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
93 static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
94 u64 size,
95 unsigned alignment,
96 unsigned long color,
97 enum drm_mm_search_flags flags);
98 static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
99 u64 size,
100 unsigned alignment,
101 unsigned long color,
102 u64 start,
103 u64 end,
104 enum drm_mm_search_flags flags);
105
drm_mm_insert_helper(struct drm_mm_node * hole_node,struct drm_mm_node * node,u64 size,unsigned alignment,unsigned long color,enum drm_mm_allocator_flags flags)106 static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
107 struct drm_mm_node *node,
108 u64 size, unsigned alignment,
109 unsigned long color,
110 enum drm_mm_allocator_flags flags)
111 {
112 struct drm_mm *mm = hole_node->mm;
113 u64 hole_start = drm_mm_hole_node_start(hole_node);
114 u64 hole_end = drm_mm_hole_node_end(hole_node);
115 u64 adj_start = hole_start;
116 u64 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 u64 tmp = adj_start;
128 unsigned rem;
129
130 rem = do_div(tmp, alignment);
131 if (rem) {
132 if (flags & DRM_MM_CREATE_TOP)
133 adj_start -= rem;
134 else
135 adj_start += alignment - rem;
136 }
137 }
138
139 BUG_ON(adj_start < hole_start);
140 BUG_ON(adj_end > hole_end);
141
142 if (adj_start == hole_start) {
143 hole_node->hole_follows = 0;
144 list_del(&hole_node->hole_stack);
145 }
146
147 node->start = adj_start;
148 node->size = size;
149 node->mm = mm;
150 node->color = color;
151 node->allocated = 1;
152
153 INIT_LIST_HEAD(&node->hole_stack);
154 list_add(&node->node_list, &hole_node->node_list);
155
156 BUG_ON(node->start + node->size > adj_end);
157
158 node->hole_follows = 0;
159 if (__drm_mm_hole_node_start(node) < hole_end) {
160 list_add(&node->hole_stack, &mm->hole_stack);
161 node->hole_follows = 1;
162 }
163 }
164
165 /**
166 * drm_mm_reserve_node - insert an pre-initialized node
167 * @mm: drm_mm allocator to insert @node into
168 * @node: drm_mm_node to insert
169 *
170 * This functions inserts an already set-up drm_mm_node into the allocator,
171 * meaning that start, size and color must be set by the caller. This is useful
172 * to initialize the allocator with preallocated objects which must be set-up
173 * before the range allocator can be set-up, e.g. when taking over a firmware
174 * framebuffer.
175 *
176 * Returns:
177 * 0 on success, -ENOSPC if there's no hole where @node is.
178 */
drm_mm_reserve_node(struct drm_mm * mm,struct drm_mm_node * node)179 int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
180 {
181 struct drm_mm_node *hole;
182 u64 end = node->start + node->size;
183 u64 hole_start;
184 u64 hole_end;
185
186 BUG_ON(node == NULL);
187
188 /* Find the relevant hole to add our node to */
189 drm_mm_for_each_hole(hole, mm, hole_start, hole_end) {
190 if (hole_start > node->start || hole_end < end)
191 continue;
192
193 node->mm = mm;
194 node->allocated = 1;
195
196 INIT_LIST_HEAD(&node->hole_stack);
197 list_add(&node->node_list, &hole->node_list);
198
199 if (node->start == hole_start) {
200 hole->hole_follows = 0;
201 list_del_init(&hole->hole_stack);
202 }
203
204 node->hole_follows = 0;
205 if (end != hole_end) {
206 list_add(&node->hole_stack, &mm->hole_stack);
207 node->hole_follows = 1;
208 }
209
210 return 0;
211 }
212
213 return -ENOSPC;
214 }
215 EXPORT_SYMBOL(drm_mm_reserve_node);
216
217 /**
218 * drm_mm_insert_node_generic - search for space and insert @node
219 * @mm: drm_mm to allocate from
220 * @node: preallocate node to insert
221 * @size: size of the allocation
222 * @alignment: alignment of the allocation
223 * @color: opaque tag value to use for this node
224 * @sflags: flags to fine-tune the allocation search
225 * @aflags: flags to fine-tune the allocation behavior
226 *
227 * The preallocated node must be cleared to 0.
