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Linux 4.1.16
[linux/fpc-iii.git] / drivers / s390 / block / dcssblk.c
blobda212813f2d5dcd301a923df946daa9c481cb06f
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 void dcssblk_release(struct gendisk *disk, fmode_t mode);
30 static void dcssblk_make_request(struct request_queue *q, struct bio *bio);
31 static long dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
32 void **kaddr, unsigned long *pfn, long size);
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
73 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
74 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
75
76 static struct device *dcssblk_root_dev;
77
78 static LIST_HEAD(dcssblk_devices);
79 static struct rw_semaphore dcssblk_devices_sem;
80
81 /*
82 * release function for segment device.
83 */
84 static void
85 dcssblk_release_segment(struct device *dev)
86 {
87 struct dcssblk_dev_info *dev_info;
88 struct segment_info *entry, *temp;
89
90 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
91 list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) {
92 list_del(&entry->lh);
93 kfree(entry);
94 }
95 kfree(dev_info);
96 module_put(THIS_MODULE);
97 }
98
99 /*
100 * get a minor number. needs to be called with
101 * down_write(&dcssblk_devices_sem) and the
102 * device needs to be enqueued before the semaphore is
103 * freed.
104 */
105 static int
106 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
107 {
108 int minor, found;
109 struct dcssblk_dev_info *entry;
110
111 if (dev_info == NULL)
112 return -EINVAL;
113 for (minor = 0; minor < (1<<MINORBITS); minor++) {
114 found = 0;
115 // test if minor available
116 list_for_each_entry(entry, &dcssblk_devices, lh)
117 if (minor == entry->gd->first_minor)
118 found++;
119 if (!found) break; // got unused minor
120 }
121 if (found)
122 return -EBUSY;
123 dev_info->gd->first_minor = minor;
124 return 0;
125 }
126
127 /*
128 * get the struct dcssblk_dev_info from dcssblk_devices
129 * for the given name.
130 * down_read(&dcssblk_devices_sem) must be held.
131 */
132 static struct dcssblk_dev_info *
133 dcssblk_get_device_by_name(char *name)
134 {
135 struct dcssblk_dev_info *entry;
136
137 list_for_each_entry(entry, &dcssblk_devices, lh) {
138 if (!strcmp(name, entry->segment_name)) {
139 return entry;
140 }
141 }
142 return NULL;
143 }
144
145 /*
146 * get the struct segment_info from seg_list
147 * for the given name.
148 * down_read(&dcssblk_devices_sem) must be held.
149 */
150 static struct segment_info *
151 dcssblk_get_segment_by_name(char *name)
152 {
153 struct dcssblk_dev_info *dev_info;
154 struct segment_info *entry;
155
156 list_for_each_entry(dev_info, &dcssblk_devices, lh) {
157 list_for_each_entry(entry, &dev_info->seg_list, lh) {
158 if (!strcmp(name, entry->segment_name))
159 return entry;
160 }
161 }
162 return NULL;
163 }
164
165 /*
166 * get the highest address of the multi-segment block.
167 */
168 static unsigned long
169 dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info)
170 {
171 unsigned long highest_addr;
172 struct segment_info *entry;
173
174 highest_addr = 0;
175 list_for_each_entry(entry, &dev_info->seg_list, lh) {
176 if (highest_addr < entry->end)
177 highest_addr = entry->end;
178 }
179 return highest_addr;
180 }
181
182 /*
183 * get the lowest address of the multi-segment block.
184 */
185 static unsigned long
186 dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info)
187 {
188 int set_first;
189 unsigned long lowest_addr;
190 struct segment_info *entry;
191
192 set_first = 0;
193 lowest_addr = 0;
194 list_for_each_entry(entry, &dev_info->seg_list, lh) {
195 if (set_first == 0) {
196 lowest_addr = entry->start;
197 set_first = 1;
198 } else {
199 if (lowest_addr > entry->start)
200 lowest_addr = entry->start;
201 }
202 }
203 return lowest_addr;
204 }
205
206 /*
207 * Check continuity of segments.
