2 * dcssblk.c -- the S/390 block driver for dcss memory
4 * Authors: Carsten Otte, Stefan Weinhuber, Gerald Schaefer
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>
16 #include <linux/completion.h>
17 #include <linux/interrupt.h>
18 #include <asm/s390_rdev.h>
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
26 #define PRINT_DEBUG(x...) printk(KERN_DEBUG DCSSBLK_NAME " debug: " x)
28 #define PRINT_DEBUG(x...) do {} while (0)
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)
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
);
41 static char dcssblk_segments
[DCSSBLK_PARM_LEN
] = "\0";
43 static int dcssblk_major
;
44 static struct block_device_operations dcssblk_devops
= {
47 .release
= dcssblk_release
,
48 .direct_access
= dcssblk_direct_access
,
51 static ssize_t
dcssblk_add_store(struct device
* dev
, struct device_attribute
*attr
, const char * buf
,
53 static ssize_t
dcssblk_remove_store(struct device
* dev
, struct device_attribute
*attr
, const char * buf
,
55 static ssize_t
dcssblk_save_store(struct device
* dev
, struct device_attribute
*attr
, const char * buf
,
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
,
60 static ssize_t
dcssblk_shared_show(struct device
*dev
, struct device_attribute
*attr
, char *buf
);
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
,
66 static DEVICE_ATTR(shared
, S_IWUSR
| S_IRUGO
, dcssblk_shared_show
,
67 dcssblk_shared_store
);
69 static struct device
*dcssblk_root_dev
;
71 struct dcssblk_dev_info
{
74 char segment_name
[BUS_ID_SIZE
];
80 unsigned char save_pending
;
81 unsigned char is_shared
;
82 struct request_queue
*dcssblk_queue
;
85 static LIST_HEAD(dcssblk_devices
);
86 static struct rw_semaphore dcssblk_devices_sem
;
89 * release function for segment device.
92 dcssblk_release_segment(struct device
*dev
)
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
);
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
106 dcssblk_assign_free_minor(struct dcssblk_dev_info
*dev_info
)
109 struct dcssblk_dev_info
*entry
;
111 if (dev_info
== NULL
)
113 for (minor
= 0; minor
< (1<<MINORBITS
); minor
++) {
115 // test if minor available
116 list_for_each_entry(entry
, &dcssblk_devices
, lh
)
117 if (minor
== MINOR(disk_devt(entry
->gd
)))
119 if (!found
) break; // got unused minor
123 dev_info
->gd
->first_minor
= minor
;
128 * get the struct dcssblk_dev_info from dcssblk_devices
129 * for the given name.
130 * down_read(&dcssblk_devices_sem) must be held.
132 static struct dcssblk_dev_info
*
133 dcssblk_get_device_by_name(char *name
)
135 struct dcssblk_dev_info
*entry
;
137 list_for_each_entry(entry
, &dcssblk_devices
, lh
) {
138 if (!strcmp(name
, entry
->segment_name
)) {
145 static void dcssblk_unregister_callback(struct device
*dev
)
147 device_unregister(dev
);
152 * device attribute for switching shared/nonshared (exclusive)
153 * operation (show + store)
156 dcssblk_shared_show(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
158 struct dcssblk_dev_info
*dev_info
;
160 dev_info
= container_of(dev
, struct dcssblk_dev_info
, dev
);
161 return sprintf(buf
, dev_info
->is_shared
? "1\n" : "0\n");
165 dcssblk_shared_store(struct device
