Date: Fri, 2 Dec 2011 22:41:58 +0100 From: Marius Strobl <marius@alchemy.franken.de> To: John Baldwin <jhb@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r228209 - head/sys/kern Message-ID: <20111202214158.GE60194@alchemy.franken.de> In-Reply-To: <4ED94215.7030109@FreeBSD.org> References: <201112022119.pB2LJEqJ009294@svn.freebsd.org> <4ED94215.7030109@FreeBSD.org>
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On Fri, Dec 02, 2011 at 04:24:37PM -0500, John Baldwin wrote: > On 12/2/11 4:19 PM, Marius Strobl wrote: > >Author: marius > >Date: Fri Dec 2 21:19:14 2011 > >New Revision: 228209 > >URL: http://svn.freebsd.org/changeset/base/228209 > > > >Log: > > - In device_probe_child(9) check the return value of > > device_set_driver(9) > > when actually setting a driver as especially ENOMEM is fatal in these > > cases. > > - Annotate other calls to device_set_devclass(9) and > > device_set_driver(9) > > without the return value being checked and that are okay to fail. > > > > Reviewed by: yongari (slightly earlier version) > > Hmm, I've always thought that new-bus overused M_NOWAIT. There are a > few places where M_NOWAIT might be appropriate (e.g. from pccbb's > interrupt routine when a cardbus card is inserted), but the boot time > probe can certainly use M_WAITOK instead. Even the pccbb case could use > M_WAITOK if it were simply deferred to a taskqueue (which it probably > should be anyway, probing and attaching a driver to a new card is far > too expensive to do directly from an interrupt handler). > In general the use of M_NOWAIT vs. M_WAITOK in bus methods is also very inconsistent across device drivers. We should decide how to handle the standard case, document it and fix things up accordingly ... I agree that M_WAITOK should be used in most of these cases. Marius
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