Date: Wed, 17 Aug 2005 13:24:30 -0400 From: John Baldwin <jhb@FreeBSD.org> To: Nate Lawson <nate@root.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, Poul-Henning Kamp <phk@FreeBSD.org>, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/fs/devfs devfs_vnops.c src/sys/kern kern_conf.c src/sys/sys conf.h Message-ID: <200508171324.32231.jhb@FreeBSD.org> In-Reply-To: <43036E25.6010508@root.org> References: <20050817082000.0B70016A437@hub.freebsd.org> <43036E25.6010508@root.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wednesday 17 August 2005 01:04 pm, Nate Lawson wrote:
> Poul-Henning Kamp wrote:
> > phk 2005-08-17 08:19:53 UTC
> >
> > FreeBSD src repository
> >
> > Modified files:
> > sys/fs/devfs devfs_vnops.c
> > sys/kern kern_conf.c
> > sys/sys conf.h
> > Log:
> > Handle device drivers with D_NEEDGIANT in a way which does not
> > penalize the 'good' drivers: Allocate a shadow cdevsw and populate
> > it with wrapper functions which grab Giant
> >
> > Revision Changes Path
> > 1.120 +0 -24 src/sys/fs/devfs/devfs_vnops.c
> > 1.190 +155 -9 src/sys/kern/kern_conf.c
> > 1.226 +1 -0 src/sys/sys/conf.h
> >
> >
> > static void
> > prep_cdevsw(struct cdevsw *devsw)
> > {
> > + struct cdevsw *dsw2;
> >
> > + if (devsw->d_flags & D_NEEDGIANT)
> > + dsw2 = malloc(sizeof *dsw2, M_DEVT, M_WAITOK);
> > + else
> > + dsw2 = NULL;
> > dev_lock();
> >
> > if (devsw->d_version != D_VERSION_01) {
>
> Is it guaranteed that prep_cdevsw() won't be called twice without a call
> to fini_cdevsw()? Otherwise, the shadow cdevsw could leak when its
> pointer is set to NULL. I'm not familiar with this code, just asking.
Err, how exactly? If devsw->d_gianttrick is already non-NULL, it just free's
dsw2.
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200508171324.32231.jhb>