*dev
, struct device_attribute
*attr
, const char *inbuf
, size_t count
)
167 struct dcssblk_dev_info
*dev_info
;
170 if ((count
> 1) && (inbuf
[1] != '\n') && (inbuf
[1] != '\0'))
172 down_write(&dcssblk_devices_sem
);
173 dev_info
= container_of(dev
, struct dcssblk_dev_info
, dev
);
174 if (atomic_read(&dev_info
->use_count
)) {
175 PRINT_ERR("share: segment %s is busy!\n",
176 dev_info
->segment_name
);
180 if (inbuf
[0] == '1') {
181 // reload segment in shared mode
182 rc
= segment_modify_shared(dev_info
->segment_name
,
185 BUG_ON(rc
== -EINVAL
);
189 dev_info
->is_shared
= 1;
190 switch (dev_info
->segment_type
) {
194 set_disk_ro(dev_info
->gd
,1);
197 } else if (inbuf
[0] == '0') {
198 // reload segment in exclusive mode
199 if (dev_info
->segment_type
== SEG_TYPE_SC
) {
200 PRINT_ERR("Segment type SC (%s) cannot be loaded in "
201 "non-shared mode\n", dev_info
->segment_name
);
205 rc
= segment_modify_shared(dev_info
->segment_name
,
208 BUG_ON(rc
== -EINVAL
);
212 dev_info
->is_shared
= 0;
213 set_disk_ro(dev_info
->gd
, 0);
223 PRINT_ERR("Could not reload segment %s, removing it now!\n",
224 dev_info
->segment_name
);
225 list_del(&dev_info
->lh
);
227 del_gendisk(dev_info
->gd
);
228 blk_cleanup_queue(dev_info
->dcssblk_queue
);
229 dev_info
->gd
->queue
= NULL
;
230 put_disk(dev_info
->gd
);
231 rc
= device_schedule_callback(dev
, dcssblk_unregister_callback
);
233 up_write(&dcssblk_devices_sem
);
238 * device attribute for save operation on current copy
239 * of the segment. If the segment is busy, saving will
240 * become pending until it gets released, which can be
241 * undone by storing a non-true value to this entry.
245 dcssblk_save_show(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
247 struct dcssblk_dev_info
*dev_info
;
249 dev_info
= container_of(dev
, struct dcssblk_dev_info
, dev
);
250 return sprintf(buf
, dev_info
->save_pending
? "1\n" : "0\n");
254 dcssblk_save_store(struct device
*dev
, struct device_attribute
*attr
, const char *inbuf
, size_t count
)
256 struct dcssblk_dev_info
*dev_info
;
258 if ((count
> 1) && (inbuf
[1] != '\n') && (inbuf
[1] != '\0'))
260 dev_info
= container_of(dev
, struct dcssblk_dev_info
, dev
);
262 down_write(&dcssblk_devices_sem
);
263 if (inbuf
[0] == '1') {
264 if (atomic_read(&dev_info
->use_count
) == 0) {
265 // device is idle => we save immediately
266 PRINT_INFO("Saving segment %s\n",
267 dev_info
->segment_name
);
268 segment_save(dev_info
->segment_name
);
270 // device is busy => we save it when it becomes
271 // idle in dcssblk_release
272 PRINT_INFO("Segment %s is currently busy, it will "
273 "be saved when it becomes idle...\n",
274 dev_info
->segment_name
);
275 dev_info
->save_pending
= 1;
277 } else if (inbuf
[0] == '0') {
278 if (dev_info
->save_pending
) {
279 // device is busy & the user wants to undo his save
281 dev_info
->save_pending
= 0;
282 PRINT_INFO("Pending save for segment %s deactivated\n",
283 dev_info
->segment_name
);
286 up_write(&dcssblk_devices_sem
);
289 up_write(&dcssblk_devices_sem
);
294 * device attribute for adding devices
297 dcssblk_add_store(struct device
*dev
, struct device_attribute