228 *
229 * Returns:
230 * 0 on success, -ENOSPC if there's no suitable hole.
231 */
drm_mm_insert_node_generic(struct drm_mm * mm,struct drm_mm_node * node,u64 size,unsigned alignment,unsigned long color,enum drm_mm_search_flags sflags,enum drm_mm_allocator_flags aflags)232 int drm_mm_insert_node_generic(struct drm_mm *mm, struct drm_mm_node *node,
233 u64 size, unsigned alignment,
234 unsigned long color,
235 enum drm_mm_search_flags sflags,
236 enum drm_mm_allocator_flags aflags)
237 {
238 struct drm_mm_node *hole_node;
239
240 hole_node = drm_mm_search_free_generic(mm, size, alignment,
241 color, sflags);
242 if (!hole_node)
243 return -ENOSPC;
244
245 drm_mm_insert_helper(hole_node, node, size, alignment, color, aflags);
246 return 0;
247 }
248 EXPORT_SYMBOL(drm_mm_insert_node_generic);
249
drm_mm_insert_helper_range(struct drm_mm_node * hole_node,struct drm_mm_node * node,u64 size,unsigned alignment,unsigned long color,u64 start,u64 end,enum drm_mm_allocator_flags flags)250 static void drm_mm_insert_helper_range(struct drm_mm_node *hole_node,
251 struct drm_mm_node *node,
252 u64 size, unsigned alignment,
253 unsigned long color,
254 u64 start, u64 end,
255 enum drm_mm_allocator_flags flags)
256 {
257 struct drm_mm *mm = hole_node->mm;
258 u64 hole_start = drm_mm_hole_node_start(hole_node);
259 u64 hole_end = drm_mm_hole_node_end(hole_node);
260 u64 adj_start = hole_start;
261 u64 adj_end = hole_end;
262
263 BUG_ON(!hole_node->hole_follows || node->allocated);
264
265 if (mm->color_adjust)
266 mm->color_adjust(hole_node, color, &adj_start, &adj_end);
267
268 adj_start = max(adj_start, start);
269 adj_end = min(adj_end, end);
270
271 if (flags & DRM_MM_CREATE_TOP)
272 adj_start = adj_end - size;
273
274 if (alignment) {
275 u64 tmp = adj_start;
276 unsigned rem;
277
278 rem = do_div(tmp, alignment);
279 if (rem) {
280 if (flags & DRM_MM_CREATE_TOP)
281 adj_start -= rem;
282 else
283 adj_start += alignment - rem;
284 }
285 }
286
287 if (adj_start == hole_start) {
288 hole_node->hole_follows = 0;
289 list_del(&hole_node->hole_stack);
290 }
291
292 node->start = adj_start;
293 node->size = size;
294 node->mm = mm;
295 node->color = color;
296 node->allocated = 1;
297
298 INIT_LIST_HEAD(&node->hole_stack);
299 list_add(&node->node_list, &hole_node->node_list);
300
301 BUG_ON(node->start < start);
302 BUG_ON(node->start < adj_start);
303 BUG_ON(node->start + node->size > adj_end);
304 BUG_ON(node->start + node->size > end);
305
306 node->hole_follows = 0;
307 if (__drm_mm_hole_node_start(node) < hole_end) {
308 list_add(&node->hole_stack, &mm->hole_stack);
309 node->hole_follows = 1;
310 }
311 }
312
313 /**
314 * drm_mm_insert_node_in_range_generic - ranged search for space and insert @node
315 * @mm: drm_mm to allocate from
316 * @node: preallocate node to insert
317 * @size: size of the allocation
318 * @alignment: alignment of the allocation
319 * @color: opaque tag value to use for this node
320 * @start: start of the allowed range for this node
321 * @end: end of the allowed range for this node
322 * @sflags: flags to fine-tune the allocation search
323 * @aflags: flags to fine-tune the allocation behavior
324 *
325 * The preallocated node must be cleared to 0.
