reproduce:
        # https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git/commit/?id=53c4f015ffc5b28880d0b68c36d99a86f9814743
        git remote add mcgrof https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git
        git fetch --no-tags mcgrof blk-iobuf-pool-v5-premap
        git checkout 53c4f015ffc5b28880d0b68c36d99a86f9814743
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs