Date: Tue, 18 Dec 2001 11:15:31 -0600 From: Alfred Perlstein <alfred@FreeBSD.org> To: Bruce Evans <bde@zeta.org.au> Cc: wollman@FreeBSD.org, net@FreeBSD.org, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: fifo fix (Re: cvs commit: src/sys/fs/fifofs fifo_vnops.c) Message-ID: <20011218111531.A59831@elvis.mu.org> In-Reply-To: <20011217122953.G82439@elvis.mu.org>; from alfred@FreeBSD.org on Mon, Dec 17, 2001 at 12:29:53PM -0600 References: <20011215151025.A82439@elvis.mu.org> <20011217230720.N13599-100000@gamplex.bde.org> <20011217122953.G82439@elvis.mu.org>
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* Alfred Perlstein <alfred@FreeBSD.org> [011217 12:47] wrote:
> * Bruce Evans <bde@zeta.org.au> [011217 07:10] wrote:
>
> > > +
> > > filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
> > > + so = (struct socket *)filetmp.f_data;
> > > + s = splnet();
> > > + oflg = so->so_state & SS_CANTRCVMORE;
> > > + if (ap->a_vp->v_fifoinfo->fi_writers == 0)
> > > + so->so_state &= ~SS_CANTRCVMORE;
> > > if (filetmp.f_data)
> > > revents |= soo_poll(&filetmp, ap->a_events, ap->a_cred,
> > > ap->a_td);
> > > + so->so_state |= oflg;
> > > + splx(s);
> >
> > I'm not happy with frobbing the socket state. I suggest frobbing the
> > events mask instead. Either use a flag to tell sopoll() to ignore
> > SS_CANTRCVMORE, or use new events POLLIN_IGNORE_EOF and
> > POLLRDNORM_IGNORE_EOF (convert the userland POLLIN/POLLRDNORM to these
> > and change sopoll() to support them).
Wait, please clarify, are you suggesting that POLLIN_IGNORE_EOF
and POLLRDNORM_IGNORE_EOF must be used by userland applications?
Or would it be an internal flag for the kernel so that here you'd
see something like:
filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
if (filetmp.f_data) {
if (ap->a_events & ~POLLIN)
ap->a_events |= POLLIN_IGNORE_EOF;
/* same for POLLRDNORM */
revents |= soo_poll(&filetmp, ap->a_events, ap->a_cred,
ap->a_td);
}
Or that the userland will just OR in POLLIN_IGNORE_EOF before calling
poll(2).
I'm not sure if I like the latter way of fixing things.
thanks,
-Alfred
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