linux-kernel - Re: [PATCH v3 3/9] bitops: Introduce find_next_andnot

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Date:   Fri, 26 Aug 2022 00:17:19 +0100
From:   Valentin Schneider <vschneid@...hat.com>
To:     Yury Norov <yury.norov@...il.com>
Cc:     netdev@...r.kernel.org, linux-rdma@...r.kernel.org,
        linux-kernel@...r.kernel.org, Saeed Mahameed <saeedm@...dia.com>,
        Leon Romanovsky <leon@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Mel Gorman <mgorman@...e.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Tony Luck <tony.luck@...el.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Gal Pressman <gal@...dia.com>,
        Tariq Toukan <tariqt@...dia.com>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>
Subject: Re: [PATCH v3 3/9] bitops: Introduce find_next_andnot_bit()

On 25/08/22 14:05, Yury Norov wrote:
> On Thu, Aug 25, 2022 at 07:12:04PM +0100, Valentin Schneider wrote:
>> In preparation of introducing for_each_cpu_andnot(), add a variant of
>> find_next_bit() that negate the bits in @addr2 when ANDing them with the
>> bits in @addr1.
>>
>> Note that the _find_next_bit() @invert argument now gets split into two:
>> @invert1 for words in @addr1, @invert2 for words in @addr2. The only
>> current users of _find_next_bit() with @invert set are:
>>   o find_next_zero_bit()
>>   o find_next_zero_bit_le()
>> and neither of these pass an @addr2, so the conversion is straightforward.
>>
>> Signed-off-by: Valentin Schneider <vschneid@...hat.com>
>
> Have you seen this series?
> https://lore.kernel.org/lkml/YwaXvphVpy5A7fSs@yury-laptop/t/
>
> It will significantly simplify your work for adding the
> find_next_andnot_bit(). If you wait a week or so, you'll most likely
> find it in -next.
>

I hadn't seen it, it does look promising. I'm about to disappear for a
week, so I'll have a look once I'm back.

> Thanks,
> Yury