Date: Wed, 13 Jun 2012 08:09:01 +0400 From: Andrey Chernov <ache@FreeBSD.ORG> To: Bruce Evans <brde@optusnet.com.au> Cc: svn-src-head@FreeBSD.ORG, svn-src-all@FreeBSD.ORG, src-committers@FreeBSD.ORG, Pawel Jakub Dawidek <pjd@FreeBSD.ORG> Subject: Re: svn commit: r236917 - head/sys/kern Message-ID: <20120613040900.GA88971@vniz.net> In-Reply-To: <20120613115111.R5323@besplex.bde.org> References: <201206112017.q5BKHKsW007722@svn.freebsd.org> <20120612114254.V1572@besplex.bde.org> <20120612115117.GB1372@garage.freebsd.pl> <20120613115111.R5323@besplex.bde.org>
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On Wed, Jun 13, 2012 at 12:37:50PM +1000, Bruce Evans wrote:
> >> On Mon, 11 Jun 2012, Pawel Jakub Dawidek wrote:
> >>> - KASSERT(fd >= 0 && fd < fdp->fd_nfiles,
> >>> + KASSERT((unsigned int)fd < fdp->fd_nfiles,
> >>> ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles));
> >>> return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0);
> >>> }
> >>
> >> This is backwards. Apart from using the worst possible (most verbose)
> >> spelling of `unsigned', it uses a type hack manually optimize away the
> >> test for fd being < 0. The compiler will do this "optimization"
> >> automatically if it is any good (or undo it if it is not), so all the
> >> hack does is obfuscate the test. With the verbose spelling of u_int,
> >> it even takes more space.
> >
> > Well, to be honest I presonally would prefer explicit check for fd being
> > less than 0, but my impression was that using cast is the most popular
> > way and I wanted this check to be consistent across our source tree.
> >
> > Feel free to change it.
>
> I'm only free to ask you to back out it out.
I agree that this change should backed out for better. It gains nothing
for modern compilers, but makes code reading harder.
--
http://ache.vniz.net/
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