208 */
209 static int
210 dcssblk_is_continuous(struct dcssblk_dev_info *dev_info)
211 {
212 int i, j, rc;
213 struct segment_info *sort_list, *entry, temp;
214
215 if (dev_info->num_of_segments <= 1)
216 return 0;
217
218 sort_list = kzalloc(
219 sizeof(struct segment_info) * dev_info->num_of_segments,
220 GFP_KERNEL);
221 if (sort_list == NULL)
222 return -ENOMEM;
223 i = 0;
224 list_for_each_entry(entry, &dev_info->seg_list, lh) {
225 memcpy(&sort_list[i], entry, sizeof(struct segment_info));
226 i++;
227 }
228
229 /* sort segments */
230 for (i = 0; i < dev_info->num_of_segments; i++)
231 for (j = 0; j < dev_info->num_of_segments; j++)
232 if (sort_list[j].start > sort_list[i].start) {
233 memcpy(&temp, &sort_list[i],
234 sizeof(struct segment_info));
235 memcpy(&sort_list[i], &sort_list[j],
236 sizeof(struct segment_info));
237 memcpy(&sort_list[j], &temp,
238 sizeof(struct segment_info));
239 }
240
241 /* check continuity */
242 for (i = 0; i < dev_info->num_of_segments - 1; i++) {
243 if ((sort_list[i].end + 1) != sort_list[i+1].start) {
244 pr_err("Adjacent DCSSs %s and %s are not "
245 "contiguous\n", sort_list[i].segment_name,
246 sort_list[i+1].segment_name);
247 rc = -EINVAL;
248 goto out;
249 }
250 /* EN and EW are allowed in a block device */
251 if (sort_list[i].segment_type != sort_list[i+1].segment_type) {
252 if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) ||
253 (sort_list[i].segment_type == SEG_TYPE_ER) ||
254 !(sort_list[i+1].segment_type &
255 SEGMENT_EXCLUSIVE) ||
256 (sort_list[i+1].segment_type == SEG_TYPE_ER)) {
257 pr_err("DCSS %s and DCSS %s have "
258 "incompatible types\n",
259 sort_list[i].segment_name,
260 sort_list[i+1].segment_name);
261 rc = -EINVAL;
262 goto out;
263 }
264 }
265 }
266 rc = 0;
267 out:
268 kfree(sort_list);
269 return rc;
270 }
271
272 /*
273 * Load a segment
274 */
275 static int
276 dcssblk_load_segment(char *name, struct segment_info **seg_info)
277 {
278 int rc;
279
280 /* already loaded? */
281 down_read(&dcssblk_devices_sem);
282 *seg_info = dcssblk_get_segment_by_name(name);
283 up_read(&dcssblk_devices_sem);
284 if (*seg_info != NULL)
285 return -EEXIST;
286
287 /* get a struct segment_info */
288 *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL);
289 if (*seg_info == NULL)
290 return -ENOMEM;
291
292 strcpy((*seg_info)->segment_name, name);
293
294 /* load the segment */
295 rc = segment_load(name, SEGMENT_SHARED,
296 &(*seg_info)->start, &(*seg_info)->end);
297 if (rc < 0) {
298 segment_warning(rc, (*seg_info)->segment_name);
299 kfree(*seg_info);
300 } else {
301 INIT_LIST_HEAD(&(*seg_info)->lh);
302 (*seg_info)->segment_type = rc;
303 }
304 return rc;
305 }
306
307 /*
308 * device attribute for switching shared/nonshared (exclusive)
309 * operation (show + store)
310 */
311 static ssize_t
312 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
313 {
314 struct dcssblk_dev_info *dev_info;
315
316 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
317 return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
318 }
319
320 static ssize_t
321 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
322 {
323 struct dcssblk_dev_info *dev_info;
324 struct segment_info *entry, *temp;
325 int rc;
326
327 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
328 return -EINVAL;
329 down_write(&dcssblk_devices_sem);
330 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
331 if (atomic_read(&dev_info->use_count)) {
332 rc = -EBUSY;
333 goto out;
334 }
335 if (inbuf[0] == '1') {
336 /* reload segments in shared mode */
337 list_for_each_entry(entry, &dev_info->seg_list, lh) {
