[PATCH] regularize blk_cleanup_queue() use
[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                                  unsigned long *data);
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 struct list_head dcssblk_devices = LIST_HEAD_INIT(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 inline int
106 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
107 {
108         int minor, found;
109         struct dcssblk_dev_info *entry;
110
111         if (dev_info == NULL)
112                 return -EINVAL;
113         for (minor = 0; minor < (1<<MINORBITS); minor++) {
114                 found = 0;
115                 // test if minor available
116                 list_for_each_entry(entry, &dcssblk_devices, lh)
117                         if (minor == entry->gd->first_minor)
118                                 found++;
119                 if (!found) break; // got unused minor
120         }
121         if (found)
122                 return -EBUSY;
123         dev_info->gd->first_minor = minor;
124         return 0;
125 }
126
127 /*
128  * get the struct dcssblk_dev_info from dcssblk_devices
129  * for the given name.
130  * down_read(&dcssblk_devices_sem) must be held.
131  */
132 static struct dcssblk_dev_info *
133 dcssblk_get_device_by_name(char *name)
134 {
135         struct dcssblk_dev_info *entry;
136
137         list_for_each_entry(entry, &dcssblk_devices, lh) {
138                 if (!strcmp(name, entry->segment_name)) {
139                         return entry;
140                 }
141         }
142         return NULL;
143 }
144
145 /*
146  * print appropriate error message for segment_load()/segment_type()
147  * return code
148  */
149 static void
150 dcssblk_segment_warn(int rc, char* seg_name)
151 {
152         switch (rc) {
153         case -ENOENT:
154                 PRINT_WARN("cannot load/query segment %s, does not exist\n",
155                            seg_name);
156                 break;
157         case -ENOSYS:
158                 PRINT_WARN("cannot load/query segment %s, not running on VM\n",
159                            seg_name);
160                 break;
161         case -EIO:
162                 PRINT_WARN("cannot load/query segment %s, hardware error\n",
163                            seg_name);
164                 break;
165         case -ENOTSUPP:
166                 PRINT_WARN("cannot load/query segment %s, is a multi-part "
167                            "segment\n", seg_name);
168                 break;
169         case -ENOSPC:
170                 PRINT_WARN("cannot load/query segment %s, overlaps with "
171                            "storage\n", seg_name);
172                 break;
173         case -EBUSY:
174                 PRINT_WARN("cannot load/query segment %s, overlaps with "
175                            "already loaded dcss\n", seg_name);
176                 break;
177         case -EPERM:
178                 PRINT_WARN("cannot load/query segment %s, already loaded in "
179                            "incompatible mode\n", seg_name);
180                 break;
181         case -ENOMEM:
182                 PRINT_WARN("cannot load/query segment %s, out of memory\n",
183                            seg_name);
184                 break;
185         case -ERANGE:
186                 PRINT_WARN("cannot load/query segment %s, exceeds kernel "
187                            "mapping range\n", seg_name);
188                 break;
189         default:
190                 PRINT_WARN("cannot load/query segment %s, return value %i\n",
191                            seg_name, rc);
192                 break;
193         }
194 }
195
196 /*
197  * device attribute for switching shared/nonshared (exclusive)
198  * operation (show + store)
199  */
200 static ssize_t
201 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
202 {
203         struct dcssblk_dev_info *dev_info;
204
205         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
206         return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
207 }
208
209 static ssize_t
210 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
211 {
212         struct dcssblk_dev_info *dev_info;
213         int rc;
214
215         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
216                 PRINT_WARN("Invalid value, must be 0 or 1\n");
217                 return -EINVAL;
218         }
219         down_write(&dcssblk_devices_sem);
220         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
221         if (atomic_read(&dev_info->use_count)) {
222                 PRINT_ERR("share: segment %s is busy!\n",
223                           dev_info->segment_name);
224                 rc = -EBUSY;
225                 goto out;
226         }
227         if (inbuf[0] == '1') {
228                 // reload segment in shared mode
229                 rc = segment_modify_shared(dev_info->segment_name,
230                                            SEGMENT_SHARED);
231                 if (rc < 0) {
232                         BUG_ON(rc == -EINVAL);
233                         if (rc == -EIO || rc == -ENOENT)
234                                 goto removeseg;
235                 } else {
236                         dev_info->is_shared = 1;
237                         switch (dev_info->segment_type) {
238                                 case SEG_TYPE_SR:
239                                 case SEG_TYPE_ER:
240                                 case SEG_TYPE_SC:
241                                         set_disk_ro(dev_info->gd,1);
242                         }
243                 }
244         } else if (inbuf[0] == '0') {
245                 // reload segment in exclusive mode
246                 if (dev_info->segment_type == SEG_TYPE_SC) {
247                         PRINT_ERR("Segment type SC (%s) cannot be loaded in "
248                                   "non-shared mode\n", dev_info->segment_name);
249                         rc = -EINVAL;
250                         goto out;
251                 }
252                 rc = segment_modify_shared(dev_info->segment_name,
253                                            SEGMENT_EXCLUSIVE);
254                 if (rc < 0) {
255                         BUG_ON(rc == -EINVAL);
256                         if (rc == -EIO || rc == -ENOENT)
257                                 goto removeseg;
258                 } else {
259                         dev_info->is_shared = 0;
260                         set_disk_ro(dev_info->gd, 0);
261                 }
262         } else {
263                 PRINT_WARN("Invalid value, must be 0 or 1\n");
264                 rc = -EINVAL;
265                 goto out;
266         }
267         rc = count;
268         goto out;
269
270 removeseg:
271         PRINT_ERR("Could not reload segment %s, removing it now!\n",
272                         dev_info->segment_name);
273         list_del(&dev_info->lh);
274
275         del_gendisk(dev_info->gd);
276         blk_cleanup_queue(dev_info->dcssblk_queue);
277         dev_info->gd->queue = NULL;
278         put_disk(dev_info->gd);
279         device_unregister(dev);
280         put_device(dev);
281 out:
282         up_write(&dcssblk_devices_sem);
283         return rc;
284 }
285
286 /*
287  * device attribute for save operation on current copy
288  * of the segment. If the segment is busy, saving will
289  * become pending until it gets released, which can be
290  * undone by storing a non-true value to this entry.
291  * (show + store)
292  */
293 static ssize_t
294 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
295 {
296         struct dcssblk_dev_info *dev_info;
297
298         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
299         return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
300 }
301
302 static ssize_t
303 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
304 {
305         struct dcssblk_dev_info *dev_info;
306
307         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
308                 PRINT_WARN("Invalid value, must be 0 or 1\n");
309                 return -EINVAL;
310         }
311         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
312
313         down_write(&dcssblk_devices_sem);
314         if (inbuf[0] == '1') {
315                 if (atomic_read(&dev_info->use_count) == 0) {
316                         // device is idle => we save immediately
317                         PRINT_INFO("Saving segment %s\n",
318                                    dev_info->segment_name);
319                         segment_save(dev_info->segment_name);
320                 }  else {
321                         // device is busy => we save it when it becomes
322                         // idle in dcssblk_release
323                         PRINT_INFO("Segment %s is currently busy, it will "
324                                    "be saved when it becomes idle...\n",
325                                    dev_info->segment_name);
326                         dev_info->save_pending = 1;
327                 }
328         } else if (inbuf[0] == '0') {
329                 if (dev_info->save_pending) {
330                         // device is busy & the user wants to undo his save
331                         // request
332                         dev_info->save_pending = 0;
333                         PRINT_INFO("Pending save for segment %s deactivated\n",
334                                         dev_info->segment_name);
335                 }
336         } else {
337                 up_write(&dcssblk_devices_sem);
338                 PRINT_WARN("Invalid value, must be 0 or 1\n");
339                 return -EINVAL;
340         }
341         up_write(&dcssblk_devices_sem);
342         return count;
343 }
344
345 /*
346  * device attribute for adding devices
347  */
348 static ssize_t
349 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
350 {
351         int rc, i;
352         struct dcssblk_dev_info *dev_info;
353         char *local_buf;
354         unsigned long seg_byte_size;
355
356         dev_info = NULL;
357         if (dev != dcssblk_root_dev) {
358                 rc = -EINVAL;
359                 goto out_nobuf;
360         }
361         local_buf = kmalloc(count + 1, GFP_KERNEL);
362         if (local_buf == NULL) {
363                 rc = -ENOMEM;
364                 goto out_nobuf;
365         }
366         /*
367          * parse input
368          */
369         for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
370                 local_buf[i] = toupper(buf[i]);
371         }
372         local_buf[i] = '\0';
373         if ((i == 0) || (i > 8)) {
374                 rc = -ENAMETOOLONG;
375                 goto out;
376         }
377         /*
378          * already loaded?
