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
,
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
== entry
->gd
->first_minor
)
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
)) {
146 * print appropriate error message for segment_load()/segment_type()
150 dcssblk_segment_warn(int rc
, char* seg_name
)
154 PRINT_WARN("cannot load/query segment %s, does not exist\n",
158 PRINT_WARN("cannot load/query segment %s, not running on VM\n",
162 PRINT_WARN("cannot load/query segment %s, hardware error\n",
166 PRINT_WARN("cannot load/query segment %s, is a multi-part "
167 "segment\n", seg_name
);
170 PRINT_WARN("cannot load/query segment %s, overlaps with "
171 "storage\n", seg_name
);
174 PRINT_WARN("cannot load/query segment %s, overlaps with "
175 "already loaded dcss\n", seg_name
);
178 PRINT_WARN("cannot load/query segment %s, already loaded in "
179 "incompatible mode\n", seg_name
);
182 PRINT_WARN("cannot load/query segment %s, out of memory\n",
186 PRINT_WARN("cannot load/query segment %s, exceeds kernel "
187 "mapping range\n", seg_name
);
190 PRINT_WARN("cannot load/query segment %s, return value %i\n",
196 static void dcssblk_unregister_callback(struct device
*dev
)
198 device_unregister(dev
);
203 * device attribute for switching shared/nonshared (exclusive)
204 * operation (show + store)
207 dcssblk_shared_show(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
209 struct dcssblk_dev_info
*dev_info
;
211 dev_info
= container_of(dev
, struct dcssblk_dev_info
, dev
);
212 return sprintf(buf
, dev_info
->is_shared
? "1\n" : "0\n");
216 dcssblk_shared_store(struct device
*dev
, struct device_attribute
*attr
, const char *inbuf
, size_t count
)
218 struct dcssblk_dev_info
*dev_info
;
221 if ((count
> 1) && (inbuf
[1] != '\n') && (inbuf
[1] != '\0')) {
222 PRINT_WARN("Invalid value, must be 0 or 1\n");
225 down_write(&dcssblk_devices_sem
);
226 dev_info
= container_of(dev
, struct dcssblk_dev_info
, dev
);
227 if (atomic_read(&dev_info
->use_count
)) {
228 PRINT_ERR("share: segment %s is busy!\n",
229 dev_info
->segment_name
);
233 if (inbuf
[0] == '1') {
234 // reload segment in shared mode
235 rc
= segment_modify_shared(dev_info
->segment_name
,
238 BUG_ON(rc
== -EINVAL
);
242 dev_info
->is_shared
= 1;
243 switch (dev_info
->segment_type
) {
247 set_disk_ro(dev_info
->gd
,1);
250 } else if (inbuf
[0] == '0') {
251 // reload segment in exclusive mode
252 if (dev_info
->segment_type
== SEG_TYPE_SC
) {
253 PRINT_ERR("Segment type SC (%s) cannot be loaded in "
254 "non-shared mode\n", dev_info
->segment_name
);
258 rc
= segment_modify_shared(dev_info
->segment_name
,
261 BUG_ON(rc
== -EINVAL
);
265 dev_info
->is_shared
= 0;
266 set_disk_ro(dev_info
->gd
, 0);
269 PRINT_WARN("Invalid value, must be 0 or 1\n");
277 PRINT_ERR("Could not reload segment %s, removing it now!\n",
278 dev_info
->segment_name
);
279 list_del(&dev_info
->lh
);
281 del_gendisk(dev_info
->gd
);
282 blk_cleanup_queue(dev_info
->dcssblk_queue
);
283 dev_info
->gd
->queue
= NULL
;
284 put_disk(dev_info
->gd
);
285 rc
= device_schedule_callback(dev
, dcssblk_unregister_callback
);
287 up_write(&dcssblk_devices_sem
);
292 * device attribute for save operation on current copy
293 * of the segment. If the segment is busy, saving will
294 * become pending until it gets released, which can be
295 * undone by storing a non-true value to this entry.
299 dcssblk_save_show(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
301 struct dcssblk_dev_info
*dev_info
;
303 dev_info
= container_of(dev
, struct dcssblk_dev_info
, dev
);
304 return sprintf(buf
, dev_info
->save_pending
? "1\n" : "0\n");
308 dcssblk_save_store(struct device
*dev
, struct device_attribute
*attr
, const char *inbuf
, size_t count
)
310 struct dcssblk_dev_info
*dev_info
;
312 if ((count
> 1) && (inbuf
[1] != '\n') && (inbuf
[1] != '\0')) {
313 PRINT_WARN("Invalid value, must be 0 or 1\n");
316 dev_info
= container_of(dev
, struct dcssblk_dev_info
, dev
);
318 down_write(&dcssblk_devices_sem
);
319 if (inbuf
[0] == '1') {
320 if (atomic_read(&dev_info
->use_count
) == 0) {
321 // device is idle => we save immediately
322 PRINT_INFO("Saving segment %s\n",
323 dev_info
->segment_name
);
324 segment_save(dev_info
->segment_name
);
326 // device is busy => we save it when it becomes
327 // idle in dcssblk_release
328 PRINT_INFO("Segment %s is currently busy, it will "
329 "be saved when it becomes idle...\n",
330 dev_info
->segment_name
);
331 dev_info
->save_pending
= 1;
333 } else if (inbuf
[0] == '0') {
334 if (dev_info
->save_pending
) {
335 // device is busy & the user wants to undo his save
337 dev_info
->save_pending
= 0;
338 PRINT_INFO("Pending save for segment %s deactivated\n",
339 dev_info
->segment_name
);
342 up_write(&dcssblk_devices_sem
);
343 PRINT_WARN("Invalid value, must be 0 or 1\n");
346 up_write(&dcssblk_devices_sem
);
351 * device attribute for adding devices
354 dcssblk_add_store(struct device
*dev
, struct device_attribute
*attr
, const char *buf
, size_t count
)
357 struct dcssblk_dev_info
*dev_info
;
359 unsigned long seg_byte_size
;
362 if (dev
!= dcssblk_root_dev
) {
366 local_buf
= kmalloc(count
+ 1, GFP_KERNEL
);
367 if (local_buf
== NULL
) {
374 for (i
= 0; ((buf
[i
] != '\0') && (buf
[i
] != '\n') && i
< count
); i
++) {
375 local_buf
[i
] = toupper(buf
[i
]);
378 if ((i
== 0) || (i
> 8)) {
385 down_read(&dcssblk_devices_sem
);
386 dev_info
= dcssblk_get_device_by_name(local_buf
);
387 up_read(&dcssblk_devices_sem
);
388 if (dev_info
!= NULL
) {
389 PRINT_WARN("Segment %s already loaded!\n", local_buf
);
394 * get a struct dcssblk_dev_info
396 dev_info
= kzalloc(sizeof(struct dcssblk_dev_info
), GFP_KERNEL
);
397 if (dev_info
== NULL
) {
402 strcpy(dev_info
->segment_name
, local_buf
);
403 strlcpy(dev_info
->dev
.bus_id
, local_buf
, BUS_ID_SIZE
);
404 dev_info
->dev
.release
= dcssblk_release_segment
;
405 INIT_LIST_HEAD(&dev_info
->lh
);
407 dev_info
->gd
= alloc_disk(DCSSBLK_MINORS_PER_DISK
);
408 if (dev_info
->gd
== NULL
) {
412 dev_info
->gd
->major
= dcssblk_major
;
413 dev_info
->gd
->fops
= &dcssblk_devops
;
414 dev_info
->dcssblk_queue
= blk_alloc_queue(GFP_KERNEL
);
415 dev_info
->gd
->queue
= dev_info
->dcssblk_queue