*attr
, const char *buf
, size_t count
)
300 struct dcssblk_dev_info
*dev_info
;
302 unsigned long seg_byte_size
;
305 if (dev
!= dcssblk_root_dev
) {
309 local_buf
= kmalloc(count
+ 1, GFP_KERNEL
);
310 if (local_buf
== NULL
) {
317 for (i
= 0; ((buf
[i
] != '\0') && (buf
[i
] != '\n') && i
< count
); i
++) {
318 local_buf
[i
] = toupper(buf
[i
]);
321 if ((i
== 0) || (i
> 8)) {
328 down_read(&dcssblk_devices_sem
);
329 dev_info
= dcssblk_get_device_by_name(local_buf
);
330 up_read(&dcssblk_devices_sem
);
331 if (dev_info
!= NULL
) {
332 PRINT_WARN("Segment %s already loaded!\n", local_buf
);
337 * get a struct dcssblk_dev_info
339 dev_info
= kzalloc(sizeof(struct dcssblk_dev_info
), GFP_KERNEL
);
340 if (dev_info
== NULL
) {
345 strcpy(dev_info
->segment_name
, local_buf
);
346 strlcpy(dev_info
->dev
.bus_id
, local_buf
, BUS_ID_SIZE
);
347 dev_info
->dev
.release
= dcssblk_release_segment
;
348 INIT_LIST_HEAD(&dev_info
->lh
);
350 dev_info
->gd
= alloc_disk(DCSSBLK_MINORS_PER_DISK
);
351 if (dev_info
->gd
== NULL
) {
355 dev_info
->gd
->major
= dcssblk_major
;
356 dev_info
->gd
->fops
= &dcssblk_devops
;
357 dev_info
->dcssblk_queue
= blk_alloc_queue(GFP_KERNEL
);
358 dev_info
->gd
->queue
= dev_info
->dcssblk_queue
;
359 dev_info
->gd
->private_data
= dev_info
;
360 dev_info
->gd
->driverfs_dev
= &dev_info
->dev
;
361 blk_queue_make_request(dev_info
->dcssblk_queue
, dcssblk_make_request
);
362 blk_queue_hardsect_size(dev_info
->dcssblk_queue
, 4096);
366 rc
= segment_load(local_buf
, SEGMENT_SHARED
,
367 &dev_info
->start
, &dev_info
->end
);
369 segment_warning(rc
, dev_info
->segment_name
);
370 goto dealloc_gendisk
;
372 seg_byte_size
= (dev_info
->end
- dev_info
->start
+ 1);
373 set_capacity(dev_info
->gd
, seg_byte_size
>> 9); // size in sectors
374 PRINT_INFO("Loaded segment %s, size = %lu Byte, "
375 "capacity = %lu (512 Byte) sectors\n", local_buf
,
376 seg_byte_size
, seg_byte_size
>> 9);
378 dev_info
->segment_type
= rc
;
379 dev_info
->save_pending
= 0;
380 dev_info
->is_shared
= 1;
381 dev_info
->dev
.parent
= dcssblk_root_dev
;
384 * get minor, add to list
386 down_write(&dcssblk_devices_sem
);
387 if (dcssblk_get_device_by_name(local_buf
)) {
388 up_write(&dcssblk_devices_sem
);
392 rc
= dcssblk_assign_free_minor(dev_info
);
394 up_write(&dcssblk_devices_sem
);
395 PRINT_ERR("No free minor number available! "
396 "Unloading segment...\n");
399 sprintf(dev_info
->gd
->disk_name
, "dcssblk%d",
400 MINOR(disk_devt(dev_info
->gd
)));
401 list_add_tail(&dev_info
->lh
, &dcssblk_devices
);
403 if (!try_module_get(THIS_MODULE
)) {
408 * register the device
410 rc
= device_register(&dev_info
->dev
);
412 PRINT_ERR("Segment %s could not be registered RC=%d\n",
414 module_put(THIS_MODULE
);
417 get_device(&dev_info
->dev
);
418 rc
= device_create_file(&dev_info
->dev
, &dev_attr_shared
);
421 rc
= device_create_file(&dev_info
->dev
, &dev_attr_save
);
425 add_disk(dev_info
->gd
);
427 switch (dev_info
->segment_type
) {
431 set_disk_ro(dev_info
->gd
,1);
434 set_disk_ro(dev_info
->gd
,0);
437 PRINT_DEBUG("Segment %s loaded successfully\n", local_buf
);
438 up_write(&dcssblk_devices_sem
);