326 *
327 * Returns:
328 * 0 on success, -ENOSPC if there's no suitable hole.
329 */
drm_mm_insert_node_in_range_generic(struct drm_mm * mm,struct drm_mm_node * node,u64 size,unsigned alignment,unsigned long color,u64 start,u64 end,enum drm_mm_search_flags sflags,enum drm_mm_allocator_flags aflags)330 int drm_mm_insert_node_in_range_generic(struct drm_mm *mm, struct drm_mm_node *node,
331 u64 size, unsigned alignment,
332 unsigned long color,
333 u64 start, u64 end,
334 enum drm_mm_search_flags sflags,
335 enum drm_mm_allocator_flags aflags)
336 {
337 struct drm_mm_node *hole_node;
338
339 hole_node = drm_mm_search_free_in_range_generic(mm,
340 size, alignment, color,
341 start, end, sflags);
342 if (!hole_node)
343 return -ENOSPC;
344
345 drm_mm_insert_helper_range(hole_node, node,
346 size, alignment, color,
347 start, end, aflags);
348 return 0;
349 }
350 EXPORT_SYMBOL(drm_mm_insert_node_in_range_generic);
351
352 /**
353 * drm_mm_remove_node - Remove a memory node from the allocator.
354 * @node: drm_mm_node to remove
355 *
356 * This just removes a node from its drm_mm allocator. The node does not need to
357 * be cleared again before it can be re-inserted into this or any other drm_mm
358 * allocator. It is a bug to call this function on a un-allocated node.
359 */
drm_mm_remove_node(struct drm_mm_node * node)360 void drm_mm_remove_node(struct drm_mm_node *node)
361 {
362 struct drm_mm *mm = node->mm;
363 struct drm_mm_node *prev_node;
364
365 if (WARN_ON(!node->allocated))
366 return;
367
368 BUG_ON(node->scanned_block || node->scanned_prev_free
369 || node->scanned_next_free);
370
371 prev_node =
372 list_entry(node->node_list.prev, struct drm_mm_node, node_list);
373
374 if (node->hole_follows) {
375 BUG_ON(__drm_mm_hole_node_start(node) ==
376 __drm_mm_hole_node_end(node));
377 list_del(&node->hole_stack);
378 } else
379 BUG_ON(__drm_mm_hole_node_start(node) !=
380 __drm_mm_hole_node_end(node));
381
382
383 if (!prev_node->hole_follows) {
384 prev_node->hole_follows = 1;
385 list_add(&prev_node->hole_stack, &mm->hole_stack);
386 } else
387 list_move(&prev_node->hole_stack, &mm->hole_stack);
388
389 list_del(&node->node_list);
390 node->allocated = 0;
391 }
392 EXPORT_SYMBOL(drm_mm_remove_node);
393
check_free_hole(u64 start,u64 end,u64 size,unsigned alignment)394 static int check_free_hole(u64 start, u64 end, u64 size, unsigned alignment)
395 {
396 if (end - start < size)
397 return 0;
398
399 if (alignment) {
400 u64 tmp = start;
401 unsigned rem;
402
403 rem = do_div(tmp, alignment);
404 if (rem)
405 start += alignment - rem;
406 }
407
408 return end >= start + size;
409 }
410
drm_mm_search_free_generic(const struct drm_mm * mm,u64 size,unsigned alignment,unsigned long color,enum drm_mm_search_flags flags)411 static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
412 u64 size,
413 unsigned alignment,
414 unsigned long color,
415 enum drm_mm_search_flags flags)
416 {
417 struct drm_mm_node *entry;
418 struct drm_mm_node *best;
419 u64 adj_start;
420 u64 adj_end;
421 u64 best_size;
422
423 BUG_ON(mm->scanned_blocks);
424
425 best = NULL;
426 best_size = ~0UL;
427
428 __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
429 flags & DRM_MM_SEARCH_BELOW) {
430 u64 hole_size = adj_end - adj_start;
431
432 if (mm->color_adjust) {
433 mm->color_adjust(entry, color, &adj_start, &adj_end);
434 if (adj_end <= adj_start)
435 continue;
436 }
437
438 if (!check_free_hole(adj_start, adj_end, size, alignment))
439 continue;
440
441 if (!(flags & DRM_MM_SEARCH_BEST))
442 return entry;
443
444 if (hole_size < best_size) {
445 best = entry;
446 best_size = hole_size;
447 }
448 }
449
450 return best;
451 }
452
drm_mm_search_free_in_range_generic(const struct drm_mm * mm,u64 size,unsigned alignment,unsigned long color,u64 start,u64 end,enum drm_mm_search_flags flags)453 static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
454 u64 size,
455 unsigned alignment,
456 unsigned long color,
457 u64 start,
458 u64 end,
459 enum drm_mm_search_flags flags)
460 {
461 struct drm_mm_node *entry;
462 struct drm_mm_node *best;
463 u64 adj_start;
464 u64 adj_end;
465 u64 best_size;
466
467 BUG_ON(mm->scanned_blocks);
468
469 best = NULL;
470 best_size = ~0UL;
471
472 __drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
473 flags & DRM_MM_SEARCH_BELOW) {
474 u64 hole_size = adj_end - adj_start;
475
476 if (mm->color_adjust) {
477 mm->color_adjust(entry, color, &adj_start, &adj_end);
478 if (adj_end <= adj_start)
479 continue;
480 }
481
482 adj_start = max(adj_start, start);
483 adj_end = min(adj_end, end);
484
485 if (!check_free_hole(adj_start, adj_end, size, alignment))
486 continue;
487
488 if (!(flags & DRM_MM_SEARCH_BEST))
489 return entry;
490
491 if (hole_size < best_size) {
492 best = entry;
493 best_size = hole_size;
494 }
495 }
496
497 return best;
498 }
499
500 /**
501 * drm_mm_replace_node - move an allocation from @old to @new
502 * @old: drm_mm_node to remove from the allocator
503 * @new: drm_mm_node which should inherit @old's allocation
504 *
505 * This is useful for when drivers embed the drm_mm_node structure and hence
506 * can't move allocations by reassigning pointers. It's a combination of remove
507 * and insert with the guarantee that the allocation start will match.
508 */
drm_mm_replace_node(struct drm_mm_node * old,struct drm_mm_node * new)509 void drm_mm_replace_node(struct drm_mm_node *old, struct drm_mm_node *new)
510 {
511 list_replace(&old->node_list, &new->node_list);
512 list_replace(&old->hole_stack, &new->hole_stack);
513 new->hole_follows = old->hole_follows;
514 new->mm = old->mm;
515 new->start = old->start;
516 new->size = old->size;
517 new->color = old->color;
518
519 old->allocated = 0;
520 new->allocated = 1;
521 }
522 EXPORT_SYMBOL(drm_mm_replace_node);
523
524 /**
525 * DOC: lru scan roaster
526 *
527 * Very often GPUs need to have continuous allocations for a given object. When
528 * evicting objects to make space for a new one it is therefore not most
529 * efficient when we simply start to select all objects from the tail of an LRU
530 * until there's a suitable hole: Especially for big objects or nodes that
531 * otherwise have special allocation constraints there's a good chance we evict
532 * lots of (smaller) objects unecessarily.
533 *
534 * The DRM range allocator supports this use-case through the scanning
535 * interfaces. First a scan operation needs to be initialized with
536 * drm_mm_init_scan() or drm_mm_init_scan_with_range(). The the driver adds
537 * objects to the roaster (probably by walking an LRU list, but this can be
538 * freely implemented) until a suitable hole is found or there's no further
539 * evitable object.
540 *
541 * The the driver must walk through all objects again in exactly the reverse
542 * order to restore the allocator state. Note that while the allocator is used
543 * in the scan mode no other operation is allowed.
544 *
545 * Finally the driver evicts all objects selected in the scan. Adding and
546 * removing an object is O(1), and since freeing a node is also O(1) the overall
547 * complexity is O(scanned_objects). So like the free stack which needs to be
548 * walked before a scan operation even begins this is linear in the number of
549 * objects. It doesn't seem to hurt badly.
550 */
551
552 /**
553 * drm_mm_init_scan - initialize lru scanning
554 * @mm: drm_mm to scan
555 * @size: size of the allocation
556 * @alignment: alignment of the allocation
557 * @color: opaque tag value to use for the allocation
558 *
559 * This simply sets up the scanning routines with the parameters for the desired
560 * hole. Note that there's no need to specify allocation flags, since they only
561 * change the place a node is allocated from within a suitable hole.
562 *
563 * Warning:
564 * As long as the scan list is non-empty, no other operations than
565 * adding/removing nodes to/from the scan list are allowed.
566 */
drm_mm_init_scan(struct drm_mm * mm,u64 size,unsigned alignment,unsigned long color)567 void drm_mm_init_scan(struct drm_mm *mm,
568 u64 size,
569 unsigned alignment,
570 unsigned long color)
571 {
572 mm->scan_color = color;
573 mm->scan_alignment = alignment;
574 mm->scan_size = size;
575 mm->scanned_blocks = 0;
576 mm->scan_hit_start = 0;
577 mm->scan_hit_end = 0;
578 mm->scan_check_range = 0;
579 mm->prev_scanned_node = NULL;
580 }
581 EXPORT_SYMBOL(drm_mm_init_scan);
582
583 /**
584 * drm_mm_init_scan - initialize range-restricted lru scanning
585 * @mm: drm_mm to scan
586 * @size: size of the allocation
587 * @alignment: alignment of the allocation
588 * @color: opaque tag value to use for the allocation
589 * @start: start of the allowed range for the allocation
590 * @end: end of the allowed range for the allocation
591 *
592 * This simply sets up the scanning routines with the parameters for the desired
593 * hole. Note that there's no need to specify allocation flags, since they only
594 * change the place a node is allocated from within a suitable hole.
595 *
596 * Warning:
597 * As long as the scan list is non-empty, no other operations than
598 * adding/removing nodes to/from the scan list are allowed.
599 */
drm_mm_init_scan_with_range(struct drm_mm * mm,u64 size,unsigned alignment,unsigned long color,u64 start,u64 end)600 void drm_mm_init_scan_with_range(struct drm_mm *mm,
601 u64 size,
602 unsigned alignment,
603 unsigned long color,
604 u64 start,
605 u64 end)
606 {
607 mm->scan_color = color;
608 mm->scan_alignment = alignment;
609 mm->scan_size = size;
610 mm->scanned_blocks = 0;
611 mm->scan_hit_start = 0;
612 mm->scan_hit_end = 0;
613 mm->scan_start = start;
614 mm->scan_end = end;
615 mm->scan_check_range = 1;
616 mm->prev_scanned_node = NULL;
617 }
618 EXPORT_SYMBOL(drm_mm_init_scan_with_range);
619
620 /**
621 * drm_mm_scan_add_block - add a node to the scan list
622 * @node: drm_mm_node to add
623 *
624 * Add a node to the scan list that might be freed to make space for the desired
625 * hole.
626 *
627 * Returns:
628 * True if a hole has been found, false otherwise.