;
416 dev_info
->gd
->private_data
= dev_info
;
417 dev_info
->gd
->driverfs_dev
= &dev_info
->dev
;
418 blk_queue_make_request(dev_info
->dcssblk_queue
, dcssblk_make_request
);
419 blk_queue_hardsect_size(dev_info
->dcssblk_queue
, 4096);
423 rc
= segment_load(local_buf
, SEGMENT_SHARED
,
424 &dev_info
->start
, &dev_info
->end
);
426 dcssblk_segment_warn(rc
, dev_info
->segment_name
);
427 goto dealloc_gendisk
;
429 seg_byte_size
= (dev_info
->end
- dev_info
->start
+ 1);
430 set_capacity(dev_info
->gd
, seg_byte_size
>> 9); // size in sectors
431 PRINT_INFO("Loaded segment %s, size = %lu Byte, "
432 "capacity = %lu (512 Byte) sectors\n", local_buf
,
433 seg_byte_size
, seg_byte_size
>> 9);
435 dev_info
->segment_type
= rc
;
436 dev_info
->save_pending
= 0;
437 dev_info
->is_shared
= 1;
438 dev_info
->dev
.parent
= dcssblk_root_dev
;
441 * get minor, add to list
443 down_write(&dcssblk_devices_sem
);
444 rc
= dcssblk_assign_free_minor(dev_info
);
446 up_write(&dcssblk_devices_sem
);
447 PRINT_ERR("No free minor number available! "
448 "Unloading segment...\n");
451 sprintf(dev_info
->gd
->disk_name
, "dcssblk%d",
452 dev_info
->gd
->first_minor
);
453 list_add_tail(&dev_info
->lh
, &dcssblk_devices
);
455 if (!try_module_get(THIS_MODULE
)) {
460 * register the device
462 rc
= device_register(&dev_info
->dev
);
464 PRINT_ERR("Segment %s could not be registered RC=%d\n",
466 module_put(THIS_MODULE
);
469 get_device(&dev_info
->dev
);
470 rc
= device_create_file(&dev_info
->dev
, &dev_attr_shared
);
473 rc
= device_create_file(&dev_info
->dev
, &dev_attr_save
);
477 add_disk(dev_info
->gd
);
479 switch (dev_info
->segment_type
) {
483 set_disk_ro(dev_info
->gd
,1);
486 set_disk_ro(dev_info
->gd
,0);
489 PRINT_DEBUG("Segment %s loaded successfully\n", local_buf
);
490 up_write(&dcssblk_devices_sem
);
495 PRINT_ERR("device_create_file() failed!\n");
496 list_del(&dev_info
->lh
);
497 blk_cleanup_queue(dev_info
->dcssblk_queue
);
498 dev_info
->gd
->queue
= NULL
;
499 put_disk(dev_info
->gd
);
500 device_unregister(&dev_info
->dev
);
501 segment_unload(dev_info
->segment_name
);
502 put_device(&dev_info
->dev
);
503 up_write(&dcssblk_devices_sem
);
506 list_del(&dev_info
->lh
);
507 up_write(&dcssblk_devices_sem
);
509 segment_unload(local_buf
);
511 blk_cleanup_queue(dev_info
->dcssblk_queue
);
512 dev_info
->gd
->queue
= NULL
;
513 put_disk(dev_info
->gd
);
523 * device attribute for removing devices
526 dcssblk_remove_store(struct device
*dev
, struct device_attribute
*attr
, const char *buf
, size_t count
)
528 struct dcssblk_dev_info
*dev_info
;
532 if (dev
!= dcssblk_root_dev
) {
535 local_buf
= kmalloc(count
+ 1, GFP_KERNEL
);
536 if (local_buf
== NULL
) {
542 for (i
= 0; ((*(buf
+i
)!='\0') && (*(buf
+i
)!='\n') && i
< count
); i
++) {
543 local_buf
[i
] = toupper(buf
