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authorLinus Torvalds <torvalds@linux-foundation.org>2008-08-29 23:18:31 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-08-29 23:25:20 -0400
commitbef69ea0dcce574a425feb0a5aa4c63dd108b9a6 (patch)
treeb678fa44657d63cb30a29ba0b73a442537f7826c /kernel
parent00aeb429a0f2daeb21979873060b81095cafe4bd (diff)
Resource handling: add 'insert_resource_expand_to_fit()' function
Not used anywhere yet, but this complements the existing plain 'insert_resource()' functionality with a version that can expand the resource we are adding in order to fix up any conflicts it has with existing resources. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/resource.c88
1 files changed, 63 insertions, 25 deletions
diff --git a/kernel/resource.c b/kernel/resource.c
index f5b518eabefe..cf0a178c7513 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -362,35 +362,21 @@ int allocate_resource(struct resource *root, struct resource *new,
362 362
363EXPORT_SYMBOL(allocate_resource); 363EXPORT_SYMBOL(allocate_resource);
364 364
365/** 365/*
366 * insert_resource - Inserts a resource in the resource tree 366 * Insert a resource into the resource tree. If successful, return NULL,
367 * @parent: parent of the new resource 367 * otherwise return the conflicting resource (compare to __request_resource())
368 * @new: new resource to insert
369 *
370 * Returns 0 on success, -EBUSY if the resource can't be inserted.
371 *
372 * This function is equivalent to request_resource when no conflict
373 * happens. If a conflict happens, and the conflicting resources
374 * entirely fit within the range of the new resource, then the new
375 * resource is inserted and the conflicting resources become children of
376 * the new resource.
377 */ 368 */
378int insert_resource(struct resource *parent, struct resource *new) 369static struct resource * __insert_resource(struct resource *parent, struct resource *new)
379{ 370{
380 int result;
381 struct resource *first, *next; 371 struct resource *first, *next;
382 372
383 write_lock(&resource_lock);
384
385 for (;; parent = first) { 373 for (;; parent = first) {
386 result = 0;
387 first = __request_resource(parent, new); 374 first = __request_resource(parent, new);
388 if (!first) 375 if (!first)
389 goto out; 376 return first;
390 377
391 result = -EBUSY;
392 if (first == parent) 378 if (first == parent)
393 goto out; 379 return first;
394 380
395 if ((first->start > new->start) || (first->end < new->end)) 381 if ((first->start > new->start) || (first->end < new->end))
396 break; 382 break;
@@ -401,15 +387,13 @@ int insert_resource(struct resource *parent, struct resource *new)
401 for (next = first; ; next = next->sibling) { 387 for (next = first; ; next = next->sibling) {
402 /* Partial overlap? Bad, and unfixable */ 388 /* Partial overlap? Bad, and unfixable */
403 if (next->start < new->start || next->end > new->end) 389 if (next->start < new->start || next->end > new->end)
404 goto out; 390 return next;
405 if (!next->sibling) 391 if (!next->sibling)
406 break; 392 break;
407 if (next->sibling->start > new->end) 393 if (next->sibling->start > new->end)
408 break; 394 break;
409 } 395 }
410 396
411 result = 0;
412
413 new->parent = parent; 397 new->parent = parent;
414 new->sibling = next->sibling; 398 new->sibling = next->sibling;
415 new->child = first; 399 new->child = first;
@@ -426,10 +410,64 @@ int insert_resource(struct resource *parent, struct resource *new)
426 next = next->sibling; 410 next = next->sibling;
427 next->sibling = new; 411 next->sibling = new;
428 } 412 }
413 return NULL;
414}
429 415
430 out: 416/**
417 * insert_resource - Inserts a resource in the resource tree
418 * @parent: parent of the new resource
419 * @new: new resource to insert
420 *
421 * Returns 0 on success, -EBUSY if the resource can't be inserted.
422 *
423 * This function is equivalent to request_resource when no conflict
424 * happens. If a conflict happens, and the conflicting resources
425 * entirely fit within the range of the new resource, then the new
426 * resource is inserted and the conflicting resources become children of
427 * the new resource.
428 */
429int insert_resource(struct resource *parent, struct resource *new)
430{
431 struct resource *conflict;
432
433 write_lock(&resource_lock);
434 conflict = __insert_resource(parent, new);
435 write_unlock(&resource_lock);
436 return conflict ? -EBUSY : 0;
437}
438
439/**
440 * insert_resource_expand_to_fit - Insert a resource into the resource tree
441 * @parent: parent of the new resource
442 * @new: new resource to insert
443 *
444 * Insert a resource into the resource tree, possibly expanding it in order
445 * to make it encompass any conflicting resources.
446 */
447void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
448{
449 if (new->parent)
450 return;
451
452 write_lock(&resource_lock);
453 for (;;) {
454 struct resource *conflict;
455
456 conflict = __insert_resource(root, new);
457 if (!conflict)
458 break;
459 if (conflict == root)
460 break;
461
462 /* Ok, expand resource to cover the conflict, then try again .. */
463 if (conflict->start < new->start)
464 new->start = conflict->start;
465 if (conflict->end > new->end)
466 new->end = conflict->end;
467
468 printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
469 }
431 write_unlock(&resource_lock); 470 write_unlock(&resource_lock);
432 return result;
433} 471}
434 472
435/** 473/**