+ /*
+ * Drop hugetlb_fault_mutex and i_mmap_rwsem before
+ * unmapping. unmapping needs to hold i_mmap_rwsem
+ * in write mode. Dropping i_mmap_rwsem in read mode
+ * here is OK as COW mappings do not interact with
+ * PMD sharing.
+ *
+ * Reacquire both after unmap operation.
+ */
+ idx = vma_hugecache_offset(h, vma, haddr);
+ hash = hugetlb_fault_mutex_hash(mapping, idx);
+ mutex_unlock(&hugetlb_fault_mutex_table[hash]);
+ i_mmap_unlock_read(mapping);
+