338 rc = segment_modify_shared(entry->segment_name,
339 SEGMENT_SHARED);
340 if (rc < 0) {
341 BUG_ON(rc == -EINVAL);
342 if (rc != -EAGAIN)
343 goto removeseg;
344 }
345 }
346 dev_info->is_shared = 1;
347 switch (dev_info->segment_type) {
348 case SEG_TYPE_SR:
349 case SEG_TYPE_ER:
350 case SEG_TYPE_SC:
351 set_disk_ro(dev_info->gd, 1);
352 }
353 } else if (inbuf[0] == '0') {
354 /* reload segments in exclusive mode */
355 if (dev_info->segment_type == SEG_TYPE_SC) {
356 pr_err("DCSS %s is of type SC and cannot be "
357 "loaded as exclusive-writable\n",
358 dev_info->segment_name);
359 rc = -EINVAL;
360 goto out;
361 }
362 list_for_each_entry(entry, &dev_info->seg_list, lh) {
363 rc = segment_modify_shared(entry->segment_name,
364 SEGMENT_EXCLUSIVE);
365 if (rc < 0) {
366 BUG_ON(rc == -EINVAL);
367 if (rc != -EAGAIN)
368 goto removeseg;
369 }
370 }
371 dev_info->is_shared = 0;
372 set_disk_ro(dev_info->gd, 0);
373 } else {
374 rc = -EINVAL;
375 goto out;
376 }
377 rc = count;
378 goto out;
379
380 removeseg:
381 pr_err("DCSS device %s is removed after a failed access mode "
382 "change\n", dev_info->segment_name);
383 temp = entry;
384 list_for_each_entry(entry, &dev_info->seg_list, lh) {
385 if (entry != temp)
386 segment_unload(entry->segment_name);
387 }
388 list_del(&dev_info->lh);
389
390 del_gendisk(dev_info->gd);
391 blk_cleanup_queue(dev_info->dcssblk_queue);
392 dev_info->gd->queue = NULL;
393 put_disk(dev_info->gd);
394 up_write(&dcssblk_devices_sem);
395
396 if (device_remove_file_self(dev, attr)) {
397 device_unregister(dev);
398 put_device(dev);
399 }
400 return rc;
401 out:
402 up_write(&dcssblk_devices_sem);
403 return rc;
404 }
405 static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
406 dcssblk_shared_store);
407
408 /*
409 * device attribute for save operation on current copy
410 * of the segment. If the segment is busy, saving will
411 * become pending until it gets released, which can be
412 * undone by storing a non-true value to this entry.
413 * (show + store)
414 */
415 static ssize_t
416 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
417 {
418 struct dcssblk_dev_info *dev_info;
419
420 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
421 return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
422 }
423
424 static ssize_t
425 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
426 {
427 struct dcssblk_dev_info *dev_info;
428 struct segment_info *entry;
429
430 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
431 return -EINVAL;
432 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
433
434 down_write(&dcssblk_devices_sem);
435 if (inbuf[0] == '1') {
436 if (atomic_read(&dev_info->use_count) == 0) {
437 // device is idle => we save immediately
438 pr_info("All DCSSs that map to device %s are "
439 "saved\n", dev_info->segment_name);
440 list_for_each_entry(entry, &dev_info->seg_list, lh) {
441 if (entry->segment_type == SEG_TYPE_EN ||
442 entry->segment_type == SEG_TYPE_SN)
443 pr_warn("DCSS %s is of type SN or EN"
444 " and cannot be saved\n",
445 entry->segment_name);
446 else
447 segment_save(entry->segment_name);
448 }
449 } else {
450 // device is busy => we save it when it becomes
451 // idle in dcssblk_release
452 pr_info("Device %s is in use, its DCSSs will be "
453 "saved when it becomes idle\n",
454 dev_info->segment_name);
455 dev_info->save_pending = 1;
456 }
457 } else if (inbuf[0] == '0') {
458 if (dev_info->save_pending) {
459 // device is busy & the user wants to undo his save
460 // request
461 dev_info->save_pending = 0;
462 pr_info("A pending save request for device %s "
463 "has been canceled\n",
