return pfn from direct_access, for XIP
[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/s390_rdev.h>
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 static int dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
39                                  void **kaddr, unsigned long *pfn);
40
41 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
42
43 static int dcssblk_major;
44 static struct block_device_operations dcssblk_devops = {
45         .owner          = THIS_MODULE,
46         .open           = dcssblk_open,
47         .release        = dcssblk_release,
48         .direct_access  = dcssblk_direct_access,
49 };
50
51 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
52                                   size_t count);
53 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
54                                   size_t count);
55 static ssize_t dcssblk_save_store(struct device * dev, struct device_attribute *attr, const char * buf,
56                                   size_t count);
57 static ssize_t dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf);
58 static ssize_t dcssblk_shared_store(struct device * dev, struct device_attribute *attr, const char * buf,
59                                   size_t count);
60 static ssize_t dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf);
61
62 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
63 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
64 static DEVICE_ATTR(save, S_IWUSR | S_IRUGO, dcssblk_save_show,
65                    dcssblk_save_store);
66 static DEVICE_ATTR(shared, S_IWUSR | S_IRUGO, dcssblk_shared_show,
67                    dcssblk_shared_store);
68
69 static struct device *dcssblk_root_dev;
70
71 struct dcssblk_dev_info {
72         struct list_head lh;
73         struct device dev;
74         char segment_name[BUS_ID_SIZE];
75         atomic_t use_count;
76         struct gendisk *gd;
77         unsigned long start;
78         unsigned long end;
79         int segment_type;
80         unsigned char save_pending;
81         unsigned char is_shared;
82         struct request_queue *dcssblk_queue;
83 };
84
85 static LIST_HEAD(dcssblk_devices);
86 static struct rw_semaphore dcssblk_devices_sem;
87
88 /*
89  * release function for segment device.
90  */
91 static void
92 dcssblk_release_segment(struct device *dev)
93 {
94         PRINT_DEBUG("segment release fn called for %s\n", dev->bus_id);
95         kfree(container_of(dev, struct dcssblk_dev_info, dev));
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 static void dcssblk_unregister_callback(struct device *dev)
146 {
147         device_unregister(dev);
148         put_device(dev);
149 }
150
151 /*
152  * device attribute for switching shared/nonshared (exclusive)
153  * operation (show + store)
154  */
155 static ssize_t
156 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
157 {
158         struct dcssblk_dev_info *dev_info;
159
160         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
161         return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
162 }
163
164 static ssize_t
165 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
166 {
167         struct dcssblk_dev_info *dev_info;
168         int rc;
169
170         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
171                 PRINT_WARN("Invalid value, must be 0 or 1\n");
172                 return -EINVAL;
173         }
174         down_write(&dcssblk_devices_sem);
175         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
176         if (atomic_read(&dev_info->use_count)) {
177                 PRINT_ERR("share: segment %s is busy!\n",
178                           dev_info->segment_name);
179                 rc = -EBUSY;
180                 goto out;
181         }
182         if (inbuf[0] == '1') {
183                 // reload segment in shared mode
184                 rc = segment_modify_shared(dev_info->segment_name,
185                                            SEGMENT_SHARED);
186                 if (rc < 0) {
187                         BUG_ON(rc == -EINVAL);
188                         if (rc != -EAGAIN)
189                                 goto removeseg;
190                 } else {
191                         dev_info->is_shared = 1;
192                         switch (dev_info->segment_type) {
193                                 case SEG_TYPE_SR:
194                                 case SEG_TYPE_ER:
195                                 case SEG_TYPE_SC:
196                                         set_disk_ro(dev_info->gd,1);
197                         }
198                 }
199         } else if (inbuf[0] == '0') {
200                 // reload segment in exclusive mode
201                 if (dev_info->segment_type == SEG_TYPE_SC) {
202                         PRINT_ERR("Segment type SC (%s) cannot be loaded in "
203                                   "non-shared mode\n", dev_info->segment_name);
204                         rc = -EINVAL;
205                         goto out;
206                 }
207                 rc = segment_modify_shared(dev_info->segment_name,
208                                            SEGMENT_EXCLUSIVE);
209                 if (rc < 0) {
210                         BUG_ON(rc == -EINVAL);
211                         if (rc != -EAGAIN)
212                                 goto removeseg;
213                 } else {
214                         dev_info->is_shared = 0;
215                         set_disk_ro(dev_info->gd, 0);
216                 }
217         } else {
218                 PRINT_WARN("Invalid value, must be 0 or 1\n");
219                 rc = -EINVAL;
220                 goto out;
221         }
222         rc = count;
223         goto out;
224
225 removeseg:
226         PRINT_ERR("Could not reload segment %s, removing it now!\n",
227                         dev_info->segment_name);
228         list_del(&dev_info->lh);
229
230         del_gendisk(dev_info->gd);
231         blk_cleanup_queue(dev_info->dcssblk_queue);
232         dev_info->gd->queue = NULL;
233         put_disk(dev_info->gd);
234         rc = device_schedule_callback(dev, dcssblk_unregister_callback);
235 out:
236         up_write(&dcssblk_devices_sem);
237         return rc;
238 }
239
240 /*
241  * device attribute for save operation on current copy
242  * of the segment. If the segment is busy, saving will
243  * become pending until it gets released, which can be
244  * undone by storing a non-true value to this entry.
