE_COUNT;
410            break;
411        default:
412            break;
413        }
414    }
415
416    kfree(orig);
417    return (!ret) ? count : ret;
418}
419
420static ssize_t rd_check_configfs_dev_params(struct se_hba *hba, struct se_subsystem_dev *se_dev)
421{
422    struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
423
424    if (!(rd_dev->rd_flags & RDF_HAS_PAGE_COUNT)) {
425        pr_debug("Missing rd_pages= parameter\n");
426        return -EINVAL;
427    }
428
429    return 0;
430}
431
432static ssize_t rd_show_configfs_dev_params(
433    struct se_hba *hba,
434    struct se_subsystem_dev *se_dev,
435    char *b)
436{
437    struct rd_dev *rd_dev = se_dev->se_dev_su_ptr;
438    ssize_t bl = sprintf(b, "TCM RamDisk ID: %u RamDisk Makeup: rd_mcp\n",
439            rd_dev->rd_dev_id);
440    bl += sprintf(b + bl, " PAGES/PAGE_SIZE: %u*%lu"
441            " SG_table_count: %u\n", rd_dev->rd_page_count,
442            PAGE_SIZE, rd_dev->sg_table_count);
443    return bl;
444}
445
446static u32 rd_get_device_rev(struct se_device *dev)
447{
448    return SCSI_SPC_2; /* Returns SPC-3 in Initiator Data */
449}
450
451static u32 rd_get_device_type(struct se_device *dev)
452{
453    return TYPE_DISK;
454}
455
456static sector_t rd_get_blocks(struct se_device *dev)
457{
458    struct rd_dev *rd_dev = dev->dev_ptr;
459    unsigned long long blocks_long = ((rd_dev->rd_page_count * PAGE_SIZE) /
460            dev->se_sub_dev->se_dev_attrib.block_size) - 1;
461
462    return blocks_long;
463}
464
465static struct spc_ops rd_spc_ops = {
466    .execute_rw = rd_execute_rw,
467};
468
469static int rd_parse_cdb(struct se_cmd *cmd)
470{
471    return sbc_parse_cdb(cmd, &rd_spc_ops);
472}
473
474static struct se_subsystem_api rd_mcp_template = {
475    .name = "rd_mcp",
476    .transport_type = TRANSPORT_PLUGIN_VHBA_VDEV,
477    .attach_hba = rd_attach_hba,
478    .detach_hba = rd_detach_hba,
479    .allocate_virtdevice = rd_allocate_virtdevice,
480    .create_virtdevice = rd_create_virtdevice,
481    .free_device = rd_free_device,
482    .parse_cdb = rd_parse_cdb,
483    .check_configfs_dev_params = rd_check_configfs_dev_params,
484    .set_configfs_dev_params = rd_set_configfs_dev_params,
485    .show_configfs_dev_params = rd_show_configfs_dev_params,
486    .get_device_rev = rd_get_device_rev,
487    .get_device_type = rd_get_device_type,
488    .get_blocks = rd_get_blocks,
489};
490
491int __init rd_module_init(void)
492{
493    int ret;
494
495    ret = transport_subsystem_register(&rd_mcp_template);
496    if (ret < 0) {
497        return ret;
498    }
499
500    return 0;
501}
502
503void rd_module_exit(void)
504{
505    transport_subsystem_release(&rd_mcp_template);
506}
507

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive