1 // SPDX-License-Identifier: GPL-2.0
3 * dcssblk.c -- the S/390 block driver for dcss memory
5 * Authors: Carsten Otte, Stefan Weinhuber, Gerald Schaefer
8 #define KMSG_COMPONENT "dcssblk"
9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
11 #include <linux/module.h>
12 #include <linux/moduleparam.h>
13 #include <linux/ctype.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/slab.h>
17 #include <linux/blkdev.h>
18 #include <linux/completion.h>
19 #include <linux/interrupt.h>
20 #include <linux/pfn_t.h>
21 #include <linux/uio.h>
22 #include <linux/dax.h>
24 #include <asm/extmem.h>
26 #define DCSSBLK_NAME "dcssblk"
27 #define DCSSBLK_MINORS_PER_DISK 1
28 #define DCSSBLK_PARM_LEN 400
29 #define DCSS_BUS_ID_SIZE 20
31 static int dcssblk_open(struct gendisk *disk, blk_mode_t mode);
32 static void dcssblk_release(struct gendisk *disk);
33 static void dcssblk_submit_bio(struct bio *bio);
34 static long dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
35 long nr_pages, enum dax_access_mode mode, void **kaddr,
38 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
40 static int dcssblk_major;
41 static const struct block_device_operations dcssblk_devops = {
43 .submit_bio = dcssblk_submit_bio,
45 .release = dcssblk_release,
48 static int dcssblk_dax_zero_page_range(struct dax_device *dax_dev,
49 pgoff_t pgoff, size_t nr_pages)
54 rc = dax_direct_access(dax_dev, pgoff, nr_pages, DAX_ACCESS,
57 return dax_mem2blk_err(rc);
59 memset(kaddr, 0, nr_pages << PAGE_SHIFT);
60 dax_flush(dax_dev, kaddr, nr_pages << PAGE_SHIFT);
64 static const struct dax_operations dcssblk_dax_ops = {
65 .direct_access = dcssblk_dax_direct_access,
66 .zero_page_range = dcssblk_dax_zero_page_range,
69 struct dcssblk_dev_info {
72 char segment_name[DCSS_BUS_ID_SIZE];
78 unsigned char save_pending;
79 unsigned char is_shared;
81 struct list_head seg_list;
82 struct dax_device *dax_dev;
87 char segment_name[DCSS_BUS_ID_SIZE];
93 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
95 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
98 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
99 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
101 static struct device *dcssblk_root_dev;
103 static LIST_HEAD(dcssblk_devices);
104 static struct rw_semaphore dcssblk_devices_sem;
107 * release function for segment device.
110 dcssblk_release_segment(struct device *dev)
112 struct dcssblk_dev_info *dev_info;
113 struct segment_info *entry, *temp;
115 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
116 list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) {
117 list_del(&entry->lh);
121 module_put(THIS_MODULE);
125 * get a minor number. needs to be called with
126 * down_write(&dcssblk_devices_sem) and the
127 * device needs to be enqueued before the semaphore is
131 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
134 struct dcssblk_dev_info *entry;
136 if (dev_info == NULL)
138 for (minor = 0; minor < (1<<MINORBITS); minor++) {
140 // test if minor available
141 list_for_each_entry(entry, &dcssblk_devices, lh)
142 if (minor == entry->gd->first_minor)
144 if (!found) break; // got unused minor
148 dev_info->gd->first_minor = minor;
153 * get the struct dcssblk_dev_info from dcssblk_devices
154 * for the given name.
155 * down_read(&dcssblk_devices_sem) must be held.
157 static struct dcssblk_dev_info *
158 dcssblk_get_device_by_name(char *name)
160 struct dcssblk_dev_info *entry;
162 list_for_each_entry(entry, &dcssblk_devices, lh) {
163 if (!strcmp(name, entry->segment_name)) {
171 * get the struct segment_info from seg_list
172 * for the given name.
173 * down_read(&dcssblk_devices_sem) must be held.
175 static struct segment_info *
176 dcssblk_get_segment_by_name(char *name)
178 struct dcssblk_dev_info *dev_info;
179 struct segment_info *entry;
181 list_for_each_entry(dev_info, &dcssblk_devices, lh) {
182 list_for_each_entry(entry, &dev_info->seg_list, lh) {
183 if (!strcmp(name, entry->segment_name))
191 * get the highest address of the multi-segment block.
194 dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info)
196 unsigned long highest_addr;
197 struct segment_info *entry;
200 list_for_each_entry(entry, &dev_info->seg_list, lh) {
201 if (highest_addr < entry->end)
202 highest_addr = entry->end;
208 * get the lowest address of the multi-segment block.
211 dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info)
214 unsigned long lowest_addr;
215 struct segment_info *entry;
219 list_for_each_entry(entry, &dev_info->seg_list, lh) {
220 if (set_first == 0) {
221 lowest_addr = entry->start;
224 if (lowest_addr > entry->start)
225 lowest_addr = entry->start;
232 * Check continuity of segments.
235 dcssblk_is_continuous(struct dcssblk_dev_info *dev_info)
238 struct segment_info *sort_list, *entry, temp;
240 if (dev_info->num_of_segments <= 1)
243 sort_list = kcalloc(dev_info->num_of_segments,
244 sizeof(struct segment_info),
246 if (sort_list == NULL)
249 list_for_each_entry(entry, &dev_info->seg_list, lh) {
250 memcpy(&sort_list[i], entry, sizeof(struct segment_info));
255 for (i = 0; i < dev_info->num_of_segments; i++)
256 for (j = 0; j < dev_info->num_of_segments; j++)
257 if (sort_list[j].start > sort_list[i].start) {
258 memcpy(&temp, &sort_list[i],
259 sizeof(struct segment_info));
260 memcpy(&sort_list[i], &sort_list[j],
261 sizeof(struct segment_info));
262 memcpy(&sort_list[j], &temp,
263 sizeof(struct segment_info));
266 /* check continuity */
267 for (i = 0; i < dev_info->num_of_segments - 1; i++) {
268 if ((sort_list[i].end + 1) != sort_list[i+1].start) {
269 pr_err("Adjacent DCSSs %s and %s are not "
270 "contiguous\n", sort_list[i].segment_name,
271 sort_list[i+1].segment_name);
275 /* EN and EW are allowed in a block device */
276 if (sort_list[i].segment_type != sort_list[i+1].segment_type) {
277 if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) ||
278 (sort_list[i].segment_type == SEG_TYPE_ER) ||
279 !(sort_list[i+1].segment_type &
280 SEGMENT_EXCLUSIVE) ||
281 (sort_list[i+1].segment_type == SEG_TYPE_ER)) {
282 pr_err("DCSS %s and DCSS %s have "
283 "incompatible types\n",
284 sort_list[i].segment_name,
285 sort_list[i+1].segment_name);
301 dcssblk_load_segment(char *name, struct segment_info **seg_info)
305 /* already loaded? */
306 down_read(&dcssblk_devices_sem);
307 *seg_info = dcssblk_get_segment_by_name(name);
308 up_read(&dcssblk_devices_sem);
309 if (*seg_info != NULL)
312 /* get a struct segment_info */
313 *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL);
314 if (*seg_info == NULL)
317 strcpy((*seg_info)->segment_name, name);
319 /* load the segment */
320 rc = segment_load(name, SEGMENT_SHARED,
321 &(*seg_info)->start, &(*seg_info)->end);
323 segment_warning(rc, (*seg_info)->segment_name);
326 INIT_LIST_HEAD(&(*seg_info)->lh);
327 (*seg_info)->segment_type = rc;
333 * device attribute for switching shared/nonshared (exclusive)
334 * operation (show + store)
337 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
339 struct dcssblk_dev_info *dev_info;
341 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
342 return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
346 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
348 struct dcssblk_dev_info *dev_info;
349 struct segment_info *entry, *temp;
352 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
354 down_write(&dcssblk_devices_sem);
355 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
356 if (atomic_read(&dev_info->use_count)) {
360 if (inbuf[0] == '1') {
361 /* reload segments in shared mode */
362 list_for_each_entry(entry, &dev_info->seg_list, lh) {
363 rc = segment_modify_shared(entry->segment_name,
366 BUG_ON(rc == -EINVAL);
371 dev_info->is_shared = 1;
372 switch (dev_info->segment_type) {
376 set_disk_ro(dev_info->gd, 1);
378 } else if (inbuf[0] == '0') {
379 /* reload segments in exclusive mode */
380 if (dev_info->segment_type == SEG_TYPE_SC) {
381 pr_err("DCSS %s is of type SC and cannot be "
382 "loaded as exclusive-writable\n",
383 dev_info->segment_name);
387 list_for_each_entry(entry, &dev_info->seg_list, lh) {
388 rc = segment_modify_shared(entry->segment_name,
391 BUG_ON(rc == -EINVAL);
396 dev_info->is_shared = 0;
397 set_disk_ro(dev_info->gd, 0);
406 pr_err("DCSS device %s is removed after a failed access mode "
407 "change\n", dev_info->segment_name);
409 list_for_each_entry(entry, &dev_info->seg_list, lh) {
411 segment_unload(entry->segment_name);
413 list_del(&dev_info->lh);
414 up_write(&dcssblk_devices_sem);
416 dax_remove_host(dev_info->gd);
417 kill_dax(dev_info->dax_dev);
418 put_dax(dev_info->dax_dev);
419 del_gendisk(dev_info->gd);
420 put_disk(dev_info->gd);
422 if (device_remove_file_self(dev, attr)) {
423 device_unregister(dev);
428 up_write(&dcssblk_devices_sem);
431 static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
432 dcssblk_shared_store);
435 * device attribute for save operation on current copy
436 * of the segment. If the segment is busy, saving will
437 * become pending until it gets released, which can be
438 * undone by storing a non-true value to this entry.
442 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
444 struct dcssblk_dev_info *dev_info;
446 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
447 return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
451 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
453 struct dcssblk_dev_info *dev_info;
454 struct segment_info *entry;
456 if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
458 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
460 down_write(&dcssblk_devices_sem);
461 if (inbuf[0] == '1') {
462 if (atomic_read(&dev_info->use_count) == 0) {
463 // device is idle => we save immediately
464 pr_info("All DCSSs that map to device %s are "
465 "saved\n", dev_info->segment_name);
466 list_for_each_entry(entry, &dev_info->seg_list, lh) {
467 if (entry->segment_type == SEG_TYPE_EN ||
468 entry->segment_type == SEG_TYPE_SN)
469 pr_warn("DCSS %s is of type SN or EN"
470 " and cannot be saved\n",
471 entry->segment_name);
473 segment_save(entry->segment_name);
476 // device is busy => we save it when it becomes
477 // idle in dcssblk_release
478 pr_info("Device %s is in use, its DCSSs will be "
479 "saved when it becomes idle\n",
480 dev_info->segment_name);
481 dev_info->save_pending = 1;
483 } else if (inbuf[0] == '0') {
484 if (dev_info->save_pending) {
485 // device is busy & the user wants to undo his save
487 dev_info->save_pending = 0;
488 pr_info("A pending save request for device %s "
489 "has been canceled\n",
490 dev_info->segment_name);
493 up_write(&dcssblk_devices_sem);
496 up_write(&dcssblk_devices_sem);
499 static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
503 * device attribute for showing all segments in a device
506 dcssblk_seglist_show(struct device *dev, struct device_attribute *attr,