379          */
380         down_read(&dcssblk_devices_sem);
381         dev_info = dcssblk_get_device_by_name(local_buf);
382         up_read(&dcssblk_devices_sem);
383         if (dev_info != NULL) {
384                 PRINT_WARN("Segment %s already loaded!\n", local_buf);
385                 rc = -EEXIST;
386                 goto out;
387         }
388         /*
389          * get a struct dcssblk_dev_info
390          */
391         dev_info = kmalloc(sizeof(struct dcssblk_dev_info), GFP_KERNEL);
392         if (dev_info == NULL) {
393                 rc = -ENOMEM;
394                 goto out;
395         }
396         memset(dev_info, 0, sizeof(struct dcssblk_dev_info));
397
398         strcpy(dev_info->segment_name, local_buf);
399         strlcpy(dev_info->dev.bus_id, local_buf, BUS_ID_SIZE);
400         dev_info->dev.release = dcssblk_release_segment;
401         INIT_LIST_HEAD(&dev_info->lh);
402
403         dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
404         if (dev_info->gd == NULL) {
405                 rc = -ENOMEM;
406                 goto free_dev_info;
407         }
408         dev_info->gd->major = dcssblk_major;
409         dev_info->gd->fops = &dcssblk_devops;
410         dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
411         dev_info->gd->queue = dev_info->dcssblk_queue;
412         dev_info->gd->private_data = dev_info;
413         dev_info->gd->driverfs_dev = &dev_info->dev;
414         /*
415          * load the segment
416          */
417         rc = segment_load(local_buf, SEGMENT_SHARED,
418                                 &dev_info->start, &dev_info->end);
419         if (rc < 0) {
420                 dcssblk_segment_warn(rc, dev_info->segment_name);
421                 goto dealloc_gendisk;
422         }
423         seg_byte_size = (dev_info->end - dev_info->start + 1);
424         set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
425         PRINT_INFO("Loaded segment %s, size = %lu Byte, "
426                    "capacity = %lu (512 Byte) sectors\n", local_buf,
427                    seg_byte_size, seg_byte_size >> 9);
428
429         dev_info->segment_type = rc;
430         dev_info->save_pending = 0;
431         dev_info->is_shared = 1;
432         dev_info->dev.parent = dcssblk_root_dev;
433
434         /*
435          * get minor, add to list
436          */
437         down_write(&dcssblk_devices_sem);
438         rc = dcssblk_assign_free_minor(dev_info);
439         if (rc) {
440                 up_write(&dcssblk_devices_sem);
441                 PRINT_ERR("No free minor number available! "
442                           "Unloading segment...\n");
443                 goto unload_seg;
444         }
445         sprintf(dev_info->gd->disk_name, "dcssblk%d",
446                 dev_info->gd->first_minor);
447         list_add_tail(&dev_info->lh, &dcssblk_devices);
448
449         if (!try_module_get(THIS_MODULE)) {
450                 rc = -ENODEV;
451                 goto list_del;
452         }
453         /*
454          * register the device
455          */
456         rc = device_register(&dev_info->dev);
457         if (rc) {
458                 PRINT_ERR("Segment %s could not be registered RC=%d\n",
459                                 local_buf, rc);
460                 module_put(THIS_MODULE);
461                 goto list_del;
462         }
463         get_device(&dev_info->dev);
464         rc = device_create_file(&dev_info->dev, &dev_attr_shared);
465         if (rc)
466                 goto unregister_dev;
