nilfs2: correct return value kernel-doc descriptions for ioctl functions

nilfs2: correct return value kernel-doc descriptions for ioctl functions

Patch series "nilfs2: fix kernel-doc comments for function return values",
v2.

This series fixes the inadequacies in the return value descriptions in
nilfs2's kernel-doc comments (mainly incorrect formatting), as well as the
lack of return value descriptions themselves, and fixes most of the
remaining warnings that are output when the kernel-doc script is run with
the "-Wall" option.

This patch (of 7):

In the kernel-doc comments for functions, there are many cases where the
format of the return value description is inaccurate, such as "Return
Value: ...", which causes many warnings to be output when the kernel-doc
script is executed with the "-Wall" option.

This fixes such incorrectly formatted return value descriptions for ioctl
functions.

Link: https://lkml.kernel.org/r/20250110010530.21872-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20250110010530.21872-2-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>