511 struct dcssblk_dev_info *dev_info;
512 struct segment_info *entry;
514 down_read(&dcssblk_devices_sem);
515 dev_info = container_of(dev, struct dcssblk_dev_info, dev);
518 list_for_each_entry(entry, &dev_info->seg_list, lh) {
519 strcpy(&buf[i], entry->segment_name);
520 i += strlen(entry->segment_name);
524 up_read(&dcssblk_devices_sem);
527 static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);
529 static struct attribute *dcssblk_dev_attrs[] = {
530 &dev_attr_shared.attr,
532 &dev_attr_seglist.attr,
535 static struct attribute_group dcssblk_dev_attr_group = {
536 .attrs = dcssblk_dev_attrs,
538 static const struct attribute_group *dcssblk_dev_attr_groups[] = {
539 &dcssblk_dev_attr_group,
544 * device attribute for adding devices
547 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
549 struct queue_limits lim = {
550 .logical_block_size = 4096,
552 int rc, i, j, num_of_segments;
553 struct dcssblk_dev_info *dev_info;
554 struct segment_info *seg_info, *temp;
556 unsigned long seg_byte_size;
560 if (dev != dcssblk_root_dev) {
564 if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) {
569 local_buf = kmalloc(count + 1, GFP_KERNEL);
570 if (local_buf == NULL) {
579 for (i = 0; (i < count && (buf[i] != '\0') && (buf[i] != '\n')); i++) {
580 for (j = i; j < count &&
583 (buf[j] != '\n'); j++) {
584 local_buf[j-i] = toupper(buf[j]);
586 local_buf[j-i] = '\0';
587 if (((j - i) == 0) || ((j - i) > 8)) {
592 rc = dcssblk_load_segment(local_buf, &seg_info);
596 * get a struct dcssblk_dev_info
598 if (num_of_segments == 0) {
599 dev_info = kzalloc(sizeof(struct dcssblk_dev_info),
601 if (dev_info == NULL) {
605 strcpy(dev_info->segment_name, local_buf);
606 dev_info->segment_type = seg_info->segment_type;
607 INIT_LIST_HEAD(&dev_info->seg_list);
609 list_add_tail(&seg_info->lh, &dev_info->seg_list);
613 if ((buf[j] == '\0') || (buf[j] == '\n'))
617 /* no trailing colon at the end of the input */
618 if ((i > 0) && (buf[i-1] == ':')) {
622 strscpy(local_buf, buf, i + 1);
623 dev_info->num_of_segments = num_of_segments;
624 rc = dcssblk_is_continuous(dev_info);
628 dev_info->start = dcssblk_find_lowest_addr(dev_info);
629 dev_info->end = dcssblk_find_highest_addr(dev_info);
631 dev_set_name(&dev_info->dev, "%s", dev_info->segment_name);
632 dev_info->dev.release = dcssblk_release_segment;
633 dev_info->dev.groups = dcssblk_dev_attr_groups;
634 INIT_LIST_HEAD(&dev_info->lh);
635 dev_info->gd = blk_alloc_disk(&lim, NUMA_NO_NODE);
636 if (IS_ERR(dev_info->gd)) {
637 rc = PTR_ERR(dev_info->gd);
640 dev_info->gd->major = dcssblk_major;
641 dev_info->gd->minors = DCSSBLK_MINORS_PER_DISK;
642 dev_info->gd->fops = &dcssblk_devops;
643 dev_info->gd->private_data = dev_info;
644 dev_info->gd->flags |= GENHD_FL_NO_PART;
645 blk_queue_flag_set(QUEUE_FLAG_DAX, dev_info->gd->queue);
647 seg_byte_size = (dev_info->end - dev_info->start + 1);
648 set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
649 pr_info("Loaded %s with total size %lu bytes and capacity %lu "
650 "sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9);
652 dev_info->save_pending = 0;
653 dev_info->is_shared = 1;
654 dev_info->dev.parent = dcssblk_root_dev;
657 *get minor, add to list
659 down_write(&dcssblk_devices_sem);
660 if (dcssblk_get_segment_by_name(local_buf)) {
664 rc = dcssblk_assign_free_minor(dev_info);
667 sprintf(dev_info->gd->disk_name, "dcssblk%d",
668 dev_info->gd->first_minor);
669 list_add_tail(&dev_info->lh, &dcssblk_devices);
671 if (!try_module_get(THIS_MODULE)) {
676 * register the device
