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USB: usbsevseg: fix max length
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / md / persistent-data / dm-btree.c
blobbd1e7ffbe26c750a26a4b9341d925a98acf632b3
1 /*
2 * Copyright (C) 2011 Red Hat, Inc.
3 *
4 * This file is released under the GPL.
5 */
6
7 #include "dm-btree-internal.h"
8 #include "dm-space-map.h"
9 #include "dm-transaction-manager.h"
10
11 #include <linux/export.h>
12 #include <linux/device-mapper.h>
13
14 #define DM_MSG_PREFIX "btree"
15
16 /*----------------------------------------------------------------
17 * Array manipulation
18 *--------------------------------------------------------------*/
19 static void memcpy_disk(void *dest, const void *src, size_t len)
20 __dm_written_to_disk(src)
21 {
22 memcpy(dest, src, len);
23 __dm_unbless_for_disk(src);
24 }
25
26 static void array_insert(void *base, size_t elt_size, unsigned nr_elts,
27 unsigned index, void *elt)
28 __dm_written_to_disk(elt)
29 {
30 if (index < nr_elts)
31 memmove(base + (elt_size * (index + 1)),
32 base + (elt_size * index),
33 (nr_elts - index) * elt_size);
34
35 memcpy_disk(base + (elt_size * index), elt, elt_size);
36 }
37
38 /*----------------------------------------------------------------*/
39
40 /* makes the assumption that no two keys are the same. */
41 static int bsearch(struct node *n, uint64_t key, int want_hi)
42 {
43 int lo = -1, hi = le32_to_cpu(n->header.nr_entries);
44
45 while (hi - lo > 1) {
46 int mid = lo + ((hi - lo) / 2);
47 uint64_t mid_key = le64_to_cpu(n->keys[mid]);
48
49 if (mid_key == key)
50 return mid;
51
52 if (mid_key < key)
53 lo = mid;
54 else
55 hi = mid;
56 }
57
58 return want_hi ? hi : lo;
59 }
60
61 int lower_bound(struct node *n, uint64_t key)
62 {
63 return bsearch(n, key, 0);
64 }
65
66 void inc_children(struct dm_transaction_manager *tm, struct node *n,
67 struct dm_btree_value_type *vt)
68 {
69 unsigned i;
70 uint32_t nr_entries = le32_to_cpu(n->header.nr_entries);
71
72 if (le32_to_cpu(n->header.flags) & INTERNAL_NODE)
73 for (i = 0; i < nr_entries; i++)
74 dm_tm_inc(tm, value64(n, i));
75 else if (vt->inc)
76 for (i = 0; i < nr_entries; i++)
77 vt->inc(vt->context,
78 value_ptr(n, i, vt->size));
79 }
80
81 static int insert_at(size_t value_size, struct node *node, unsigned index,
82 uint64_t key, void *value)
83 __dm_written_to_disk(value)
84 {
85 uint32_t nr_entries = le32_to_cpu(node->header.nr_entries);
86 __le64 key_le = cpu_to_le64(key);
87
88 if (index > nr_entries ||
89 index >= le32_to_cpu(node->header.max_entries)) {
90 DMERR("too many entries in btree node for insert");
91 __dm_unbless_for_disk(value);
92 return -ENOMEM;
93 }
94
95 __dm_bless_for_disk(&key_le);
96
97 array_insert(node->keys, sizeof(*node->keys), nr_entries, index, &key_le);
98 array_insert(value_base(node), value_size, nr_entries, index, value);
99 node->header.nr_entries = cpu_to_le32(nr_entries + 1);
100
101 return 0;
102 }
103
104 /*----------------------------------------------------------------*/
105
106 /*
107 * We want 3n entries (for some n). This works more nicely for repeated
108 * insert remove loops than (2n + 1).
109 */
110 static uint32_t calc_max_entries(size_t value_size, size_t block_size)
111 {
112 uint32_t total, n;
113 size_t elt_size = sizeof(uint64_t) + value_size; /* key + value */
114
115 block_size -= sizeof(struct node_header);
116 total = block_size / elt_size;
117 n = total / 3; /* rounds down */
118
119 return 3 * n;
120 }
121
122 int dm_btree_empty(struct dm_btree_info *info, dm_block_t *root)
123 {
124 int r;
125 struct dm_block *b;
126 struct node *n;
127 size_t block_size;
128 uint32_t max_entries;
129
130 r = new_block(info, &b);
131 if (r < 0)
132 return r;
133
134 block_size = dm_bm_block_size(dm_tm_get_bm(info->tm));
135 max_entries = calc_max_entries(info->value_type.size, block_size);
136
137 n = dm_block_data(b);
138 memset(n, 0, block_size);
139 n->header.flags = cpu_to_le32(LEAF_NODE);
140 n->header.nr_entries = cpu_to_le32(0);
141 n->header.max_entries = cpu_to_le32(max_entries);
142 n->header.value_size = cpu_to_le32(info->value_type.size);
143
144 *root = dm_block_location(b);
145 return unlock_block(info, b);
146 }
147 EXPORT_SYMBOL_GPL(dm_btree_empty);
148
149 /*----------------------------------------------------------------*/
150
151 /*
152 * Deletion uses a recursive algorithm, since we have limited stack space
153 * we explicitly manage our own stack on the heap.
154 */
155 #define MAX_SPINE_DEPTH 64
156 struct frame {
157 struct dm_block *b;
158 struct node *n;
159 unsigned level;
160 unsigned nr_children;
161 unsigned current_child;
162 };
163
164 struct del_stack {
165 struct dm_transaction_manager *tm;
166 int top;
167 struct frame spine[MAX_SPINE_DEPTH];
168 };
169
170 static int top_frame(struct del_stack *s, struct frame **f)
171 {
172 if (s->top < 0) {
173 DMERR("btree deletion stack empty");
174 return -EINVAL;
175 }
176
177 *f = s->spine + s->top;
178
179 return 0;
180 }
181
182 static int unprocessed_frames(struct del_stack *s)
183 {
184 return s->top >= 0;
185 }
186
187 static int push_frame(struct del_stack *s, dm_block_t b, unsigned level)
188 {
189 int r;
190 uint32_t ref_count;
191
192 if (s->top >= MAX_SPINE_DEPTH - 1) {
193 DMERR("btree deletion stack out of memory");
194 return -ENOMEM;
195 }
196
197 r = dm_tm_ref(s->tm, b, &ref_count);
198 if (r)
199 return r;
200
201 if (ref_count > 1)
202 /*
203 * This is a shared node, so we can just decrement it's
204 * reference counter and leave the children.
205 */
206 dm_tm_dec(s->tm, b);
207
208 else {
209 struct frame *f = s->spine + ++s->top;
210
211 r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b);
212 if (r) {
213 s->top--;
214 return r;
215 }
216
217 f->n = dm_block_data(f->b);
218 f->level = level;
219 f->nr_children = le32_to_cpu(f->n->header.nr_entries);
220 f->current_child = 0;
221 }
222
223 return 0;
224 }
225
226 static void pop_frame(struct del_stack *s)
227 {
228 struct frame *f = s->spine + s->top--;
229
230 dm_tm_dec(s->tm, dm_block_location(f->b));
231 dm_tm_unlock(s->tm, f->b);
232 }
233
234 int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
235 {
236 int r;
237 struct del_stack *s;
238
239 s = kmalloc(sizeof(*s), GFP_KERNEL);
240 if (!s)
241 return -ENOMEM;
242 s->tm = info->tm;
243 s->top = -1;
244
245 r = push_frame(s, root, 1);
246 if (r)
247 goto out;
248
249 while (unprocessed_frames(s)) {
250 uint32_t flags;
251 struct frame *f;
252 dm_block_t b;
253
254 r = top_frame(s, &f);
255 if (r)
256 goto out;
257
258 if (f->current_child >= f->nr_children) {
259 pop_frame(s);
260 continue;
261 }
262
263 flags = le32_to_cpu(f->n->header.flags);
264 if (flags & INTERNAL_NODE) {
265 b = value64(f->n, f->current_child);
266 f->current_child++;
267 r = push_frame(s, b, f->level);
268 if (r)
269 goto out;
270
271 } else if (f->level != (info->levels - 1)) {
272 b = value64(f->n, f->current_child);
