Linux-2.6.12-rc2
[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 #include <linux/module.h>
8 #include <linux/moduleparam.h>
9 #include <linux/ctype.h>
10 #include <linux/errno.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/blkdev.h>
14 #include <asm/extmem.h>
15 #include <asm/io.h>
16 #include <linux/completion.h>
17 #include <linux/interrupt.h>
18 #include <asm/ccwdev.h>         // for s390_root_dev_(un)register()
19
20 //#define DCSSBLK_DEBUG         /* Debug messages on/off */
21 #define DCSSBLK_NAME "dcssblk"
22 #define DCSSBLK_MINORS_PER_DISK 1
23 #define DCSSBLK_PARM_LEN 400
24
25 #ifdef DCSSBLK_DEBUG
26 #define PRINT_DEBUG(x...) printk(KERN_DEBUG DCSSBLK_NAME " debug: " x)
27 #else
28 #define PRINT_DEBUG(x...) do {} while (0)
29 #endif
30 #define PRINT_INFO(x...)  printk(KERN_INFO DCSSBLK_NAME " info: " x)
31 #define PRINT_WARN(x...)  printk(KERN_WARNING DCSSBLK_NAME " warning: " x)
32 #define PRINT_ERR(x...)   printk(KERN_ERR DCSSBLK_NAME " error: " x)
33
34
35 static int dcssblk_open(struct inode *inode, struct file *filp);
36 static int dcssblk_release(struct inode *inode, struct file *filp);
37 static int dcssblk_make_request(struct request_queue *q, struct bio *bio);
38
39 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
40
41 static int dcssblk_major;
42 static struct block_device_operations dcssblk_devops = {
43         .owner   = THIS_MODULE,
44         .open    = dcssblk_open,
45         .release = dcssblk_release,
46 };
47
48 static ssize_t dcssblk_add_store(struct device * dev, const char * buf,
49                                   size_t count);
50 static ssize_t dcssblk_remove_store(struct device * dev, const char * buf,
51                                   size_t count);
52 static ssize_t dcssblk_save_store(struct device * dev, const char * buf,
53                                   size_t count);
54 static ssize_t dcssblk_save_show(struct device *dev, char *buf);
55 static ssize_t dcssblk_shared_store(struct device * dev, const char * buf,
56                                   size_t count);
57 static ssize_t dcssblk_shared_show(struct device *dev, char *buf);
58
59 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
60 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
61 static DEVICE_ATTR(save, S_IWUSR | S_IRUGO, dcssblk_save_show,
62                    dcssblk_save_store);
63 static DEVICE_ATTR(shared, S_IWUSR | S_IRUGO, dcssblk_shared_show,
64                    dcssblk_shared_store);
65
66 static struct device *dcssblk_root_dev;
67
68 struct dcssblk_dev_info {
69         struct list_head lh;
70         struct device dev;
71         char segment_name[BUS_ID_SIZE];
72         atomic_t use_count;
73         struct gendisk *gd;
74         unsigned long start;
75         unsigned long end;
76         int segment_type;
77         unsigned char save_pending;
78         unsigned char is_shared;
79         struct request_queue *dcssblk_queue;
80 };
81
82 static struct list_head dcssblk_devices = LIST_HEAD_INIT(dcssblk_devices);
83 static struct rw_semaphore dcssblk_devices_sem;
84
85 /*
86  * release function for segment device.
87  */
88 static void
89 dcssblk_release_segment(struct device *dev)
90 {
91         PRINT_DEBUG("segment release fn called for %s\n", dev->bus_id);
92         kfree(container_of(dev, struct dcssblk_dev_info, dev));
93         module_put(THIS_MODULE);
94 }
95
96 /*
97  * get a minor number. needs to be called with
98  * down_write(&dcssblk_devices_sem) and the
99  * device needs to be enqueued before the semaphore is
100  * freed.
101  */
102 static inline int
103 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
104 {
105         int minor, found;
106         struct dcssblk_dev_info *entry;
107
108         if (dev_info == NULL)
109                 return -EINVAL;
110         for (minor = 0; minor < (1<<MINORBITS); minor++) {
111                 found = 0;
112                 // test if minor available
113                 list_for_each_entry(entry, &dcssblk_devices, lh)
114                         if (minor == entry->gd->first_minor)
115                                 found++;
116                 if (!found) break; // got unused minor
117         }
118         if (found)
119                 return -EBUSY;
120         dev_info->gd->first_minor = minor;
121         return 0;
122 }
123
124 /*
125  * get the struct dcssblk_dev_info from dcssblk_devices
126  * for the given name.
