From: Damien Le Moal <dlemoal@kernel•org>
To: Murphy Zhou <jencce.kernel@gmail•com>,
linux-block@vger•kernel.org,
Linux-Next <linux-next@vger•kernel.org>
Subject: Re: ioprio_set can take 8 as the PROCESS CLASS_BE ioprio value
Date: Fri, 26 May 2023 16:42:02 +0900 [thread overview]
Message-ID: <97ffe91e-bb31-cceb-fb7e-8f7a2252734f@kernel.org> (raw)
In-Reply-To: <CADJHv_sedgbfxvZkKHjC6quKvxR+E54noFCVF93MvhyK6bwRoA@mail.gmail.com>
On 5/26/23 16:27, Murphy Zhou wrote:
> Hi Damien,
>
> Since these commits:
>
> scsi: block: Introduce ioprio hints
> scsi: block: ioprio: Clean up interface definition
>
> go into linux-next tree, ioprio_set can take the value of 8
> as the PROCESS CLASS_BE ioprio parameter, returning
> success but actually it is setting to 0 due to the mask roundup.
>
> The LTP test case ioprio_set03[1] covers this boundary value
> testing, which starts to fail since then.
>
> This does not look as expected. Could you help to take a look?
Before the patches, the ioprio level of 8 could indeed be set, but that was
actually totally meaningless since the kernel components that use the priority
level all are limited to the range [0..7]. And why the level value 8 could be
seen, the effective level would have been 0. So at least, with the changes, we
are not lying to the user...
I am not sure what this ioprio_set03 test is trying to check.
>
> Thanks,
> Murphy
>
> [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/ioprio/ioprio_set03.c
--
Damien Le Moal
Western Digital Research
next prev parent reply other threads:[~2023-05-26 7:42 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-26 7:27 ioprio_set can take 8 as the PROCESS CLASS_BE ioprio value Murphy Zhou
2023-05-26 7:42 ` Damien Le Moal [this message]
2023-05-27 0:02 ` Murphy Zhou
2023-05-29 2:28 ` Damien Le Moal
2023-05-29 5:46 ` Murphy Zhou
2023-05-29 13:15 ` Murphy Zhou
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