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1/**************************************************************************
2 *
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 *
27 **************************************************************************/
28
29/*
30 * Generic simple memory manager implementation. Intended to be used as a base
31 * class implementation for more advanced memory managers.
32 *
33 * Note that the algorithm used is quite simple and there might be substantial
34 * performance gains if a smarter free list is implemented. Currently it is just an
35 * unordered stack of free regions. This could easily be improved if an RB-tree
36 * is used instead. At least if we expect heavy fragmentation.
37 *
38 * Aligned allocations can also see improvement.
39 *
40 * Authors:
41 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
42 */
43
44#include <drm/drmP.h>
45#include <drm/drm_mm.h>
46#include <linux/slab.h>
47#include <linux/seq_file.h>
48#include <linux/export.h>
49#include <linux/interval_tree_generic.h>
50
51/**
52 * DOC: Overview
53 *
54 * drm_mm provides a simple range allocator. The drivers are free to use the
55 * resource allocator from the linux core if it suits them, the upside of drm_mm
56 * is that it's in the DRM core. Which means that it's easier to extend for
57 * some of the crazier special purpose needs of gpus.
58 *
59 * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
60 * Drivers are free to embed either of them into their own suitable
61 * datastructures. drm_mm itself will not do any allocations of its own, so if
62 * drivers choose not to embed nodes they need to still allocate them
63 * themselves.
64 *
65 * The range allocator also supports reservation of preallocated blocks. This is
66 * useful for taking over initial mode setting configurations from the firmware,
67 * where an object needs to be created which exactly matches the firmware's
68 * scanout target. As long as the range is still free it can be inserted anytime
69 * after the allocator is initialized, which helps with avoiding looped
70 * depencies in the driver load sequence.
71 *
72 * drm_mm maintains a stack of most recently freed holes, which of all
73 * simplistic datastructures seems to be a fairly decent approach to clustering
74 * allocations and avoiding too much fragmentation. This means free space
75 * searches are O(num_holes). Given that all the fancy features drm_mm supports
76 * something better would be fairly complex and since gfx thrashing is a fairly
77 * steep cliff not a real concern. Removing a node again is O(1).
78 *
79 * drm_mm supports a few features: Alignment and range restrictions can be
80 * supplied. Further more every &drm_mm_node has a color value (which is just an
81 * opaqua unsigned long) which in conjunction with a driver callback can be used
82 * to implement sophisticated placement restrictions. The i915 DRM driver uses
83 * this to implement guard pages between incompatible caching domains in the
84 * graphics TT.
85 *
86 * Two behaviors are supported for searching and allocating: bottom-up and top-down.
87 * The default is bottom-up. Top-down allocation can be used if the memory area
88 * has different restrictions, or just to reduce fragmentation.
89 *
90 * Finally iteration helpers to walk all nodes and all holes are provided as are
91 * some basic allocator dumpers for debugging.
92 */
93
94static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
95 u64 size,
96 unsigned alignment,
97 unsigned long color,
98 enum drm_mm_search_flags flags);
99static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
100 u64 size,
101 unsigned alignment,
102 unsigned long color,
103 u64 start,
104 u64 end,
105 enum drm_mm_search_flags flags);
106
107#ifdef CONFIG_DRM_DEBUG_MM
108#include <linux/stackdepot.h>
109
110#define STACKDEPTH 32
111#define BUFSZ 4096
112
113static noinline void save_stack(struct drm_mm_node *node)
114{
115 unsigned long entries[STACKDEPTH];
116 struct stack_trace trace = {
117 .entries = entries,
118 .max_entries = STACKDEPTH,
119 .skip = 1
120 };
121
122 save_stack_trace(&trace);
123 if (trace.nr_entries != 0 &&
124 trace.entries[trace.nr_entries-1] == ULONG_MAX)
125 trace.nr_entries--;
126
127 /* May be called under spinlock, so avoid sleeping */
128 node->stack = depot_save_stack(&trace, GFP_NOWAIT);
129}
130
131static void show_leaks(struct drm_mm *mm)
132{
133 struct drm_mm_node *node;
134 unsigned long entries[STACKDEPTH];
135 char *buf;
136
137 buf = kmalloc(BUFSZ, GFP_KERNEL);
138 if (!buf)
139 return;
140
141 list_for_each_entry(node, &mm->head_node.node_list, node_list) {
142 struct stack_trace trace = {
143 .entries = entries,
144 .max_entries = STACKDEPTH
145 };
146
147 if (!node->stack) {
148 DRM_ERROR("node [%08llx + %08llx]: unknown owner\n",
149 node->start, node->size);
150 continue;
151 }
152
153 depot_fetch_stack(node->stack, &trace);
154 snprint_stack_trace(buf, BUFSZ, &trace, 0);
155 DRM_ERROR("node [%08llx + %08llx]: inserted at\n%s",
156 node->start, node->size, buf);
157 }
158
159 kfree(buf);
160}
161
162#undef STACKDEPTH
163#undef BUFSZ
164#else
165static void save_stack(struct drm_mm_node *node) { }
166static void show_leaks(struct drm_mm *mm) { }
167#endif
168
169#define START(node) ((node)->start)
170#define LAST(node) ((node)->start + (node)->size - 1)
171
172INTERVAL_TREE_DEFINE(struct drm_mm_node, rb,
173 u64, __subtree_last,
174 START, LAST, static inline, drm_mm_interval_tree)
175
176struct drm_mm_node *
177__drm_mm_interval_first(struct drm_mm *mm, u64 start, u64 last)
178{
179 return drm_mm_interval_tree_iter_first(&mm->interval_tree,
180 start, last);
181}
182EXPORT_SYMBOL(__drm_mm_interval_first);
183
184static void drm_mm_interval_tree_add_node(struct drm_mm_node *hole_node,
185 struct drm_mm_node *node)
186{
187 struct drm_mm *mm = hole_node->mm;
188 struct rb_node **link, *rb;
189 struct drm_mm_node *parent;
190
191 node->__subtree_last = LAST(node);
192
193 if (hole_node->allocated) {
194 rb = &hole_node->rb;
195 while (rb) {
196 parent = rb_entry(rb, struct drm_mm_node, rb);
197 if (parent->__subtree_last >= node->__subtree_last)
198 break;
199
200 parent->__subtree_last = node->__subtree_last;
201 rb = rb_parent(rb);
202 }
203
204 rb = &hole_node->rb;
205 link = &hole_node->rb.rb_right;
206 } else {
207 rb = NULL;
208 link = &mm->interval_tree.rb_node;
209 }
210
211 while (*link) {
212 rb = *link;
213 parent = rb_entry(rb, struct drm_mm_node, rb);
214 if (parent->__subtree_last < node->__subtree_last)
215 parent->__subtree_last = node->__subtree_last;
216 if (node->start < parent->start)
217 link = &parent->rb.rb_left;
218 else
219 link = &parent->rb.rb_right;
220 }
221
222 rb_link_node(&node->rb, rb, link);
223 rb_insert_augmented(&node->rb,
224 &mm->interval_tree,
225 &drm_mm_interval_tree_augment);
226}
227
228static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
229 struct drm_mm_node *node,
230 u64 size, unsigned alignment,
231 unsigned long color,
232 enum drm_mm_allocator_flags flags)
233{
234 struct drm_mm *mm = hole_node->mm;
235 u64 hole_start = drm_mm_hole_node_start(hole_node);
236 u64 hole_end = drm_mm_hole_node_end(hole_node);
237 u64 adj_start = hole_start;
238 u64 adj_end = hole_end;
239
240 BUG_ON(node->allocated);
241
242 if (mm->color_adjust)
243 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
244
245 if (flags & DRM_MM_CREATE_TOP)
246 adj_start = adj_end - size;
247
248 if (alignment) {
249 u64 tmp = adj_start;
250 unsigned rem;
251
252 rem = do_div(tmp, alignment);
253 if (rem) {
254 if (flags & DRM_MM_CREATE_TOP)
255 adj_start -= rem;
256 else
257 adj_start += alignment - rem;
258 }
259 }
260
261 BUG_ON(adj_start < hole_start);
262 BUG_ON(adj_end > hole_end);
263
264 if (adj_start == hole_start) {
265 hole_node->hole_follows = 0;
266 list_del(&hole_node->hole_stack);
267 }
268
269 node->start = adj_start;
270 node->size = size;
271 node->mm = mm;
272 node->color = color;
273 node->allocated = 1;
274
275 list_add(&node->node_list, &hole_node->node_list);
276
277 drm_mm_interval_tree_add_node(hole_node, node);
278
279 BUG_ON(node->start + node->size > adj_end);
280
281 node->hole_follows = 0;
282 if (__drm_mm_hole_node_start(node) < hole_end) {
283 list_add(&node->hole_stack, &mm->hole_stack);
284 node->hole_follows = 1;
285 }
286
287 save_stack(node);
288}
289
290/**
291 * drm_mm_reserve_node - insert an pre-initialized node
292 * @mm: drm_mm allocator to insert @node into
293 * @node: drm_mm_node to insert
294 *
295 * This functions inserts an already set-up drm_mm_node into the allocator,
296 * meaning that start, size and color must be set by the caller. This is useful
297 * to initialize the allocator with preallocated objects which must be set-up
298 * before the range allocator can be set-up, e.g. when taking over a firmware
299 * framebuffer.
300 *
301 * Returns:
302 * 0 on success, -ENOSPC if there's no hole where @node is.
303 */
304int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
305{
306 u64 end = node->start + node->size;
307 struct drm_mm_node *hole;
308 u64 hole_start, hole_end;
309 u64 adj_start, adj_end;
310
311 if (WARN_ON(node->size == 0))
312 return -EINVAL;
313
314 end = node->start + node->size;
315
316 /* Find the relevant hole to add our node to */
317 hole = drm_mm_interval_tree_iter_first(&mm->interval_tree,
318 node->start, ~(u64)0);
319 if (hole) {
320 if (hole->start < end)
321 return -ENOSPC;
322 } else {
323 hole = list_entry(&mm->head_node.node_list,
324 typeof(*hole), node_list);
325 }
326
327 hole = list_last_entry(&hole->node_list, typeof(*hole), node_list);
328 if (!hole->hole_follows)
329 return -ENOSPC;
330
331 adj_start = hole_start = __drm_mm_hole_node_start(hole);
332 adj_end = hole_end = __drm_mm_hole_node_end(hole);
333
334 if (mm->color_adjust)
335 mm->color_adjust(hole, node->color, &adj_start, &adj_end);
336
337 if (adj_start > node->start || adj_end < end)
338 return -ENOSPC;
339
340 node->mm = mm;
341 node->allocated = 1;
342
343 list_add(&node->node_list, &hole->node_list);
344
345 drm_mm_interval_tree_add_node(hole, node);
346
347 if (node->start == hole_start) {
348 hole->hole_follows = 0;
349 list_del(&hole->hole_stack);
350 }
351
352 node->hole_follows = 0;
353 if (end != hole_end) {
354 list_add(&node->hole_stack, &mm->hole_stack);
355 node->hole_follows = 1;
356 }
357
358 save_stack(node);
359
360 return 0;
361}
362EXPORT_SYMBOL(drm_mm_reserve_node);
363
364/**
365 * drm_mm_insert_node_generic - search for space and insert @node
366 * @mm: drm_mm to allocate from
367 * @node: preallocate node to insert
368 * @size: size of the allocation
369 * @alignment: alignment of the allocation
370 * @color: opaque tag value to use for this node
371 * @sflags: flags to fine-tune the allocation search
372 * @aflags: flags to fine-tune the allocation behavior
373 *
374 * The preallocated node must be cleared to 0.
375 *
376 * Returns:
377 * 0 on success, -ENOSPC if there's no suitable hole.
378 */
379int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
380 u64 size, unsigned alignment,
381 unsigned long color,
382 enum drm_mm_search_flags sflags,
383 enum drm_mm_allocator_flags aflags)
384{
385 struct drm_mm_node *hole_node;
386
387 if (WARN_ON(size == 0))
388 return -EINVAL;
389
390 hole_node = drm_mm_search_free_generic(mm, size, alignment,
391 color, sflags);
392 if (!hole_node)
393 return -ENOSPC;
394
395 drm_mm_insert_helper(hole_node, node, size, alignment, color, aflags);
396 return 0;
397}
398EXPORT_SYMBOL(drm_mm_insert_node_generic);
399
400static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
401 struct drm_mm_node *node,
402 u64 size, unsigned alignment,
403 unsigned long color,
404 u64 start, u64 end,
405 enum drm_mm_allocator_flags flags)
406{
407 struct drm_mm *mm = hole_node->mm;
408 u64 hole_start = drm_mm_hole_node_start(hole_node);
409 u64 hole_end = drm_mm_hole_node_end(hole_node);
410 u64 adj_start = hole_start;
411 u64 adj_end = hole_end;
412
413 BUG_ON(!hole_node->hole_follows || node->allocated);
414
415 if (adj_start < start)
416 adj_start = start;
417 if (adj_end > end)
418 adj_end = end;
419
420 if (mm->color_adjust)
421 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
422
423 if (flags & DRM_MM_CREATE_TOP)
424 adj_start = adj_end - size;
425
426 if (alignment) {
427 u64 tmp = adj_start;
428 unsigned rem;
429
430 rem = do_div(tmp, alignment);
431 if (rem) {
432 if (flags & DRM_MM_CREATE_TOP)
433 adj_start -= rem;
434 else
435 adj_start += alignment - rem;
436 }
437 }
438
439 if (adj_start == hole_start) {
440 hole_node->hole_follows = 0;
441 list_del(&hole_node->hole_stack);
442 }
443
444 node->start = adj_start;
445 node->size = size;
446 node->mm = mm;
447 node->color = color;
448 node->allocated = 1;
449
450 list_add(&node->node_list, &hole_node->node_list);
451
452 drm_mm_interval_tree_add_node(hole_node, node);
453
454 BUG_ON(node->start < start);
455 BUG_ON(node->start < adj_start);
456 BUG_ON(node->start + node->size > adj_end);
457 BUG_ON(node->start + node->size > end);
458
459 node->hole_follows = 0;
460 if (__drm_mm_hole_node_start(node) < hole_end) {
461 list_add(&node->hole_stack, &mm->hole_stack);
462 node->hole_follows = 1;
463 }
464
465 save_stack(node);
466}
467
468/**
469 * drm_mm_insert_node_in_range_generic - ranged search for space and insert @node
470 * @mm: drm_mm to allocate from
471 * @node: preallocate node to insert
472 * @size: size of the allocation
473 * @alignment: alignment of the allocation
474 * @color: opaque tag value to use for this node
475 * @start: start of the allowed range for this node
476 * @end: end of the allowed range for this node
477 * @sflags: flags to fine-tune the allocation search
478 * @aflags: flags to fine-tune the allocation behavior
479 *
480 * The preallocated node must be cleared to 0.
481 *
482 * Returns:
483 * 0 on success, -ENOSPC if there's no suitable hole.
