Re: [PATCH 4/4] rpc.gssd: don't call poll() twice a second.

["J. Bruce Fields" <bfields@redhat.com>]

On Tue, Jul 31, 2012 at 02:23:36PM -0700, Chuck Lever wrote:
> 
> On Jul 31, 2012, at 2:00 PM, J. Bruce Fields wrote:
> 
> > From: "J. Bruce Fields" <bfields@redhat.com>
> > 
> > Use ppoll instead.
> > 
> > (This breaks compatibility with kernels before 2.6.16 and glibc before
> > 2.4).
> 
> I think I prefer seeing this wrapped with some autoconf machinery to allow nfs-utils to continue to build on earlier systems.

I was assuming we could drop support for older systems.

If not, then'd I'd much prefer to go back to the self-pipe trick than to
deal with autoconf and  ifdef'ing out all this stuff.

--b.

> 
> > Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> > ---
> > utils/gssd/gssd_main_loop.c |   12 +++++-------
> > 1 file changed, 5 insertions(+), 7 deletions(-)
> > 
> > diff --git a/utils/gssd/gssd_main_loop.c b/utils/gssd/gssd_main_loop.c
> > index 142c8c5..2d20fa2 100644
> > --- a/utils/gssd/gssd_main_loop.c
> > +++ b/utils/gssd/gssd_main_loop.c
> > @@ -186,13 +186,14 @@ gssd_run()
> > 	struct sigaction	dn_act = {
> > 		.sa_handler = dir_notify_handler
> > 	};
> > -	sigset_t		set;
> > +	sigset_t		set, emptyset;
> > 
> > 	sigemptyset(&dn_act.sa_mask);
> > 	sigaction(DNOTIFY_SIGNAL, &dn_act, NULL);
> > 
> > -	/* just in case the signal is blocked... */
> > +	sigemptyset(&emptyset);
> > 	sigemptyset(&set);
> > +	/* just in case the signal is blocked... */
> > 	sigaddset(&set, DNOTIFY_SIGNAL);
> > 	sigprocmask(SIG_UNBLOCK, &set, NULL);
> > 
> > @@ -210,16 +211,13 @@ gssd_run()
> > 				exit(1);
> > 			}
> > 		}
> > -		/* race condition here: dir_changed could be set before we
> > -		 * enter the poll, and we'd never notice if it weren't for the
> > -		 * timeout. */
> > -		ret = poll(pollarray, pollsize, POLL_MILLISECS);
> > +		ret = ppoll(pollarray, pollsize, NULL, &emptyset);
> > 		if (ret < 0) {
> > 			if (errno != EINTR)
> > 				printerr(0,
> > 					 "WARNING: error return from poll\n");
> > 		} else if (ret == 0) {
> > -			/* timeout */
> > +			printerr(0, "WARNING: unexpected timeout\n");
> > 		} else { /* ret > 0 */
> > 			scan_poll_results(ret);
> > 		}
> > -- 
> > 1.7.9.5
> > 
> > --
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> 
> --
> Chuck Lever
> chuck[dot]lever[at]oracle[dot]com
> 
> 
>