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Date:   Wed, 13 Apr 2022 16:21:40 +0800
From:   Muchun Song <songmuchun@bytedance.com>
To:     "liupeng (DM)" <liupeng256@huawei.com>
Cc:     mike.kravetz@oracle.com, david@redhat.com,
        akpm@linux-foundation.org, yaozhenguo1@gmail.com,
        baolin.wang@linux.alibaba.com, liuyuntao10@huawei.com,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/4] hugetlb: Fix return value of __setup handlers
Message-ID: <YlaIFL8TCRfiFFgR@FVFYT0MHHV2J.usts.net>
References: <20220413032915.251254-1-liupeng256@huawei.com>
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 <5bbf45e7-1d92-f543-5cfc-bc0141999d46@huawei.com>
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On Wed, Apr 13, 2022 at 04:16:11PM +0800, liupeng (DM) wrote:
> 
> On 2022/4/13 15:55, Muchun Song wrote:
> > On Wed, Apr 13, 2022 at 03:29:14AM +0000, Peng Liu wrote:
> > > When __setup() return '0', using invalid option values causes the
> > > entire kernel boot option string to be reported as Unknown. Hugetlb
> > > calls __setup() and will return '0' when set invalid parameter
> > > string.
> > > 
> > > The following phenomenon is observed:
> > >   cmdline:
> > >    hugepagesz=1Y hugepages=1
> > >   dmesg:
> > >    HugeTLB: unsupported hugepagesz=1Y
> > >    HugeTLB: hugepages=1 does not follow a valid hugepagesz, ignoring
> > >    Unknown kernel command line parameters "hugepagesz=1Y hugepages=1"
> > > 
> > > Since hugetlb will print warning/error information before return for
> > > invalid parameter string, just use return '1' to avoid print again.
> > > 
> > Can't return -EINVAL? It is weird to return 1 on failure.
> > 
> > Thanks.
> > 
> > .
> 
> Not against "return -EINVAL", but consistent with:
> 1d02b444b8d1 ("tracing: Fix return value of __setup handlers")

I think it is better not return 1.  I don't think it's a good habit we
should follow.

Thanks.

Thanks.