+ spin_lock(&hugetlb_lock);
+
+ /*
+ * Check for a node specific request.
+ * Changing node specific huge page count may require a corresponding
+ * change to the global count. In any case, the passed node mask
+ * (nodes_allowed) will restrict alloc/free to the specified node.
+ */
+ if (nid != NUMA_NO_NODE) {
+ unsigned long old_count = count;
+
+ count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
+ /*
+ * User may have specified a large count value which caused the
+ * above calculation to overflow. In this case, they wanted
+ * to allocate as many huge pages as possible. Set count to
+ * largest possible value to align with their intention.
+ */
+ if (count < old_count)
+ count = ULONG_MAX;
+ }
+
+ /*
+ * Gigantic pages runtime allocation depend on the capability for large
+ * page range allocation.
+ * If the system does not provide this feature, return an error when
+ * the user tries to allocate gigantic pages but let the user free the
+ * boottime allocated gigantic pages.
+ */
+ if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
+ if (count > persistent_huge_pages(h)) {
+ spin_unlock(&hugetlb_lock);
+ return -EINVAL;
+ }
+ /* Fall through to decrease pool */
+ }