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    SubjectRe: Why is CONFIG_FHANDLE an option??
    On Fri, 10 Jun 2011, Al Viro wrote:

    > On Sat, Jun 11, 2011 at 12:14:02AM +0200, Jesper Juhl wrote:
    > > Hello
    > >
    > > I just configured a new kernel based on a recent git checkout and when I
    > > had copied in my old configuration and did a "make oldconfig"I was greeted
    > > with
    > >
    > > open by fhandle syscalls (FHANDLE) [N/y/?] (NEW)
    > >
    > > Ok, so I read the help text description and learn that it's about two new
    > > syscalls - open_by_handle_at(2) and name_to_handle_at(2).
    > >
    > > My first thought at this point was "why are new syscalls even an option"?
    > >
    > > Syscalls are in my oppinion ABI - having optional syscalls is just about
    > > as bad as removing a syscall. It basically means that users cannot know if
    > > the syscall is there and will need to test (it's bad enough having to
    > > check the kernel version, having to check for specific syscalls as well
    > > is just, well, annoying at best).
    > >
    > > Why are we making these optional?
    >
    > Why not? Software needs to test *anyway*, since it might run on earlier
    > kernels. And "does that syscall return -ENOSYS" is self-documenting,
    > while "is the version higher than $MAGIC_NUMBER" is *not*. Especially since
    > there's such thing as backports.
    >
    > If you need to check that syscall is there, _check_ _it_. Don't breed
    > dependencies on version numbers.

    Well, sometimes you may want to make it a requirement that whomever
    deploys your software runs Linux X.Y.Z or whatever.. You don't want to
    make it "run Linux X.Y.Z with syscalls A, B, C enabled" etc.

    Sometimes it's nice to draw lines in sand and just say "from this day
    forward we support so and so".


    --
    Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
    Don't top-post http://www.catb.org/jargon/html/T/top-post.html
    Plain text mails only, please.



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