467         rc = device_create_file(&dev_info->dev, &dev_attr_save);
468         if (rc)
469                 goto unregister_dev;
470
471         add_disk(dev_info->gd);
472
473         blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
474         blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
475
476         switch (dev_info->segment_type) {
477                 case SEG_TYPE_SR:
478                 case SEG_TYPE_ER:
479                 case SEG_TYPE_SC:
480                         set_disk_ro(dev_info->gd,1);
481                         break;
482                 default:
483                         set_disk_ro(dev_info->gd,0);
484                         break;
485         }
486         PRINT_DEBUG("Segment %s loaded successfully\n", local_buf);
487         up_write(&dcssblk_devices_sem);
488         rc = count;
489         goto out;
490
491 unregister_dev:
492         PRINT_ERR("device_create_file() failed!\n");
493         list_del(&dev_info->lh);
494         blk_cleanup_queue(dev_info->dcssblk_queue);
495         dev_info->gd->queue = NULL;
496         put_disk(dev_info->gd);
497         device_unregister(&dev_info->dev);
498         segment_unload(dev_info->segment_name);
499         put_device(&dev_info->dev);
500         up_write(&dcssblk_devices_sem);
501         goto out;
502 list_del:
503         list_del(&dev_info->lh);
504         up_write(&dcssblk_devices_sem);
505 unload_seg:
506         segment_unload(local_buf);
507 dealloc_gendisk:
508         blk_cleanup_queue(dev_info->dcssblk_queue);
509         dev_info->gd->queue = NULL;
510         put_disk(dev_info->gd);
511 free_dev_info:
512         kfree(dev_info);
513 out:
514         kfree(local_buf);
515 out_nobuf:
516         return rc;
517 }
518
519 /*
520  * device attribute for removing devices
521  */
522 static ssize_t
523 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
524 {
525         struct dcssblk_dev_info *dev_info;
526         int rc, i;
527         char *local_buf;
528
529         if (dev != dcssblk_root_dev) {
530                 return -EINVAL;
531         }
532         local_buf = kmalloc(count + 1, GFP_KERNEL);
533         if (local_buf == NULL) {
534                 return -ENOMEM;
535         }
536         /*
537          * parse input
538          */
539         for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
540                 local_buf[i] = toupper(buf[i]);
541         }
542         local_buf[i] = '\0';
543         if ((i == 0) || (i > 8)) {
544                 rc = -ENAMETOOLONG;
545                 goto out_buf;
546         }
547
548         down_write(&dcssblk_devices_sem);
549         dev_info = dcssblk_get_device_by_name(local_buf);
550         if (dev_info == NULL) {
551                 up_write(&dcssblk_devices_sem);
552                 PRINT_WARN("Segment %s is not loaded!\n", local_buf);
553                 rc = -ENODEV;
554                 goto out_buf;
555         }
556         if (atomic_read(&dev_info->use_count) != 0) {
557                 up_write(&dcssblk_devices_sem);
558                 PRINT_WARN("Segment %s is in use!\n", local_buf);
559                 rc = -EBUSY;
560                 goto out_buf;
561         }
562         list_del(&dev_info->lh);
563
564         del_gendisk(dev_info->gd);
565         blk_cleanup_queue(dev_info->dcssblk_queue);
566         dev_info->gd->queue = NULL;
567         put_disk(dev_info->gd);
568         device_unregister(&dev_info->dev);
569         segment_unload(dev_info->segment_name);
