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From:   John Ogness <john.ogness@linutronix.de>
To:     Petr Mladek <pmladek@suse.com>
Cc:     Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH printk v2 3/4] printk: Skip unfinalized records in panic
In-Reply-To: <ZS_puLYK4TZR12Cx@alley>
References: <20231013204340.1112036-1-john.ogness@linutronix.de>
 <20231013204340.1112036-4-john.ogness@linutronix.de>
 <ZS5vrte2OZXcIc9L@alley> <87mswh6iwq.fsf@jogness.linutronix.de>
 <ZS_Vg4vvT29LxWSD@alley> <ZS_puLYK4TZR12Cx@alley>
Date:   Mon, 23 Oct 2023 11:59:58 +0206
Message-ID: <87v8ax1x6x.fsf@jogness.linutronix.de>
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On 2023-10-18, Petr Mladek <pmladek@suse.com> wrote:
> I think about "empty line record" and "records with missing data".
> And I would rename NO_LPOS to EMPTY_LINE_LPOS to make the meaning
> more obvious.

OK.

> Also it would make sense to use 0x2 for EMPTY_LINE_LPOS and
>
> #define FAILED_LPOS		0x1
> #define EMPTY_LINE_LPOS		0x2
> #define DATALESS_LPOS_MASK	(FAILED_LPOS | EMPTY_LINE_LPOS)
>
> #define LPOS_DATALESS(lpos)	((lpos) & DATALESS_LPOS_MASK)

The existing debugging tools use bit0 to identify if there is data. Bit1
is really the _reason_ for the missing data. This can be seen in the
definition of LPOS_DATALESS(), but it needs to be documented
better. (Ideally where FAILED_LPOS and EMPTY_LINE_LPOS are defined.)

John