Date: Thu, 6 Jun 2019 11:00:00 -0700 From: John Baldwin <jhb@FreeBSD.org> To: Mark Johnston <markj@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r348745 - head/sys/net Message-ID: <f181a5e6-8507-b8ac-6a33-fba82e3bdbd5@FreeBSD.org> In-Reply-To: <20190606174339.GA3015@raichu> References: <201906061622.x56GMTmT076525@repo.freebsd.org> <61b60bb0-da61-00cf-5fca-69ac306ce6d2@FreeBSD.org> <20190606174339.GA3015@raichu>
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On 6/6/19 10:43 AM, Mark Johnston wrote: > On Thu, Jun 06, 2019 at 10:13:13AM -0700, John Baldwin wrote: >> On 6/6/19 9:22 AM, Mark Johnston wrote: >>> Author: markj >>> Date: Thu Jun 6 16:22:29 2019 >>> New Revision: 348745 >>> URL: https://svnweb.freebsd.org/changeset/base/348745 >>> >>> Log: >>> Conditionalize an in_epoch() call on INVARIANTS. >>> >>> Its result is only used to determine whether to perform further >>> INVARIANTS-only checks. Remove a stale comment while here. >>> >>> Submitted by: Sebastian Huber <sebastian.huber@embedded-brains.de> >>> MFC after: 1 week >>> >>> Modified: >>> head/sys/net/if_lagg.c >>> >>> Modified: head/sys/net/if_lagg.c >>> ============================================================================== >>> --- head/sys/net/if_lagg.c Thu Jun 6 16:20:50 2019 (r348744) >>> +++ head/sys/net/if_lagg.c Thu Jun 6 16:22:29 2019 (r348745) >>> @@ -1955,12 +1955,10 @@ lagg_link_active(struct lagg_softc *sc, struct lagg_po >>> * Search a port which reports an active link state. >>> */ >>> >>> - /* >>> - * This is called with either LAGG_RLOCK() held or >>> - * LAGG_XLOCK(sc) held. >>> - */ >>> +#ifdef INVARIANTS >>> if (!in_epoch(net_epoch_preempt)) >>> LAGG_XLOCK_ASSERT(sc); >>> +#endif >> >> FWIW, the comment wasn't stale but on purpose (I added it when I added the check). >> The idea is to be the equivalent of >> >> assert(in_epoch(net_epoch_preempt) || lagg_xlocked(sc)) >> >> However, I couldn't write it that way, so I use LAGG_XLOCK_ASSERT when !in_epoch >> returns false. > > We could add > > #ifdef INVARIANTS > #define LAGG_ASSERT_LOCKED(_sc) (sx_xlocked(&(_sc)->sc_sx) || in_epoch(net_epoch_preempt)) > #else > #define LAGG_ASSERT_LOCKED(_sc) > #endif Hmm, ok I guess. I just like using sx_assert when possible as you get line numbers, etc. Maybe MPASS would work though since it does that. You also don't need the extra #ifdef in that case either: #define LAGG_ASSERT_LOCKED(_sc) MPASS(sx_xlocked(&(_sc)->sc_sx) || in_epoch(net_epoch_preempt)) -- John Baldwin
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