There are a number of kernel-doc comments for functions that are missing return values, which also causes a number of warnings when the kernel-doc script is run with the "-Wall" option. Fix this issue by adding proper return value descriptions, and improve code maintainability. Link: https://lkml.kernel.org/r/20250110010530.21872-7-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Cc: "Brian G ." <gissf1@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>