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Use dentry_path() to create full path to inode object
[pohmelfs.git] / drivers / s390 / block / dcssblk.c
bloba5a55da2a1ac14752c426f4a0a00e4fb4f11521c
1 /*
2 * dcssblk.c -- the S/390 block driver for dcss memory
3 *
4 * Authors: Carsten Otte, Stefan Weinhuber, Gerald Schaefer
5 */
6
7 #define KMSG_COMPONENT "dcssblk"
8 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
9
10 #include <linux/module.h>
11 #include <linux/moduleparam.h>
12 #include <linux/ctype.h>
13 #include <linux/errno.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/blkdev.h>
17 #include <linux/completion.h>
18 #include <linux/interrupt.h>
19 #include <linux/platform_device.h>
20 #include <asm/extmem.h>
21 #include <asm/io.h>
22
23 #define DCSSBLK_NAME "dcssblk"
24 #define DCSSBLK_MINORS_PER_DISK 1
25 #define DCSSBLK_PARM_LEN 400
26 #define DCSS_BUS_ID_SIZE 20
27
28 static int dcssblk_open(struct block_device *bdev, fmode_t mode);
29 static int dcssblk_release(struct gendisk *disk, fmode_t mode);
30 static void dcssblk_make_request(struct request_queue *q, struct bio *bio);
31 static int dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
32 void **kaddr, unsigned long *pfn);
33
34 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
35
36 static int dcssblk_major;
37 static const struct block_device_operations dcssblk_devops = {
38 .owner = THIS_MODULE,
39 .open = dcssblk_open,
40 .release = dcssblk_release,
41 .direct_access = dcssblk_direct_access,
42 };
43
44 struct dcssblk_dev_info {
45 struct list_head lh;
46 struct device dev;
47 char segment_name[DCSS_BUS_ID_SIZE];
48 atomic_t use_count;
49 struct gendisk *gd;
50 unsigned long start;
51 unsigned long end;
52 int segment_type;
53 unsigned char save_pending;
54 unsigned char is_shared;
55 struct request_queue *dcssblk_queue;
56 int num_of_segments;
57 struct list_head seg_list;
58 };
59
60 struct segment_info {
61 struct list_head lh;
62 char segment_name[DCSS_BUS_ID_SIZE];
63 unsigned long start;
64 unsigned long end;
65 int segment_type;
66 };
67
68 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
69 size_t count);
70 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
71 size_t count);
72 static ssize_t dcssblk_save_store(struct device * dev, struct device_attribute *attr, const char * buf,
73 size_t count);
74 static ssize_t dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf);
75 static ssize_t dcssblk_shared_store(struct device * dev, struct device_attribute *attr, const char * buf,
76 size_t count);
77 static ssize_t dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf);
78 static ssize_t dcssblk_seglist_show(struct device *dev,
79 struct device_attribute *attr,
80 char *buf);
81
82 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
83 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
84 static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
85 dcssblk_save_store);
86 static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
87 dcssblk_shared_store);
88 static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);
89
90 static struct device *dcssblk_root_dev;
91
92 static LIST_HEAD(dcssblk_devices);
93 static struct rw_semaphore dcssblk_devices_sem;
94
95 /*
96 * release function for segment device.
97 */
98 static void
99 dcssblk_release_segment(struct device *dev)
100 {
101 struct dcssblk_dev_info *dev_info;
102 struct segment_info *entry, *temp;
103
104 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
105 list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) {
106 list_del(&entry->lh);
107 kfree(entry);
108 }
109 kfree(dev_info);
110 module_put(THIS_MODULE);
111 }
112
113 /*
114 * get a minor number. needs to be called with
115 * down_write(&dcssblk_devices_sem) and the
116 * device needs to be enqueued before the semaphore is
117 * freed.
118 */
119 static int
120 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
121 {
122 int minor, found;
123 struct dcssblk_dev_info *entry;
124
125 if (dev_info == NULL)
126 return -EINVAL;
127 for (minor = 0; minor < (1<<MINORBITS); minor++) {
128 found = 0;
129 // test if minor available
130 list_for_each_entry(entry, &dcssblk_devices, lh)
131 if (minor == entry->gd->first_minor)
132 found++;
133 if (!found) break; // got unused minor
134 }
135 if (found)
136 return -EBUSY;
137 dev_info->gd->first_minor = minor;
138 return 0;
139 }
140
141 /*
142 * get the struct dcssblk_dev_info from dcssblk_devices
143 * for the given name.
144 * down_read(&dcssblk_devices_sem) must be held.
145 */
146 static struct dcssblk_dev_info *
147 dcssblk_get_device_by_name(char *name)
148 {
149 struct dcssblk_dev_info *entry;
150
151 list_for_each_entry(entry, &dcssblk_devices, lh) {
152 if (!strcmp(name, entry->segment_name)) {
153 return entry;
154 }
155 }
156 return NULL;
157 }
158
159 /*
160 * get the struct segment_info from seg_list
161 * for the given name.
162 * down_read(&dcssblk_devices_sem) must be held.
163 */
164 static struct segment_info *
165 dcssblk_get_segment_by_name(char *name)
166 {
167 struct dcssblk_dev_info *dev_info;
168 struct segment_info *entry;
169
170 list_for_each_entry(dev_info, &dcssblk_devices, lh) {
171 list_for_each_entry(entry, &dev_info->seg_list, lh) {
172 if (!strcmp(name, entry->segment_name))
173 return entry;
174 }
175 }
176 return NULL;
177 }
178
179 /*
180 * get the highest address of the multi-segment block.
181 */
182 static unsigned long
183 dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info)
184 {
185 unsigned long highest_addr;
186 struct segment_info *entry;
187
188 highest_addr = 0;
189 list_for_each_entry(entry, &dev_info->seg_list, lh) {
190 if (highest_addr < entry->end)
191 highest_addr = entry->end;
192 }
193 return highest_addr;
194 }
195
196 /*
197 * get the lowest address of the multi-segment block.
198 */
199 static unsigned long
200 dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info)
201 {
202 int set_first;
203 unsigned long lowest_addr;
204 struct segment_info *entry;
205
206 set_first = 0;
207 lowest_addr = 0;
208 list_for_each_entry(entry, &dev_info->seg_list, lh) {
209 if (set_first == 0) {
210 lowest_addr = entry->start;
211 set_first = 1;
212 } else {
213 if (lowest_addr > entry->start)
214 lowest_addr = entry->start;
215 }
216 }
217 return lowest_addr;
218 }
219
220 /*
221 * Check continuity of segments.
222 */
223 static int
224 dcssblk_is_continuous(struct dcssblk_dev_info *dev_info)
225 {
226 int i, j, rc;
227 struct segment_info *sort_list, *entry, temp;
228
229 if (dev_info->num_of_segments <= 1)
230 return 0;
231
232 sort_list = kzalloc(
233 sizeof(struct segment_info) * dev_info->num_of_segments,
234 GFP_KERNEL);
235 if (sort_list == NULL)
236 return -ENOMEM;
237 i = 0;
238 list_for_each_entry(entry, &dev_info->seg_list, lh) {
239 memcpy(&sort_list[i], entry, sizeof(struct segment_info));
240 i++;
241 }
242
243 /* sort segments */
244 for (i = 0; i < dev_info->num_of_segments; i++)
245 for (j = 0; j < dev_info->num_of_segments; j++)
246 if (sort_list[j].start > sort_list[i].start) {
247 memcpy(&temp, &sort_list[i],
248 sizeof(struct segment_info));
249 memcpy(&sort_list[i], &sort_list[j],
250 sizeof(struct segment_info));
251 memcpy(&sort_list[j], &temp,
252 sizeof(struct segment_info));
253 }
254
255 /* check continuity */
256 for (i = 0; i < dev_info->num_of_segments - 1; i++) {
257 if ((sort_list[i].end + 1) != sort_list[i+1].start) {
258 pr_err("Adjacent DCSSs %s and %s are not "
259 "contiguous\n", sort_list[i].segment_name,
260 sort_list[i+1].segment_name);
261 rc = -EINVAL;
262 goto out;
263 }
264 /* EN and EW are allowed in a block device */
265 if (sort_list[i].segment_type != sort_list[i+1].segment_type) {
266 if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) ||
267 (sort_list[i].segment_type == SEG_TYPE_ER) ||
268 !(sort_list[i+1].segment_type &
269 SEGMENT_EXCLUSIVE) ||
270 (sort_list[i+1].segment_type == SEG_TYPE_ER)) {
271 pr_err("DCSS %s and DCSS %s have "
272 "incompatible types\n",
273 sort_list[i].segment_name,
274 sort_list[i+1].segment_name);
275 rc = -EINVAL;
276 goto out;
277 }
278 }
279 }
280 rc = 0;
281 out:
282 kfree(sort_list);
283 return rc;
284 }
285
286 /*
287 * Load a segment
288 */
289 static int
290 dcssblk_load_segment(char *name, struct segment_info **seg_info)
291 {
292 int rc;
293
294 /* already loaded? */
295 down_read(&dcssblk_devices_sem);
296 *seg_info = dcssblk_get_segment_by_name(name);
297 up_read(&dcssblk_devices_sem);
298 if (*seg_info != NULL)
299 return -EEXIST;
300
301 /* get a struct segment_info */
302 *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL);
303 if (*seg_info == NULL)
304 return -ENOMEM;
305
306 strcpy((*seg_info)->segment_name, name);
307
308 /* load the segment */
309 rc = segment_load(name, SEGMENT_SHARED,
310 &(*seg_info)->start, &(*seg_info)->end);
311 if (rc < 0) {
312 segment_warning(rc, (*seg_info)->segment_name);
313 kfree(*seg_info);
314 } else {
315 INIT_LIST_HEAD(&(*seg_info)->lh);
316 (*seg_info)->segment_type = rc;
317 }
318 return rc;
319 }
320
321 static void dcssblk_unregister_callback(struct device *dev)
322 {
323 device_unregister(dev);
324 put_device(dev);
325 }
326
327 /*
328 * device attribute for switching shared/nonshared (exclusive)
329 * operation (show + store)
330 */
331 static ssize_t
332 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
333 {
334 struct dcssblk_dev_info *dev_info;
335
336 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
337 return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
338 }
339
340 static ssize_t
341 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
342 {
343 struct dcssblk_dev_info *dev_info;
344 struct segment_info *entry, *temp;
345 int rc;
346
347 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
348 return -EINVAL;
349 down_write(&dcssblk_devices_sem);
350 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
351 if (atomic_read(&dev_info->use_count)) {
352 rc = -EBUSY;
353 goto out;
354 }
355 if (inbuf[0] == '1') {
356 /* reload segments in shared mode */
357 list_for_each_entry(entry, &dev_info->seg_list, lh) {
358 rc = segment_modify_shared(entry->segment_name,
359 SEGMENT_SHARED);
360 if (rc < 0) {
361 BUG_ON(rc == -EINVAL);
362 if (rc != -EAGAIN)
363 goto removeseg;
364 }
365 }
366 dev_info->is_shared = 1;
367 switch (dev_info->segment_type) {
368 case SEG_TYPE_SR:
369 case SEG_TYPE_ER:
370 case SEG_TYPE_SC:
371 set_disk_ro(dev_info->gd, 1);
372 }
373 } else if (inbuf[0] == '0') {
374 /* reload segments in exclusive mode */
375 if (dev_info->segment_type == SEG_TYPE_SC) {
376 pr_err("DCSS %s is of type SC and cannot be "
377 "loaded as exclusive-writable\n",
378 dev_info->segment_name);
379 rc = -EINVAL;
380 goto out;
381 }
382 list_for_each_entry(entry, &dev_info->seg_list, lh) {
383 rc = segment_modify_shared(entry->segment_name,
384 SEGMENT_EXCLUSIVE);
385 if (rc < 0) {
386 BUG_ON(rc == -EINVAL);
387 if (rc != -EAGAIN)
388 goto removeseg;
389 }
390 }
391 dev_info->is_shared = 0;
392 set_disk_ro(dev_info->gd, 0);
393 } else {
394 rc = -EINVAL;
395 goto out;
396 }
397 rc = count;
398 goto out;
399
400 removeseg:
401 pr_err("DCSS device %s is removed after a failed access mode "
402 "change\n", dev_info->segment_name);
403 temp = entry;
404 list_for_each_entry(entry, &dev_info->seg_list, lh) {
405 if (entry != temp)
406 segment_unload(entry->segment_name);
407 }
408 list_del(&dev_info->lh);
409
410 del_gendisk(dev_info->gd);
411 blk_cleanup_queue(dev_info->dcssblk_queue);
412 dev_info->gd->queue = NULL;
413 put_disk(dev_info->gd);
414 rc = device_schedule_callback(dev, dcssblk_unregister_callback);
415 out:
416 up_write(&dcssblk_devices_sem);
417 return rc;
418 }
419
420 /*
421 * device attribute for save operation on current copy
422 * of the segment. If the segment is busy, saving will
423 * become pending until it gets released, which can be
424 * undone by storing a non-true value to this entry.
