Date: Fri, 19 Nov 2010 16:31:44 -0500 From: Attilio Rao <attilio@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Jung-uk Kim <jkim@freebsd.org> Subject: Re: svn commit: r215544 - head/sys/kern Message-ID: <AANLkTimzP7hNYFqsYgFW4Vzuj-cOWO%2Bq9nU4vFMTJ3R=@mail.gmail.com> In-Reply-To: <201011191621.25520.jhb@freebsd.org> References: <201011191943.oAJJhv3i087205@svn.freebsd.org> <201011191609.31308.jkim@FreeBSD.org> <201011191621.25520.jhb@freebsd.org>
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2010/11/19 John Baldwin <jhb@freebsd.org>: > On Friday, November 19, 2010 4:09:28 pm Jung-uk Kim wrote: >> On Friday 19 November 2010 02:43 pm, Attilio Rao wrote: >> > Author: attilio >> > Date: Fri Nov 19 19:43:56 2010 >> > New Revision: 215544 >> > URL: http://svn.freebsd.org/changeset/base/215544 >> > >> > Log: >> > Scan the list in reverse order for the shutdown handlers of >> > loaded modules. This way, when there is a dependency between two >> > modules, the handler of the latter probed runs first. >> > >> > This is a similar approach as the modules are unloaded in the >> > same linkerfile. >> > >> > Sponsored by: Sandvine Incorporated >> > Submitted by: Nima Misaghian <nmisaghian at sandvine dot com> >> > MFC after: 1 week >> >> Hmm... It is not directly related but I was thinking about doing >> similar things for sys/kern/subr_bus.c. What do you think about the >> attached patch? > > Hmm, the patches for suspend and resume that I had for this took the opposite > order, they did suspend in forward order, but resume in backwards order. > Like so: > > --- //depot/vendor/freebsd/src/sys/kern/subr_bus.c 2010-11-17 22:30:24.000000000 0000 > +++ //depot/user/jhb/acpipci/kern/subr_bus.c 2010-11-19 17:19:02.000000000 00 > @@ -3426,9 +3429,9 @@ > TAILQ_FOREACH(child, &dev->children, link) { > error = DEVICE_SUSPEND(child); > if (error) { > - for (child2 = TAILQ_FIRST(&dev->children); > - child2 && child2 != child; > - child2 = TAILQ_NEXT(child2, link)) > + for (child2 = TAILQ_PREV(child, device_list, link); > + child2 != NULL; > + child2 = TAILQ_PREV(child2, device_list, link)) > DEVICE_RESUME(child2); > return (error); > } > @@ -3447,7 +3450,7 @@ > { > device_t child; > > - TAILQ_FOREACH(child, &dev->children, link) { > + TAILQ_FOREACH_REVERSE(child, &dev->children, device_list, link) { > DEVICE_RESUME(child); > /* if resume fails, there's nothing we can usefully do... */ > } > > (Likely mangled whitespace.) > > I couldn't convince myself which order was "more" correct for suspend and resume. Considering loading in starting point, I think suspend should go in reverse logic and resume in the same module load logic. So that dependent modules are suspended first and resumed after. Don't you agree? Attilio -- Peace can only be achieved by understanding - A. Einstein
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