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Resources: insert identical resources above existing resources

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If you have two resources which aree exactly the same size,
insert_resource() currently inserts the new one below the existing one. 
This is wrong because there's no way to insert a resource of the same size
above an existing one.

I took this opportunity to rewrite the initial loop to be a for-loop
instead of a goto-loop and fix the documentation.

Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Matthew Wilcox 2006-06-30 02:31:24 -07:00 committed by Greg Kroah-Hartman
parent b278240839
commit d33b6fba2c
1 changed files with 16 additions and 16 deletions
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32
kernel/resource.c
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@ -344,12 +344,11 @@ EXPORT_SYMBOL(allocate_resource);
* *
* Returns 0 on success, -EBUSY if the resource can't be inserted. * Returns 0 on success, -EBUSY if the resource can't be inserted.
* *
* This function is equivalent of request_resource when no conflict * This function is equivalent to request_resource when no conflict
* happens. If a conflict happens, and the conflicting resources * happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new * entirely fit within the range of the new resource, then the new
* resource is inserted and the conflicting resources become childs of * resource is inserted and the conflicting resources become children of
* the new resource. Otherwise the new resource becomes the child of * the new resource.
* the conflicting resource
*/ */
int insert_resource(struct resource *parent, struct resource *new) int insert_resource(struct resource *parent, struct resource *new)
{ {
@ -357,20 +356,21 @@ int insert_resource(struct resource *parent, struct resource *new)
struct resource *first, *next; struct resource *first, *next;
write_lock(&resource_lock); write_lock(&resource_lock);
begin:
result = 0;
first = __request_resource(parent, new);
if (!first)
goto out;
result = -EBUSY; for (;; parent = first) {
if (first == parent) result = 0;
goto out; first = __request_resource(parent, new);
if (!first)
goto out;
/* Resource fully contained by the clashing resource? Recurse into it */ result = -EBUSY;
if (first->start <= new->start && first->end >= new->end) { if (first == parent)
parent = first; goto out;
goto begin;
if ((first->start > new->start) || (first->end < new->end))
break;
if ((first->start == new->start) && (first->end == new->end))
break;
} }
for (next = first; ; next = next->sibling) { for (next = first; ; next = next->sibling) {