127  * down_read(&dcssblk_devices_sem) must be held.
128  */
129 static struct dcssblk_dev_info *
130 dcssblk_get_device_by_name(char *name)
131 {
132         struct dcssblk_dev_info *entry;
133
134         list_for_each_entry(entry, &dcssblk_devices, lh) {
135                 if (!strcmp(name, entry->segment_name)) {
136                         return entry;
137                 }
138         }
139         return NULL;
140 }
141
142 /*
143  * print appropriate error message for segment_load()/segment_type()
144  * return code
145  */
146 static void
147 dcssblk_segment_warn(int rc, char* seg_name)
148 {
149         switch (rc) {
150         case -ENOENT:
151                 PRINT_WARN("cannot load/query segment %s, does not exist\n",
152                            seg_name);
153                 break;
154         case -ENOSYS:
155                 PRINT_WARN("cannot load/query segment %s, not running on VM\n",
156                            seg_name);
157                 break;
158         case -EIO:
159                 PRINT_WARN("cannot load/query segment %s, hardware error\n",
160                            seg_name);
161                 break;
162         case -ENOTSUPP:
163                 PRINT_WARN("cannot load/query segment %s, is a multi-part "
164                            "segment\n", seg_name);
165                 break;
166         case -ENOSPC:
167                 PRINT_WARN("cannot load/query segment %s, overlaps with "
168                            "storage\n", seg_name);
169                 break;
170         case -EBUSY:
171                 PRINT_WARN("cannot load/query segment %s, overlaps with "
172                            "already loaded dcss\n", seg_name);
173                 break;
174         case -EPERM:
175                 PRINT_WARN("cannot load/query segment %s, already loaded in "
176                            "incompatible mode\n", seg_name);
177                 break;
178         case -ENOMEM:
179                 PRINT_WARN("cannot load/query segment %s, out of memory\n",
180                            seg_name);
181                 break;
182         case -ERANGE:
183                 PRINT_WARN("cannot load/query segment %s, exceeds kernel "
184                            "mapping range\n", seg_name);
185                 break;
186         default:
187                 PRINT_WARN("cannot load/query segment %s, return value %i\n",
188                            seg_name, rc);
189                 break;
190         }
191 }
192
193 /*
194  * device attribute for switching shared/nonshared (exclusive)
195  * operation (show + store)
196  */
197 static ssize_t
198 dcssblk_shared_show(struct device *dev, char *buf)
199 {
200         struct dcssblk_dev_info *dev_info;
201
202         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
203         return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
204 }
205
206 static ssize_t
207 dcssblk_shared_store(struct device *dev, const char *inbuf, size_t count)
208 {
209         struct dcssblk_dev_info *dev_info;
210         int rc;
211
212         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
213                 PRINT_WARN("Invalid value, must be 0 or 1\n");
214                 return -EINVAL;
215         }
216         down_write(&dcssblk_devices_sem);
217         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
218         if (atomic_read(&dev_info->use_count)) {
219                 PRINT_ERR("share: segment %s is busy!\n",
220                           dev_info->segment_name);
221                 rc = -EBUSY;
222                 goto out;
223         }
224         if (inbuf[0] == '1') {
225                 // reload segment in shared mode
226                 rc = segment_modify_shared(dev_info->segment_name,
227                                            SEGMENT_SHARED);
228                 if (rc < 0) {
229                         BUG_ON(rc == -EINVAL);
230                         if (rc == -EIO || rc == -ENOENT)
231                                 goto removeseg;
232                 } else {
233                         dev_info->is_shared = 1;
234                         switch (dev_info->segment_type) {
235                                 case SEG_TYPE_SR:
236                                 case SEG_TYPE_ER:
237                                 case SEG_TYPE_SC:
238                                         set_disk_ro(dev_info->gd,1);
239                         }
240                 }
241         } else if (inbuf[0] == '0') {
242                 // reload segment in exclusive mode
243                 if (dev_info->segment_type == SEG_TYPE_SC) {
244                         PRINT_ERR("Segment type SC (%s) cannot be loaded in "
245                                   "non-shared mode\n", dev_info->segment_name);
246                         rc = -EINVAL;
247                         goto out;
248                 }
249                 rc = segment_modify_shared(dev_info->segment_name,
250                                            SEGMENT_EXCLUSIVE);
251                 if (rc < 0) {
252                         BUG_ON(rc == -EINVAL);
253                         if (rc == -EIO || rc == -ENOENT)
254                                 goto removeseg;
255                 } else {
256                         dev_info->is_shared = 0;
257                         set_disk_ro(dev_info->gd, 0);
258                 }
259         } else {
260                 PRINT_WARN("Invalid value, must be 0 or 1\n");
261                 rc = -EINVAL;
262                 goto out;
263         }
264         rc = count;
265         goto out;
266
267 removeseg:
268         PRINT_ERR("Could not reload segment %s, removing it now!\n",
269                         dev_info->segment_name);
270         list_del(&dev_info->lh);
271
272         del_gendisk(dev_info->gd);
273         blk_put_queue(dev_info->dcssblk_queue);
274         dev_info->gd->queue = NULL;
275         put_disk(dev_info->gd);
276         device_unregister(dev);
277         put_device(dev);
278 out:
279         up_write(&dcssblk_devices_sem);
280         return rc;
281 }
282
283 /*
284  * device attribute for save operation on current copy
285  * of the segment. If the segment is busy, saving will
286  * become pending until it gets released, which can be
287  * undone by storing a non-true value to this entry.