245  * (show + store)
246  */
247 static ssize_t
248 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
249 {
250         struct dcssblk_dev_info *dev_info;
251
252         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
253         return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
254 }
255
256 static ssize_t
257 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
258 {
259         struct dcssblk_dev_info *dev_info;
260
261         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
262                 PRINT_WARN("Invalid value, must be 0 or 1\n");
263                 return -EINVAL;
264         }
265         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
266
267         down_write(&dcssblk_devices_sem);
268         if (inbuf[0] == '1') {
269                 if (atomic_read(&dev_info->use_count) == 0) {
270                         // device is idle => we save immediately
271                         PRINT_INFO("Saving segment %s\n",
272                                    dev_info->segment_name);
273                         segment_save(dev_info->segment_name);
274                 }  else {
275                         // device is busy => we save it when it becomes
276                         // idle in dcssblk_release
277                         PRINT_INFO("Segment %s is currently busy, it will "
278                                    "be saved when it becomes idle...\n",
279                                    dev_info->segment_name);
280                         dev_info->save_pending = 1;
281                 }
282         } else if (inbuf[0] == '0') {
283                 if (dev_info->save_pending) {
284                         // device is busy & the user wants to undo his save
285                         // request
286                         dev_info->save_pending = 0;
287                         PRINT_INFO("Pending save for segment %s deactivated\n",
288                                         dev_info->segment_name);
289                 }
290         } else {
291                 up_write(&dcssblk_devices_sem);
292                 PRINT_WARN("Invalid value, must be 0 or 1\n");
293                 return -EINVAL;
294         }
295         up_write(&dcssblk_devices_sem);
296         return count;
297 }
298
299 /*
300  * device attribute for adding devices
301  */
302 static ssize_t
303 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
304 {
305         int rc, i;
306         struct dcssblk_dev_info *dev_info;
307         char *local_buf;
308         unsigned long seg_byte_size;
309
310         dev_info = NULL;
311         if (dev != dcssblk_root_dev) {
312                 rc = -EINVAL;
313                 goto out_nobuf;
314         }
315         local_buf = kmalloc(count + 1, GFP_KERNEL);
316         if (local_buf == NULL) {
317                 rc = -ENOMEM;
318                 goto out_nobuf;
319         }
320         /*
321          * parse input
322          */
323         for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
324                 local_buf[i] = toupper(buf[i]);
325         }
326         local_buf[i] = '\0';
327         if ((i == 0) || (i > 8)) {
328                 rc = -ENAMETOOLONG;
329                 goto out;
330         }
331         /*
332          * already loaded?
333          */
334         down_read(&dcssblk_devices_sem);
335         dev_info = dcssblk_get_device_by_name(local_buf);
336         up_read(&dcssblk_devices_sem);
337         if (dev_info != NULL) {
338                 PRINT_WARN("Segment %s already loaded!\n", local_buf);
339                 rc = -EEXIST;
340                 goto out;
341         }
342         /*
343          * get a struct dcssblk_dev_info
344          */
345         dev_info = kzalloc(sizeof(struct dcssblk_dev_info), GFP_KERNEL);
346         if (dev_info == NULL) {
347                 rc = -ENOMEM;
348                 goto out;
349         }
350
351         strcpy(dev_info->segment_name, local_buf);
352         strlcpy(dev_info->dev.bus_id, local_buf, BUS_ID_SIZE);
353         dev_info->dev.release = dcssblk_release_segment;
354         INIT_LIST_HEAD(&dev_info->lh);
355
356         dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
357         if (dev_info->gd == NULL) {
358                 rc = -ENOMEM;
359                 goto free_dev_info;
360         }
361         dev_info->gd->major = dcssblk_major;
362         dev_info->gd->fops = &dcssblk_devops;
363         dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
364         dev_info->gd->queue = dev_info->dcssblk_queue;
365         dev_info->gd->private_data = dev_info;
366         dev_info->gd->driverfs_dev = &dev_info->dev;
367         blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
368         blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
369         /*
370          * load the segment
371          */
372         rc = segment_load(local_buf, SEGMENT_SHARED,
373                                 &dev_info->start, &dev_info->end);
374         if (rc < 0) {
375                 segment_warning(rc, dev_info->segment_name);
376                 goto dealloc_gendisk;
377         }
378         seg_byte_size = (dev_info->end - dev_info->start + 1);
379         set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
380         PRINT_INFO("Loaded segment %s, size = %lu Byte, "
381                    "capacity = %lu (512 Byte) sectors\n", local_buf,
382                    seg_byte_size, seg_byte_size >> 9);
383
384         dev_info->segment_type = rc;
385         dev_info->save_pending = 0;
386         dev_info->is_shared = 1;
387         dev_info->dev.parent = dcssblk_root_dev;
388
389         /*
390          * get minor, add to list
391          */
392         down_write(&dcssblk_devices_sem);
393         rc = dcssblk_assign_free_minor(dev_info);
394         if (rc) {
395                 up_write(&dcssblk_devices_sem);
396                 PRINT_ERR("No free minor number available! "
397                           "Unloading segment...\n");
398                 goto unload_seg;
399         }
400         sprintf(dev_info->gd->disk_name, "dcssblk%d",
401                 dev_info->gd->first_minor);
402         list_add_tail(&dev_info->lh, &dcssblk_devices);
403
404         if (!try_module_get(THIS_MODULE)) {
405                 rc = -ENODEV;
406                 goto list_del;
407         }
408         /*
409          * register the device
410          */
411         rc = device_register(&dev_info->dev);
412         if (rc) {
413                 PRINT_ERR("Segment %s could not be registered RC=%d\n",
414                                 local_buf, rc);
415                 module_put(THIS_MODULE);
416                 goto list_del;
417         }
418         get_device(&dev_info->dev);
419         rc = device_create_file(&dev_info->dev, &dev_attr_shared);
420         if (rc)
421                 goto unregister_dev;
422         rc = device_create_file(&dev_info->dev, &dev_attr_save);
423         if (rc)
424                 goto unregister_dev;
425
426         add_disk(dev_info->gd);
427
428         switch (dev_info->segment_type) {
429                 case SEG_TYPE_SR:
430                 case SEG_TYPE_ER:
431                 case SEG_TYPE_SC:
432                         set_disk_ro(dev_info->gd,1);
433                         break;
434                 default:
435                         set_disk_ro(dev_info->gd,0);
436                         break;
437         }
438         PRINT_DEBUG("Segment %s loaded successfully\n", local_buf);
439         up_write(&dcssblk_devices_sem);
440         rc = count;
441         goto out;
442
443 unregister_dev:
444         PRINT_ERR("device_create_file() failed!\n");
445         list_del(&dev_info->lh);
446         blk_cleanup_queue(dev_info->dcssblk_queue);
447         dev_info->gd->queue = NULL;
448         put_disk(dev_info->gd);
449         device_unregister(&dev_info->dev);
450         segment_unload(dev_info->segment_name);
451         put_device(&dev_info->dev);
452         up_write(&dcssblk_devices_sem);
453         goto out;
454 list_del:
455         list_del(&dev_info->lh);
456         up_write(&dcssblk_devices_sem);
457 unload_seg:
458         segment_unload(local_buf);
459 dealloc_gendisk:
460         blk_cleanup_queue(dev_info->dcssblk_queue);
461         dev_info->gd->queue = NULL;
462         put_disk(dev_info->gd);
463 free_dev_info:
464         kfree(dev_info);
465 out:
466         kfree(local_buf);
467 out_nobuf:
468         return rc;
469 }
470
471 /*
472  * device attribute for removing devices
473  */
474 static ssize_t
475 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
476 {
477         struct dcssblk_dev_info *dev_info;
478         int rc, i;
479         char *local_buf;
480
481         if (dev != dcssblk_root_dev) {
482                 return -EINVAL;
483         }
484         local_buf = kmalloc(count + 1, GFP_KERNEL);
485         if (local_buf == NULL) {
486                 return -ENOMEM;
487         }
488         /*
489          * parse input
490          */
491         for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
492                 local_buf[i] = toupper(buf[i]);
493         }
494         local_buf[i] = '\0';
495         if ((i == 0) || (i > 8)) {
496                 rc = -ENAMETOOLONG;
497                 goto out_buf;
498         }
499
500         down_write(&dcssblk_devices_sem);
501         dev_info = dcssblk_get_device_by_name(local_buf);
502         if (dev_info == NULL) {
503                 up_write(&dcssblk_devices_sem);
504                 PRINT_WARN("Segment %s is not loaded!\n", local_buf);
505                 rc = -ENODEV;
506                 goto out_buf;
507         }
508         if (atomic_read(&dev_info->use_count) != 0) {
509                 up_write(&dcssblk_devices_sem);
510                 PRINT_WARN("Segment %s is in use!\n", local_buf);
511                 rc = -EBUSY;
512                 goto out_buf;
513         }
514         list_del(&dev_info->lh);
515
516         del_gendisk(dev_info->gd);
517         blk_cleanup_queue(dev_info->dcssblk_queue);
518         dev_info->gd->queue = NULL;
519         put_disk(dev_info->gd);
520         device_unregister(&dev_info->dev);
521         segment_unload(dev_info->segment_name);
522         PRINT_DEBUG("Segment %s unloaded successfully\n",
523                         dev_info->segment_name);
524         put_device(&dev_info->dev);
525         up_write(&dcssblk_devices_sem);
526
527         rc = count;
528 out_buf:
529         kfree(local_buf);
530         return rc;
531 }
532
533 static int
534 dcssblk_open(struct inode *inode, struct file *filp)
535 {
536         struct dcssblk_dev_info *dev_info;
537         int rc;
538
539         dev_info = inode->i_bdev->bd_disk->private_data;
540         if (NULL == dev_info) {
541                 rc = -ENODEV;
542                 goto out;
543         }
544         atomic_inc(&dev_info->use_count);
545         inode->i_bdev->bd_block_size = 4096;
546         rc = 0;
547 out:
548         return rc;
549 }
550
551 static int
552 dcssblk_release(struct inode *inode, struct file *filp)
553 {
554         struct dcssblk_dev_info *dev_info;
555         int rc;
556
557         dev_info = inode->i_bdev->bd_disk->private_data;
558         if (NULL == dev_info) {
559                 rc = -ENODEV;
560                 goto out;
561         }
562         down_write(&dcssblk_devices_sem);
563         if (atomic_dec_and_test(&dev_info->use_count)
564             && (dev_info->save_pending)) {
565                 PRINT_INFO("Segment %s became idle and is being saved now\n",
566                             dev_info->segment_name);
567                 segment_save(dev_info->segment_name);
568                 dev_info->save_pending = 0;
569         }
570         up_write(&dcssblk_devices_sem);
571         rc = 0;
572 out:
573         return rc;
574 }
575
576 static int
577 dcssblk_make_request(struct request_queue *q, struct bio *bio)
578 {
579         struct dcssblk_dev_info *dev_info;
580         struct bio_vec *bvec;
581         unsigned long index;
582         unsigned long page_addr;
583         unsigned long source_addr;
584         unsigned long bytes_done;
585         int i;
586
587         bytes_done = 0;
588         dev_info = bio->bi_bdev->bd_disk->private_data;
589         if (dev_info == NULL)
590                 goto fail;
591         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
592                 /* Request is not page-aligned. */
593                 goto fail;
594         if (((bio->bi_size >> 9) + bio->bi_sector)
595                         > get_capacity(bio->bi_bdev->bd_disk)) {
596                 /* Request beyond end of DCSS segment. */
597                 goto fail;
598         }
599         /* verify data transfer direction */
600         if (dev_info->is_shared) {
601                 switch (dev_info->segment_type) {
602                 case SEG_TYPE_SR:
603                 case SEG_TYPE_ER:
604                 case SEG_TYPE_SC:
605                         /* cannot write to these segments */
606                         if (bio_data_dir(bio) == WRITE) {
607                                 PRINT_WARN("rejecting write to ro segment %s\n", dev_info->dev.bus_id);
608                                 goto fail;
609                         }
610                 }
611         }
612
613         index = (bio->bi_sector >> 3);
614         bio_for_each_segment(bvec, bio, i) {
615                 page_addr = (unsigned long)
616                         page_address(bvec->bv_page) + bvec->bv_offset;
617                 source_addr = dev_info->start + (index<<12) + bytes_done;
618                 if (unlikely((page_addr & 4095) != 0) || (bvec->bv_len & 4095) != 0)
619                         // More paranoia.
