From: Christoph Hellwig <hch@infradead.org>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: paulmck@kernel.org, Christoph Hellwig <hch@infradead.org>,
Peter Zijlstra <peterz@infradead.org>,
rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-team@meta.com, rostedt@goodmis.org, andrii@kernel.org
Subject: Re: [PATCH rcu] srcu: Guarantee non-negative return value from srcu_read_lock()
Date: Tue, 22 Oct 2024 23:40:48 -0700 [thread overview]
Message-ID: <ZxiacAA9LIWv70Xp@infradead.org> (raw)
In-Reply-To: <CAEf4BzbyctiXq8L5MQmCtVqGSN8uawUmNXJMm-X8jDcp8QQ86g@mail.gmail.com>
On Tue, Oct 22, 2024 at 10:29:13AM -0700, Andrii Nakryiko wrote:
> >
> > Would this work?
> >
> > #define SRCU_INVALID_INDEX -1
> >
>
> But why?
Becaue it very clearly documents what is going on.
>It's a nice property to have an int-returning API where valid
> values are only >= 0, so callers are free to use the entire negative
> range (not just -1) for whatever they need to store in case there is
> no srcu_idx value.
Well, if you have a concrete use case for that we can probably live
with it, but I'd rather have that use case extremely well documented,
as it will be very puzzling to the reader.
next prev parent reply other threads:[~2024-10-23 6:40 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-21 22:13 [PATCH rcu] srcu: Guarantee non-negative return value from srcu_read_lock() Paul E. McKenney
2024-10-21 23:50 ` Andrii Nakryiko
2024-10-22 0:21 ` Paul E. McKenney
2024-10-22 2:01 ` Andrii Nakryiko
2024-10-22 3:30 ` Paul E. McKenney
2024-10-22 3:40 ` Andrii Nakryiko
2024-10-22 7:07 ` Peter Zijlstra
2024-10-22 14:27 ` Paul E. McKenney
2024-10-22 6:51 ` Christoph Hellwig
2024-10-22 7:06 ` Peter Zijlstra
2024-10-22 7:07 ` Christoph Hellwig
2024-10-22 7:10 ` Peter Zijlstra
2024-10-22 7:13 ` Christoph Hellwig
2024-10-22 14:26 ` Paul E. McKenney
2024-10-22 17:29 ` Andrii Nakryiko
2024-10-23 6:40 ` Christoph Hellwig [this message]
2024-10-23 16:34 ` Andrii Nakryiko
2024-10-23 16:46 ` Alan Huang
2024-10-23 16:59 ` Andrii Nakryiko
2024-10-23 6:58 ` Alan Huang
2024-10-23 16:40 ` Paul E. McKenney
2024-10-23 16:56 ` Alan Huang
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