Re: [PATCH v2 2/4] Add fchmodat4(), a new syscall

Al Viro
2019-07-17T01:48:02Z

On Tue, Jul 16, 2019 at 06:27:17PM -0700, Palmer Dabbelt wrote:

> -int do_fchmodat(int dfd, const char __user *filename, umode_t mode)
> +int do_fchmodat4(int dfd, const char __user *filename, umode_t mode, int flags)
> {
> struct path path;
> int error;
> - unsigned int lookup_flags = LOOKUP_FOLLOW;
> + unsigned int lookup_flags;
> +
> + if (unlikely(flags & ~AT_SYMLINK_NOFOLLOW))
> + return -EINVAL;
> +
> + lookup_flags = flags & AT_SYMLINK_NOFOLLOW ? 0 : LOOKUP_FOLLOW;
> +

Why not do that in sys_fchmodat4() itself, passing lookup_flags to
do_fchmodat() and updating old callers to pass it 0 as extra argument?