570         PRINT_DEBUG("Segment %s unloaded successfully\n",
571                         dev_info->segment_name);
572         put_device(&dev_info->dev);
573         up_write(&dcssblk_devices_sem);
574
575         rc = count;
576 out_buf:
577         kfree(local_buf);
578         return rc;
579 }
580
581 static int
582 dcssblk_open(struct inode *inode, struct file *filp)
583 {
584         struct dcssblk_dev_info *dev_info;
585         int rc;
586
587         dev_info = inode->i_bdev->bd_disk->private_data;
588         if (NULL == dev_info) {
589                 rc = -ENODEV;
590                 goto out;
591         }
592         atomic_inc(&dev_info->use_count);
593         inode->i_bdev->bd_block_size = 4096;
594         rc = 0;
595 out:
596         return rc;
597 }
598
599 static int
600 dcssblk_release(struct inode *inode, struct file *filp)
601 {
602         struct dcssblk_dev_info *dev_info;
603         int rc;
604
605         dev_info = inode->i_bdev->bd_disk->private_data;
606         if (NULL == dev_info) {
607                 rc = -ENODEV;
608                 goto out;
609         }
610         down_write(&dcssblk_devices_sem);
611         if (atomic_dec_and_test(&dev_info->use_count)
612             && (dev_info->save_pending)) {
613                 PRINT_INFO("Segment %s became idle and is being saved now\n",
614                             dev_info->segment_name);
615                 segment_save(dev_info->segment_name);
616                 dev_info->save_pending = 0;
617         }
618         up_write(&dcssblk_devices_sem);
619         rc = 0;
620 out:
621         return rc;
622 }
623
624 static int
625 dcssblk_make_request(request_queue_t *q, struct bio *bio)
626 {
627         struct dcssblk_dev_info *dev_info;
628         struct bio_vec *bvec;
629         unsigned long index;
630         unsigned long page_addr;
631         unsigned long source_addr;
632         unsigned long bytes_done;
633         int i;
634
635         bytes_done = 0;
636         dev_info = bio->bi_bdev->bd_disk->private_data;
637         if (dev_info == NULL)
638                 goto fail;
639         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
640                 /* Request is not page-aligned. */
641                 goto fail;
642         if (((bio->bi_size >> 9) + bio->bi_sector)
643                         > get_capacity(bio->bi_bdev->bd_disk)) {
644                 /* Request beyond end of DCSS segment. */
645                 goto fail;
646         }
647         /* verify data transfer direction */
648         if (dev_info->is_shared) {
649                 switch (dev_info->segment_type) {
650                 case SEG_TYPE_SR:
651                 case SEG_TYPE_ER:
652                 case SEG_TYPE_SC:
653                         /* cannot write to these segments */
654                         if (bio_data_dir(bio) == WRITE) {
655                                 PRINT_WARN("rejecting write to ro segment %s\n", dev_info->dev.bus_id);
656                                 goto fail;
657                         }
658                 }
659         }
660
661         index = (bio->bi_sector >> 3);
662         bio_for_each_segment(bvec, bio, i) {
663                 page_addr = (unsigned long)
664                         page_address(bvec->bv_page) + bvec->bv_offset;
665                 source_addr = dev_info->start + (index<<12) + bytes_done;
666                 if (unlikely(page_addr & 4095) != 0 || (bvec->bv_len & 4095) != 0)
667                         // More paranoia.