484 */
485int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,
486 u64 size, unsigned alignment,
487 unsigned long color,
488 u64 start, u64 end,
489 enum drm_mm_search_flags sflags,
490 enum drm_mm_allocator_flags aflags)
491{
492 struct drm_mm_node *hole_node;
493
494 if (WARN_ON(size == 0))
495 return -EINVAL;
496
497 hole_node = drm_mm_search_free_in_range_generic(mm,
498 size, alignment, color,
499 start, end, sflags);
500 if (!hole_node)
501 return -ENOSPC;
502
503 drm_mm_insert_helper_range(hole_node, node,
504 size, alignment, color,
505 start, end, aflags);
506 return 0;
507}
508EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic);
509
510/**
511 * drm_mm_remove_node - Remove a memory node from the allocator.
512 * @node: drm_mm_node to remove
513 *
514 * This just removes a node from its drm_mm allocator. The node does not need to
515 * be cleared again before it can be re-inserted into this or any other drm_mm
516 * allocator. It is a bug to call this function on a un-allocated node.
517 */
518void drm_mm_remove_node(struct drm_mm_node *node)
519{
520 struct drm_mm *mm = node->mm;
521 struct drm_mm_node *prev_node;
522
523 if (WARN_ON(!node->allocated))
524 return;
525
526 BUG_ON(node->scanned_block || node->scanned_prev_free
527 || node->scanned_next_free);
528
529 prev_node =
530 list_entry(node->node_list.prev, struct drm_mm_node, node_list);
531
532 if (node->hole_follows) {
533 BUG_ON(__drm_mm_hole_node_start(node) ==
534 __drm_mm_hole_node_end(node));
535 list_del(&node->hole_stack);
536 } else
537 BUG_ON(__drm_mm_hole_node_start(node) !=
538 __drm_mm_hole_node_end(node));
539
540
541 if (!prev_node->hole_follows) {
542 prev_node->hole_follows = 1;
543 list_add(&prev_node->hole_stack, &mm->hole_stack);
544 } else
545 list_move(&prev_node->hole_stack, &mm->hole_stack);
546
547 drm_mm_interval_tree_remove(node, &mm->interval_tree);
548 list_del(&node->node_list);
549 node->allocated = 0;
550}
551EXPORT_SYMBOL(drm_mm_remove_node);
552
553static int check_free_hole(u64 start, u64 end, u64 size, unsigned alignment)
554{
555 if (end - start < size)
556 return 0;
557
558 if (alignment) {
559 u64 tmp = start;
560 unsigned rem;
561
562 rem = do_div(tmp, alignment);
563 if (rem)
564 start += alignment - rem;
565 }
566
567 return end >= start + size;
568}
569
570static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
571 u64 size,
572 unsigned alignment,
573 unsigned long color,
574 enum drm_mm_search_flags flags)
575{
576 struct drm_mm_node *entry;
577 struct drm_mm_node *best;
578 u64 adj_start;
579 u64 adj_end;
580 u64 best_size;
581
582 BUG_ON(mm->scanned_blocks);
583
584 best = NULL;
585 best_size = ~0UL;
586
587 __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
588 flags & DRM_MM_SEARCH_BELOW) {
589 u64 hole_size = adj_end - adj_start;
590
591 if (mm->color_adjust) {
592 mm->color_adjust(entry, color, &adj_start, &adj_end);
593 if (adj_end <= adj_start)
594 continue;
595 }
596
597 if (!check_free_hole(adj_start, adj_end, size, alignment))
598 continue;
599
600 if (!(flags & DRM_MM_SEARCH_BEST))
601 return entry;
602
603 if (hole_size < best_size) {
604 best = entry;
605 best_size = hole_size;
606 }
607 }
608
609 return best;
610}
611
612static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
613 u64 size,
614 unsigned alignment,
615 unsigned long color,
616 u64 start,
617 u64 end,
618 enum drm_mm_search_flags flags)
619{
620 struct drm_mm_node *entry;
621 struct drm_mm_node *best;
622 u64 adj_start;
623 u64 adj_end;
624 u64 best_size;
625
626 BUG_ON(mm->scanned_blocks);
627
628 best = NULL;
629 best_size = ~0UL;
630
631 __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
632 flags & DRM_MM_SEARCH_BELOW) {
633 u64 hole_size = adj_end - adj_start;
634
635 if (adj_start < start)
636 adj_start = start;
637 if (adj_end > end)
638 adj_end = end;
639
640 if (mm->color_adjust) {
641 mm->color_adjust(entry, color, &adj_start, &adj_end);
642 if (adj_end <= adj_start)
643 continue;
644 }
645
646 if (!check_free_hole(adj_start, adj_end, size, alignment))
647 continue;
648
649 if (!(flags & DRM_MM_SEARCH_BEST))
650 return entry;
651
652 if (hole_size < best_size) {
653 best = entry;
654 best_size = hole_size;
655 }
656 }
657
658 return best;
659}
660
661/**
662 * drm_mm_replace_node - move an allocation from @old to @new
663 * @old: drm_mm_node to remove from the allocator
664 * @new: drm_mm_node which should inherit @old's allocation
665 *
666 * This is useful for when drivers embed the drm_mm_node structure and hence
667 * can't move allocations by reassigning pointers. It's a combination of remove
668 * and insert with the guarantee that the allocation start will match.
669 */
670void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
671{
672 list_replace(&old->node_list, &new->node_list);
673 list_replace(&old->hole_stack, &new->hole_stack);
674 rb_replace_node(&old->rb, &new->rb, &old->mm->interval_tree);
675 new->hole_follows = old->hole_follows;
676 new->mm = old->mm;
677 new->start = old->start;
678 new->size = old->size;
679 new->color = old->color;
680 new->__subtree_last = old->__subtree_last;
681
682 old->allocated = 0;
683 new->allocated = 1;
684}
685EXPORT_SYMBOL(drm_mm_replace_node);
686
687/**
688 * DOC: lru scan roaster
689 *
690 * Very often GPUs need to have continuous allocations for a given object. When
691 * evicting objects to make space for a new one it is therefore not most
692 * efficient when we simply start to select all objects from the tail of an LRU
693 * until there's a suitable hole: Especially for big objects or nodes that
694 * otherwise have special allocation constraints there's a good chance we evict
695 * lots of (smaller) objects unecessarily.
696 *
697 * The DRM range allocator supports this use-case through the scanning
698 * interfaces. First a scan operation needs to be initialized with
699 * drm_mm_init_scan() or drm_mm_init_scan_with_range(). The the driver adds
700 * objects to the roaster (probably by walking an LRU list, but this can be
701 * freely implemented) until a suitable hole is found or there's no further
702 * evitable object.
703 *
704 * The the driver must walk through all objects again in exactly the reverse
705 * order to restore the allocator state. Note that while the allocator is used
706 * in the scan mode no other operation is allowed.
707 *
708 * Finally the driver evicts all objects selected in the scan. Adding and
709 * removing an object is O(1), and since freeing a node is also O(1) the overall
710 * complexity is O(scanned_objects). So like the free stack which needs to be
711 * walked before a scan operation even begins this is linear in the number of
712 * objects. It doesn't seem to hurt badly.
713 */
714
715/**
716 * drm_mm_init_scan - initialize lru scanning
717 * @mm: drm_mm to scan
718 * @size: size of the allocation
719 * @alignment: alignment of the allocation
720 * @color: opaque tag value to use for the allocation
721 *
722 * This simply sets up the scanning routines with the parameters for the desired
723 * hole. Note that there's no need to specify allocation flags, since they only
724 * change the place a node is allocated from within a suitable hole.
