linux-kernel - Re: [PATCH v2 1/2] printk_ringbuffer: don't needlessly wrap data blocks around

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Message-ID: <84ikhwev7o.fsf@jogness.linutronix.de>
Date: Fri, 05 Sep 2025 18:16:35 +0206
From: John Ogness <john.ogness@...utronix.de>
To: Daniil Tatianin <d-tatianin@...dex-team.ru>, Petr Mladek <pmladek@...e.com>
Cc: linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
 Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: Re: [PATCH v2 1/2] printk_ringbuffer: don't needlessly wrap data
 blocks around

On 2025-09-05, Daniil Tatianin <d-tatianin@...dex-team.ru> wrote:
> On 9/5/25 6:27 PM, John Ogness wrote:
>> On 2025-09-05, Daniil Tatianin <d-tatianin@...dex-team.ru> wrote:
>>> diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c
>>> index d9fb053cff67..99989a9ce4b4 100644
>>> --- a/kernel/printk/printk_ringbuffer.c
>>> +++ b/kernel/printk/printk_ringbuffer.c
>>> @@ -1234,14 +1245,14 @@ static const char *get_data(struct prb_data_ring *data_ring,
>>>   	}
>>>   
>>>   	/* Regular data block: @begin less than @next and in same wrap. */
>>> -	if (DATA_WRAPS(data_ring, blk_lpos->begin) == DATA_WRAPS(data_ring, blk_lpos->next) &&
>>> +	if (!is_blk_wrapped(data_ring, blk_lpos->begin, blk_lpos->next) &&
>>>   	    blk_lpos->begin < blk_lpos->next) {
>>>   		db = to_block(data_ring, blk_lpos->begin);
>>>   		*data_size = blk_lpos->next - blk_lpos->begin;
>>>   
>>>   	/* Wrapping data block: @begin is one wrap behind @next. */
>>> -	} else if (DATA_WRAPS(data_ring, blk_lpos->begin + DATA_SIZE(data_ring)) ==
>>> -		   DATA_WRAPS(data_ring, blk_lpos->next)) {
>>> +	} else if (!is_blk_wrapped(data_ring,
>>> +		   blk_lpos->begin + DATA_SIZE(data_ring), blk_lpos->next)) {
>> It would look nicer if the arguments of the function were indented to
>> the function parenthesis:
>>
>> 	} else if (!is_blk_wrapped(data_ring, blk_lpos->begin +
>> 				   DATA_SIZE(data_ring), blk_lpos->next)) {
>
> Would you like me to resend with this addressed?

Knowing Petr, I would say "yes". :-)

But wait for Petr's response before sending anything.

John