273 f->current_child++;
274 r = push_frame(s, b, f->level + 1);
275 if (r)
276 goto out;
277
278 } else {
279 if (info->value_type.dec) {
280 unsigned i;
281
282 for (i = 0; i < f->nr_children; i++)
283 info->value_type.dec(info->value_type.context,
284 value_ptr(f->n, i, info->value_type.size));
285 }
286 f->current_child = f->nr_children;
287 }
288 }
289
290 out:
291 kfree(s);
292 return r;
293 }
294 EXPORT_SYMBOL_GPL(dm_btree_del);
295
296 /*----------------------------------------------------------------*/
297
298 static int btree_lookup_raw(struct ro_spine *s, dm_block_t block, uint64_t key,
299 int (*search_fn)(struct node *, uint64_t),
300 uint64_t *result_key, void *v, size_t value_size)
301 {
302 int i, r;
303 uint32_t flags, nr_entries;
304
305 do {
306 r = ro_step(s, block);
307 if (r < 0)
308 return r;
309
310 i = search_fn(ro_node(s), key);
311
312 flags = le32_to_cpu(ro_node(s)->header.flags);
313 nr_entries = le32_to_cpu(ro_node(s)->header.nr_entries);
314 if (i < 0 || i >= nr_entries)
315 return -ENODATA;
316
317 if (flags & INTERNAL_NODE)
318 block = value64(ro_node(s), i);
319
320 } while (!(flags & LEAF_NODE));
321
322 *result_key = le64_to_cpu(ro_node(s)->keys[i]);
323 memcpy(v, value_ptr(ro_node(s), i, value_size), value_size);
324
325 return 0;
326 }
327
328 int dm_btree_lookup(struct dm_btree_info *info, dm_block_t root,
329 uint64_t *keys, void *value_le)
330 {
331 unsigned level, last_level = info->levels - 1;
332 int r = -ENODATA;
333 uint64_t rkey;
334 __le64 internal_value_le;
335 struct ro_spine spine;
336
337 init_ro_spine(&spine, info);
338 for (level = 0; level < info->levels; level++) {
339 size_t size;
340 void *value_p;
341
342 if (level == last_level) {
343 value_p = value_le;
344 size = info->value_type.size;
345
346 } else {
347 value_p = &internal_value_le;
348 size = sizeof(uint64_t);
349 }
350
351 r = btree_lookup_raw(&spine, root, keys[level],
352 lower_bound, &rkey,
353 value_p, size);
354
355 if (!r) {
356 if (rkey != keys[level]) {
357 exit_ro_spine(&spine);
358 return -ENODATA;
359 }
360 } else {
361 exit_ro_spine(&spine);
362 return r;
363 }
364
365 root = le64_to_cpu(internal_value_le);
366 }
367 exit_ro_spine(&spine);
368
369 return r;
370 }
371 EXPORT_SYMBOL_GPL(dm_btree_lookup);
372
373 /*
374 * Splits a node by creating a sibling node and shifting half the nodes
375 * contents across. Assumes there is a parent node, and it has room for
376 * another child.
377 *
378 * Before:
379 * +--------+
380 * | Parent |
381 * +--------+
382 * |
383 * v
384 * +----------+
385 * | A ++++++ |
386 * +----------+
387 *
388 *
389 * After:
390 * +--------+
391 * | Parent |
392 * +--------+
393 * | |
394 * v +------+
395 * +---------+ |
396 * | A* +++ | v
397 * +---------+ +-------+
398 * | B +++ |
399 * +-------+
400 *
401 * Where A* is a shadow of A.
402 */
403 static int btree_split_sibling(struct shadow_spine *s, dm_block_t root,
404 unsigned parent_index, uint64_t key)
405 {
406 int r;
407 size_t size;
408 unsigned nr_left, nr_right;
409 struct dm_block *left, *right, *parent;
410 struct node *ln, *rn, *pn;
411 __le64 location;
412
413 left = shadow_current(s);
414
415 r = new_block(s->info, &right);
416 if (r < 0)
417 return r;
418
419 ln = dm_block_data(left);
420 rn = dm_block_data(right);
421
422 nr_left = le32_to_cpu(ln->header.nr_entries) / 2;
423 nr_right = le32_to_cpu(ln->header.nr_entries) - nr_left;
424
425 ln->header.nr_entries = cpu_to_le32(nr_left);
426
427 rn->header.flags = ln->header.flags;
428 rn->header.nr_entries = cpu_to_le32(nr_right);
429 rn->header.max_entries = ln->header.max_entries;
430 rn->header.value_size = ln->header.value_size;
431 memcpy(rn->keys, ln->keys + nr_left, nr_right * sizeof(rn->keys[0]));
432
433 size = le32_to_cpu(ln->header.flags) & INTERNAL_NODE ?