725 *
726 * Warning:
727 * As long as the scan list is non-empty, no other operations than
728 * adding/removing nodes to/from the scan list are allowed.
729 */
730void drm_mm_init_scan(struct drm_mm *mm,
731 u64 size,
732 unsigned alignment,
733 unsigned long color)
734{
735 mm->scan_color = color;
736 mm->scan_alignment = alignment;
737 mm->scan_size = size;
738 mm->scanned_blocks = 0;
739 mm->scan_hit_start = 0;
740 mm->scan_hit_end = 0;
741 mm->scan_check_range = 0;
742 mm->prev_scanned_node = NULL;
743}
744EXPORT_SYMBOL(drm_mm_init_scan);
745
746/**
747 * drm_mm_init_scan - initialize range-restricted lru scanning
748 * @mm: drm_mm to scan
749 * @size: size of the allocation
750 * @alignment: alignment of the allocation
751 * @color: opaque tag value to use for the allocation
752 * @start: start of the allowed range for the allocation
753 * @end: end of the allowed range for the allocation
754 *
755 * This simply sets up the scanning routines with the parameters for the desired
756 * hole. Note that there's no need to specify allocation flags, since they only
757 * change the place a node is allocated from within a suitable hole.
758 *
759 * Warning:
760 * As long as the scan list is non-empty, no other operations than
761 * adding/removing nodes to/from the scan list are allowed.
762 */
763void drm_mm_init_scan_with_range(struct drm_mm *mm,
764 u64 size,
765 unsigned alignment,
766 unsigned long color,
767 u64 start,
768 u64 end)
769{
770 mm->scan_color = color;
771 mm->scan_alignment = alignment;
772 mm->scan_size = size;
773 mm->scanned_blocks = 0;
774 mm->scan_hit_start = 0;
775 mm->scan_hit_end = 0;
776 mm->scan_start = start;
777 mm->scan_end = end;
778 mm->scan_check_range = 1;
779 mm->prev_scanned_node = NULL;
780}
781EXPORT_SYMBOL(drm_mm_init_scan_with_range);
782
783/**
784 * drm_mm_scan_add_block - add a node to the scan list
785 * @node: drm_mm_node to add
786 *
787 * Add a node to the scan list that might be freed to make space for the desired
788 * hole.
789 *
790 * Returns:
791 * True if a hole has been found, false otherwise.
792 */
793bool drm_mm_scan_add_block(struct drm_mm_node *node)
794{
795 struct drm_mm *mm = node->mm;
796 struct drm_mm_node *prev_node;
797 u64 hole_start, hole_end;
798 u64 adj_start, adj_end;
799
800 mm->scanned_blocks++;
801
802 BUG_ON(node->scanned_block);
803 node->scanned_block = 1;
804
805 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
806 node_list);
807
808 node->scanned_preceeds_hole = prev_node->hole_follows;
809 prev_node->hole_follows = 1;
810 list_del(&node->node_list);
811 node->node_list.prev = &prev_node->node_list;
812 node->node_list.next = &mm->prev_scanned_node->node_list;
813 mm->prev_scanned_node = node;
814
815 adj_start = hole_start = drm_mm_hole_node_start(prev_node);
816 adj_end = hole_end = drm_mm_hole_node_end(prev_node);
817
818 if (mm->scan_check_range) {
819 if (adj_start < mm->scan_start)
820 adj_start = mm->scan_start;
821 if (adj_end > mm->scan_end)
822 adj_end = mm->scan_end;
823 }
824
825 if (mm->color_adjust)
826 mm->color_adjust(prev_node, mm->scan_color,
827 &adj_start, &adj_end);
828
829 if (check_free_hole(adj_start, adj_end,
830 mm->scan_size, mm->scan_alignment)) {
831 mm->scan_hit_start = hole_start;
832 mm->scan_hit_end = hole_end;
833 return true;
834 }
835
836 return false;
837}
838EXPORT_SYMBOL(drm_mm_scan_add_block);
839
840/**
841 * drm_mm_scan_remove_block - remove a node from the scan list
842 * @node: drm_mm_node to remove
843 *
844 * Nodes _must_ be removed in the exact same order from the scan list as they
845 * have been added, otherwise the internal state of the memory manager will be
846 * corrupted.
847 *
848 * When the scan list is empty, the selected memory nodes can be freed. An
849 * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
850 * return the just freed block (because its at the top of the free_stack list).
851 *
852 * Returns:
853 * True if this block should be evicted, false otherwise. Will always
854 * return false when no hole has been found.
855 */
856bool drm_mm_scan_remove_block(struct drm_mm_node *node)
857{
858 struct drm_mm *mm = node->mm;
859 struct drm_mm_node *prev_node;
860
861 mm->scanned_blocks--;
862
863 BUG_ON(!node->scanned_block);
864 node->scanned_block = 0;
865
866 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
867 node_list);
868
869 prev_node->hole_follows = node->scanned_preceeds_hole;
870 list_add(&node->node_list, &prev_node->node_list);
871
872 return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&
873 node->start < mm->scan_hit_end);
874}
875EXPORT_SYMBOL(drm_mm_scan_remove_block);
876
877/**
878 * drm_mm_clean - checks whether an allocator is clean
879 * @mm: drm_mm allocator to check
880 *
881 * Returns:
882 * True if the allocator is completely free, false if there's still a node
883 * allocated in it.
884 */
885bool drm_mm_clean(struct drm_mm * mm)
886{
887 struct list_head *head = &mm->head_node.node_list;
888
889 return (head->next->next == head);
890}
891EXPORT_SYMBOL(drm_mm_clean);
892
893/**
894 * drm_mm_init - initialize a drm-mm allocator
895 * @mm: the drm_mm structure to initialize
896 * @start: start of the range managed by @mm
897 * @size: end of the range managed by @mm
898 *
899 * Note that @mm must be cleared to 0 before calling this function.
900 */
901void drm_mm_init(struct drm_mm * mm, u64 start, u64 size)
902{
903 INIT_LIST_HEAD(&mm->hole_stack);
904 mm->scanned_blocks = 0;
905
906 /* Clever trick to avoid a special case in the free hole tracking. */
907 INIT_LIST_HEAD(&mm->head_node.node_list);
908 mm->head_node.allocated = 0;
909 mm->head_node.hole_follows = 1;
910 mm->head_node.scanned_block = 0;
911 mm->head_node.scanned_prev_free = 0;
912 mm->head_node.scanned_next_free = 0;
913 mm->head_node.mm = mm;
914 mm->head_node.start = start + size;
915 mm->head_node.size = start - mm->head_node.start;
916 list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
917
918 mm->interval_tree = RB_ROOT;
919
920 mm->color_adjust = NULL;
921}
922EXPORT_SYMBOL(drm_mm_init);
923
924/**
925 * drm_mm_takedown - clean up a drm_mm allocator
926 * @mm: drm_mm allocator to clean up
927 *
928 * Note that it is a bug to call this function on an allocator which is not
929 * clean.
930 */
931void drm_mm_takedown(struct drm_mm *mm)
932{
933 if (WARN(!list_empty(&mm->head_node.node_list),
934 "Memory manager not clean during takedown.\n"))
935 show_leaks(mm);
936
937}
938EXPORT_SYMBOL(drm_mm_takedown);
939
940static u64 drm_mm_debug_hole(struct drm_mm_node *entry,
941 const char *prefix)
942{
943 u64 hole_start, hole_end, hole_size;
944
945 if (entry->hole_follows) {
946 hole_start = drm_mm_hole_node_start(entry);
947 hole_end = drm_mm_hole_node_end(entry);
948 hole_size = hole_end - hole_start;
949 pr_debug("%s %#llx-%#llx: %llu: free\n", prefix, hole_start,
950 hole_end, hole_size);
951 return hole_size;
952 }
953
954 return 0;
955}
956
957/**
958 * drm_mm_debug_table - dump allocator state to dmesg
959 * @mm: drm_mm allocator to dump
960 * @prefix: prefix to use for dumping to dmesg
961 */
962void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
963{
964 struct drm_mm_node *entry;
965 u64 total_used = 0, total_free = 0, total = 0;
966
967 total_free += drm_mm_debug_hole(&mm->head_node, prefix);
968
969 drm_mm_for_each_node(entry, mm) {
970 pr_debug("%s %#llx-%#llx: %llu: used\n", prefix, entry->start,
971 entry->start + entry->size, entry->size);
972 total_used += entry->size;
973 total_free += drm_mm_debug_hole(entry, prefix);
974 }
975 total = total_free + total_used;
976
977 pr_debug("%s total: %llu, used %llu free %llu\n", prefix, total,
978 total_used, total_free);
979}
980EXPORT_SYMBOL(drm_mm_debug_table);
981
982#if defined(CONFIG_DEBUG_FS)
983static u64 drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry)
984{
985 u64 hole_start, hole_end, hole_size;
986
987 if (entry->hole_follows) {
988 hole_start = drm_mm_hole_node_start(entry);
989 hole_end = drm_mm_hole_node_end(entry);
990 hole_size = hole_end - hole_start;
991 seq_printf(m, "%#018llx-%#018llx: %llu: free\n", hole_start,
992 hole_end, hole_size);
993 return hole_size;
994 }
995
996 return 0;
997}
998
999/**
1000 * drm_mm_dump_table - dump allocator state to a seq_file
1001 * @m: seq_file to dump to
1002 * @mm: drm_mm allocator to dump
1003 */
1004int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
1005{
1006 struct drm_mm_node *entry;
1007 u64 total_used = 0, total_free = 0, total = 0;
1008
1009 total_free += drm_mm_dump_hole(m, &mm->head_node);
1010
1011 drm_mm_for_each_node(entry, mm) {
1012 seq_printf(m, "%#018llx-%#018llx: %llu: used\n", entry->start,
1013 entry->start + entry->size, entry->size);
1014 total_used += entry->size;
1015 total_free += drm_mm_dump_hole(m, entry);
1016 }
1017 total = total_free + total_used;
1018
1019 seq_printf(m, "total: %llu, used %llu free %llu\n", total,
1020 total_used, total_free);
1021 return 0;
1022}
1023EXPORT_SYMBOL(drm_mm_dump_table);
1024#endif
1/**************************************************************************
2 *
3 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND., USA.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
21 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
22 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
23 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
24 * USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 *
27 **************************************************************************/
28
29/*
30 * Generic simple memory manager implementation. Intended to be used as a base
31 * class implementation for more advanced memory managers.
32 *
33 * Note that the algorithm used is quite simple and there might be substantial
34 * performance gains if a smarter free list is implemented. Currently it is just an
35 * unordered stack of free regions. This could easily be improved if an RB-tree
36 * is used instead. At least if we expect heavy fragmentation.
37 *
38 * Aligned allocations can also see improvement.
39 *
40 * Authors:
41 * Thomas Hellström <thomas-at-tungstengraphics-dot-com>
42 */
43
44#include <drm/drmP.h>
45#include <drm/drm_mm.h>
46#include <linux/slab.h>
47#include <linux/seq_file.h>
48#include <linux/export.h>
49
50/**
51 * DOC: Overview
52 *
53 * drm_mm provides a simple range allocator. The drivers are free to use the
54 * resource allocator from the linux core if it suits them, the upside of drm_mm
55 * is that it's in the DRM core. Which means that it's easier to extend for
56 * some of the crazier special purpose needs of gpus.
57 *
58 * The main data struct is &drm_mm, allocations are tracked in &drm_mm_node.
59 * Drivers are free to embed either of them into their own suitable
60 * datastructures. drm_mm itself will not do any allocations of its own, so if
61 * drivers choose not to embed nodes they need to still allocate them
62 * themselves.
63 *
64 * The range allocator also supports reservation of preallocated blocks. This is
65 * useful for taking over initial mode setting configurations from the firmware,
66 * where an object needs to be created which exactly matches the firmware's
67 * scanout target. As long as the range is still free it can be inserted anytime
68 * after the allocator is initialized, which helps with avoiding looped
69 * depencies in the driver load sequence.
70 *
71 * drm_mm maintains a stack of most recently freed holes, which of all
72 * simplistic datastructures seems to be a fairly decent approach to clustering
73 * allocations and avoiding too much fragmentation. This means free space
74 * searches are O(num_holes). Given that all the fancy features drm_mm supports
75 * something better would be fairly complex and since gfx thrashing is a fairly
76 * steep cliff not a real concern. Removing a node again is O(1).
77 *
78 * drm_mm supports a few features: Alignment and range restrictions can be
79 * supplied. Further more every &drm_mm_node has a color value (which is just an
80 * opaqua unsigned long) which in conjunction with a driver callback can be used
81 * to implement sophisticated placement restrictions. The i915 DRM driver uses
82 * this to implement guard pages between incompatible caching domains in the
83 * graphics TT.
84 *
85 * Two behaviors are supported for searching and allocating: bottom-up and top-down.
86 * The default is bottom-up. Top-down allocation can be used if the memory area
87 * has different restrictions, or just to reduce fragmentation.
88 *
89 * Finally iteration helpers to walk all nodes and all holes are provided as are
90 * some basic allocator dumpers for debugging.
91 */
92
93static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
94 unsigned long size,
95 unsigned alignment,
96 unsigned long color,
97 enum drm_mm_search_flags flags);
98static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
99 unsigned long size,
100 unsigned alignment,
101 unsigned long color,
102 unsigned long start,
103 unsigned long end,
104 enum drm_mm_search_flags flags);
105
106static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
107 struct drm_mm_node *node,
108 unsigned long size, unsigned alignment,
109 unsigned long color,
110 enum drm_mm_allocator_flags flags)
111{
112 struct drm_mm *mm = hole_node->mm;
113 unsigned long hole_start = drm_mm_hole_node_start(hole_node);
114 unsigned long hole_end = drm_mm_hole_node_end(hole_node);
115 unsigned long adj_start = hole_start;
116 unsigned long adj_end = hole_end;
117
118 BUG_ON(node->allocated);
119
120 if (mm->color_adjust)
121 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
122
123 if (flags & DRM_MM_CREATE_TOP)
124 adj_start = adj_end - size;
125
126 if (alignment) {
127 unsigned tmp = adj_start % alignment;
128 if (tmp) {
129 if (flags & DRM_MM_CREATE_TOP)
130 adj_start -= tmp;
131 else
132 adj_start += alignment - tmp;
133 }
134 }
135
136 BUG_ON(adj_start < hole_start);
137 BUG_ON(adj_end > hole_end);
138
139 if (adj_start == hole_start) {
140 hole_node->hole_follows = 0;
141 list_del(&hole_node->hole_stack);
142 }
143
144 node->start = adj_start;
145 node->size = size;
146 node->mm = mm;
147 node->color = color;
148 node->allocated = 1;
149
150 INIT_LIST_HEAD(&node->hole_stack);
151 list_add(&node->node_list, &hole_node->node_list);
152
153 BUG_ON(node->start + node->size > adj_end);
154
155 node->hole_follows = 0;
156 if (__drm_mm_hole_node_start(node) < hole_end) {
157 list_add(&node->hole_stack, &mm->hole_stack);
158 node->hole_follows = 1;
159 }
160}
161
162/**
163 * drm_mm_reserve_node - insert an pre-initialized node
164 * @mm: drm_mm allocator to insert @node into
165 * @node: drm_mm_node to insert
166 *
167 * This functions inserts an already set-up drm_mm_node into the allocator,
168 * meaning that start, size and color must be set by the caller. This is useful
169 * to initialize the allocator with preallocated objects which must be set-up
170 * before the range allocator can be set-up, e.g. when taking over a firmware
171 * framebuffer.
