From: Peter Zijlstra <peterz@infradead.org>
To: Fabian Frederick <fabf@skynet.be>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/14] locking/atomic: import atomic_dec_not_zero()
Date: Wed, 1 Feb 2017 10:25:21 +0100 [thread overview]
Message-ID: <20170201092521.GS6515@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <457832747.1616728.1485896108161.open-xchange@webmail.nmp.proximus.be>
On Tue, Jan 31, 2017 at 09:55:08PM +0100, Fabian Frederick wrote:
> Once again it's just about readability:
I feel APIs should be about common use-cases, not about sporadic weird cases.
> "add -1 unless value is zero" looks more complex in code than "dec not zero"
> but maybe it's just a matter of taste :) It it's not the case why would there be
> more sense about having
> atomic_inc_not_zero() globally ?
inc_not_zero() has a very strong use-case, its for lockless refcount
increment. Incrementing a 0 reference count is bad because the object
will be freed and you'll have a use-after-free.
Arguably, once we move reference counting over to its own type, it would
make sense to remove it from atomic, specifically to discourage that use
case.
next prev parent reply other threads:[~2017-02-01 9:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-30 18:39 Fabian Frederick
2017-01-31 7:33 ` Ingo Molnar
2017-01-31 10:41 ` Peter Zijlstra
2017-01-31 17:41 ` Fabian Frederick
2017-01-31 19:17 ` Peter Zijlstra
2017-01-31 20:55 ` Fabian Frederick
2017-02-01 9:25 ` Peter Zijlstra [this message]
2017-02-01 19:24 ` Fabian Frederick
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