434 sizeof(uint64_t) : s->info->value_type.size;
435 memcpy(value_ptr(rn, 0, size), value_ptr(ln, nr_left, size),
436 size * nr_right);
437
438 /*
439 * Patch up the parent
440 */
441 parent = shadow_parent(s);
442
443 pn = dm_block_data(parent);
444 location = cpu_to_le64(dm_block_location(left));
445 __dm_bless_for_disk(&location);
446 memcpy_disk(value_ptr(pn, parent_index, sizeof(__le64)),
447 &location, sizeof(__le64));
448
449 location = cpu_to_le64(dm_block_location(right));
450 __dm_bless_for_disk(&location);
451
452 r = insert_at(sizeof(__le64), pn, parent_index + 1,
453 le64_to_cpu(rn->keys[0]), &location);
454 if (r)
455 return r;
456
457 if (key < le64_to_cpu(rn->keys[0])) {
458 unlock_block(s->info, right);
459 s->nodes[1] = left;
460 } else {
461 unlock_block(s->info, left);
462 s->nodes[1] = right;
463 }
464
465 return 0;
466 }
467
468 /*
469 * Splits a node by creating two new children beneath the given node.
470 *
471 * Before:
472 * +----------+
473 * | A ++++++ |
474 * +----------+
475 *
476 *
477 * After:
478 * +------------+
479 * | A (shadow) |
480 * +------------+
481 * | |
482 * +------+ +----+
483 * | |
484 * v v
485 * +-------+ +-------+
486 * | B +++ | | C +++ |
487 * +-------+ +-------+
488 */
489 static int btree_split_beneath(struct shadow_spine *s, uint64_t key)
490 {
491 int r;
492 size_t size;
493 unsigned nr_left, nr_right;
494 struct dm_block *left, *right, *new_parent;
495 struct node *pn, *ln, *rn;
496 __le64 val;
497
498 new_parent = shadow_current(s);
499
500 r = new_block(s->info, &left);
501 if (r < 0)
502 return r;
503
504 r = new_block(s->info, &right);
505 if (r < 0) {
506 /* FIXME: put left */
507 return r;
508 }
509
510 pn = dm_block_data(new_parent);
511 ln = dm_block_data(left);
512 rn = dm_block_data(right);
513
514 nr_left = le32_to_cpu(pn->header.nr_entries) / 2;
515 nr_right = le32_to_cpu(pn->header.nr_entries) - nr_left;
516
517 ln->header.flags = pn->header.flags;
518 ln->header.nr_entries = cpu_to_le32(nr_left);
519 ln->header.max_entries = pn->header.max_entries;
520 ln->header.value_size = pn->header.value_size;
521
522 rn->header.flags = pn->header.flags;
523 rn->header.nr_entries = cpu_to_le32(nr_right);
524 rn->header.max_entries = pn->header.max_entries;
525 rn->header.value_size = pn->header.value_size;
526
527 memcpy(ln->keys, pn->keys, nr_left * sizeof(pn->keys[0]));
528 memcpy(rn->keys, pn->keys + nr_left, nr_right * sizeof(pn->keys[0]));
529
530 size = le32_to_cpu(pn->header.flags) & INTERNAL_NODE ?