172 *
173 * Returns:
174 * 0 on success, -ENOSPC if there's no hole where @node is.
175 */
176int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
177{
178 struct drm_mm_node *hole;
179 unsigned long end = node->start + node->size;
180 unsigned long hole_start;
181 unsigned long hole_end;
182
183 BUG_ON(node == NULL);
184
185 /* Find the relevant hole to add our node to */
186 drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
187 if (hole_start > node->start || hole_end < end)
188 continue;
189
190 node->mm = mm;
191 node->allocated = 1;
192
193 INIT_LIST_HEAD(&node->hole_stack);
194 list_add(&node->node_list, &hole->node_list);
195
196 if (node->start == hole_start) {
197 hole->hole_follows = 0;
198 list_del_init(&hole->hole_stack);
199 }
200
201 node->hole_follows = 0;
202 if (end != hole_end) {
203 list_add(&node->hole_stack, &mm->hole_stack);
204 node->hole_follows = 1;
205 }
206
207 return 0;
208 }
209
210 return -ENOSPC;
211}
212EXPORT_SYMBOL(drm_mm_reserve_node);
213
214/**
215 * drm_mm_insert_node_generic - search for space and insert @node
216 * @mm: drm_mm to allocate from
217 * @node: preallocate node to insert
218 * @size: size of the allocation
219 * @alignment: alignment of the allocation
220 * @color: opaque tag value to use for this node
221 * @sflags: flags to fine-tune the allocation search
222 * @aflags: flags to fine-tune the allocation behavior
223 *
224 * The preallocated node must be cleared to 0.
225 *
226 * Returns:
227 * 0 on success, -ENOSPC if there's no suitable hole.
228 */
229int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
230 unsigned long size, unsigned alignment,
231 unsigned long color,
232 enum drm_mm_search_flags sflags,
233 enum drm_mm_allocator_flags aflags)
234{
235 struct drm_mm_node *hole_node;
236
237 hole_node = drm_mm_search_free_generic(mm, size, alignment,
238 color, sflags);
239 if (!hole_node)
240 return -ENOSPC;
241
242 drm_mm_insert_helper(hole_node, node, size, alignment, color, aflags);
243 return 0;
244}
245EXPORT_SYMBOL(drm_mm_insert_node_generic);
246
247static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
248 struct drm_mm_node *node,
249 unsigned long size, unsigned alignment,
250 unsigned long color,
251 unsigned long start, unsigned long end,
252 enum drm_mm_allocator_flags flags)
253{
254 struct drm_mm *mm = hole_node->mm;
255 unsigned long hole_start = drm_mm_hole_node_start(hole_node);
256 unsigned long hole_end = drm_mm_hole_node_end(hole_node);
257 unsigned long adj_start = hole_start;
258 unsigned long adj_end = hole_end;
259
260 BUG_ON(!hole_node->hole_follows || node->allocated);
261
262 if (adj_start < start)
263 adj_start = start;
264 if (adj_end > end)
265 adj_end = end;
266
267 if (flags & DRM_MM_CREATE_TOP)
268 adj_start = adj_end - size;
269
270 if (mm->color_adjust)
271 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
272
273 if (alignment) {
274 unsigned tmp = adj_start % alignment;
275 if (tmp) {
276 if (flags & DRM_MM_CREATE_TOP)
277 adj_start -= tmp;
278 else
279 adj_start += alignment - tmp;
280 }
281 }
282
283 if (adj_start == hole_start) {
284 hole_node->hole_follows = 0;
285 list_del(&hole_node->hole_stack);
286 }
287
288 node->start = adj_start;
289 node->size = size;
290 node->mm = mm;
291 node->color = color;
292 node->allocated = 1;
293
294 INIT_LIST_HEAD(&node->hole_stack);
295 list_add(&node->node_list, &hole_node->node_list);
296
297 BUG_ON(node->start < start);
298 BUG_ON(node->start < adj_start);
299 BUG_ON(node->start + node->size > adj_end);
300 BUG_ON(node->start + node->size > end);
301
302 node->hole_follows = 0;
303 if (__drm_mm_hole_node_start(node) < hole_end) {
304 list_add(&node->hole_stack, &mm->hole_stack);
305 node->hole_follows = 1;
306 }
307}
308
309/**
310 * drm_mm_insert_node_in_range_generic - ranged search for space and insert @node
311 * @mm: drm_mm to allocate from
312 * @node: preallocate node to insert
313 * @size: size of the allocation
314 * @alignment: alignment of the allocation
315 * @color: opaque tag value to use for this node
316 * @start: start of the allowed range for this node
317 * @end: end of the allowed range for this node
318 * @sflags: flags to fine-tune the allocation search
319 * @aflags: flags to fine-tune the allocation behavior
320 *
321 * The preallocated node must be cleared to 0.
322 *
323 * Returns:
324 * 0 on success, -ENOSPC if there's no suitable hole.
325 */
326int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,
327 unsigned long size, unsigned alignment,
328 unsigned long color,
329 unsigned long start, unsigned long end,
330 enum drm_mm_search_flags sflags,
331 enum drm_mm_allocator_flags aflags)
332{
333 struct drm_mm_node *hole_node;
334
335 hole_node = drm_mm_search_free_in_range_generic(mm,
336 size, alignment, color,
337 start, end, sflags);
338 if (!hole_node)
339 return -ENOSPC;
340
341 drm_mm_insert_helper_range(hole_node, node,
342 size, alignment, color,
343 start, end, aflags);
344 return 0;
345}
346EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic);
347
348/**
349 * drm_mm_remove_node - Remove a memory node from the allocator.
350 * @node: drm_mm_node to remove
351 *
352 * This just removes a node from its drm_mm allocator. The node does not need to
353 * be cleared again before it can be re-inserted into this or any other drm_mm
354 * allocator. It is a bug to call this function on a un-allocated node.
