Messages in this thread | | | Subject | Re: [PATCH RT 1/5] net: Properly annotate the try-lock for the seqlock | From | Mike Galbraith <> | Date | Sat, 14 Nov 2020 20:00:07 +0100 |
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On Fri, 2020-11-13 at 14:14 -0600, Tom Zanussi wrote: > > This patch seems to fix it for me:
If there was any discussion about this patch, I missed it.
> From 4855377d0cb34b1b67a5c6d84cc8609c9da0bc3e Mon Sep 17 00:00:00 2001 > Message-Id: <4855377d0cb34b1b67a5c6d84cc8609c9da0bc3e.1605297603.git.zanussi@kernel.org> > From: Tom Zanussi <zanussi@kernel.org> > Date: Fri, 13 Nov 2020 13:04:15 -0600 > Subject: [PATCH] net: Add missing __raw_write_seqcount_end() and > seqcount_release() > > The patch ('net: Properly annotate the try-lock for the seqlock") adds > __raw_write_seqcount_begin() in qdisc_run_begin() but omits the > corresponding __raw_write_seqcount_end() and seqcount_release() in > qdisc_run_end(). > > Add it unconditionally, since qdisc_run_end() is never called unless > qdisc_run_begin() succeeds, and if it succeeds, > __raw_write_seqcount_begin() seqcount_acquire() will have been called. > > Signed-off-by: Tom Zanussi <zanussi@kernel.org> > --- > include/net/sch_generic.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h > index 112d2dca8b08..c5ccce4f8f62 100644 > --- a/include/net/sch_generic.h > +++ b/include/net/sch_generic.h > @@ -192,7 +192,11 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc) > static inline void qdisc_run_end(struct Qdisc *qdisc) > { > #ifdef CONFIG_PREEMPT_RT > + seqcount_t *s = &qdisc->running.seqcount; > + > write_sequnlock(&qdisc->running); > + __raw_write_seqcount_end(s); > + seqcount_release(&s->dep_map, 1, _RET_IP_); > #else > write_seqcount_end(&qdisc->running); > #endif
__raw_write_seqcount_end() is an integral part of write_sequnlock(), but we do seem to be missing a seqcount_release() in 5.4-rt.
-Mike
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