425 * (show + store)
426 */
427 static ssize_t
428 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
429 {
430 struct dcssblk_dev_info *dev_info;
431
432 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
433 return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
434 }
435
436 static ssize_t
437 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
438 {
439 struct dcssblk_dev_info *dev_info;
440 struct segment_info *entry;
441
442 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
443 return -EINVAL;
444 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
445
446 down_write(&dcssblk_devices_sem);
447 if (inbuf[0] == '1') {
448 if (atomic_read(&dev_info->use_count) == 0) {
449 // device is idle => we save immediately
450 pr_info("All DCSSs that map to device %s are "
451 "saved\n", dev_info->segment_name);
452 list_for_each_entry(entry, &dev_info->seg_list, lh) {
453 segment_save(entry->segment_name);
454 }
455 } else {
456 // device is busy => we save it when it becomes
457 // idle in dcssblk_release
458 pr_info("Device %s is in use, its DCSSs will be "
459 "saved when it becomes idle\n",
460 dev_info->segment_name);
461 dev_info->save_pending = 1;
462 }
463 } else if (inbuf[0] == '0') {
464 if (dev_info->save_pending) {
465 // device is busy & the user wants to undo his save
466 // request
467 dev_info->save_pending = 0;
468 pr_info("A pending save request for device %s "
469 "has been canceled\n",
470 dev_info->segment_name);
471 }
472 } else {
473 up_write(&dcssblk_devices_sem);
474 return -EINVAL;
475 }
476 up_write(&dcssblk_devices_sem);
477 return count;
478 }
479
480 /*
481 * device attribute for showing all segments in a device
482 */
483 static ssize_t
484 dcssblk_seglist_show(struct device *dev, struct device_attribute *attr,
485 char *buf)
486 {
487 int i;
488
489 struct dcssblk_dev_info *dev_info;
490 struct segment_info *entry;
491
492 down_read(&dcssblk_devices_sem);
493 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
494 i = 0;
495 buf[0] = '\0';
496 list_for_each_entry(entry, &dev_info->seg_list, lh) {
497 strcpy(&buf[i], entry->segment_name);
498 i += strlen(entry->segment_name);
499 buf[i] = '\n';
500 i++;
501 }
502 up_read(&dcssblk_devices_sem);
503 return i;
504 }
505
506 /*
507 * device attribute for adding devices
508 */
509 static ssize_t
510 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
511 {
512 int rc, i, j, num_of_segments;
513 struct dcssblk_dev_info *dev_info;
514 struct segment_info *seg_info, *temp;
515 char *local_buf;
516 unsigned long seg_byte_size;
517
518 dev_info = NULL;
519 seg_info = NULL;
520 if (dev != dcssblk_root_dev) {
521 rc = -EINVAL;
522 goto out_nobuf;
523 }
524 if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) {
525 rc = -ENAMETOOLONG;
526 goto out_nobuf;
527 }
528
529 local_buf = kmalloc(count + 1, GFP_KERNEL);
530 if (local_buf == NULL) {
531 rc = -ENOMEM;
532 goto out_nobuf;
533 }
534
535 /*
536 * parse input
537 */
538 num_of_segments = 0;
539 for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
540 for (j = i; (buf[j] != ':') &&
541 (buf[j] != '\0') &&
542 (buf[j] != '\n') &&
543 j < count; j++) {
544 local_buf[j-i] = toupper(buf[j]);
545 }
546 local_buf[j-i] = '\0';
547 if (((j - i) == 0) || ((j - i) > 8)) {
548 rc = -ENAMETOOLONG;
549 goto seg_list_del;
550 }
551
552 rc = dcssblk_load_segment(local_buf, &seg_info);
553 if (rc < 0)
554 goto seg_list_del;
555 /*
556 * get a struct dcssblk_dev_info
557 */
558 if (num_of_segments == 0) {
559 dev_info = kzalloc(sizeof(struct dcssblk_dev_info),
560 GFP_KERNEL);
561 if (dev_info == NULL) {
562 rc = -ENOMEM;
563 goto out;
564 }
565 strcpy(dev_info->segment_name, local_buf);