629 */
drm_mm_scan_add_block(struct drm_mm_node * node)630 bool drm_mm_scan_add_block(struct drm_mm_node *node)
631 {
632 struct drm_mm *mm = node->mm;
633 struct drm_mm_node *prev_node;
634 u64 hole_start, hole_end;
635 u64 adj_start, adj_end;
636
637 mm->scanned_blocks++;
638
639 BUG_ON(node->scanned_block);
640 node->scanned_block = 1;
641
642 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
643 node_list);
644
645 node->scanned_preceeds_hole = prev_node->hole_follows;
646 prev_node->hole_follows = 1;
647 list_del(&node->node_list);
648 node->node_list.prev = &prev_node->node_list;
649 node->node_list.next = &mm->prev_scanned_node->node_list;
650 mm->prev_scanned_node = node;
651
652 adj_start = hole_start = drm_mm_hole_node_start(prev_node);
653 adj_end = hole_end = drm_mm_hole_node_end(prev_node);
654
655 if (mm->scan_check_range) {
656 if (adj_start < mm->scan_start)
657 adj_start = mm->scan_start;
658 if (adj_end > mm->scan_end)
659 adj_end = mm->scan_end;
660 }
661
662 if (mm->color_adjust)
663 mm->color_adjust(prev_node, mm->scan_color,
664 &adj_start, &adj_end);
665
666 if (check_free_hole(adj_start, adj_end,
667 mm->scan_size, mm->scan_alignment)) {
668 mm->scan_hit_start = hole_start;
669 mm->scan_hit_end = hole_end;
670 return true;
671 }
672
673 return false;
674 }
675 EXPORT_SYMBOL(drm_mm_scan_add_block);
676
677 /**
678 * drm_mm_scan_remove_block - remove a node from the scan list
679 * @node: drm_mm_node to remove
680 *
681 * Nodes _must_ be removed in the exact same order from the scan list as they
682 * have been added, otherwise the internal state of the memory manager will be
683 * corrupted.
684 *
685 * When the scan list is empty, the selected memory nodes can be freed. An
686 * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
687 * return the just freed block (because its at the top of the free_stack list).
688 *
689 * Returns:
690 * True if this block should be evicted, false otherwise. Will always
691 * return false when no hole has been found.
692 */
drm_mm_scan_remove_block(struct drm_mm_node * node)693 bool drm_mm_scan_remove_block(struct drm_mm_node *node)
694 {
695 struct drm_mm *mm = node->mm;
696 struct drm_mm_node *prev_node;
697
698 mm->scanned_blocks--;
699
700 BUG_ON(!node->scanned_block);
701 node->scanned_block = 0;
702
703 prev_node = list_entry(node->node_list.prev, struct drm_mm_node,
704 node_list);
705
706 prev_node->hole_follows = node->scanned_preceeds_hole;
707 list_add(&node->node_list, &prev_node->node_list);
708
709 return (drm_mm_hole_node_end(node) > mm->scan_hit_start &&
710 node->start < mm->scan_hit_end);
711 }
712 EXPORT_SYMBOL(drm_mm_scan_remove_block);
713
714 /**
715 * drm_mm_clean - checks whether an allocator is clean
716 * @mm: drm_mm allocator to check
717 *
718 * Returns:
719 * True if the allocator is completely free, false if there's still a node
720 * allocated in it.
721 */
drm_mm_clean(struct drm_mm * mm)722 bool drm_mm_clean(struct drm_mm * mm)
723 {
724 struct list_head *head = &mm->head_node.node_list;
725
726 return (head->next->next == head);
727 }
728 EXPORT_SYMBOL(drm_mm_clean);
729
730 /**
731 * drm_mm_init - initialize a drm-mm allocator
732 * @mm: the drm_mm structure to initialize
733 * @start: start of the range managed by @mm
734 * @size: end of the range managed by @mm
735 *
736 * Note that @mm must be cleared to 0 before calling this function.
737 */
drm_mm_init(struct drm_mm * mm,u64 start,u64 size)738 void drm_mm_init(struct drm_mm * mm, u64 start, u64 size)
739 {
740 INIT_LIST_HEAD(&mm->hole_stack);
741 mm->scanned_blocks = 0;
742
743 /* Clever trick to avoid a special case in the free hole tracking. */
744 INIT_LIST_HEAD(&mm->head_node.node_list);
745 INIT_LIST_HEAD(&mm->head_node.hole_stack);
746 mm->head_node.hole_follows = 1;
747 mm->head_node.scanned_block = 0;
748 mm->head_node.scanned_prev_free = 0;
749 mm->head_node.scanned_next_free = 0;
750 mm->head_node.mm = mm;
751 mm->head_node.start = start + size;
752 mm->head_node.size = start - mm->head_node.start;
753 list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
754
755 mm->color_adjust = NULL;
756 }
757 EXPORT_SYMBOL(drm_mm_init);
758
759 /**
760 * drm_mm_takedown - clean up a drm_mm allocator
761 * @mm: drm_mm allocator to clean up
762 *
763 * Note that it is a bug to call this function on an allocator which is not
764 * clean.
