Date: Wed, 21 Jul 2004 11:37:50 +0100 From: Doug Rabson <dfr@nlsystems.com> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: freebsd-arch@freebsd.org Subject: Re: kldunload DIAGNOSTIC idea... Message-ID: <1090406270.7114.2.camel@builder02.qubesoft.com> In-Reply-To: <79980.1090401699@critter.freebsd.dk> References: <79980.1090401699@critter.freebsd.dk>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, 2004-07-21 at 10:21, Poul-Henning Kamp wrote: > In message <200407211010.08159.dfr@nlsystems.com>, Doug Rabson writes: > > >The original intention was that drivers use the > >device_busy()/device_unbusy() counter to handle these things. In some > >cases, just calling device_busy() from fooopen() and device_unbusy() > >from fooclose() is sufficient. > > That is not enough. All methods in cdevsw, and things not in cdevsw > (clone handlers, call backs, etc etc) needs to refcount. > > I have a lot of this working in a tree here, and will commit it once > I have gone over it a few more times. Methods in cdevsw which can't be called unless the device is opened can rely on a single counter managed by open/close in most cases. Other callbacks may or may not need extra handling depending on whether or not the callback can persist past close. Will you use the existing device_busy() counter or will each driver use its own counter?
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1090406270.7114.2.camel>