620                         goto fail;
621                 if (bio_data_dir(bio) == READ) {
622                         memcpy((void*)page_addr, (void*)source_addr,
623                                 bvec->bv_len);
624                 } else {
625                         memcpy((void*)source_addr, (void*)page_addr,
626                                 bvec->bv_len);
627                 }
628                 bytes_done += bvec->bv_len;
629         }
630         bio_endio(bio, 0);
631         return 0;
632 fail:
633         bio_io_error(bio);
634         return 0;
635 }
636
637 static int
638 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
639                         void **kaddr, unsigned long *pfn)
640 {
641         struct dcssblk_dev_info *dev_info;
642         unsigned long pgoff;
643
644         dev_info = bdev->bd_disk->private_data;
645         if (!dev_info)
646                 return -ENODEV;
647         if (secnum % (PAGE_SIZE/512))
648                 return -EINVAL;
649         pgoff = secnum / (PAGE_SIZE / 512);
650         if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
651                 return -ERANGE;
652         *kaddr = (void *) (dev_info->start+pgoff*PAGE_SIZE);
653         *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
654
655         return 0;
656 }
657
658 static void
659 dcssblk_check_params(void)
660 {
661         int rc, i, j, k;
662         char buf[9];
663         struct dcssblk_dev_info *dev_info;
664
665         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
666              i++) {
667                 for (j = i; (dcssblk_segments[j] != ',')  &&
668                             (dcssblk_segments[j] != '\0') &&
669                             (dcssblk_segments[j] != '(')  &&
670                             (j - i) < 8; j++)
671                 {
672                         buf[j-i] = dcssblk_segments[j];
673                 }
674                 buf[j-i] = '\0';
675                 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
676                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
677                         for (k = 0; buf[k] != '\0'; k++)
678                                 buf[k] = toupper(buf[k]);
679                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
680                                 down_read(&dcssblk_devices_sem);
681                                 dev_info = dcssblk_get_device_by_name(buf);
682                                 up_read(&dcssblk_devices_sem);
683                                 if (dev_info)
684                                         dcssblk_shared_store(&dev_info->dev,
685                                                              NULL, "0\n", 2);
686                         }
687                 }
688                 while ((dcssblk_segments[j] != ',') &&
689                        (dcssblk_segments[j] != '\0'))
690                 {
691                         j++;
692                 }
693                 if (dcssblk_segments[j] == '\0')
694                         break;
695                 i = j;
696         }
697 }
698
699 /*
700  * The init/exit functions.
701  */
702 static void __exit
703 dcssblk_exit(void)
704 {
705         PRINT_DEBUG("DCSSBLOCK EXIT...\n");
706         s390_root_dev_unregister(dcssblk_root_dev);
707         unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
708         PRINT_DEBUG("...finished!\n");
709 }
710
711 static int __init
712 dcssblk_init(void)
713 {
714         int rc;
715
716         PRINT_DEBUG("DCSSBLOCK INIT...\n");
717         dcssblk_root_dev = s390_root_dev_register("dcssblk");
718         if (IS_ERR(dcssblk_root_dev)) {
719                 PRINT_ERR("device_register() failed!\n");
720                 return PTR_ERR(dcssblk_root_dev);
721         }
722         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
723         if (rc) {
724                 PRINT_ERR("device_create_file(add) failed!\n");
725                 s390_root_dev_unregister(dcssblk_root_dev);
726                 return rc;
727         }
728         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
729         if (rc) {
730                 PRINT_ERR("device_create_file(remove) failed!\n");
731                 s390_root_dev_unregister(dcssblk_root_dev);
732                 return rc;
733         }
734         rc = register_blkdev(0, DCSSBLK_NAME);
735         if (rc < 0) {
736                 PRINT_ERR("Can't get dynamic major!\n");
737                 s390_root_dev_unregister(dcssblk_root_dev);
738                 return rc;
739         }
740         dcssblk_major = rc;
741         init_rwsem(&dcssblk_devices_sem);
742
743         dcssblk_check_params();
744
745         PRINT_DEBUG("...finished!\n");
746         return 0;
747 }
748
749 module_init(dcssblk_init);
750 module_exit(dcssblk_exit);
751
752 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
753 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
754                  "comma-separated list, each name max. 8 chars.\n"
755                  "Adding \"(local)\" to segment name equals echoing 0 to "
756                  "/sys/devices/dcssblk/<segment name>/shared after loading "
757                  "the segment - \n"
758                  "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
759
760 MODULE_LICENSE("GPL");