288  * (show + store)
289  */
290 static ssize_t
291 dcssblk_save_show(struct device *dev, char *buf)
292 {
293         struct dcssblk_dev_info *dev_info;
294
295         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
296         return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
297 }
298
299 static ssize_t
300 dcssblk_save_store(struct device *dev, const char *inbuf, size_t count)
301 {
302         struct dcssblk_dev_info *dev_info;
303
304         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
305                 PRINT_WARN("Invalid value, must be 0 or 1\n");
306                 return -EINVAL;
307         }
308         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
309
310         down_write(&dcssblk_devices_sem);
311         if (inbuf[0] == '1') {
312                 if (atomic_read(&dev_info->use_count) == 0) {
313                         // device is idle => we save immediately
314                         PRINT_INFO("Saving segment %s\n",
315                                    dev_info->segment_name);
316                         segment_save(dev_info->segment_name);
317                 }  else {
318                         // device is busy => we save it when it becomes
319                         // idle in dcssblk_release
320                         PRINT_INFO("Segment %s is currently busy, it will "
321                                    "be saved when it becomes idle...\n",
322                                    dev_info->segment_name);
323                         dev_info->save_pending = 1;
324                 }
325         } else if (inbuf[0] == '0') {
326                 if (dev_info->save_pending) {
327                         // device is busy & the user wants to undo his save
328                         // request
329                         dev_info->save_pending = 0;
330                         PRINT_INFO("Pending save for segment %s deactivated\n",
331                                         dev_info->segment_name);
332                 }
333         } else {
334                 up_write(&dcssblk_devices_sem);
335                 PRINT_WARN("Invalid value, must be 0 or 1\n");
336                 return -EINVAL;
337         }
338         up_write(&dcssblk_devices_sem);
339         return count;
340 }
341
342 /*
343  * device attribute for adding devices
344  */
345 static ssize_t
346 dcssblk_add_store(struct device *dev, const char *buf, size_t count)
347 {
348         int rc, i;
349         struct dcssblk_dev_info *dev_info;
350         char *local_buf;
351         unsigned long seg_byte_size;
352
353         dev_info = NULL;
354         if (dev != dcssblk_root_dev) {
355                 rc = -EINVAL;
356                 goto out_nobuf;
357         }
358         local_buf = kmalloc(count + 1, GFP_KERNEL);
359         if (local_buf == NULL) {
360                 rc = -ENOMEM;
361                 goto out_nobuf;
362         }
363         /*
364          * parse input
365          */
366         for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
367                 local_buf[i] = toupper(buf[i]);
368         }
369         local_buf[i] = '\0';
370         if ((i == 0) || (i > 8)) {
371                 rc = -ENAMETOOLONG;
372                 goto out;
373         }
374         /*
375          * already loaded?