566 dev_info->segment_type = seg_info->segment_type;
567 INIT_LIST_HEAD(&dev_info->seg_list);
568 }
569 list_add_tail(&seg_info->lh, &dev_info->seg_list);
570 num_of_segments++;
571 i = j;
572
573 if ((buf[j] == '\0') || (buf[j] == '\n'))
574 break;
575 }
576
577 /* no trailing colon at the end of the input */
578 if ((i > 0) && (buf[i-1] == ':')) {
579 rc = -ENAMETOOLONG;
580 goto seg_list_del;
581 }
582 strlcpy(local_buf, buf, i + 1);
583 dev_info->num_of_segments = num_of_segments;
584 rc = dcssblk_is_continuous(dev_info);
585 if (rc < 0)
586 goto seg_list_del;
587
588 dev_info->start = dcssblk_find_lowest_addr(dev_info);
589 dev_info->end = dcssblk_find_highest_addr(dev_info);
590
591 dev_set_name(&dev_info->dev, dev_info->segment_name);
592 dev_info->dev.release = dcssblk_release_segment;
593 INIT_LIST_HEAD(&dev_info->lh);
594 dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
595 if (dev_info->gd == NULL) {
596 rc = -ENOMEM;
597 goto seg_list_del;
598 }
599 dev_info->gd->major = dcssblk_major;
600 dev_info->gd->fops = &dcssblk_devops;
601 dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
602 dev_info->gd->queue = dev_info->dcssblk_queue;
603 dev_info->gd->private_data = dev_info;
604 dev_info->gd->driverfs_dev = &dev_info->dev;
605 blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
606 blk_queue_logical_block_size(dev_info->dcssblk_queue, 4096);
607
608 seg_byte_size = (dev_info->end - dev_info->start + 1);
609 set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
610 pr_info("Loaded %s with total size %lu bytes and capacity %lu "
611 "sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9);
612
613 dev_info->save_pending = 0;
614 dev_info->is_shared = 1;
615 dev_info->dev.parent = dcssblk_root_dev;
616
617 /*
618 *get minor, add to list
619 */
620 down_write(&dcssblk_devices_sem);
621 if (dcssblk_get_segment_by_name(local_buf)) {
622 rc = -EEXIST;
623 goto release_gd;
624 }
625 rc = dcssblk_assign_free_minor(dev_info);
626 if (rc)
627 goto release_gd;
628 sprintf(dev_info->gd->disk_name, "dcssblk%d",
629 dev_info->gd->first_minor);
630 list_add_tail(&dev_info->lh, &dcssblk_devices);
631
632 if (!try_module_get(THIS_MODULE)) {
633 rc = -ENODEV;
634 goto dev_list_del;
635 }
636 /*
637 * register the device
638 */
639 rc = device_register(&dev_info->dev);
640 if (rc) {
641 module_put(THIS_MODULE);
642 goto dev_list_del;
643 }
644 get_device(&dev_info->dev);
645 rc = device_create_file(&dev_info->dev, &dev_attr_shared);
646 if (rc)
647 goto unregister_dev;
648 rc = device_create_file(&dev_info->dev, &dev_attr_save);
649 if (rc)
650 goto unregister_dev;
651 rc = device_create_file(&dev_info->dev, &dev_attr_seglist);
652 if (rc)
653 goto unregister_dev;
654
655 add_disk(dev_info->gd);
656
657 switch (dev_info->segment_type) {
658 case SEG_TYPE_SR:
659 case SEG_TYPE_ER:
660 case SEG_TYPE_SC:
661 set_disk_ro(dev_info->gd,1);
662 break;
663 default:
664 set_disk_ro(dev_info->gd,0);
665 break;
666 }
667 up_write(&dcssblk_devices_sem);
668 rc = count;
669 goto out;
670
671 unregister_dev:
672 list_del(&dev_info->lh);
673 blk_cleanup_queue(dev_info->dcssblk_queue);
674 dev_info->gd->queue = NULL;
675 put_disk(dev_info->gd);
676 device_unregister(&dev_info->dev);
677 list_for_each_entry(seg_info, &dev_info->seg_list, lh) {
678 segment_unload(seg_info->segment_name);
679 }
680 put_device(&dev_info->dev);
681 up_write(&dcssblk_devices_sem);
682 goto out;
683 dev_list_del:
684 list_del(&dev_info->lh);
685 release_gd:
686 blk_cleanup_queue(dev_info->dcssblk_queue);
687 dev_info->gd->queue = NULL;
688 put_disk(dev_info->gd);
689 up_write(&dcssblk_devices_sem);
690 seg_list_del:
691 if (dev_info == NULL)
692 goto out;
693 list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) {