678 rc = device_register(&dev_info->dev);
682 dev_info->dax_dev = alloc_dax(dev_info, &dcssblk_dax_ops);
683 if (IS_ERR(dev_info->dax_dev)) {
684 rc = PTR_ERR(dev_info->dax_dev);
685 dev_info->dax_dev = NULL;
688 set_dax_synchronous(dev_info->dax_dev);
689 rc = dax_add_host(dev_info->dax_dev, dev_info->gd);
693 get_device(&dev_info->dev);
694 rc = device_add_disk(&dev_info->dev, dev_info->gd, NULL);
698 switch (dev_info->segment_type) {
702 set_disk_ro(dev_info->gd,1);
705 set_disk_ro(dev_info->gd,0);
708 up_write(&dcssblk_devices_sem);
713 put_device(&dev_info->dev);
714 dax_remove_host(dev_info->gd);
716 kill_dax(dev_info->dax_dev);
717 put_dax(dev_info->dax_dev);
719 list_del(&dev_info->lh);
720 put_disk(dev_info->gd);
721 list_for_each_entry(seg_info, &dev_info->seg_list, lh) {
722 segment_unload(seg_info->segment_name);
724 put_device(&dev_info->dev);
725 up_write(&dcssblk_devices_sem);
728 list_del(&dev_info->lh);
730 put_disk(dev_info->gd);
731 up_write(&dcssblk_devices_sem);
733 if (dev_info == NULL)
735 list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) {
736 list_del(&seg_info->lh);
737 segment_unload(seg_info->segment_name);
748 * device attribute for removing devices
751 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
753 struct dcssblk_dev_info *dev_info;
754 struct segment_info *entry;
758 if (dev != dcssblk_root_dev) {
761 local_buf = kmalloc(count + 1, GFP_KERNEL);
762 if (local_buf == NULL) {
768 for (i = 0; (i < count && (*(buf+i)!='\0') && (*(buf+i)!='\n')); i++) {
769 local_buf[i] = toupper(buf[i]);
772 if ((i == 0) || (i > 8)) {
777 down_write(&dcssblk_devices_sem);
778 dev_info = dcssblk_get_device_by_name(local_buf);
779 if (dev_info == NULL) {
780 up_write(&dcssblk_devices_sem);
781 pr_warn("Device %s cannot be removed because it is not a known device\n",
786 if (atomic_read(&dev_info->use_count) != 0) {
787 up_write(&dcssblk_devices_sem);
788 pr_warn("Device %s cannot be removed while it is in use\n",
794 list_del(&dev_info->lh);
795 /* unload all related segments */
796 list_for_each_entry(entry, &dev_info->seg_list, lh)
797 segment_unload(entry->segment_name);
798 up_write(&dcssblk_devices_sem);
800 dax_remove_host(dev_info->gd);
801 kill_dax(dev_info->dax_dev);
802 put_dax(dev_info->dax_dev);
803 del_gendisk(dev_info->gd);
804 put_disk(dev_info->gd);
806 device_unregister(&dev_info->dev);
807 put_device(&dev_info->dev);
816 dcssblk_open(struct gendisk *disk, blk_mode_t mode)
818 struct dcssblk_dev_info *dev_info = disk->private_data;
821 if (NULL == dev_info) {
825 atomic_inc(&dev_info->use_count);
832 dcssblk_release(struct gendisk *disk)
834 struct dcssblk_dev_info *dev_info = disk->private_data;
835 struct segment_info *entry;
841 down_write(&dcssblk_devices_sem);
842 if (atomic_dec_and_test(&dev_info->use_count)
843 && (dev_info->save_pending)) {
844 pr_info("Device %s has become idle and is being saved "
845 "now\n", dev_info->segment_name);
846 list_for_each_entry(entry, &dev_info->seg_list, lh) {
847 if (entry->segment_type == SEG_TYPE_EN ||
848 entry->segment_type == SEG_TYPE_SN)
849 pr_warn("DCSS %s is of type SN or EN and cannot"
850 " be saved\n", entry->segment_name);
852 segment_save(entry->segment_name);
854 dev_info->save_pending = 0;
856 up_write(&dcssblk_devices_sem);
860 dcssblk_submit_bio(struct bio *bio)
862 struct dcssblk_dev_info *dev_info;
864 struct bvec_iter iter;
867 unsigned long source_addr;
868 unsigned long bytes_done;
871 dev_info = bio->bi_bdev->bd_disk->private_data;
872 if (dev_info == NULL)
874 if (!IS_ALIGNED(bio->bi_iter.bi_sector, 8) ||