376          */
377         down_read(&dcssblk_devices_sem);
378         dev_info = dcssblk_get_device_by_name(local_buf);
379         up_read(&dcssblk_devices_sem);
380         if (dev_info != NULL) {
381                 PRINT_WARN("Segment %s already loaded!\n", local_buf);
382                 rc = -EEXIST;
383                 goto out;
384         }
385         /*
386          * get a struct dcssblk_dev_info
387          */
388         dev_info = kmalloc(sizeof(struct dcssblk_dev_info), GFP_KERNEL);
389         if (dev_info == NULL) {
390                 rc = -ENOMEM;
391                 goto out;
392         }
393         memset(dev_info, 0, sizeof(struct dcssblk_dev_info));
394
395         strcpy(dev_info->segment_name, local_buf);
396         strlcpy(dev_info->dev.bus_id, local_buf, BUS_ID_SIZE);
397         dev_info->dev.release = dcssblk_release_segment;
398         INIT_LIST_HEAD(&dev_info->lh);
399
400         dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
401         if (dev_info->gd == NULL) {
402                 rc = -ENOMEM;
403                 goto free_dev_info;
404         }
405         dev_info->gd->major = dcssblk_major;
406         dev_info->gd->fops = &dcssblk_devops;
407         dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
408         dev_info->gd->queue = dev_info->dcssblk_queue;
409         dev_info->gd->private_data = dev_info;
410         dev_info->gd->driverfs_dev = &dev_info->dev;
411         /*
412          * load the segment
413          */
414         rc = segment_load(local_buf, SEGMENT_SHARED,
415                                 &dev_info->start, &dev_info->end);
416         if (rc < 0) {
417                 dcssblk_segment_warn(rc, dev_info->segment_name);
418                 goto dealloc_gendisk;
419         }
420         seg_byte_size = (dev_info->end - dev_info->start + 1);
421         set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
422         PRINT_INFO("Loaded segment %s, size = %lu Byte, "
423                    "capacity = %lu (512 Byte) sectors\n", local_buf,
424                    seg_byte_size, seg_byte_size >> 9);
425
426         dev_info->segment_type = rc;
427         dev_info->save_pending = 0;
428         dev_info->is_shared = 1;
429         dev_info->dev.parent = dcssblk_root_dev;
430
431         /*
432          * get minor, add to list
433          */
434         down_write(&dcssblk_devices_sem);
435         rc = dcssblk_assign_free_minor(dev_info);
436         if (rc) {
437                 up_write(&dcssblk_devices_sem);
438                 PRINT_ERR("No free minor number available! "
439                           "Unloading segment...\n");
440                 goto unload_seg;
441         }
442         sprintf(dev_info->gd->disk_name, "dcssblk%d",
443                 dev_info->gd->first_minor);
444         list_add_tail(&dev_info->lh, &dcssblk_devices);
445
446         if (!try_module_get(THIS_MODULE)) {
447                 rc = -ENODEV;
448                 goto list_del;
449         }
450         /*
451          * register the device
452          */
453         rc = device_register(&dev_info->dev);
454         if (rc) {
455                 PRINT_ERR("Segment %s could not be registered RC=%d\n",
456                                 local_buf, rc);
457                 module_put(THIS_MODULE);
458                 goto list_del;
459         }
460         get_device(&dev_info->dev);
461         rc = device_create_file(&dev_info->dev, &dev_attr_shared);
462         if (rc)
463                 goto unregister_dev;
464         rc = device_create_file(&dev_info->dev, &dev_attr_save);
465         if (rc)
466                 goto unregister_dev;
467
468         add_disk(dev_info->gd);
469
470         blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
471         blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
472
473         switch (dev_info->segment_type) {
474                 case SEG_TYPE_SR:
475                 case SEG_TYPE_ER:
476                 case SEG_TYPE_SC:
477                         set_disk_ro(dev_info->gd,1);
478                         break;
479                 default:
480                         set_disk_ro(dev_info->gd,0);
481                         break;
482         }
483         PRINT_DEBUG("Segment %s loaded successfully\n", local_buf);
484         up_write(&dcssblk_devices_sem);
485         rc = count;
486         goto out;
487
488 unregister_dev:
489         PRINT_ERR("device_create_file() failed!\n");
490         list_del(&dev_info->lh);
491         blk_put_queue(dev_info->dcssblk_queue);
492         dev_info->gd->queue = NULL;
493         put_disk(dev_info->gd);
494         device_unregister(&dev_info->dev);
495         segment_unload(dev_info->segment_name);
496         put_device(&dev_info->dev);
497         up_write(&dcssblk_devices_sem);
498         goto out;
499 list_del:
500         list_del(&dev_info->lh);
501         up_write(&dcssblk_devices_sem);
502 unload_seg:
503         segment_unload(local_buf);