464 dev_info->segment_name);
465 }
466 } else {
467 up_write(&dcssblk_devices_sem);
468 return -EINVAL;
469 }
470 up_write(&dcssblk_devices_sem);
471 return count;
472 }
473 static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
474 dcssblk_save_store);
475
476 /*
477 * device attribute for showing all segments in a device
478 */
479 static ssize_t
480 dcssblk_seglist_show(struct device *dev, struct device_attribute *attr,
481 char *buf)
482 {
483 int i;
484
485 struct dcssblk_dev_info *dev_info;
486 struct segment_info *entry;
487
488 down_read(&dcssblk_devices_sem);
489 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
490 i = 0;
491 buf[0] = '\0';
492 list_for_each_entry(entry, &dev_info->seg_list, lh) {
493 strcpy(&buf[i], entry->segment_name);
494 i += strlen(entry->segment_name);
495 buf[i] = '\n';
496 i++;
497 }
498 up_read(&dcssblk_devices_sem);
499 return i;
500 }
501 static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);
502
503 static struct attribute *dcssblk_dev_attrs[] = {
504 &dev_attr_shared.attr,
505 &dev_attr_save.attr,
506 &dev_attr_seglist.attr,
507 NULL,
508 };
509 static struct attribute_group dcssblk_dev_attr_group = {
510 .attrs = dcssblk_dev_attrs,
511 };
512 static const struct attribute_group *dcssblk_dev_attr_groups[] = {
513 &dcssblk_dev_attr_group,
514 NULL,
515 };
516
517 /*
518 * device attribute for adding devices
519 */
520 static ssize_t
521 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
522 {
523 int rc, i, j, num_of_segments;
524 struct dcssblk_dev_info *dev_info;
525 struct segment_info *seg_info, *temp;
526 char *local_buf;
527 unsigned long seg_byte_size;
528
529 dev_info = NULL;
530 seg_info = NULL;
531 if (dev != dcssblk_root_dev) {
532 rc = -EINVAL;
533 goto out_nobuf;
534 }
535 if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) {
536 rc = -ENAMETOOLONG;
537 goto out_nobuf;
538 }
539
540 local_buf = kmalloc(count + 1, GFP_KERNEL);
541 if (local_buf == NULL) {
542 rc = -ENOMEM;
543 goto out_nobuf;
544 }
545
546 /*
547 * parse input
548 */
549 num_of_segments = 0;
550 for (i = 0; (i < count && (buf[i] != '\0') && (buf[i] != '\n')); i++) {
551 for (j = i; (buf[j] != ':') &&
552 (buf[j] != '\0') &&
553 (buf[j] != '\n') &&
554 j < count; j++) {
555 local_buf[j-i] = toupper(buf[j]);
556 }
557 local_buf[j-i] = '\0';
558 if (((j - i) == 0) || ((j - i) > 8)) {
559 rc = -ENAMETOOLONG;
560 goto seg_list_del;
561 }
562
563 rc = dcssblk_load_segment(local_buf, &seg_info);
564 if (rc < 0)
565 goto seg_list_del;
566 /*
567 * get a struct dcssblk_dev_info
568 */
569 if (num_of_segments == 0) {
570 dev_info = kzalloc(sizeof(struct dcssblk_dev_info),
571 GFP_KERNEL);
572 if (dev_info == NULL) {
573 rc = -ENOMEM;
574 goto out;
575 }
576 strcpy(dev_info->segment_name, local_buf);
577 dev_info->segment_type = seg_info->segment_type;
578 INIT_LIST_HEAD(&dev_info->seg_list);
579 }
580 list_add_tail(&seg_info->lh, &dev_info->seg_list);
581 num_of_segments++;
582 i = j;
583
584 if ((buf[j] == '\0') || (buf[j] == '\n'))
585 break;
586 }
587
588 /* no trailing colon at the end of the input */
589 if ((i > 0) && (buf[i-1] == ':')) {
590 rc = -ENAMETOOLONG;
591 goto seg_list_del;
592 }
593 strlcpy(local_buf, buf, i + 1);
594 dev_info->num_of_segments = num_of_segments;
595 rc = dcssblk_is_continuous(dev_info);
596 if (rc < 0)
597 goto seg_list_del;
598
599 dev_info->start = dcssblk_find_lowest_addr(dev_info);
600 dev_info->end = dcssblk_find_highest_addr(dev_info);
601
602 dev_set_name(&dev_info->dev, "%s", dev_info->segment_name);
603 dev_info->dev.release = dcssblk_release_segment;
604 dev_info->dev.groups = dcssblk_dev_attr_groups;
