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Message-ID: <12aa1043-14c3-0f95-6cb4-f7a021268ae4@kernel.dk>
Date:   Fri, 30 Sep 2022 10:35:38 -0600
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Subject: Re: block: wrong return value by bio_end_sector?
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To:     Paolo Valente <paolo.valente@linaro.org>,
        Arie van der Hoeven <arie.vanderhoeven@seagate.com>,
        Tyler Erickson <tyler.erickson@seagate.com>,
        Muhammad Ahmad <muhammad.ahmad@seagate.com>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Jan Kara <jack@suse.cz>,
        "andrea.righi@canonical.com" <andrea.righi@canonical.com>,
        "glen.valante@linaro.org" <glen.valante@linaro.org>,
        Michael English <michael.english@seagate.com>,
        Andrew Ring <andrew.ring@seagate.com>,
        Varun Boddu <varunreddy.boddu@seagate.com>,
        Damien Le Moal <damien.lemoal@wdc.com>
References: <D4FC5552-B3C8-4118-B3C8-C6BF20C793B4@linaro.org>
From:   Jens Axboe <axboe@kernel.dk>
In-Reply-To: <D4FC5552-B3C8-4118-B3C8-C6BF20C793B4@linaro.org>
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On 9/30/22 9:59 AM, Paolo Valente wrote:
> Hi Jens, Damien, all other possibly interested people,
> this is to raise attention on a mistake that has emerged in a
> thread on a bfq extension for multi-actuary drives [1].
> 
> The mistake is apparently in the macro bio_end_sector (defined in
> include/linux/bio.h), which seems to be translated (incorrectly) as
> sector+size, and not as sector+size-1.
> 
> For your convenience, I'm pasting a detailed description of the
> problem, by Tyler (description taken from the above thread [1]).

I'm a little confused - currently it returns non-inclusive end, the
proposed change just make it inclusive. In general in the kernel the
former is used, and this one follows that.

-- 
Jens Axboe