9b43ae94beba1dea263e1687d38060e9a1f243d6
[linux-3.10.git] / drivers / s390 / block / dcssblk.c
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 int 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 int
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 0;
875 fail:
876         bio_io_error(bio);
877         return 0;
878 }
879
880 static int
881 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
882                         void **kaddr, unsigned long *pfn)
883 {
884         struct dcssblk_dev_info *dev_info;
885         unsigned long pgoff;
886
887         dev_info = bdev->bd_disk->private_data;
888         if (!dev_info)
889                 return -ENODEV;
890         if (secnum % (PAGE_SIZE/512))
891                 return -EINVAL;
892         pgoff = secnum / (PAGE_SIZE / 512);
893         if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
894                 return -ERANGE;
895         *kaddr = (void *) (dev_info->start+pgoff*PAGE_SIZE);
896         *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
897
898         return 0;
899 }
900
901 static void
902 dcssblk_check_params(void)
903 {
904         int rc, i, j, k;
905         char buf[DCSSBLK_PARM_LEN + 1];
906         struct dcssblk_dev_info *dev_info;
907
908         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
909              i++) {
910                 for (j = i; (dcssblk_segments[j] != ',')  &&
911                             (dcssblk_segments[j] != '\0') &&
912                             (dcssblk_segments[j] != '(')  &&
913                             (j < DCSSBLK_PARM_LEN); j++)
914                 {
915                         buf[j-i] = dcssblk_segments[j];
916                 }
917                 buf[j-i] = '\0';
918                 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
919                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
920                         for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
921                                 buf[k] = toupper(buf[k]);
922                         buf[k] = '\0';
923                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
924                                 down_read(&dcssblk_devices_sem);
925                                 dev_info = dcssblk_get_device_by_name(buf);
926                                 up_read(&dcssblk_devices_sem);
927                                 if (dev_info)
928                                         dcssblk_shared_store(&dev_info->dev,
929                                                              NULL, "0\n", 2);
930                         }
931                 }
932                 while ((dcssblk_segments[j] != ',') &&
933                        (dcssblk_segments[j] != '\0'))
934                 {
935                         j++;
936                 }
937                 if (dcssblk_segments[j] == '\0')
938                         break;
939                 i = j;
940         }
941 }
942
943 /*
944  * Suspend / Resume
945  */
946 static int dcssblk_freeze(struct device *dev)
947 {
948         struct dcssblk_dev_info *dev_info;
949         int rc = 0;
950
951         list_for_each_entry(dev_info, &dcssblk_devices, lh) {
952                 switch (dev_info->segment_type) {
953                         case SEG_TYPE_SR:
954                         case SEG_TYPE_ER:
955                         case SEG_TYPE_SC:
956                                 if (!dev_info->is_shared)
957                                         rc = -EINVAL;
958                                 break;
959                         default:
960                                 rc = -EINVAL;
961                                 break;
962                 }
963                 if (rc)
964                         break;
965         }
966         if (rc)
967                 pr_err("Suspending the system failed because DCSS device %s "
968                        "is writable\n",
969                        dev_info->segment_name);
970         return rc;
971 }
972
973 static int dcssblk_restore(struct device *dev)
974 {
975         struct dcssblk_dev_info *dev_info;
976         struct segment_info *entry;
977         unsigned long start, end;
978         int rc = 0;
979
980         list_for_each_entry(dev_info, &dcssblk_devices, lh) {
981                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
982                         segment_unload(entry->segment_name);
983                         rc = segment_load(entry->segment_name, SEGMENT_SHARED,
984                                           &start, &end);
985                         if (rc < 0) {
986 // TODO in_use check ?
987                                 segment_warning(rc, entry->segment_name);
988                                 goto out_panic;
989                         }
990                         if (start != entry->start || end != entry->end) {
991                                 pr_err("The address range of DCSS %s changed "
992                                        "while the system was suspended\n",
993                                        entry->segment_name);
994                                 goto out_panic;
995                         }
996                 }
997         }
998         return 0;
999 out_panic:
1000         panic("fatal dcssblk resume error\n");
1001 }
1002
1003 static int dcssblk_thaw(struct device *dev)
1004 {
1005         return 0;
1006 }
1007
1008 static const struct dev_pm_ops dcssblk_pm_ops = {
1009         .freeze         = dcssblk_freeze,
1010         .thaw           = dcssblk_thaw,
1011         .restore        = dcssblk_restore,
1012 };
1013
1014 static struct platform_driver dcssblk_pdrv = {
1015         .driver = {
1016                 .name   = "dcssblk",
1017                 .owner  = THIS_MODULE,
1018                 .pm     = &dcssblk_pm_ops,
1019         },
1020 };
1021
1022 static struct platform_device *dcssblk_pdev;
1023
1024
1025 /*
1026  * The init/exit functions.
1027  */
1028 static void __exit
1029 dcssblk_exit(void)
1030 {
1031         platform_device_unregister(dcssblk_pdev);
1032         platform_driver_unregister(&dcssblk_pdrv);
1033         root_device_unregister(dcssblk_root_dev);
1034         unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
1035 }
1036
1037 static int __init
1038 dcssblk_init(void)
1039 {
1040         int rc;
1041
1042         rc = platform_driver_register(&dcssblk_pdrv);
1043         if (rc)
1044                 return rc;
1045
1046         dcssblk_pdev = platform_device_register_simple("dcssblk", -1, NULL,
1047                                                         0);
1048         if (IS_ERR(dcssblk_pdev)) {
1049                 rc = PTR_ERR(dcssblk_pdev);
1050                 goto out_pdrv;
1051         }
1052
1053         dcssblk_root_dev = root_device_register("dcssblk");
1054         if (IS_ERR(dcssblk_root_dev)) {
1055                 rc = PTR_ERR(dcssblk_root_dev);
1056                 goto out_pdev;
1057         }
1058         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
1059         if (rc)
1060                 goto out_root;
1061         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
1062         if (rc)
1063                 goto out_root;
1064         rc = register_blkdev(0, DCSSBLK_NAME);
1065         if (rc < 0)
1066                 goto out_root;
1067         dcssblk_major = rc;
1068         init_rwsem(&dcssblk_devices_sem);
1069
1070         dcssblk_check_params();
1071         return 0;
1072
1073 out_root:
1074         root_device_unregister(dcssblk_root_dev);
1075 out_pdev:
1076         platform_device_unregister(dcssblk_pdev);
1077 out_pdrv:
1078         platform_driver_unregister(&dcssblk_pdrv);
1079         return rc;
1080 }
1081
1082 module_init(dcssblk_init);
1083 module_exit(dcssblk_exit);
1084
1085 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
1086 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
1087                  "comma-separated list, names in each set separated "
1088                  "by commas are separated by colons, each set contains "
1089                  "names of contiguous segments and each name max. 8 chars.\n"
1090                  "Adding \"(local)\" to the end of each set equals echoing 0 "
1091                  "to /sys/devices/dcssblk/<device name>/shared after loading "
1092                  "the contiguous segments - \n"
1093                  "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
1094
1095 MODULE_LICENSE("GPL");