668                         goto fail;
669                 if (bio_data_dir(bio) == READ) {
670                         memcpy((void*)page_addr, (void*)source_addr,
671                                 bvec->bv_len);
672                 } else {
673                         memcpy((void*)source_addr, (void*)page_addr,
674                                 bvec->bv_len);
675                 }
676                 bytes_done += bvec->bv_len;
677         }
678         bio_endio(bio, bytes_done, 0);
679         return 0;
680 fail:
681         bio_io_error(bio, bio->bi_size);
682         return 0;
683 }
684
685 static int
686 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
687                         unsigned long *data)
688 {
689         struct dcssblk_dev_info *dev_info;
690         unsigned long pgoff;
691
692         dev_info = bdev->bd_disk->private_data;
693         if (!dev_info)
694                 return -ENODEV;
695         if (secnum % (PAGE_SIZE/512))
696                 return -EINVAL;
697         pgoff = secnum / (PAGE_SIZE / 512);
698         if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
699                 return -ERANGE;
700         *data = (unsigned long) (dev_info->start+pgoff*PAGE_SIZE);
701         return 0;
702 }
703
704 static void
705 dcssblk_check_params(void)
706 {
707         int rc, i, j, k;
708         char buf[9];
709         struct dcssblk_dev_info *dev_info;
710
711         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
712              i++) {
713                 for (j = i; (dcssblk_segments[j] != ',')  &&
714                             (dcssblk_segments[j] != '\0') &&
715                             (dcssblk_segments[j] != '(')  &&
716                             (j - i) < 8; j++)
717                 {
718                         buf[j-i] = dcssblk_segments[j];
719                 }
720                 buf[j-i] = '\0';
721                 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
722                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
723                         for (k = 0; buf[k] != '\0'; k++)
724                                 buf[k] = toupper(buf[k]);
725                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
726                                 down_read(&dcssblk_devices_sem);
727                                 dev_info = dcssblk_get_device_by_name(buf);
728                                 up_read(&dcssblk_devices_sem);
729                                 if (dev_info)
730                                         dcssblk_shared_store(&dev_info->dev,
731                                                              NULL, "0\n", 2);
732                         }
733                 }
734                 while ((dcssblk_segments[j] != ',') &&
735                        (dcssblk_segments[j] != '\0'))
736                 {
737                         j++;
738                 }
739                 if (dcssblk_segments[j] == '\0')
740                         break;
741                 i = j;
742         }
743 }
744
745 /*
746  * The init/exit functions.
747  */
748 static void __exit
749 dcssblk_exit(void)
750 {
751         int rc;
752
753         PRINT_DEBUG("DCSSBLOCK EXIT...\n");
754         s390_root_dev_unregister(dcssblk_root_dev);
755         rc = unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
756         if (rc) {
757                 PRINT_ERR("unregister_blkdev() failed!\n");
758         }
759         PRINT_DEBUG("...finished!\n");
760 }
761
762 static int __init
763 dcssblk_init(void)
764 {
765         int rc;
766
767         PRINT_DEBUG("DCSSBLOCK INIT...\n");
768         dcssblk_root_dev = s390_root_dev_register("dcssblk");
769         if (IS_ERR(dcssblk_root_dev)) {
770                 PRINT_ERR("device_register() failed!\n");
771                 return PTR_ERR(dcssblk_root_dev);
772         }
773         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
774         if (rc) {
775                 PRINT_ERR("device_create_file(add) failed!\n");
776                 s390_root_dev_unregister(dcssblk_root_dev);
777                 return rc;
778         }
779         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
780         if (rc) {
781                 PRINT_ERR("device_create_file(remove) failed!\n");
782                 s390_root_dev_unregister(dcssblk_root_dev);
783                 return rc;
784         }
785         rc = register_blkdev(0, DCSSBLK_NAME);
786         if (rc < 0) {
787                 PRINT_ERR("Can't get dynamic major!\n");
788                 s390_root_dev_unregister(dcssblk_root_dev);
789                 return rc;
790         }
791         dcssblk_major = rc;
792         init_rwsem(&dcssblk_devices_sem);
793
794         dcssblk_check_params();
795
796         PRINT_DEBUG("...finished!\n");
797         return 0;
798 }
799
800 module_init(dcssblk_init);
801 module_exit(dcssblk_exit);
802
803 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
804 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
805                  "comma-separated list, each name max. 8 chars.\n"
806                  "Adding \"(local)\" to segment name equals echoing 0 to "
807                  "/sys/devices/dcssblk/<segment name>/shared after loading "
808                  "the segment - \n"
809                  "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
810
811 MODULE_LICENSE("GPL");