694 list_del(&seg_info->lh);
695 segment_unload(seg_info->segment_name);
696 kfree(seg_info);
697 }
698 kfree(dev_info);
699 out:
700 kfree(local_buf);
701 out_nobuf:
702 return rc;
703 }
704
705 /*
706 * device attribute for removing devices
707 */
708 static ssize_t
709 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
710 {
711 struct dcssblk_dev_info *dev_info;
712 struct segment_info *entry;
713 int rc, i;
714 char *local_buf;
715
716 if (dev != dcssblk_root_dev) {
717 return -EINVAL;
718 }
719 local_buf = kmalloc(count + 1, GFP_KERNEL);
720 if (local_buf == NULL) {
721 return -ENOMEM;
722 }
723 /*
724 * parse input
725 */
726 for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
727 local_buf[i] = toupper(buf[i]);
728 }
729 local_buf[i] = '\0';
730 if ((i == 0) || (i > 8)) {
731 rc = -ENAMETOOLONG;
732 goto out_buf;
733 }
734
735 down_write(&dcssblk_devices_sem);
736 dev_info = dcssblk_get_device_by_name(local_buf);
737 if (dev_info == NULL) {
738 up_write(&dcssblk_devices_sem);
739 pr_warning("Device %s cannot be removed because it is not a "
740 "known device\n", local_buf);
741 rc = -ENODEV;
742 goto out_buf;
743 }
744 if (atomic_read(&dev_info->use_count) != 0) {
745 up_write(&dcssblk_devices_sem);
746 pr_warning("Device %s cannot be removed while it is in "
747 "use\n", local_buf);
748 rc = -EBUSY;
749 goto out_buf;
750 }
751
752 list_del(&dev_info->lh);
753 del_gendisk(dev_info->gd);
754 blk_cleanup_queue(dev_info->dcssblk_queue);
755 dev_info->gd->queue = NULL;
756 put_disk(dev_info->gd);
757 device_unregister(&dev_info->dev);
758
759 /* unload all related segments */
760 list_for_each_entry(entry, &dev_info->seg_list, lh)
761 segment_unload(entry->segment_name);
762
763 put_device(&dev_info->dev);
764 up_write(&dcssblk_devices_sem);
765
766 rc = count;
767 out_buf:
768 kfree(local_buf);
769 return rc;
770 }
771
772 static int
773 dcssblk_open(struct block_device *bdev, fmode_t mode)
774 {
775 struct dcssblk_dev_info *dev_info;
776 int rc;
777
778 dev_info = bdev->bd_disk->private_data;
779 if (NULL == dev_info) {
780 rc = -ENODEV;
781 goto out;
782 }
783 atomic_inc(&dev_info->use_count);
784 bdev->bd_block_size = 4096;
785 rc = 0;
786 out:
787 return rc;
788 }
789
790 static int
791 dcssblk_release(struct gendisk *disk, fmode_t mode)
792 {
793 struct dcssblk_dev_info *dev_info = disk->private_data;
794 struct segment_info *entry;
795 int rc;
796
797 if (!dev_info) {
798 rc = -ENODEV;
799 goto out;
800 }
801 down_write(&dcssblk_devices_sem);
802 if (atomic_dec_and_test(&dev_info->use_count)
803 && (dev_info->save_pending)) {
804 pr_info("Device %s has become idle and is being saved "
805 "now\n", dev_info->segment_name);
806 list_for_each_entry(entry, &dev_info->seg_list, lh) {
807 segment_save(entry->segment_name);
808 }
809 dev_info->save_pending = 0;
810 }
811 up_write(&dcssblk_devices_sem);
812 rc = 0;
813 out:
814 return rc;
815 }
816
817 static void
818 dcssblk_make_request(struct request_queue *q, struct bio *bio)
819 {
820 struct dcssblk_dev_info *dev_info;
821 struct bio_vec *bvec;
822 unsigned long index;
823 unsigned long page_addr;
824 unsigned long source_addr;
825 unsigned long bytes_done;
826 int i;
827
828 bytes_done = 0;
829 dev_info = bio->bi_bdev->bd_disk->private_data;
830 if (dev_info == NULL)
831 goto fail;
832 if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
833 /* Request is not page-aligned. */
834 goto fail;
835 if (((bio->bi_size >> 9) + bio->bi_sector)
836 > get_capacity(bio->bi_bdev->bd_disk)) {
837 /* Request beyond end of DCSS segment. */
838 goto fail;
839 }
840 /* verify data transfer direction */
841 if (dev_info->is_shared) {
842 switch (dev_info->segment_type) {
