Date: Tue, 21 Oct 2003 14:42:56 -0700 From: "Matthew Jacob" <mjacob@feral.com> To: "'Poul-Henning Kamp'" <phk@phk.freebsd.dk> Cc: 'Kris Kennaway' <kris@obsecurity.org> Subject: RE: Sleeping on "isp_mboxwaiting" with the following non-sleepablelocks held: Message-ID: <000001c3981c$49fc17b0$23a610ac@win2k> In-Reply-To: <13910.1066772731@critter.freebsd.dk>
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Well, I don't agree with the design here, but it is what it is. I'll make the change that you've added a requirement for. -----Original Message----- From: Poul-Henning Kamp [mailto:phk@phk.freebsd.dk] Sent: Tuesday, October 21, 2003 2:46 PM To: mjacob@feral.com Cc: 'Kris Kennaway'; alpha@freebsd.org; current@freebsd.org Subject: Re: Sleeping on "isp_mboxwaiting" with the following non-sleepablelocks held: In message <000801c3981a$8abc6540$23a610ac@win2k>, "Matthew Jacob" writes: >So? How about some details and context? > >I thought was told that being able to use locks in HBAs is fine. I had >them on for a while, and then had them off. I turned them on again over >a month ago. I'm somewhat surprised to see that a problem shows up now. > >*I* do the right thing with locks, IMO. I hold them in my module when I >enter and release them if/when I leave. Seeing a lock held by some >random caller causing me to blow up to me seems to be a hole in the >architecture, but I'd be the first to admit that I hardly am up to date >on what the rules of the road are now so such an opinion is >ill-informed. The lock held in this case, is not "some random caller", that is a mutex held specifically to expose device drivers which try to sleep in their ->strategy() function. You cannot sleep in the strategy() function because that would hold op I/O, and therefore likely lead to deadlock. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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