Date: Mon, 08 Sep 2003 15:38:22 -0400 From: "Dan Langille" <dan@langille.org> To: freebsd-hackers@FreeBSD.org Cc: Kern Sibbald <kern@sibbald.com> Subject: Re: comments on proposed uthread_write.c changes Message-ID: <3F5CA26E.18181.1574B67E@localhost> In-Reply-To: <3F5B89B3.11367.112C1E2D@localhost> References: <Pine.GSO.4.10.10309071218420.11986-100000@pcnet5.pcnet.com>
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On 7 Sep 2003 at 19:40, Dan Langille wrote:
> On 7 Sep 2003 at 12:32, Daniel Eischen wrote:
>
> > On Sun, 7 Sep 2003, Dan Langille wrote:
> >
> > > A problem with pthreads and EOT has been identified. See PR 56274. It
> > > was suggested the solution was probably just a matter of changing one of
> > > the >0 tests to >=0 in uthread_write.c
> > >
> > > Any comments on that?
> >
> > I don't know that a return of 0 isn't valid for other devices.
> > If this is the case, a return of 0 for blocking writes may break
> > other applications.
> >
> > The patch isn't quite correct (at least looking at -current srcs).
> > Lines 98-99 are:
> >
> > if (blocking && ((n < 0 && (errno == EWOULDBLOCK ||
> > errno == EAGAIN)) || (n >= 0 && num < nbytes))) {
> >
> > This will get entered first if n == 0, and I don't think your
> > proposed patch would have any effect. I think you would have
> > to change the "n >= 0" above to be "n > 0" in conjunction with
> > your patch.
>
> Ahh thank you. That explains why the test results with the original
> patch did not differ from -STABLE or 5.1-RELEASE. After adding your
> suggestions, we have had success.
Oh I was wrong, very wrong. The test code I ran had not been
compiled with pthreads. Kern found my mistake after he was unable to
reproduce my [false] results.
It appears the problem is not with uthread_write.c... Or at least not
in the areas we are changing.
Suggestions?
--
Dan Langille : http://www.langille.org/
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