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From: Andrew Morton <akpm@linux-foundation.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Dmitry Vyukov <dvyukov@google.com>,
	Clark Williams <williams@redhat.com>,
	Alexander Potapenko <glider@google.com>,
	kasan-dev <kasan-dev@googlegroups.com>,
	Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-rt-users@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] mm/kasan: make quarantine_lock a raw_spinlock_t
Date: Fri, 12 Oct 2018 16:56:55 -0700	[thread overview]
Message-ID: <20181012165655.f067886428a394dc7fbae7af@linux-foundation.org> (raw)
In-Reply-To: <20181010214945.5owshc3mlrh74z4b@linutronix.de>

On Wed, 10 Oct 2018 23:49:45 +0200 Sebastian Andrzej Siewior <bigeasy@linutronix.de> wrote:

> On 2018-10-10 11:57:41 [+0200], Dmitry Vyukov wrote:
> > Yes. Clark's patch looks good to me. Probably would be useful to add a
> > comment as to why raw spinlock is used (otherwise somebody may
> > refactor it back later).
> 
> If you really insist, I could add something but this didn't happen so
> far. git's changelog should provide enough information why to why it was
> changed.

Requiring code readers to look up changelogs in git is rather user-hostile.
There are several reasons for using raw_*, so an explanatory comment at
each site is called for.

However it would be smarter to stop "using raw_* for several reasons". 
Instead, create a differently named variant for each such reason.  ie, do

/*
 * Nice comment goes here.  It explains all the possible reasons why -rt
 * might use a raw_spin_lock when a spin_lock could otherwise be used.
 */
#define raw_spin_lock_for_rt	raw_spinlock

Then use raw_spin_lock_for_rt() at all such sites.

  parent reply	other threads:[~2018-10-12 23:57 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-18 15:29 [PATCH RT] rt: convert mm/kasan/quarantine_lock to raw_spinlock Clark Williams
2018-09-18 20:34 ` kbuild test robot
2018-10-05 16:37   ` Sebastian Andrzej Siewior
2018-10-18  9:04     ` [kbuild-all] " Rong Chen
2018-10-05 16:30 ` [PATCH] kasan: convert kasan/quarantine_lock " Sebastian Andrzej Siewior
2018-10-05 16:33   ` Sebastian Andrzej Siewior
2018-10-08  0:47     ` Clark Williams
2018-10-08  9:15     ` Dmitry Vyukov
2018-10-09 14:27       ` Sebastian Andrzej Siewior
2018-10-10  8:25         ` Dmitry Vyukov
2018-10-10  9:29           ` Sebastian Andrzej Siewior
2018-10-10  9:45             ` Dmitry Vyukov
2018-10-10  9:53               ` Sebastian Andrzej Siewior
2018-10-10  9:57                 ` Dmitry Vyukov
2018-10-10 21:49                   ` [PATCH] mm/kasan: make quarantine_lock a raw_spinlock_t Sebastian Andrzej Siewior
2018-10-11  8:03                     ` Dmitry Vyukov
2018-10-12 23:56                     ` Andrew Morton [this message]
2018-10-13 13:50                       ` Peter Zijlstra
2018-10-15 23:35                         ` Andrew Morton
2018-10-19 10:58                           ` Peter Zijlstra

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