Understanding interrupted system calls

[Joe Marcus Clarke]

On Wed, 2007-09-19 at 01:12 +1000, Bruce Evans wrote:
> On Wed, 12 Sep 2007, Joe Marcus Clarke wrote:
> 
> Sorry this reply took so long.
> 
> > On Sun, 2007-09-02 at 14:17 +1000, Bruce Evans wrote:
> >>> From Jilles' previous reply:
> >>>>> The fixed version would then be
> >>>>>
> >>>>> 	error = tsleep(&scp->smode, PZERO|PCATCH, "waitvt", 0);
> >>
> >> I think this is right.  The kernel should never loop on ERESTART like this.
> >> Please fix the remaining style bug in it (missing spaces around binary
> >> operator).
> >
> > Bruce, I didn't know if you saw my fix, if it needs more work, or if
> > you're going to commit it?  I'd really like to get this fixed before
> > 7.0.  Should I open a PR to track it?  Thanks.
> >
> > http://www.marcuscom.com/downloads/syscons.c.diff
> > http://www.marcuscom.com/downloads/pcvt_ext.c (-STABLE only)
> 
> I saw a new style bug in it, but wasn't going to complain.  Now I will :-).
> 
> % --- src/sys/dev/syscons/syscons.c.orig	2007-09-02 23:04:15.000000000 -0400
> % +++ src/sys/dev/syscons/syscons.c	2007-09-02 23:05:06.000000000 -0400
> % @@ -1073,8 +1073,7 @@ scioctl(struct cdev *dev, u_long cmd, ca
> %  	scp = sc_get_stat(SC_DEV(sc, i));
> %  	if (scp == scp->sc->cur_scp)
> %  	    return 0;
> % -	while ((error=tsleep(&scp->smode, PZERO|PCATCH,
> % -			     "waitvt", 0)) == ERESTART) ;
> % +	error = tsleep(&scp->smode, (PZERO|PCATCH), "waitvt", 0);
> %  	return error;
> % 
> %      case VT_GETACTIVE:		/* get active vty # */
> 
> It now has extra parentheses, and still doesn't have spaces around the
> binary operator.

I re-read your first email twice, and read it as "put parentheses around
the binary operator" both times.  Sorry for being so dense.  A space
makes more sense.

> 
> In pcvt_ext.c.diff, the changes are larger and I only glanced at most
> of them, but noticed that the formatting of the `PZERO | PCATCH' are
> was already what I want but was changed to the above (2 changes instead
> of 1).  pcvt is almost dead and its style so unusual that it is difficult
> to be bug for bug compatible with, so I would try to avoid making any
> style changes in it.
> 
> Please commit all the changes, preferably after fixing the style bugs.

Thanks, will do after approval from re.

Joe

-- 
Joe Marcus Clarke
FreeBSD GNOME Team      ::      gnome at FreeBSD.org
FreeNode / #freebsd-gnome
http://www.FreeBSD.org/gnome
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