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Date:   Fri, 15 Sep 2023 20:43:35 +0200
From:   Oleg Nesterov <oleg@redhat.com>
To:     Alexey Gladkov <legion@kernel.org>
Cc:     Boqun Feng <boqun.feng@gmail.com>, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Rik van Riel <riel@surriel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Waiman Long <longman@redhat.com>,
        Will Deacon <will@kernel.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/5] seqlock: introduce seqprop_lock/unlock
Message-ID: <20230915184334.GA1650@redhat.com>
References: <20230913154907.GA26210@redhat.com>
 <20230913155000.GA26248@redhat.com>
 <ZQShm4QAeAtjR8EK@example.org>
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On 09/15, Alexey Gladkov wrote:
>
> On Wed, Sep 13, 2023 at 05:50:00PM +0200, Oleg Nesterov wrote:
> > +									\
> > +static __always_inline void						\
> > +__seqprop_##lockname##_lock(seqcount_##lockname##_t *s,			\
> > +				locktype *lock)				\
> > +{									\
> > +	__SEQ_LOCK(WARN_ON_ONCE(s->lock != lock));			\
> > +	lockbase##_lock(lock);						\
> > +}									\
> > +									\
> > +static __always_inline void						\
> > +__seqprop_##lockname##_unlock(seqcount_##lockname##_t *s,		\
> > +				locktype *lock)				\
> > +{									\
> > +	lockbase##_unlock(lock); 					\
> >  }
>
> Why are you creating a new method with an unused argument s ?

To make it consistent/symmetrical with _lock() which does
__SEQ_LOCK(WARN_ON_ONCE(s->lock != lock)). _unlock() could do the
same check as well, but somehow I decided it would be too much.

And with other "methods". Say, __seqprop_##lockname##_preemptible(s)
doesn't use 's' too.

Otherwise they both do not need the 1st seqcount_##lockname##_t *s
argument.

Oleg.