504 dealloc_gendisk:
505         blk_put_queue(dev_info->dcssblk_queue);
506         dev_info->gd->queue = NULL;
507         put_disk(dev_info->gd);
508 free_dev_info:
509         kfree(dev_info);
510 out:
511         kfree(local_buf);
512 out_nobuf:
513         return rc;
514 }
515
516 /*
517  * device attribute for removing devices
518  */
519 static ssize_t
520 dcssblk_remove_store(struct device *dev, const char *buf, size_t count)
521 {
522         struct dcssblk_dev_info *dev_info;
523         int rc, i;
524         char *local_buf;
525
526         if (dev != dcssblk_root_dev) {
527                 return -EINVAL;
528         }
529         local_buf = kmalloc(count + 1, GFP_KERNEL);
530         if (local_buf == NULL) {
531                 return -ENOMEM;
532         }
533         /*
534          * parse input
535          */
536         for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
537                 local_buf[i] = toupper(buf[i]);
538         }
539         local_buf[i] = '\0';
540         if ((i == 0) || (i > 8)) {
541                 rc = -ENAMETOOLONG;
542                 goto out_buf;
543         }
544
545         down_write(&dcssblk_devices_sem);
546         dev_info = dcssblk_get_device_by_name(local_buf);
547         if (dev_info == NULL) {
548                 up_write(&dcssblk_devices_sem);
549                 PRINT_WARN("Segment %s is not loaded!\n", local_buf);
550                 rc = -ENODEV;
551                 goto out_buf;
552         }
553         if (atomic_read(&dev_info->use_count) != 0) {
554                 up_write(&dcssblk_devices_sem);
555                 PRINT_WARN("Segment %s is in use!\n", local_buf);
556                 rc = -EBUSY;
557                 goto out_buf;
558         }
559         list_del(&dev_info->lh);
560
561         del_gendisk(dev_info->gd);
562         blk_put_queue(dev_info->dcssblk_queue);
563         dev_info->gd->queue = NULL;
564         put_disk(dev_info->gd);
565         device_unregister(&dev_info->dev);
566         segment_unload(dev_info->segment_name);
567         PRINT_DEBUG("Segment %s unloaded successfully\n",
568                         dev_info->segment_name);
569         put_device(&dev_info->dev);
570         up_write(&dcssblk_devices_sem);
571
572         rc = count;
573 out_buf:
574         kfree(local_buf);
575         return rc;
576 }
577
578 static int
579 dcssblk_open(struct inode *inode, struct file *filp)
580 {
581         struct dcssblk_dev_info *dev_info;
582         int rc;
583
584         dev_info = inode->i_bdev->bd_disk->private_data;
585         if (NULL == dev_info) {
586                 rc = -ENODEV;
587                 goto out;
588         }
589         atomic_inc(&dev_info->use_count);
590         inode->i_bdev->bd_block_size = 4096;
591         rc = 0;
592 out:
593         return rc;
594 }
595
596 static int
597 dcssblk_release(struct inode *inode, struct file *filp)
598 {
599         struct dcssblk_dev_info *dev_info;
600         int rc;
601
602         dev_info = inode->i_bdev->bd_disk->private_data;
603         if (NULL == dev_info) {
604                 rc = -ENODEV;
605                 goto out;
606         }
607         down_write(&dcssblk_devices_sem);
608         if (atomic_dec_and_test(&dev_info->use_count)
609             && (dev_info->save_pending)) {
610                 PRINT_INFO("Segment %s became idle and is being saved now\n",
611                             dev_info->segment_name);
612                 segment_save(dev_info->segment_name);
613                 dev_info->save_pending = 0;
614         }
615         up_write(&dcssblk_devices_sem);
616         rc = 0;
617 out:
618         return rc;
619 }
620
621 static int
622 dcssblk_make_request(request_queue_t *q, struct bio *bio)
623 {
624         struct dcssblk_dev_info *dev_info;
625         struct bio_vec *bvec;
626         unsigned long index;
627         unsigned long page_addr;
628         unsigned long source_addr;
629         unsigned long bytes_done;
630         int i;
631
632         bytes_done = 0;
633         dev_info = bio->bi_bdev->bd_disk->private_data;
634         if (dev_info == NULL)
635                 goto fail;
636         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
637                 /* Request is not page-aligned. */
638                 goto fail;
639         if (((bio->bi_size >> 9) + bio->bi_sector)
640                         > get_capacity(bio->bi_bdev->bd_disk)) {
641                 /* Request beyond end of DCSS segment. */
642                 goto fail;
643         }
644         index = (bio->bi_sector >> 3);
645         bio_for_each_segment(bvec, bio, i) {
646                 page_addr = (unsigned long)
647                         page_address(bvec->bv_page) + bvec->bv_offset;
648                 source_addr = dev_info->start + (index<<12) + bytes_done;
649                 if (unlikely(page_addr & 4095) != 0 || (bvec->bv_len & 4095) != 0)
650                         // More paranoia.