605 INIT_LIST_HEAD(&dev_info->lh);
606 dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
607 if (dev_info->gd == NULL) {
608 rc = -ENOMEM;
609 goto seg_list_del;
610 }
611 dev_info->gd->major = dcssblk_major;
612 dev_info->gd->fops = &dcssblk_devops;
613 dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
614 dev_info->gd->queue = dev_info->dcssblk_queue;
615 dev_info->gd->private_data = dev_info;
616 dev_info->gd->driverfs_dev = &dev_info->dev;
617 blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
618 blk_queue_logical_block_size(dev_info->dcssblk_queue, 4096);
619
620 seg_byte_size = (dev_info->end - dev_info->start + 1);
621 set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
622 pr_info("Loaded %s with total size %lu bytes and capacity %lu "
623 "sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9);
624
625 dev_info->save_pending = 0;
626 dev_info->is_shared = 1;
627 dev_info->dev.parent = dcssblk_root_dev;
628
629 /*
630 *get minor, add to list
631 */
632 down_write(&dcssblk_devices_sem);
633 if (dcssblk_get_segment_by_name(local_buf)) {
634 rc = -EEXIST;
635 goto release_gd;
636 }
637 rc = dcssblk_assign_free_minor(dev_info);
638 if (rc)
639 goto release_gd;
640 sprintf(dev_info->gd->disk_name, "dcssblk%d",
641 dev_info->gd->first_minor);
642 list_add_tail(&dev_info->lh, &dcssblk_devices);
643
644 if (!try_module_get(THIS_MODULE)) {
645 rc = -ENODEV;
646 goto dev_list_del;
647 }
648 /*
649 * register the device
650 */
651 rc = device_register(&dev_info->dev);
652 if (rc)
653 goto put_dev;
654
655 get_device(&dev_info->dev);
656 add_disk(dev_info->gd);
657
658 switch (dev_info->segment_type) {
659 case SEG_TYPE_SR:
660 case SEG_TYPE_ER:
661 case SEG_TYPE_SC:
662 set_disk_ro(dev_info->gd,1);
663 break;
664 default:
665 set_disk_ro(dev_info->gd,0);
666 break;
667 }
668 up_write(&dcssblk_devices_sem);
669 rc = count;
670 goto out;
671
672 put_dev:
673 list_del(&dev_info->lh);
674 blk_cleanup_queue(dev_info->dcssblk_queue);
675 dev_info->gd->queue = NULL;
676 put_disk(dev_info->gd);
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 void
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
796 if (!dev_info) {
797 WARN_ON(1);
798 return;
799 }
800 down_write(&dcssblk_devices_sem);
801 if (atomic_dec_and_test(&dev_info->use_count)
802 && (dev_info->save_pending)) {
803 pr_info("Device %s has become idle and is being saved "
804 "now\n", dev_info->segment_name);
805 list_for_each_entry(entry, &dev_info->seg_list, lh) {
806 if (entry->segment_type == SEG_TYPE_EN ||
807 entry->segment_type == SEG_TYPE_SN)
808 pr_warn("DCSS %s is of type SN or EN and cannot"
809 " be saved\n", entry->segment_name);
810 else
811 segment_save(entry->segment_name);
812 }
813 dev_info->save_pending = 0;
814 }
815 up_write(&dcssblk_devices_sem);
816 }
817
818 static void
819 dcssblk_make_request(struct request_queue *q, struct bio *bio)
820 {
821 struct dcssblk_dev_info *dev_info;
822 struct bio_vec bvec;
823 struct bvec_iter iter;
824 unsigned long index;
825 unsigned long page_addr;
826 unsigned long source_addr;
827 unsigned long bytes_done;
828
829 bytes_done = 0;
830 dev_info = bio->bi_bdev->bd_disk->private_data;
831 if (dev_info == NULL)
832 goto fail;
833 if ((bio->bi_iter.bi_sector & 7) != 0 ||
834 (bio->bi_iter.bi_size & 4095) != 0)
835 /* Request is not page-aligned. */
836 goto fail;
837 if (bio_end_sector(bio) > get_capacity(bio->bi_bdev->bd_disk)) {
838 /* Request beyond end of DCSS segment. */
839 goto fail;
840 }
841 /* verify data transfer direction */
842 if (dev_info->is_shared) {
843 switch (dev_info->segment_type) {