355 */
356void drm_mm_remove_node(struct drm_mm_node *node)
357{
358 struct drm_mm *mm = node->mm;
359 struct drm_mm_node *prev_node;
360
361 if (WARN_ON(!node->allocated))
362 return;
363
364 BUG_ON(node->scanned_block || node->scanned_prev_free
365 || node->scanned_next_free);
366
367 prev_node =
368 list_entry(node->node_list.prev, struct drm_mm_node, node_list);
369
370 if (node->hole_follows) {
371 BUG_ON(__drm_mm_hole_node_start(node) ==
372 __drm_mm_hole_node_end(node));
373 list_del(&node->hole_stack);
374 } else
375 BUG_ON(__drm_mm_hole_node_start(node) !=
376 __drm_mm_hole_node_end(node));
377
378
379 if (!prev_node->hole_follows) {
380 prev_node->hole_follows = 1;
381 list_add(&prev_node->hole_stack, &mm->hole_stack);
382 } else
383 list_move(&prev_node->hole_stack, &mm->hole_stack);
384
385 list_del(&node->node_list);
386 node->allocated = 0;
387}
388EXPORT_SYMBOL(drm_mm_remove_node);
389
390static int check_free_hole(unsigned long start, unsigned long end,
391 unsigned long size, unsigned alignment)
392{
393 if (end - start < size)
394 return 0;
395
396 if (alignment) {
397 unsigned tmp = start % alignment;
398 if (tmp)
399 start += alignment - tmp;
400 }
401
402 return end >= start + size;
403}
404
405static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
406 unsigned long size,
407 unsigned alignment,
408 unsigned long color,
409 enum drm_mm_search_flags flags)
410{
411 struct drm_mm_node *entry;
412 struct drm_mm_node *best;
413 unsigned long adj_start;
414 unsigned long adj_end;
415 unsigned long best_size;
416
417 BUG_ON(mm->scanned_blocks);
418
419 best = NULL;
420 best_size = ~0UL;
421
422 __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
423 flags & DRM_MM_SEARCH_BELOW) {
424 unsigned long hole_size = adj_end - adj_start;
425
426 if (mm->color_adjust) {
427 mm->color_adjust(entry, color, &adj_start, &adj_end);
428 if (adj_end <= adj_start)
429 continue;
430 }
431
432 if (!check_free_hole(adj_start, adj_end, size, alignment))
433 continue;
434
435 if (!(flags & DRM_MM_SEARCH_BEST))
436 return entry;
437
438 if (hole_size < best_size) {
439 best = entry;
440 best_size = hole_size;
441 }
442 }
443
444 return best;
445}
446
447static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
448 unsigned long size,
449 unsigned alignment,
450 unsigned long color,
451 unsigned long start,
452 unsigned long end,
453 enum drm_mm_search_flags flags)
454{
455 struct drm_mm_node *entry;
456 struct drm_mm_node *best;
457 unsigned long adj_start;
458 unsigned long adj_end;
459 unsigned long best_size;
460
461 BUG_ON(mm->scanned_blocks);
462
463 best = NULL;
464 best_size = ~0UL;
465
466 __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
467 flags & DRM_MM_SEARCH_BELOW) {
468 unsigned long hole_size = adj_end - adj_start;
469
470 if (adj_start < start)
471 adj_start = start;
472 if (adj_end > end)
473 adj_end = end;
474
475 if (mm->color_adjust) {
476 mm->color_adjust(entry, color, &adj_start, &adj_end);
477 if (adj_end <= adj_start)
478 continue;
479 }
480
481 if (!check_free_hole(adj_start, adj_end, size, alignment))
482 continue;
483
484 if (!(flags & DRM_MM_SEARCH_BEST))
485 return entry;
486
487 if (hole_size < best_size) {
488 best = entry;
489 best_size = hole_size;
490 }
491 }
492
493 return best;
494}
495
496/**
497 * drm_mm_replace_node - move an allocation from @old to @new
498 * @old: drm_mm_node to remove from the allocator
499 * @new: drm_mm_node which should inherit @old's allocation
500 *
501 * This is useful for when drivers embed the drm_mm_node structure and hence
502 * can't move allocations by reassigning pointers. It's a combination of remove
503 * and insert with the guarantee that the allocation start will match.
504 */
505void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
506{
507 list_replace(&old->node_list, &new->node_list);
508 list_replace(&old->hole_stack, &new->hole_stack);
509 new->hole_follows = old->hole_follows;
510 new->mm = old->mm;
511 new->start = old->start;
512 new->size = old->size;
513 new->color = old->color;
514
515 old->allocated = 0;
516 new->allocated = 1;
517}
518EXPORT_SYMBOL(drm_mm_replace_node);
519
520/**
521 * DOC: lru scan roaster
522 *
523 * Very often GPUs need to have continuous allocations for a given object. When
524 * evicting objects to make space for a new one it is therefore not most
525 * efficient when we simply start to select all objects from the tail of an LRU
526 * until there's a suitable hole: Especially for big objects or nodes that
527 * otherwise have special allocation constraints there's a good chance we evict
528 * lots of (smaller) objects unecessarily.
529 *
530 * The DRM range allocator supports this use-case through the scanning
531 * interfaces. First a scan operation needs to be initialized with
532 * drm_mm_init_scan() or drm_mm_init_scan_with_range(). The the driver adds
533 * objects to the roaster (probably by walking an LRU list, but this can be
534 * freely implemented) until a suitable hole is found or there's no further
535 * evitable object.
536 *
537 * The the driver must walk through all objects again in exactly the reverse
538 * order to restore the allocator state. Note that while the allocator is used
539 * in the scan mode no other operation is allowed.
540 *
541 * Finally the driver evicts all objects selected in the scan. Adding and
542 * removing an object is O(1), and since freeing a node is also O(1) the overall
543 * complexity is O(scanned_objects). So like the free stack which needs to be
544 * walked before a scan operation even begins this is linear in the number of
545 * objects. It doesn't seem to hurt badly.
546 */
547
548/**
549 * drm_mm_init_scan - initialize lru scanning
550 * @mm: drm_mm to scan
551 * @size: size of the allocation
552 * @alignment: alignment of the allocation
553 * @color: opaque tag value to use for the allocation
554 *
555 * This simply sets up the scanning routines with the parameters for the desired
556 * hole. Note that there's no need to specify allocation flags, since they only
557 * change the place a node is allocated from within a suitable hole.
558 *
559 * Warning:
560 * As long as the scan list is non-empty, no other operations than
561 * adding/removing nodes to/from the scan list are allowed.
562 */
563void drm_mm_init_scan(struct drm_mm *mm,
564 unsigned long size,
565 unsigned alignment,
566 unsigned long color)
567{
568 mm->scan_color = color;
569 mm->scan_alignment = alignment;
570 mm->scan_size = size;
571 mm->scanned_blocks = 0;
572 mm->scan_hit_start = 0;
573 mm->scan_hit_end = 0;
574 mm->scan_check_range = 0;
575 mm->prev_scanned_node = NULL;
576}
577EXPORT_SYMBOL(drm_mm_init_scan);
578
579/**
580 * drm_mm_init_scan - initialize range-restricted lru scanning
581 * @mm: drm_mm to scan
582 * @size: size of the allocation
583 * @alignment: alignment of the allocation
584 * @color: opaque tag value to use for the allocation
585 * @start: start of the allowed range for the allocation
586 * @end: end of the allowed range for the allocation
587 *
588 * This simply sets up the scanning routines with the parameters for the desired
589 * hole. Note that there's no need to specify allocation flags, since they only
590 * change the place a node is allocated from within a suitable hole.
591 *
592 * Warning:
593 * As long as the scan list is non-empty, no other operations than
594 * adding/removing nodes to/from the scan list are allowed.
595 */
596void drm_mm_init_scan_with_range(struct drm_mm *mm,
597 unsigned long size,
598 unsigned alignment,
599 unsigned long color,
600 unsigned long start,
601 unsigned long end)
602{
603 mm->scan_color = color;
604 mm->scan_alignment = alignment;
605 mm->scan_size = size;
606 mm->scanned_blocks = 0;
607 mm->scan_hit_start = 0;
608 mm->scan_hit_end = 0;
609 mm->scan_start = start;
610 mm->scan_end = end;
611 mm->scan_check_range = 1;
612 mm->prev_scanned_node = NULL;
613}
614EXPORT_SYMBOL(drm_mm_init_scan_with_range);
615
616/**
617 * drm_mm_scan_add_block - add a node to the scan list
618 * @node: drm_mm_node to add
619 *
620 * Add a node to the scan list that might be freed to make space for the desired
621 * hole.
622 *
623 * Returns:
624 * True if a hole has been found, false otherwise.
