From owner-freebsd-alpha@FreeBSD.ORG Tue Oct 21 14:45:41 2003 Return-Path: Delivered-To: freebsd-alpha@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DC88216A4B3; Tue, 21 Oct 2003 14:45:41 -0700 (PDT) Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id BB53B43FCB; Tue, 21 Oct 2003 14:45:40 -0700 (PDT) (envelope-from phk@phk.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.12.10/8.12.10) with ESMTP id h9LLjVv6013911; Tue, 21 Oct 2003 23:45:31 +0200 (CEST) (envelope-from phk@phk.freebsd.dk) To: mjacob@feral.com From: "Poul-Henning Kamp" In-Reply-To: Your message of "Tue, 21 Oct 2003 14:30:21 PDT." <000801c3981a$8abc6540$23a610ac@win2k> Date: Tue, 21 Oct 2003 23:45:31 +0200 Message-ID: <13910.1066772731@critter.freebsd.dk> cc: alpha@freebsd.org cc: current@freebsd.org cc: 'Kris Kennaway' Subject: Re: Sleeping on "isp_mboxwaiting" with the following non-sleepablelocks held: X-BeenThere: freebsd-alpha@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Porting FreeBSD to the Alpha List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Oct 2003 21:45:42 -0000 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.