844 case SEG_TYPE_SR:
845 case SEG_TYPE_ER:
846 case SEG_TYPE_SC:
847 /* cannot write to these segments */
848 if (bio_data_dir(bio) == WRITE) {
849 pr_warning("Writing to %s failed because it "
850 "is a read-only device\n",
851 dev_name(&dev_info->dev));
852 goto fail;
853 }
854 }
855 }
856
857 index = (bio->bi_iter.bi_sector >> 3);
858 bio_for_each_segment(bvec, bio, iter) {
859 page_addr = (unsigned long)
860 page_address(bvec.bv_page) + bvec.bv_offset;
861 source_addr = dev_info->start + (index<<12) + bytes_done;
862 if (unlikely((page_addr & 4095) != 0) || (bvec.bv_len & 4095) != 0)
863 // More paranoia.
864 goto fail;
865 if (bio_data_dir(bio) == READ) {
866 memcpy((void*)page_addr, (void*)source_addr,
867 bvec.bv_len);
868 } else {
869 memcpy((void*)source_addr, (void*)page_addr,
870 bvec.bv_len);
871 }
872 bytes_done += bvec.bv_len;
873 }
874 bio_endio(bio, 0);
875 return;
876 fail:
877 bio_io_error(bio);
878 }
879
880 static long
881 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
882 void **kaddr, unsigned long *pfn, long size)
883 {
884 struct dcssblk_dev_info *dev_info;
885 unsigned long offset, dev_sz;
886
887 dev_info = bdev->bd_disk->private_data;
888 if (!dev_info)
889 return -ENODEV;
890 dev_sz = dev_info->end - dev_info->start;
891 offset = secnum * 512;
892 *kaddr = (void *) (dev_info->start + offset);
893 *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
894
895 return dev_sz - offset;
896 }
897
898 static void
899 dcssblk_check_params(void)
900 {
901 int rc, i, j, k;
902 char buf[DCSSBLK_PARM_LEN + 1];
903 struct dcssblk_dev_info *dev_info;
904
905 for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
906 i++) {
907 for (j = i; (dcssblk_segments[j] != ',') &&
908 (dcssblk_segments[j] != '\0') &&
909 (dcssblk_segments[j] != '(') &&
910 (j < DCSSBLK_PARM_LEN); j++)
911 {
912 buf[j-i] = dcssblk_segments[j];
913 }
914 buf[j-i] = '\0';
915 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
916 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
917 for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
918 buf[k] = toupper(buf[k]);
919 buf[k] = '\0';
920 if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
921 down_read(&dcssblk_devices_sem);
922 dev_info = dcssblk_get_device_by_name(buf);
923 up_read(&dcssblk_devices_sem);
924 if (dev_info)
925 dcssblk_shared_store(&dev_info->dev,
926 NULL, "0\n", 2);
927 }
928 }
929 while ((dcssblk_segments[j] != ',') &&
930 (dcssblk_segments[j] != '\0'))
931 {
932 j++;
933 }
934 if (dcssblk_segments[j] == '\0')
935 break;
936 i = j;
937 }
938 }
939
940 /*
941 * Suspend / Resume
942 */
943 static int dcssblk_freeze(struct device *dev)
944 {
945 struct dcssblk_dev_info *dev_info;
946 int rc = 0;
947
948 list_for_each_entry(dev_info, &dcssblk_devices, lh) {
949 switch (dev_info->segment_type) {
950 case SEG_TYPE_SR:
951 case SEG_TYPE_ER:
952 case SEG_TYPE_SC:
953 if (!dev_info->is_shared)
954 rc = -EINVAL;
955 break;
956 default:
957 rc = -EINVAL;
958 break;
959 }
960 if (rc)
961 break;
962 }
963 if (rc)
964 pr_err("Suspending the system failed because DCSS device %s "
965 "is writable\n",
966 dev_info->segment_name);
967 return rc;
968 }
969
970 static int dcssblk_restore(struct device *dev)
971 {
972 struct dcssblk_dev_info *dev_info;
973 struct segment_info *entry;
974 unsigned long start, end;
975 int rc = 0;
976
977 list_for_each_entry(dev_info, &dcssblk_devices, lh) {
978 list_for_each_entry(entry, &dev_info->seg_list, lh) {
979 segment_unload(entry->segment_name);
980 rc = segment_load(entry->segment_name, SEGMENT_SHARED,
981 &start, &end);
982 if (rc < 0) {
983 // TODO in_use check ?