531 sizeof(__le64) : s->info->value_type.size;
532 memcpy(value_ptr(ln, 0, size), value_ptr(pn, 0, size), nr_left * size);
533 memcpy(value_ptr(rn, 0, size), value_ptr(pn, nr_left, size),
534 nr_right * size);
535
536 /* new_parent should just point to l and r now */
537 pn->header.flags = cpu_to_le32(INTERNAL_NODE);
538 pn->header.nr_entries = cpu_to_le32(2);
539 pn->header.max_entries = cpu_to_le32(
540 calc_max_entries(sizeof(__le64),
541 dm_bm_block_size(
542 dm_tm_get_bm(s->info->tm))));
543 pn->header.value_size = cpu_to_le32(sizeof(__le64));
544
545 val = cpu_to_le64(dm_block_location(left));
546 __dm_bless_for_disk(&val);
547 pn->keys[0] = ln->keys[0];
548 memcpy_disk(value_ptr(pn, 0, sizeof(__le64)), &val, sizeof(__le64));
549
550 val = cpu_to_le64(dm_block_location(right));
551 __dm_bless_for_disk(&val);
552 pn->keys[1] = rn->keys[0];
553 memcpy_disk(value_ptr(pn, 1, sizeof(__le64)), &val, sizeof(__le64));
554
555 /*
556 * rejig the spine. This is ugly, since it knows too
557 * much about the spine
558 */
559 if (s->nodes[0] != new_parent) {
560 unlock_block(s->info, s->nodes[0]);
561 s->nodes[0] = new_parent;
562 }
563 if (key < le64_to_cpu(rn->keys[0])) {
564 unlock_block(s->info, right);
565 s->nodes[1] = left;
566 } else {
567 unlock_block(s->info, left);
568 s->nodes[1] = right;
569 }
570 s->count = 2;
571
572 return 0;
573 }
574
575 static int btree_insert_raw(struct shadow_spine *s, dm_block_t root,
576 struct dm_btree_value_type *vt,
577 uint64_t key, unsigned *index)
578 {
579 int r, i = *index, top = 1;
580 struct node *node;
581
582 for (;;) {
583 r = shadow_step(s, root, vt);
584 if (r < 0)
585 return r;
586
587 node = dm_block_data(shadow_current(s));
588
589 /*
590 * We have to patch up the parent node, ugly, but I don't
591 * see a way to do this automatically as part of the spine
592 * op.
593 */
594 if (shadow_has_parent(s) && i >= 0) { /* FIXME: second clause unness. */
595 __le64 location = cpu_to_le64(dm_block_location(shadow_current(s)));
596
597 __dm_bless_for_disk(&location);
598 memcpy_disk(value_ptr(dm_block_data(shadow_parent(s)), i, sizeof(uint64_t)),
599 &location, sizeof(__le64));
600 }
601
602 node = dm_block_data(shadow_current(s));
603
604 if (node->header.nr_entries == node->header.max_entries) {
605 if (top)
606 r = btree_split_beneath(s, key);
607 else
608 r = btree_split_sibling(s, root, i, key);
609
610 if (r < 0)
611 return r;
612 }
613
614 node = dm_block_data(shadow_current(s));
615
616 i = lower_bound(node, key);
617
618 if (le32_to_cpu(node->header.flags) & LEAF_NODE)
619 break;
620
621 if (i < 0) {
622 /* change the bounds on the lowest key */
623 node->keys[0] = cpu_to_le64(key);
624 i = 0;
625 }
626
627 root = value64(node, i);
628 top = 0;
629 }
630
631 if (i < 0 || le64_to_cpu(node->keys[i]) != key)
632 i++;
633
634 *index = i;
635 return 0;
636 }
637
638 static int insert(struct dm_btree_info *info, dm_block_t root,
639 uint64_t *keys, void *value, dm_block_t *new_root,
640 int *inserted)
641 __dm_written_to_disk(value)
642 {
643 int r, need_insert;
644 unsigned level, index = -1, last_level = info->levels - 1;
645 dm_block_t block = root;
646 struct shadow_spine spine;
647 struct node *n;
648 struct dm_btree_value_type le64_type;
649
650 le64_type.context = NULL;
651 le64_type.size = sizeof(__le64);
652 le64_type.inc = NULL;
653 le64_type.dec = NULL;
654 le64_type.equal = NULL;
655
656 init_shadow_spine(&spine, info);
657
658 for (level = 0; level < (info->levels - 1); level++) {
659 r = btree_insert_raw(&spine, block, &le64_type, keys[level], &index);
660 if (r < 0)
661 goto bad;
662