625 */
626bool drm_mm_scan_add_block(struct drm_mm_node *node)
627{
628 struct drm_mm *mm = node->mm;
629 struct drm_mm_node *prev_node;
630 unsigned long hole_start, hole_end;
631 unsigned long adj_start, adj_end;
632
633 mm->scanned_blocks++;
634
635 BUG_ON(node->scanned_block);
636 node->scanned_block = 1;
637
638 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
639 node_list);
640
641 node->scanned_preceeds_hole = prev_node->hole_follows;
642 prev_node->hole_follows = 1;
643 list_del(&node->node_list);
644 node->node_list.prev = &prev_node->node_list;
645 node->node_list.next = &mm->prev_scanned_node->node_list;
646 mm->prev_scanned_node = node;
647
648 adj_start = hole_start = drm_mm_hole_node_start(prev_node);
649 adj_end = hole_end = drm_mm_hole_node_end(prev_node);
650
651 if (mm->scan_check_range) {
652 if (adj_start < mm->scan_start)
653 adj_start = mm->scan_start;
654 if (adj_end > mm->scan_end)
655 adj_end = mm->scan_end;
656 }
657
658 if (mm->color_adjust)
659 mm->color_adjust(prev_node, mm->scan_color,
660 &adj_start, &adj_end);
661
662 if (check_free_hole(adj_start, adj_end,
663 mm->scan_size, mm->scan_alignment)) {
664 mm->scan_hit_start = hole_start;
665 mm->scan_hit_end = hole_end;
666 return true;
667 }
668
669 return false;
670}
671EXPORT_SYMBOL(drm_mm_scan_add_block);
672
673/**
674 * drm_mm_scan_remove_block - remove a node from the scan list
675 * @node: drm_mm_node to remove
676 *
677 * Nodes _must_ be removed in the exact same order from the scan list as they
678 * have been added, otherwise the internal state of the memory manager will be
679 * corrupted.
680 *
681 * When the scan list is empty, the selected memory nodes can be freed. An
682 * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
683 * return the just freed block (because its at the top of the free_stack list).
684 *
685 * Returns:
686 * True if this block should be evicted, false otherwise. Will always
687 * return false when no hole has been found.
688 */
689bool drm_mm_scan_remove_block(struct drm_mm_node *node)
690{
691 struct drm_mm *mm = node->mm;
692 struct drm_mm_node *prev_node;
693
694 mm->scanned_blocks--;
695
696 BUG_ON(!node->scanned_block);
697 node->scanned_block = 0;
698
699 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
700 node_list);
701
702 prev_node->hole_follows = node->scanned_preceeds_hole;
703 list_add(&node->node_list, &prev_node->node_list);
704
705 return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&
706 node->start < mm->scan_hit_end);
707}
708EXPORT_SYMBOL(drm_mm_scan_remove_block);
709
710/**
711 * drm_mm_clean - checks whether an allocator is clean
712 * @mm: drm_mm allocator to check
713 *
714 * Returns:
715 * True if the allocator is completely free, false if there's still a node
716 * allocated in it.
717 */
718bool drm_mm_clean(struct drm_mm * mm)
719{
720 struct list_head *head = &mm->head_node.node_list;
721
722 return (head->next->next == head);
723}
724EXPORT_SYMBOL(drm_mm_clean);
725
726/**
727 * drm_mm_init - initialize a drm-mm allocator
728 * @mm: the drm_mm structure to initialize
729 * @start: start of the range managed by @mm
730 * @size: end of the range managed by @mm
731 *
732 * Note that @mm must be cleared to 0 before calling this function.
733 */
734void drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
735{
736 INIT_LIST_HEAD(&mm->hole_stack);
737 mm->scanned_blocks = 0;
738
739 /* Clever trick to avoid a special case in the free hole tracking. */
740 INIT_LIST_HEAD(&mm->head_node.node_list);
741 INIT_LIST_HEAD(&mm->head_node.hole_stack);
742 mm->head_node.hole_follows = 1;
743 mm->head_node.scanned_block = 0;
744 mm->head_node.scanned_prev_free = 0;
745 mm->head_node.scanned_next_free = 0;
746 mm->head_node.mm = mm;
747 mm->head_node.start = start + size;
748 mm->head_node.size = start - mm->head_node.start;
749 list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
750
751 mm->color_adjust = NULL;
752}
753EXPORT_SYMBOL(drm_mm_init);
754
755/**
756 * drm_mm_takedown - clean up a drm_mm allocator
757 * @mm: drm_mm allocator to clean up
758 *
759 * Note that it is a bug to call this function on an allocator which is not
760 * clean.
761 */
762void drm_mm_takedown(struct drm_mm * mm)
763{
764 WARN(!list_empty(&mm->head_node.node_list),
765 "Memory manager not clean during takedown.\n");
766}
767EXPORT_SYMBOL(drm_mm_takedown);
768
769static unsigned long drm_mm_debug_hole(struct drm_mm_node *entry,
770 const char *prefix)
771{
772 unsigned long hole_start, hole_end, hole_size;
773
774 if (entry->hole_follows) {
775 hole_start = drm_mm_hole_node_start(entry);
776 hole_end = drm_mm_hole_node_end(entry);
777 hole_size = hole_end - hole_start;
778 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: free\n",
779 prefix, hole_start, hole_end,
780 hole_size);
781 return hole_size;
782 }
783
784 return 0;
785}
786
787/**
788 * drm_mm_debug_table - dump allocator state to dmesg
789 * @mm: drm_mm allocator to dump
790 * @prefix: prefix to use for dumping to dmesg
791 */
792void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
793{
794 struct drm_mm_node *entry;
795 unsigned long total_used = 0, total_free = 0, total = 0;
796
797 total_free += drm_mm_debug_hole(&mm->head_node, prefix);
798
799 drm_mm_for_each_node(entry, mm) {
800 printk(KERN_DEBUG "%s 0x%08lx-0x%08lx: %8lu: used\n",
801 prefix, entry->start, entry->start + entry->size,
802 entry->size);
803 total_used += entry->size;
804 total_free += drm_mm_debug_hole(entry, prefix);
805 }
806 total = total_free + total_used;
807
808 printk(KERN_DEBUG "%s total: %lu, used %lu free %lu\n", prefix, total,
809 total_used, total_free);
810}
811EXPORT_SYMBOL(drm_mm_debug_table);
812
813#if defined(CONFIG_DEBUG_FS)
814static unsigned long drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry)
815{
816 unsigned long hole_start, hole_end, hole_size;
817
818 if (entry->hole_follows) {
819 hole_start = drm_mm_hole_node_start(entry);
820 hole_end = drm_mm_hole_node_end(entry);
821 hole_size = hole_end - hole_start;
822 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: free\n",
823 hole_start, hole_end, hole_size);
824 return hole_size;
825 }
826
827 return 0;
828}
829
830/**
831 * drm_mm_dump_table - dump allocator state to a seq_file
832 * @m: seq_file to dump to
833 * @mm: drm_mm allocator to dump
834 */
835int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
836{
837 struct drm_mm_node *entry;
838 unsigned long total_used = 0, total_free = 0, total = 0;
839
840 total_free += drm_mm_dump_hole(m, &mm->head_node);
841
842 drm_mm_for_each_node(entry, mm) {
843 seq_printf(m, "0x%08lx-0x%08lx: 0x%08lx: used\n",
844 entry->start, entry->start + entry->size,
845 entry->size);
846 total_used += entry->size;
847 total_free += drm_mm_dump_hole(m, entry);
848 }
849 total = total_free + total_used;
850
851 seq_printf(m, "total: %lu, used %lu free %lu\n", total, total_used, total_free);
852 return 0;
853}
854EXPORT_SYMBOL(drm_mm_dump_table);
855#endif