+ * reallocate_resource - allocate a slot in the resource tree given range & alignment.
+ * The resource will be relocated if the new size cannot be reallocated in the
+ * current location.
+ *
+ * @root: root resource descriptor
+ * @old: resource descriptor desired by caller
+ * @newsize: new size of the resource descriptor
+ * @constraint: the size and alignment constraints to be met.
+ */
+int reallocate_resource(struct resource *root, struct resource *old,
+ resource_size_t newsize,
+ struct resource_constraint *constraint)
+{
+ int err=0;
+ struct resource new = *old;
+ struct resource *conflict;
+
+ write_lock(&resource_lock);
+
+ if ((err = __find_resource(root, old, &new, newsize, constraint)))
+ goto out;
+
+ if (resource_contains(&new, old)) {
+ old->start = new.start;
+ old->end = new.end;
+ goto out;
+ }
+
+ if (old->child) {
+ err = -EBUSY;
+ goto out;
+ }
+
+ if (resource_contains(old, &new)) {
+ old->start = new.start;
+ old->end = new.end;
+ } else {
+ __release_resource(old);
+ *old = new;
+ conflict = __request_resource(root, old);
+ BUG_ON(conflict);
+ }
+out:
+ write_unlock(&resource_lock);
+ return err;
+}
+
+
+/**
+ * allocate_resource - allocate empty slot in the resource tree given range & alignment.
+ * The resource will be reallocated with a new size if it was already allocated