663 n = dm_block_data(shadow_current(&spine));
664 need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
665 (le64_to_cpu(n->keys[index]) != keys[level]));
666
667 if (need_insert) {
668 dm_block_t new_tree;
669 __le64 new_le;
670
671 r = dm_btree_empty(info, &new_tree);
672 if (r < 0)
673 goto bad;
674
675 new_le = cpu_to_le64(new_tree);
676 __dm_bless_for_disk(&new_le);
677
678 r = insert_at(sizeof(uint64_t), n, index,
679 keys[level], &new_le);
680 if (r)
681 goto bad;
682 }
683
684 if (level < last_level)
685 block = value64(n, index);
686 }
687
688 r = btree_insert_raw(&spine, block, &info->value_type,
689 keys[level], &index);
690 if (r < 0)
691 goto bad;
692
693 n = dm_block_data(shadow_current(&spine));
694 need_insert = ((index >= le32_to_cpu(n->header.nr_entries)) ||
695 (le64_to_cpu(n->keys[index]) != keys[level]));
696
697 if (need_insert) {
698 if (inserted)
699 *inserted = 1;
700
701 r = insert_at(info->value_type.size, n, index,
702 keys[level], value);
703 if (r)
704 goto bad_unblessed;
705 } else {
706 if (inserted)
707 *inserted = 0;
708
709 if (info->value_type.dec &&
710 (!info->value_type.equal ||
711 !info->value_type.equal(
712 info->value_type.context,
713 value_ptr(n, index, info->value_type.size),
714 value))) {
715 info->value_type.dec(info->value_type.context,
716 value_ptr(n, index, info->value_type.size));
717 }
718 memcpy_disk(value_ptr(n, index, info->value_type.size),
719 value, info->value_type.size);
720 }
721
722 *new_root = shadow_root(&spine);
723 exit_shadow_spine(&spine);
724
725 return 0;
726
727 bad:
728 __dm_unbless_for_disk(value);
729 bad_unblessed:
730 exit_shadow_spine(&spine);
731 return r;
732 }
733
734 int dm_btree_insert(struct dm_btree_info *info, dm_block_t root,
735 uint64_t *keys, void *value, dm_block_t *new_root)
736 __dm_written_to_disk(value)
737 {
738 return insert(info, root, keys, value, new_root, NULL);
739 }
740 EXPORT_SYMBOL_GPL(dm_btree_insert);
741
742 int dm_btree_insert_notify(struct dm_btree_info *info, dm_block_t root,
743 uint64_t *keys, void *value, dm_block_t *new_root,
744 int *inserted)
745 __dm_written_to_disk(value)
746 {
747 return insert(info, root, keys, value, new_root, inserted);
748 }
749 EXPORT_SYMBOL_GPL(dm_btree_insert_notify);
750
751 /*----------------------------------------------------------------*/
752
753 static int find_highest_key(struct ro_spine *s, dm_block_t block,
754 uint64_t *result_key, dm_block_t *next_block)
755 {
756 int i, r;
757 uint32_t flags;
758
759 do {
760 r = ro_step(s, block);
761 if (r < 0)
762 return r;
763
764 flags = le32_to_cpu(ro_node(s)->header.flags);
765 i = le32_to_cpu(ro_node(s)->header.nr_entries);
766 if (!i)
767 return -ENODATA;
768 else
769 i--;
770
771 *result_key = le64_to_cpu(ro_node(s)->keys[i]);
772 if (next_block || flags & INTERNAL_NODE)
773 block = value64(ro_node(s), i);
774
775 } while (flags & INTERNAL_NODE);
776
777 if (next_block)
778 *next_block = block;
779 return 0;
780 }
781
782 int dm_btree_find_highest_key(struct dm_btree_info *info, dm_block_t root,
783 uint64_t *result_keys)
784 {
785 int r = 0, count = 0, level;
786 struct ro_spine spine;
787
788 init_ro_spine(&spine, info);
789 for (level = 0; level < info->levels; level++) {
790 r = find_highest_key(&spine, root, result_keys + level,
791 level == info->levels - 1 ? NULL : &root);
792 if (r == -ENODATA) {
793 r = 0;
794 break;
795
796 } else if (r)
797 break;
798
799 count++;
800 }
801 exit_ro_spine(&spine);
802
803 return r ? r : count;
804 }
805 EXPORT_SYMBOL_GPL(dm_btree_find_highest_key);
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree