From owner-freebsd-hackers Fri Mar 14 00:28:15 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id AAA06933 for hackers-outgoing; Fri, 14 Mar 1997 00:28:15 -0800 (PST) Received: from helbig.informatik.ba-stuttgart.de (helbig.informatik.ba-stuttgart.de [141.31.166.22]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id AAA06876 for ; Fri, 14 Mar 1997 00:27:48 -0800 (PST) Received: (from helbig@localhost) by helbig.informatik.ba-stuttgart.de (8.8.5/8.8.5) id JAA00226; Fri, 14 Mar 1997 09:26:09 +0100 (MET) From: Wolfgang Helbig Message-Id: <199703140826.JAA00226@helbig.informatik.ba-stuttgart.de> Subject: Re: dscheck() and the processor level? In-Reply-To: <199703140233.VAA00748@lakes.water.net> from Thomas David Rivers at "Mar 13, 97 09:33:57 pm" To: ponds!rivers@dg-rtp.dg.com (Thomas David Rivers) Date: Fri, 14 Mar 1997 09:26:09 +0100 (MET) Cc: hackers@freebsd.org X-Mailer: ELM [version 2.4ME+ PL30 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Hi > > I don't think it's the case that this needs to be at splbio(), but > could someone take a gander at that and let me know? [I'm a little > fuzzy on just exactly when you should set the processor level to "bio" - > just what are we protecting when we do that?] We won't be interrupted by interrupt sources marked with "bio" in the kernel config file. Let's assume you have IRQ 14 and IRQ 15 set up for your IDE-controller, primary and secondary channel. In the GENERIC configuration file both are marked with "bio" (in the wdc0/wdc1 line). So if you don't want your wd-interrupt service routine start running while you are reading or changing common data-structures you have to code splbio(). Others interrupts like keyboard or clock still will get through and interrupt you. This is very well explained in man 9 spl. Wolfgang