843 case SEG_TYPE_SR:
844 case SEG_TYPE_ER:
845 case SEG_TYPE_SC:
846 /* cannot write to these segments */
847 if (bio_data_dir(bio) == WRITE) {
848 pr_warning("Writing to %s failed because it "
849 "is a read-only device\n",
850 dev_name(&dev_info->dev));
851 goto fail;
852 }
853 }
854 }
855
856 index = (bio->bi_sector >> 3);
857 bio_for_each_segment(bvec, bio, i) {
858 page_addr = (unsigned long)
859 page_address(bvec->bv_page) + bvec->bv_offset;
860 source_addr = dev_info->start + (index<<12) + bytes_done;
861 if (unlikely((page_addr & 4095) != 0) || (bvec->bv_len & 4095) != 0)
862 // More paranoia.
863 goto fail;
864 if (bio_data_dir(bio) == READ) {
865 memcpy((void*)page_addr, (void*)source_addr,
866 bvec->bv_len);
867 } else {
868 memcpy((void*)source_addr, (void*)page_addr,
869 bvec->bv_len);
870 }
871 bytes_done += bvec->bv_len;
872 }
873 bio_endio(bio, 0);
874 return;
875 fail:
876 bio_io_error(bio);
877 }
878
879 static int
880 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
881 void **kaddr, unsigned long *pfn)
882 {
883 struct dcssblk_dev_info *dev_info;
884 unsigned long pgoff;
885
886 dev_info = bdev->bd_disk->private_data;
887 if (!dev_info)
888 return -ENODEV;
889 if (secnum % (PAGE_SIZE/512))
890 return -EINVAL;
891 pgoff = secnum / (PAGE_SIZE / 512);
892 if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
893 return -ERANGE;
894 *kaddr = (void *) (dev_info->start+pgoff*PAGE_SIZE);
895 *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
896
897 return 0;
898 }
899
900 static void
901 dcssblk_check_params(void)
902 {
903 int rc, i, j, k;
904 char buf[DCSSBLK_PARM_LEN + 1];
905 struct dcssblk_dev_info *dev_info;
906
907 for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
908 i++) {
909 for (j = i; (dcssblk_segments[j] != ',') &&
910 (dcssblk_segments[j] != '\0') &&
911 (dcssblk_segments[j] != '(') &&
912 (j < DCSSBLK_PARM_LEN); j++)
913 {
914 buf[j-i] = dcssblk_segments[j];
915 }
916 buf[j-i] = '\0';
917 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
918 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
919 for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
920 buf[k] = toupper(buf[k]);
921 buf[k] = '\0';
922 if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
923 down_read(&dcssblk_devices_sem);
924 dev_info = dcssblk_get_device_by_name(buf);
925 up_read(&dcssblk_devices_sem);
926 if (dev_info)
927 dcssblk_shared_store(&dev_info->dev,
928 NULL, "0\n", 2);
929 }
930 }
931 while ((dcssblk_segments[j] != ',') &&
932 (dcssblk_segments[j] != '\0'))
933 {
934 j++;
935 }
936 if (dcssblk_segments[j] == '\0')
937 break;
938 i = j;
939 }
940 }
941
942 /*
943 * Suspend / Resume
944 */
945 static int dcssblk_freeze(struct device *dev)
946 {
947 struct dcssblk_dev_info *dev_info;
948 int rc = 0;
949
950 list_for_each_entry(dev_info, &dcssblk_devices, lh) {
951 switch (dev_info->segment_type) {
952 case SEG_TYPE_SR:
953 case SEG_TYPE_ER:
954 case SEG_TYPE_SC:
955 if (!dev_info->is_shared)
956 rc = -EINVAL;
957 break;
958 default:
959 rc = -EINVAL;
960 break;
961 }
962 if (rc)
963 break;
964 }
965 if (rc)
966 pr_err("Suspending the system failed because DCSS device %s "
967 "is writable\n",
968 dev_info->segment_name);
969 return rc;
970 }
971
972 static int dcssblk_restore(struct device *dev)
973 {
974 struct dcssblk_dev_info *dev_info;
975 struct segment_info *entry;
976 unsigned long start, end;
977 int rc = 0;
978
979 list_for_each_entry(dev_info, &dcssblk_devices, lh) {
980 list_for_each_entry(entry, &dev_info->seg_list, lh) {
981 segment_unload(entry->segment_name);
982 rc = segment_load(entry->segment_name, SEGMENT_SHARED,
983 &start, &end);
984 if (rc < 0) {
985 // TODO in_use check ?
