linux-kernel - Re: [PATCH] srcu: remove never used variable

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Message-Id: <20180223012057.GO2855@linux.vnet.ibm.com>
Date:   Thu, 22 Feb 2018 17:20:57 -0800
From:   "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:     Zhouyi Zhou <zhouzhouyi@...il.com>
Cc:     "josh@...htriplett.org" <josh@...htriplett.org>,
        "rostedt@...dmis.org" <rostedt@...dmis.org>,
        "mathieu.desnoyers@...icios.com" <mathieu.desnoyers@...icios.com>,
        "jiangshanlai@...il.com" <jiangshanlai@...il.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] srcu: remove never used variable

On Fri, Feb 23, 2018 at 09:04:05AM +0800, Zhouyi Zhou wrote:
> Thanks Paul for reviewing

And thank you for your interest in SRCU!  I am pretty sure that other
bugs still remain.  ;-)

							Thanx, Paul

> Cheers
> Zhouyi
> 
> On Friday, February 23, 2018, Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
> wrote:
> 
> > On Thu, Feb 22, 2018 at 06:52:37AM +0000, zhouzhouyi@...il.com wrote:
> > > From: Zhouyi Zhou <zhouzhouyi@...il.com>
> > >
> > > In function srcu_gp_end, the variable idxnext is never used after assign,
> > > remove it and its assign statement.
> > >
> > > Signed-off-by: Zhouyi Zhou <zhouzhouyi@...il.com>
> >
> > Good catch, but Byungchul Park beat you to it.  Please see commit
> > a72da917f186 ("srcu: Remove dead code in srcu_gp_end()") in -rcu.
> >
> >                                                         Thanx, Paul
> >
> > > ---
> > >  kernel/rcu/srcutree.c | 2 --
> > >  1 file changed, 2 deletions(-)
> > >
> > > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> > > index d5cea81..1241715 100644
> > > --- a/kernel/rcu/srcutree.c
> > > +++ b/kernel/rcu/srcutree.c
> > > @@ -531,7 +531,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
> > >       unsigned long flags;
> > >       unsigned long gpseq;
> > >       int idx;
> > > -     int idxnext;
> > >       unsigned long mask;
> > >       struct srcu_data *sdp;
> > >       struct srcu_node *snp;
> > > @@ -555,7 +554,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
> > >
> > >       /* Initiate callback invocation as needed. */
> > >       idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
> > > -     idxnext = (idx + 1) % ARRAY_SIZE(snp->srcu_have_cbs);
> > >       rcu_for_each_node_breadth_first(sp, snp) {
> > >               spin_lock_irq_rcu_node(snp);
> > >               cbs = false;
> > > --
> > > 2.1.4
> > >
> >
> >