[i
]);
546 if ((i
== 0) || (i
> 8)) {
551 down_write(&dcssblk_devices_sem
);
552 dev_info
= dcssblk_get_device_by_name(local_buf
);
553 if (dev_info
== NULL
) {
554 up_write(&dcssblk_devices_sem
);
555 PRINT_WARN("Segment %s is not loaded!\n", local_buf
);
559 if (atomic_read(&dev_info
->use_count
) != 0) {
560 up_write(&dcssblk_devices_sem
);
561 PRINT_WARN("Segment %s is in use!\n", local_buf
);
565 list_del(&dev_info
->lh
);
567 del_gendisk(dev_info
->gd
);
568 blk_cleanup_queue(dev_info
->dcssblk_queue
);
569 dev_info
->gd
->queue
= NULL
;
570 put_disk(dev_info
->gd
);
571 device_unregister(&dev_info
->dev
);
572 segment_unload(dev_info
->segment_name
);
573 PRINT_DEBUG("Segment %s unloaded successfully\n",
574 dev_info
->segment_name
);
575 put_device(&dev_info
->dev
);
576 up_write(&dcssblk_devices_sem
);
585 dcssblk_open(struct inode
*inode
, struct file
*filp
)
587 struct dcssblk_dev_info
*dev_info
;
590 dev_info
= inode
->i_bdev
->bd_disk
->private_data
;
591 if (NULL
== dev_info
) {
595 atomic_inc(&dev_info
->use_count
);
596 inode
->i_bdev
->bd_block_size
= 4096;
603 dcssblk_release(struct inode
*inode
, struct file
*filp
)
605 struct dcssblk_dev_info
*dev_info
;
608 dev_info
= inode
->i_bdev
->bd_disk
->private_data
;
609 if (NULL
== dev_info
) {
613 down_write(&dcssblk_devices_sem
);
614 if (atomic_dec_and_test(&dev_info
->use_count
)
615 && (dev_info
->save_pending
)) {
616 PRINT_INFO("Segment %s became idle and is being saved now\n",
617 dev_info
->segment_name
);
618 segment_save(dev_info
->segment_name
);
619 dev_info
->save_pending
= 0;
621 up_write(&dcssblk_devices_sem
);
628 dcssblk_make_request(struct request_queue
*q
, struct bio
*bio
)
630 struct dcssblk_dev_info
*dev_info
;
631 struct bio_vec
*bvec
;
633 unsigned long page_addr
;
634 unsigned long source_addr
;
635 unsigned long bytes_done
;
639 dev_info
= bio
->bi_bdev
->bd_disk
->private_data
;
640 if (dev_info
== NULL
)
642 if ((bio
->bi_sector
& 7) != 0 || (bio
->bi_size
& 4095) != 0)
643 /* Request is not page-aligned. */
645 if (((bio
->bi_size
>> 9) + bio
->bi_sector
)
646 > get_capacity(bio
->bi_bdev
->bd_disk
)) {
647 /* Request beyond end of DCSS segment. */
650 /* verify data transfer direction */
651 if (dev_info
->is_shared
) {
652 switch (dev_info
->segment_type
) {
656 /* cannot write to these segments */
657 if (bio_data_dir(bio
) == WRITE
) {
658 PRINT_WARN("rejecting write to ro segment %s\n", dev_info
->dev
.bus_id
);
664 index
= (bio
->bi_sector
>> 3);
665 bio_for_each_segment(bvec
, bio
, i
) {
666 page_addr
= (unsigned long)
667 page_address(bvec
->bv_page
) + bvec
->bv_offset
;
668 source_addr
= dev_info
->start
+ (index
<<12) + bytes_done
;
669 if (unlikely((page_addr
& 4095) != 0) || (bvec
->bv_len
& 4095) != 0)
672 if (bio_data_dir(bio
) == READ
) {
673 memcpy((void*)page_addr