651                         goto fail;
652                 if (bio_data_dir(bio) == READ) {
653                         memcpy((void*)page_addr, (void*)source_addr,
654                                 bvec->bv_len);
655                 } else {
656                         memcpy((void*)source_addr, (void*)page_addr,
657                                 bvec->bv_len);
658                 }
659                 bytes_done += bvec->bv_len;
660         }
661         bio_endio(bio, bytes_done, 0);
662         return 0;
663 fail:
664         bio_io_error(bio, bytes_done);
665         return 0;
666 }
667
668 static void
669 dcssblk_check_params(void)
670 {
671         int rc, i, j, k;
672         char buf[9];
673         struct dcssblk_dev_info *dev_info;
674
675         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
676              i++) {
677                 for (j = i; (dcssblk_segments[j] != ',')  &&
678                             (dcssblk_segments[j] != '\0') &&
679                             (dcssblk_segments[j] != '(')  &&
680                             (j - i) < 8; j++)
681                 {
682                         buf[j-i] = dcssblk_segments[j];
683                 }
684                 buf[j-i] = '\0';
685                 rc = dcssblk_add_store(dcssblk_root_dev, buf, j-i);
686                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
687                         for (k = 0; buf[k] != '\0'; k++)
688                                 buf[k] = toupper(buf[k]);
689                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
690                                 down_read(&dcssblk_devices_sem);
691                                 dev_info = dcssblk_get_device_by_name(buf);
692                                 up_read(&dcssblk_devices_sem);
693                                 if (dev_info)
694                                         dcssblk_shared_store(&dev_info->dev,
695                                                              "0\n", 2);
696                         }
697                 }
698                 while ((dcssblk_segments[j] != ',') &&
699                        (dcssblk_segments[j] != '\0'))
700                 {
701                         j++;
702                 }
703                 if (dcssblk_segments[j] == '\0')
704                         break;
705                 i = j;
706         }
707 }
708
709 /*
710  * The init/exit functions.
711  */
712 static void __exit
713 dcssblk_exit(void)
714 {
715         int rc;
716
717         PRINT_DEBUG("DCSSBLOCK EXIT...\n");
718         s390_root_dev_unregister(dcssblk_root_dev);
719         rc = unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
720         if (rc) {
721                 PRINT_ERR("unregister_blkdev() failed!\n");
722         }
723         PRINT_DEBUG("...finished!\n");
724 }
725
726 static int __init
727 dcssblk_init(void)
728 {
729         int rc;
730
731         PRINT_DEBUG("DCSSBLOCK INIT...\n");
732         dcssblk_root_dev = s390_root_dev_register("dcssblk");
733         if (IS_ERR(dcssblk_root_dev)) {
734                 PRINT_ERR("device_register() failed!\n");
735                 return PTR_ERR(dcssblk_root_dev);
736         }
737         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
738         if (rc) {
739                 PRINT_ERR("device_create_file(add) failed!\n");
740                 s390_root_dev_unregister(dcssblk_root_dev);
741                 return rc;
742         }
743         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
744         if (rc) {
745                 PRINT_ERR("device_create_file(remove) failed!\n");
746                 s390_root_dev_unregister(dcssblk_root_dev);
747                 return rc;
748         }
749         rc = register_blkdev(0, DCSSBLK_NAME);
750         if (rc < 0) {
751                 PRINT_ERR("Can't get dynamic major!\n");
752                 s390_root_dev_unregister(dcssblk_root_dev);
753                 return rc;
754         }
755         dcssblk_major = rc;
756         init_rwsem(&dcssblk_devices_sem);
757
758         dcssblk_check_params();
759
760         PRINT_DEBUG("...finished!\n");
761         return 0;
762 }
763
764 module_init(dcssblk_init);
765 module_exit(dcssblk_exit);
766
767 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
768 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
769                  "comma-separated list, each name max. 8 chars.\n"
770                  "Adding \"(local)\" to segment name equals echoing 0 to "
771                  "/sys/devices/dcssblk/<segment name>/shared after loading "
772                  "the segment - \n"
773                  "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
774
775 MODULE_LICENSE("GPL");