From owner-cvs-src@FreeBSD.ORG Tue Jul 22 15:44:17 2003 Return-Path: Delivered-To: cvs-src@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 55DC937B401; Tue, 22 Jul 2003 15:44:17 -0700 (PDT) Received: from harmony.village.org (rover.bsdimp.com [204.144.255.66]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0673143FB1; Tue, 22 Jul 2003 15:43:44 -0700 (PDT) (envelope-from imp@bsdimp.com) Received: from localhost (warner@rover2.village.org [10.0.0.1]) by harmony.village.org (8.12.9/8.12.3) with ESMTP id h6MMgWFL052417; Tue, 22 Jul 2003 16:42:32 -0600 (MDT) (envelope-from imp@bsdimp.com) Date: Tue, 22 Jul 2003 16:42:23 -0600 (MDT) Message-Id: <20030722.164223.00776481.imp@bsdimp.com> To: jhb@FreeBSD.org From: "M. Warner Losh" In-Reply-To: References: <20030722.151828.83724752.imp@bsdimp.com> X-Mailer: Mew version 2.2 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit cc: phk@phk.freebsd.dk cc: src-committers@FreeBSD.org cc: bde@zeta.org.au cc: paul@freebsd-services.com cc: cvs-src@FreeBSD.org cc: das@FreeBSD.org cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/dev/lnc if_lnc.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Jul 2003 22:44:18 -0000 In message: John Baldwin writes: : : On 22-Jul-2003 M. Warner Losh wrote: : > In message: <20030722163007.GA6080@HAL9000.homeunix.com> : > David Schultz writes: : >: There is reason for concern about cases where inline really is : >: misused, either because it massively increases code size or : >: because it is unimportant to performance and detracts from : >: debuggability. But I would not like to see a policy that shifts : >: the burden of proof onto authors of new code.[1] A policy about : >: gratuitous sweeps through other people's code, on the other : >: hand... : > : > There's one other place that we use inlining. We use it to make sure : > that modules do not contain references to certain symbols. For : > example: : > : > /* : > * make this inline so that we don't have to worry about dangling references : > * to it in the modules or the code. : > */ : > static __inline const struct pccard_product * : > pccard_product_lookup(device_t dev, const struct pccard_product *tab, : > size_t ent_size, pccard_product_match_fn matchfn) : > { : > return CARD_DO_PRODUCT_LOOKUP(device_get_parent(dev), dev, : > tab, ent_size, matchfn); : > } : > : > We do this to get the type safty of the function call and not have to : > make that a macro. We do *NOT* want references to : > pccard_product_lookup, but the CARD_DO_.. kobj call allows the : > indirection that makes it possible to use the same module in kernels : > with and without pccard support. : > : > This isn't either of the performance or size trade-offs. It is a : > design decision to use inline over #define. If the new gcc breaks : > this, then it becomes a #define... : : I think that this is a bandaid solution though. Ideally if you : load a device driver, it really contains several modules: one base : module for the base code and one module for each bus attachment. : The base attachment must link for the load to complete, but if a : bus attachment doesn't link due to missing symbols because that : bus isn't present in the kernel, it's not an error. At least that's : how I think it should work. The acpi module already has this issue : now that it calls pci and isa functions. I tried playing with that, but it is also a hard problem. You then have strong ordering issues, which makes it hard to unload pccard and reload it w/o unloading all things that depend on it. Eg, I don't want to have to unload the if_wi_pccard driver when I want to unload and reload pccard.ko. Warner