443 list_del(&dev_info
->lh
);
444 blk_cleanup_queue(dev_info
->dcssblk_queue
);
445 dev_info
->gd
->queue
= NULL
;
446 put_disk(dev_info
->gd
);
447 device_unregister(&dev_info
->dev
);
448 segment_unload(dev_info
->segment_name
);
449 put_device(&dev_info
->dev
);
450 up_write(&dcssblk_devices_sem
);
453 list_del(&dev_info
->lh
);
454 up_write(&dcssblk_devices_sem
);
456 segment_unload(local_buf
);
458 blk_cleanup_queue(dev_info
->dcssblk_queue
);
459 dev_info
->gd
->queue
= NULL
;
460 put_disk(dev_info
->gd
);
470 * device attribute for removing devices
473 dcssblk_remove_store(struct device
*dev
, struct device_attribute
*attr
, const char *buf
, size_t count
)
475 struct dcssblk_dev_info
*dev_info
;
479 if (dev
!= dcssblk_root_dev
) {
482 local_buf
= kmalloc(count
+ 1, GFP_KERNEL
);
483 if (local_buf
== NULL
) {
489 for (i
= 0; ((*(buf
+i
)!='\0') && (*(buf
+i
)!='\n') && i
< count
); i
++) {
490 local_buf
[i
] = toupper(buf
[i
]);
493 if ((i
== 0) || (i
> 8)) {
498 down_write(&dcssblk_devices_sem
);
499 dev_info
= dcssblk_get_device_by_name(local_buf
);
500 if (dev_info
== NULL
) {
501 up_write(&dcssblk_devices_sem
);
502 PRINT_WARN("Segment %s is not loaded!\n", local_buf
);
506 if (atomic_read(&dev_info
->use_count
) != 0) {
507 up_write(&dcssblk_devices_sem
);
508 PRINT_WARN("Segment %s is in use!\n", local_buf
);
512 list_del(&dev_info
->lh
);
514 del_gendisk(dev_info
->gd
);
515 blk_cleanup_queue(dev_info
->dcssblk_queue
);
516 dev_info
->gd
->queue
= NULL
;
517 put_disk(dev_info
->gd
);
518 device_unregister(&dev_info
->dev
);
519 segment_unload(dev_info
->segment_name
);
520 PRINT_DEBUG("Segment %s unloaded successfully\n",
521 dev_info
->segment_name
);
522 put_device(&dev_info
->dev
);
523 up_write(&dcssblk_devices_sem
);
532 dcssblk_open(struct inode
*inode
, struct file
*filp
)
534 struct dcssblk_dev_info
*dev_info
;
537 dev_info
= inode
->i_bdev
->bd_disk
->private_data
;
538 if (NULL
== dev_info
) {
542 atomic_inc(&dev_info
->use_count
);
543 inode
->i_bdev
->bd_block_size
= 4096;
550 dcssblk_release(struct inode
*inode
, struct file
*filp
)
552 struct dcssblk_dev_info
*dev_info
;
555 dev_info
= inode
->i_bdev
->bd_disk
->private_data
;
556 if (NULL
== dev_info
) {
560 down_write(&dcssblk_devices_sem
);
561 if (atomic_dec_and_test(&dev_info
->use_count
)
562 && (dev_info
->save_pending
)) {
563 PRINT_INFO("Segment %s became idle and is being saved now\n",
564 dev_info
->segment_name
);
565 segment_save(dev_info
->segment_name
);
566 dev_info
->save_pending
= 0;
568 up_write(&dcssblk_devices_sem
);
575 dcssblk_make_request(struct request_queue
*q
, struct bio
*bio
)
577 struct dcssblk_dev_info
*dev_info
;
578 struct bio_vec
*bvec
;
580 unsigned long page_addr
;
581 unsigned long source_addr
;
582 unsigned long bytes_done
;
586 dev_info
= bio
->bi_bdev
->bd_disk
->private_data
;
587 if (dev_info
== NULL
)
589 if ((bio
->bi_sector
& 7) != 0 || (bio
->bi_size
& 4095) != 0)
590 /* Request is not page-aligned. */
592 if (((bio
->bi_size
>> 9) + bio
->bi_sector
)
593 > get_capacity(bio
->bi_bdev
->bd_disk
)) {
594 /* Request beyond end of DCSS segment. */
597 /* verify data transfer direction */
598 if (dev_info
->is_shared
) {
599 switch (dev_info
->segment_type
) {
603 /* cannot write to these segments */
604 if (bio_data_dir(bio
) == WRITE
) {
605 PRINT_WARN("rejecting write to ro segment %s\n", dev_info
->dev
.bus_id
);
611 index
= (bio
->bi_sector
>> 3);
612 bio_for_each_segment(bvec
, bio
, i
) {
613 page_addr
= (unsigned long)
614 page_address(bvec
->bv_page
) + bvec
->bv_offset
;
615 source_addr
= dev_info
->start
+ (index
<<12) + bytes_done
;
616 if (unlikely((page_addr
& 4095) != 0) || (bvec
->bv_len
& 4095) != 0)
619 if (bio_data_dir(bio
) == READ
) {
620 memcpy((void*)page_addr
, (void*)source_addr
,
623 memcpy((void*)source_addr
, (void*)page_addr
,
626 bytes_done
+= bvec
->bv_len
;
636 dcssblk_direct_access (struct block_device
*bdev
, sector_t secnum
,
637 void **kaddr
, unsigned long *pfn
)
639 struct dcssblk_dev_info
*dev_info
;
642 dev_info
= bdev
->bd_disk
->private_data
;
645 if (secnum
% (PAGE_SIZE
/512))
647 pgoff
= secnum
/ (PAGE_SIZE
/ 512);
648 if ((pgoff
+1)*PAGE_SIZE
-1 > dev_info
->end
- dev_info
->start
)
650 *kaddr
= (void *) (dev_info
->start
+pgoff
*PAGE_SIZE
);
651 *pfn
= virt_to_phys(*kaddr
) >> PAGE_SHIFT
;
657 dcssblk_check_params(void)
661 struct dcssblk_dev_info
*dev_info
;
663 for (i
= 0; (i
< DCSSBLK_PARM_LEN
) && (dcssblk_segments
[i
] != '\0');
665 for (j
= i
; (dcssblk_segments
[j
] != ',') &&
666 (dcssblk_segments
[j
] != '\0') &&
667 (dcssblk_segments
[j
] != '(') &&
670 buf
[j
-i
] = dcssblk_segments
[j
];
673 rc
= dcssblk_add_store(dcssblk_root_dev
, NULL
, buf
, j
-i
);
674 if ((rc
>= 0) && (dcssblk_segments
[j
] == '(')) {
675 for (k
= 0; buf
[k
] != '\0'; k
++)
676 buf
[k
] = toupper(buf
[k
]);
677 if (!strncmp(&dcssblk_segments
[j
], "(local)", 7)) {
678 down_read(&dcssblk_devices_sem
);
679 dev_info
= dcssblk_get_device_by_name(buf
);
680 up_read(&dcssblk_devices_sem
);
682 dcssblk_shared_store(&dev_info
->dev
,
686 while ((dcssblk_segments
[j
] != ',') &&
687 (dcssblk_segments
[j
] != '\0'))
691 if (dcssblk_segments
[j
] == '\0')
698 * The init/exit functions.
703 s390_root_dev_unregister(dcssblk_root_dev
);
704 unregister_blkdev(dcssblk_major
, DCSSBLK_NAME
);
712 dcssblk_root_dev
= s390_root_dev_register("dcssblk");
713 if (IS_ERR(dcssblk_root_dev
))
714 return PTR_ERR(dcssblk_root_dev
);
715 rc
= device_create_file(dcssblk_root_dev
, &dev_attr_add
);
717 s390_root_dev_unregister(dcssblk_root_dev
);
720 rc
= device_create_file(dcssblk_root_dev
, &dev_attr_remove
);
722 s390_root_dev_unregister(dcssblk_root_dev
);
725 rc
= register_blkdev(0, DCSSBLK_NAME
);
727 s390_root_dev_unregister(dcssblk_root_dev
);
731 init_rwsem(&dcssblk_devices_sem
);
733 dcssblk_check_params();
738 module_init(dcssblk_init
);
739 module_exit(dcssblk_exit
);
741 module_param_string(segments
, dcssblk_segments
, DCSSBLK_PARM_LEN
, 0444);
742 MODULE_PARM_DESC(segments
, "Name of DCSS segment(s) to be loaded, "
743 "comma-separated list, each name max. 8 chars.\n"
744 "Adding \"(local)\" to segment name equals echoing 0 to "
745 "/sys/devices/dcssblk/<segment name>/shared after loading "
747 "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
749 MODULE_LICENSE("GPL");