765 */
drm_mm_takedown(struct drm_mm * mm)766 void drm_mm_takedown(struct drm_mm * mm)
767 {
768 WARN(!list_empty(&mm->head_node.node_list),
769 "Memory manager not clean during takedown.\n");
770 }
771 EXPORT_SYMBOL(drm_mm_takedown);
772
drm_mm_debug_hole(struct drm_mm_node * entry,const char * prefix)773 static u64 drm_mm_debug_hole(struct drm_mm_node *entry,
774 const char *prefix)
775 {
776 u64 hole_start, hole_end, hole_size;
777
778 if (entry->hole_follows) {
779 hole_start = drm_mm_hole_node_start(entry);
780 hole_end = drm_mm_hole_node_end(entry);
781 hole_size = hole_end - hole_start;
782 pr_debug("%s %#llx-%#llx: %llu: free\n", prefix, hole_start,
783 hole_end, hole_size);
784 return hole_size;
785 }
786
787 return 0;
788 }
789
790 /**
791 * drm_mm_debug_table - dump allocator state to dmesg
792 * @mm: drm_mm allocator to dump
793 * @prefix: prefix to use for dumping to dmesg
794 */
drm_mm_debug_table(struct drm_mm * mm,const char * prefix)795 void drm_mm_debug_table(struct drm_mm *mm, const char *prefix)
796 {
797 struct drm_mm_node *entry;
798 u64 total_used = 0, total_free = 0, total = 0;
799
800 total_free += drm_mm_debug_hole(&mm->head_node, prefix);
801
802 drm_mm_for_each_node(entry, mm) {
803 pr_debug("%s %#llx-%#llx: %llu: used\n", prefix, entry->start,
804 entry->start + entry->size, entry->size);
805 total_used += entry->size;
806 total_free += drm_mm_debug_hole(entry, prefix);
807 }
808 total = total_free + total_used;
809
810 pr_debug("%s total: %llu, used %llu free %llu\n", prefix, total,
811 total_used, total_free);
812 }
813 EXPORT_SYMBOL(drm_mm_debug_table);
814
815 #if defined(CONFIG_DEBUG_FS)
drm_mm_dump_hole(struct seq_file * m,struct drm_mm_node * entry)816 static u64 drm_mm_dump_hole(struct seq_file *m, struct drm_mm_node *entry)
817 {
818 u64 hole_start, hole_end, hole_size;
819
820 if (entry->hole_follows) {
821 hole_start = drm_mm_hole_node_start(entry);
822 hole_end = drm_mm_hole_node_end(entry);
823 hole_size = hole_end - hole_start;
824 seq_printf(m, "%#018llx-%#018llx: %llu: free\n", hole_start,
825 hole_end, hole_size);
826 return hole_size;
827 }
828
829 return 0;
830 }
831
832 /**
833 * drm_mm_dump_table - dump allocator state to a seq_file
834 * @m: seq_file to dump to
835 * @mm: drm_mm allocator to dump
836 */
drm_mm_dump_table(struct seq_file * m,struct drm_mm * mm)837 int drm_mm_dump_table(struct seq_file *m, struct drm_mm *mm)
838 {
839 struct drm_mm_node *entry;
840 u64 total_used = 0, total_free = 0, total = 0;
841
842 total_free += drm_mm_dump_hole(m, &mm->head_node);
843
844 drm_mm_for_each_node(entry, mm) {
845 seq_printf(m, "%#018llx-%#018llx: %llu: used\n", entry->start,
846 entry->start + entry->size, entry->size);
847 total_used += entry->size;
848 total_free += drm_mm_dump_hole(m, entry);
849 }
850 total = total_free + total_used;
851
852 seq_printf(m, "total: %llu, used %llu free %llu\n", total,
853 total_used, total_free);
854 return 0;
855 }
856 EXPORT_SYMBOL(drm_mm_dump_table);
857 #endif
858