From: "Paul E. McKenney" <paulmck@kernel.org>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Josh Triplett <josh@joshtriplett.org>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Joel Fernandes <joel@joelfernandes.org>,
Boqun Feng <boqun.feng@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
rcu@vger.kernel.org, Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH] refscale: Optimize process_durations()
Date: Wed, 1 Nov 2023 03:24:36 -0700 [thread overview]
Message-ID: <014c446a-23c4-40f9-9512-6869a9b02117@paulmck-laptop> (raw)
In-Reply-To: <37ab9219-a049-4a43-b555-83b1629e5a48@wanadoo.fr>
On Wed, Nov 01, 2023 at 08:41:39AM +0100, Christophe JAILLET wrote:
> Le 31/10/2023 à 23:47, Paul E. McKenney a écrit :
> > On Tue, Oct 31, 2023 at 11:21:14AM -0700, Paul E. McKenney wrote:
> > > On Mon, Oct 30, 2023 at 09:55:16AM -0700, Davidlohr Bueso wrote:
> > > > On Sat, 28 Oct 2023, Christophe JAILLET wrote:
> > > >
> > > > > process_durations() is not a hot path, but there is no good reason to
> > > > > iterate over and over the data already in 'buf'.
> > > > >
> > > > > Using a seq_buf saves some useless strcat() and the need of a temp buffer.
> > > > > Data is written directly at the correct place.
> > > >
> > > > Makes sense.
> > > >
> > > > Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
> > >
> > > Queued and pushed, thank you all!
> >
> > But an allmodconfig build complains about seq_buf_putc() being undefined,
> > that is, not exported. I suspect that other seq_buf_*() functions in
> > this patch might also be complained about.
> >
> > I am dropping this for the moment. Please make it pass an allmodconfig
> > build so that I can pull it in again. Please see below for the commit.
>
> Ouch!
Believe me, I know that feeling! ;-)
> seq_buf_init(), seq_buf_terminate(), seq_buf_clear() are inlined functions
> in a .h file, so shouldn't be a problem.
>
> seq_buf_printf() is exported, but seq_buf_putc() is not!
> Really odd to me.
>
> Kees Cook (added in cc) suggests to use this API (see [1]) to avoid some
> potential issues and ease the management of NULL terminated strings in
> buffers. (#LinuxHardening).
>
> I'll propose to add the missing EXPORT_SYMBOL_GPL.
Very good, looking forward to seeing the result.
Thanx, Paul
> CJ
>
> [1]: https://lore.kernel.org/all/202310241629.0A4206316F@keescook/
>
prev parent reply other threads:[~2023-11-01 10:24 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-28 17:04 [PATCH] refscale: Optimize process_durations() Christophe JAILLET
2023-10-28 21:30 ` Steven Rostedt
2023-10-30 16:55 ` Davidlohr Bueso
2023-10-31 18:21 ` Paul E. McKenney
2023-10-31 22:47 ` Paul E. McKenney
2023-11-01 7:41 ` Christophe JAILLET
2023-11-01 10:24 ` Paul E. McKenney [this message]
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