984 segment_warning(rc, entry->segment_name);
985 goto out_panic;
986 }
987 if (start != entry->start || end != entry->end) {
988 pr_err("The address range of DCSS %s changed "
989 "while the system was suspended\n",
990 entry->segment_name);
991 goto out_panic;
992 }
993 }
994 }
995 return 0;
996 out_panic:
997 panic("fatal dcssblk resume error\n");
998 }
999
1000 static int dcssblk_thaw(struct device *dev)
1001 {
1002 return 0;
1003 }
1004
1005 static const struct dev_pm_ops dcssblk_pm_ops = {
1006 .freeze = dcssblk_freeze,
1007 .thaw = dcssblk_thaw,
1008 .restore = dcssblk_restore,
1009 };
1010
1011 static struct platform_driver dcssblk_pdrv = {
1012 .driver = {
1013 .name = "dcssblk",
1014 .pm = &dcssblk_pm_ops,
1015 },
1016 };
1017
1018 static struct platform_device *dcssblk_pdev;
1019
1020
1021 /*
1022 * The init/exit functions.
1023 */
1024 static void __exit
1025 dcssblk_exit(void)
1026 {
1027 platform_device_unregister(dcssblk_pdev);
1028 platform_driver_unregister(&dcssblk_pdrv);
1029 root_device_unregister(dcssblk_root_dev);
1030 unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
1031 }
1032
1033 static int __init
1034 dcssblk_init(void)
1035 {
1036 int rc;
1037
1038 rc = platform_driver_register(&dcssblk_pdrv);
1039 if (rc)
1040 return rc;
1041
1042 dcssblk_pdev = platform_device_register_simple("dcssblk", -1, NULL,
1043 0);
1044 if (IS_ERR(dcssblk_pdev)) {
1045 rc = PTR_ERR(dcssblk_pdev);
1046 goto out_pdrv;
1047 }
1048
1049 dcssblk_root_dev = root_device_register("dcssblk");
1050 if (IS_ERR(dcssblk_root_dev)) {
1051 rc = PTR_ERR(dcssblk_root_dev);
1052 goto out_pdev;
1053 }
1054 rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
1055 if (rc)
1056 goto out_root;
1057 rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
1058 if (rc)
1059 goto out_root;
1060 rc = register_blkdev(0, DCSSBLK_NAME);
1061 if (rc < 0)
1062 goto out_root;
1063 dcssblk_major = rc;
1064 init_rwsem(&dcssblk_devices_sem);
1065
1066 dcssblk_check_params();
1067 return 0;
1068
1069 out_root:
1070 root_device_unregister(dcssblk_root_dev);
1071 out_pdev:
1072 platform_device_unregister(dcssblk_pdev);
1073 out_pdrv:
1074 platform_driver_unregister(&dcssblk_pdrv);
1075 return rc;
1076 }
1077
1078 module_init(dcssblk_init);
1079 module_exit(dcssblk_exit);
1080
1081 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
1082 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
1083 "comma-separated list, names in each set separated "
1084 "by commas are separated by colons, each set contains "
1085 "names of contiguous segments and each name max. 8 chars.\n"
1086 "Adding \"(local)\" to the end of each set equals echoing 0 "
1087 "to /sys/devices/dcssblk/<device name>/shared after loading "
1088 "the contiguous segments - \n"
1089 "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
1090
1091 MODULE_LICENSE("GPL");
Linux with added FPC-III support