986 segment_warning(rc, entry->segment_name);
987 goto out_panic;
988 }
989 if (start != entry->start || end != entry->end) {
990 pr_err("The address range of DCSS %s changed "
991 "while the system was suspended\n",
992 entry->segment_name);
993 goto out_panic;
994 }
995 }
996 }
997 return 0;
998 out_panic:
999 panic("fatal dcssblk resume error\n");
1000 }
1001
1002 static int dcssblk_thaw(struct device *dev)
1003 {
1004 return 0;
1005 }
1006
1007 static const struct dev_pm_ops dcssblk_pm_ops = {
1008 .freeze = dcssblk_freeze,
1009 .thaw = dcssblk_thaw,
1010 .restore = dcssblk_restore,
1011 };
1012
1013 static struct platform_driver dcssblk_pdrv = {
1014 .driver = {
1015 .name = "dcssblk",
1016 .owner = THIS_MODULE,
1017 .pm = &dcssblk_pm_ops,
1018 },
1019 };
1020
1021 static struct platform_device *dcssblk_pdev;
1022
1023
1024 /*
1025 * The init/exit functions.
1026 */
1027 static void __exit
1028 dcssblk_exit(void)
1029 {
1030 platform_device_unregister(dcssblk_pdev);
1031 platform_driver_unregister(&dcssblk_pdrv);
1032 root_device_unregister(dcssblk_root_dev);
1033 unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
1034 }
1035
1036 static int __init
1037 dcssblk_init(void)
1038 {
1039 int rc;
1040
1041 rc = platform_driver_register(&dcssblk_pdrv);
1042 if (rc)
1043 return rc;
1044
1045 dcssblk_pdev = platform_device_register_simple("dcssblk", -1, NULL,
1046 0);
1047 if (IS_ERR(dcssblk_pdev)) {
1048 rc = PTR_ERR(dcssblk_pdev);
1049 goto out_pdrv;
1050 }
1051
1052 dcssblk_root_dev = root_device_register("dcssblk");
1053 if (IS_ERR(dcssblk_root_dev)) {
1054 rc = PTR_ERR(dcssblk_root_dev);
1055 goto out_pdev;
1056 }
1057 rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
1058 if (rc)
1059 goto out_root;
1060 rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
1061 if (rc)
1062 goto out_root;
1063 rc = register_blkdev(0, DCSSBLK_NAME);
1064 if (rc < 0)
1065 goto out_root;
1066 dcssblk_major = rc;
1067 init_rwsem(&dcssblk_devices_sem);
1068
1069 dcssblk_check_params();
1070 return 0;
1071
1072 out_root:
1073 root_device_unregister(dcssblk_root_dev);
1074 out_pdev:
1075 platform_device_unregister(dcssblk_pdev);
1076 out_pdrv:
1077 platform_driver_unregister(&dcssblk_pdrv);
1078 return rc;
1079 }
1080
1081 module_init(dcssblk_init);
1082 module_exit(dcssblk_exit);
1083
1084 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
1085 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
1086 "comma-separated list, names in each set separated "
1087 "by commas are separated by colons, each set contains "
1088 "names of contiguous segments and each name max. 8 chars.\n"
1089 "Adding \"(local)\" to the end of each set equals echoing 0 "
1090 "to /sys/devices/dcssblk/<device name>/shared after loading "
1091 "the contiguous segments - \n"
1092 "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
1093
1094 MODULE_LICENSE("GPL");