Resources: insert identical resources above existing resources
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>
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@ -344,12 +344,11 @@ EXPORT_SYMBOL(allocate_resource);
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*
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* Returns 0 on success, -EBUSY if the resource can't be inserted.
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*
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* This function is equivalent of request_resource when no conflict
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* This function is equivalent to request_resource when no conflict
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* happens. If a conflict happens, and the conflicting resources
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* entirely fit within the range of the new resource, then the new
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* resource is inserted and the conflicting resources become childs of
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* the new resource. Otherwise the new resource becomes the child of
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* the conflicting resource
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* resource is inserted and the conflicting resources become children of
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* the new resource.
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*/
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int insert_resource(struct resource *parent, struct resource *new)
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{
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@ -357,20 +356,21 @@ int insert_resource(struct resource *parent, struct resource *new)
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struct resource *first, *next;
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write_lock(&resource_lock);
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begin:
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result = 0;
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first = __request_resource(parent, new);
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if (!first)
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goto out;
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result = -EBUSY;
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if (first == parent)
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goto out;
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for (;; parent = first) {
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result = 0;
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first = __request_resource(parent, new);
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if (!first)
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goto out;
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/* Resource fully contained by the clashing resource? Recurse into it */
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if (first->start <= new->start && first->end >= new->end) {
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parent = first;
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goto begin;
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result = -EBUSY;
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if (first == parent)
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goto out;
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if ((first->start > new->start) || (first->end < new->end))
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break;
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if ((first->start == new->start) && (first->end == new->end))
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break;
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}
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for (next = first; ; next = next->sibling) {
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