From mboxrd@z Thu Jan  1 00:00:00 1970
From: Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC PATCH v1 07/25] printk-rb: add functionality required by printk
Date: Tue, 12 Feb 2019 09:15:36 -0800
Message-ID: <CAHk-=whToBNHN_X_BQkO4zSyhSBaGqTH8XEtxg2_AxoBdDnEdg@mail.gmail.com>
References: <20190212143003.48446-1-john.ogness@linutronix.de> <20190212143003.48446-8-john.ogness@linutronix.de>
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To: John Ogness <john.ogness@linutronix.de>
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On Tue, Feb 12, 2019 at 6:30 AM John Ogness <john.ogness@linutronix.de> wrote:
>
> +                       while (atomic_long_read(&rb->lost)) {
> +                               atomic_long_dec(&rb->lost);
> +                               rb->seq++;
> +                       }

This looks like crazy garbage. It's neither atomic nor sane.

Why isn't it something like

    if (atomic_long_read(&rb->lost)) {
        long lost = atomic_xchg(&rb->lost, 0);
        rb->seq += lost;
    }

instead?

                Linus