Man page 9 : reallocate_resource

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.

int reallocate_resource(struct resource *  root , struct resource *  old , resource_size_t  newsize , struct resource_constraint *  constraint );

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.