drivers/gpu/drm/drm_mm.c

   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  *
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  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                                                 unsigned long 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                                                 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
 106 static 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  */
 176 int 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 }
 212 EXPORT_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  */
 229 int 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 }
 245 EXPORT_SYMBOL(drm_mm_insert_node_generic);
 246
 247 static 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  */
 326 int 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 }
 346 EXPORT_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  */
 356 void 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 }
 388 EXPORT_SYMBOL(drm_mm_remove_node);
 389
 390 static 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
 405 static 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
 447 static 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  */
 505 void 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 }
 518 EXPORT_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  */
 563 void 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 }
 577 EXPORT_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  */
 596 void 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 }
 614 EXPORT_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  */
 626 bool 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 }
 671 EXPORT_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  */
 689 bool 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 }
 708 EXPORT_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  */
 718 bool 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 }
 724 EXPORT_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  */
 734 void 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 }
 753 EXPORT_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  */
 762 void 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 }
 767 EXPORT_SYMBOL(drm_mm_takedown);
 768
 769 static 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  */
 792 void 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 }
 811 EXPORT_SYMBOL(drm_mm_debug_table);
 812
 813 #if defined(CONFIG_DEBUG_FS)
 814 static 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  */
 835 int 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 }
 854 EXPORT_SYMBOL(drm_mm_dump_table);
 855 #endif