875 !IS_ALIGNED(bio->bi_iter.bi_size, PAGE_SIZE))
876 /* Request is not page-aligned. */
878 /* verify data transfer direction */
879 if (dev_info->is_shared) {
880 switch (dev_info->segment_type) {
884 /* cannot write to these segments */
885 if (bio_data_dir(bio) == WRITE) {
886 pr_warn("Writing to %s failed because it is a read-only device\n",
887 dev_name(&dev_info->dev));
893 index = (bio->bi_iter.bi_sector >> 3);
894 bio_for_each_segment(bvec, bio, iter) {
895 page_addr = bvec_virt(&bvec);
896 source_addr = dev_info->start + (index<<12) + bytes_done;
897 if (unlikely(!IS_ALIGNED((unsigned long)page_addr, PAGE_SIZE) ||
898 !IS_ALIGNED(bvec.bv_len, PAGE_SIZE)))
901 if (bio_data_dir(bio) == READ)
902 memcpy(page_addr, __va(source_addr), bvec.bv_len);
904 memcpy(__va(source_addr), page_addr, bvec.bv_len);
905 bytes_done += bvec.bv_len;
914 __dcssblk_direct_access(struct dcssblk_dev_info *dev_info, pgoff_t pgoff,
915 long nr_pages, void **kaddr, pfn_t *pfn)
917 resource_size_t offset = pgoff * PAGE_SIZE;
918 unsigned long dev_sz;
920 dev_sz = dev_info->end - dev_info->start + 1;
922 *kaddr = (void *) dev_info->start + offset;
924 *pfn = __pfn_to_pfn_t(PFN_DOWN(dev_info->start + offset),
925 PFN_DEV|PFN_SPECIAL);
927 return (dev_sz - offset) / PAGE_SIZE;
931 dcssblk_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
932 long nr_pages, enum dax_access_mode mode, void **kaddr,
935 struct dcssblk_dev_info *dev_info = dax_get_private(dax_dev);
937 return __dcssblk_direct_access(dev_info, pgoff, nr_pages, kaddr, pfn);
941 dcssblk_check_params(void)
944 char buf[DCSSBLK_PARM_LEN + 1];
945 struct dcssblk_dev_info *dev_info;
947 for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
949 for (j = i; (j < DCSSBLK_PARM_LEN) &&
950 (dcssblk_segments[j] != ',') &&
951 (dcssblk_segments[j] != '\0') &&
952 (dcssblk_segments[j] != '('); j++)
954 buf[j-i] = dcssblk_segments[j];
957 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
958 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
959 for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
960 buf[k] = toupper(buf[k]);
962 if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
963 down_read(&dcssblk_devices_sem);
964 dev_info = dcssblk_get_device_by_name(buf);
965 up_read(&dcssblk_devices_sem);
967 dcssblk_shared_store(&dev_info->dev,
971 while ((dcssblk_segments[j] != ',') &&
972 (dcssblk_segments[j] != '\0'))
976 if (dcssblk_segments[j] == '\0')
983 * The init/exit functions.
988 root_device_unregister(dcssblk_root_dev);
989 unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
997 dcssblk_root_dev = root_device_register("dcssblk");
998 if (IS_ERR(dcssblk_root_dev))
999 return PTR_ERR(dcssblk_root_dev);
1000 rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
1003 rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
1006 rc = register_blkdev(0, DCSSBLK_NAME);
1010 init_rwsem(&dcssblk_devices_sem);
1012 dcssblk_check_params();
1016 root_device_unregister(dcssblk_root_dev);
1021 module_init(dcssblk_init);
1022 module_exit(dcssblk_exit);
1024 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
1025 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
1026 "comma-separated list, names in each set separated "
1027 "by commas are separated by colons, each set contains "
1028 "names of contiguous segments and each name max. 8 chars.\n"
1029 "Adding \"(local)\" to the end of each set equals echoing 0 "
1030 "to /sys/devices/dcssblk/<device name>/shared after loading "
1031 "the contiguous segments - \n"
1032 "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
1034 MODULE_LICENSE("GPL");