, (void*)source_addr
,
676 memcpy((void*)source_addr
, (void*)page_addr
,
679 bytes_done
+= bvec
->bv_len
;
689 dcssblk_direct_access (struct block_device
*bdev
, sector_t secnum
,
692 struct dcssblk_dev_info
*dev_info
;
695 dev_info
= bdev
->bd_disk
->private_data
;
698 if (secnum
% (PAGE_SIZE
/512))
700 pgoff
= secnum
/ (PAGE_SIZE
/ 512);
701 if ((pgoff
+1)*PAGE_SIZE
-1 > dev_info
->end
- dev_info
->start
)
703 *data
= (unsigned long) (dev_info
->start
+pgoff
*PAGE_SIZE
);
708 dcssblk_check_params(void)
712 struct dcssblk_dev_info
*dev_info
;
714 for (i
= 0; (i
< DCSSBLK_PARM_LEN
) && (dcssblk_segments
[i
] != '\0');
716 for (j
= i
; (dcssblk_segments
[j
] != ',') &&
717 (dcssblk_segments
[j
] != '\0') &&
718 (dcssblk_segments
[j
] != '(') &&
721 buf
[j
-i
] = dcssblk_segments
[j
];
724 rc
= dcssblk_add_store(dcssblk_root_dev
, NULL
, buf
, j
-i
);
725 if ((rc
>= 0) && (dcssblk_segments
[j
] == '(')) {
726 for (k
= 0; buf
[k
] != '\0'; k
++)
727 buf
[k
] = toupper(buf
[k
]);
728 if (!strncmp(&dcssblk_segments
[j
], "(local)", 7)) {
729 down_read(&dcssblk_devices_sem
);
730 dev_info
= dcssblk_get_device_by_name(buf
);
731 up_read(&dcssblk_devices_sem
);
733 dcssblk_shared_store(&dev_info
->dev
,
737 while ((dcssblk_segments
[j
] != ',') &&
738 (dcssblk_segments
[j
] != '\0'))
742 if (dcssblk_segments
[j
] == '\0')
749 * The init/exit functions.
754 PRINT_DEBUG("DCSSBLOCK EXIT...\n");
755 s390_root_dev_unregister(dcssblk_root_dev
);
756 unregister_blkdev(dcssblk_major
, DCSSBLK_NAME
);
757 PRINT_DEBUG("...finished!\n");
765 PRINT_DEBUG("DCSSBLOCK INIT...\n");
766 dcssblk_root_dev
= s390_root_dev_register("dcssblk");
767 if (IS_ERR(dcssblk_root_dev
)) {
768 PRINT_ERR("device_register() failed!\n");
769 return PTR_ERR(dcssblk_root_dev
);
771 rc
= device_create_file(dcssblk_root_dev
, &dev_attr_add
);
773 PRINT_ERR("device_create_file(add) failed!\n");
774 s390_root_dev_unregister(dcssblk_root_dev
);
777 rc
= device_create_file(dcssblk_root_dev
, &dev_attr_remove
);
779 PRINT_ERR("device_create_file(remove) failed!\n");
780 s390_root_dev_unregister(dcssblk_root_dev
);
783 rc
= register_blkdev(0, DCSSBLK_NAME
);
785 PRINT_ERR("Can't get dynamic major!\n");
786 s390_root_dev_unregister(dcssblk_root_dev
);
790 init_rwsem(&dcssblk_devices_sem
);
792 dcssblk_check_params();
794 PRINT_DEBUG("...finished!\n");
798 module_init(dcssblk_init
);
799 module_exit(dcssblk_exit
);
801 module_param_string(segments
, dcssblk_segments
, DCSSBLK_PARM_LEN
, 0444);
802 MODULE_PARM_DESC(segments
, "Name of DCSS segment(s) to be loaded, "
803 "comma-separated list, each name max. 8 chars.\n"
804 "Adding \"(local)\" to segment name equals echoing 0 to "
805 "/sys/devices/dcssblk/<segment name>/shared after loading "
807 "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
809 MODULE_LICENSE("GPL");