Date: Tue, 25 Nov 2008 10:20:30 -0700 (MST) From: "M. Warner Losh" <imp@bsdimp.com> To: huntting@glarp.com Cc: drivers@FreeBSD.org Subject: Re: mutex quandry Message-ID: <20081125.102030.-1272479009.imp@bsdimp.com> In-Reply-To: <200811251707.mAPH7JRg090619@antediluvian.glarp.com> References: <20081124.134236.723203643.imp@bsdimp.com> <200811251707.mAPH7JRg090619@antediluvian.glarp.com>
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In message: <200811251707.mAPH7JRg090619@antediluvian.glarp.com>
Brad Huntting <huntting@glarp.com> writes:
:
: >: The combination of checking sc_running and incrementing sc_inuse
: >: needs to be atomic (hence a mutex around them) but at some point
: >: detach() has to destroy the mutex but my code may still need to use
: >: it.
: >
: >Your solution to this is to make sure that never happens. Anything
: >else is really racy. If you are destroying your mutex and allowing
: >detach to return, the entire sc is freed, so you're dead from that
: >anyway...
:
: Fair enough. I guess I was just too focused on my small part of
: the larger system.
:
: But that brings up another issue. How do my (kernel level) users
: know if my module is loaded or not? I cant find any section 9 docs
: on kernal loadable modules. Am I looking in the wrong place? Or
: do I just need to read the source.
It should be documented in section 9. Use level users can do a
kldstat to find this information. I think kern_kldload will load the
module, but I'm not sure how to get status. I've cc'd drivers@ to see
if someone there knows.
Warner
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