Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   "Chris Mason" <clm@fb.com>
To:     Christoph Hellwig <hch@infradead.org>
CC:     Nick Terrell <terrelln@fb.com>,
        Nick Terrell <nickrterrell@gmail.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        <linux-crypto@vger.kernel.org>,
        Btrfs BTRFS <linux-btrfs@vger.kernel.org>,
        <squashfs-devel@lists.sourceforge.net>,
        <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>, Kernel Team <Kernel-team@fb.com>,
        Petr Malat <oss@malat.biz>, Johannes Weiner <jweiner@fb.com>,
        Niket Agarwal <niketa@fb.com>, Yann Collet <cyan@fb.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v4 0/9] Update to zstd-1.4.6
Date:   Fri, 02 Oct 2020 09:42:29 -0400
Message-ID: <3E8AACF8-5168-4D19-B47F-8611B292D540@fb.com>
In-Reply-To: <20201002065454.GA29993@infradead.org>
References: <20200930065318.3326526-1-nickrterrell@gmail.com>
 <20200930065336.GA13656@infradead.org>
 <8743398B-0BBB-424E-A6A7-9D8AE4EFE8ED@fb.com>
 <20201002065454.GA29993@infradead.org>
Content-Type: text/plain; format=flowed
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
Received: from [100.109.10.224] (2620:10d:c091:480::1:504f) by MN2PR15CA0006.namprd15.prod.outlook.com (2603:10b6:208:1b4::19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3433.32 via Frontend Transport; Fri, 2 Oct 2020 13:42:31 +0000
X-MS-PublicTrafficType: Email
X-MS-Office365-Filtering-Correlation-Id: 649b3745-3c8b-4014-f79b-08d866d9033f
X-MS-TrafficTypeDiagnostic: BLAPR15MB3825:
X-MS-Exchange-Transport-Forked: True
X-Microsoft-Antispam-PRVS: <BLAPR15MB382523E849622A96D357D538D3310@BLAPR15MB3825.namprd15.prod.outlook.com>
X-FB-Source: Internal
X-MS-Oob-TLC-OOBClassifiers: OLM:9508;
X-MS-Exchange-SenderADCheck: 1
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info: KyQeqWgUGDE0KgpPHpxBp7wnE9wRM4Fwyjoqc1sKZGq3wjQPiZL76jR/V6lJVX2TZ/DtLVqR7VdYCt9ZLIqfp3BKRLg9mnfcbs25nZqvtTbuss2vpMe2eoc2egqg7Dt3lAzZVptOrV8PrnFi5nZRTjlCJ9mF3dQMZLyoPkzIKthjh6R3KMtFWGSLaAQhyGv0sn6NkUwQmH+Y5YORsX7uD1fNAUaIvInnje7bSQvDwYfbsplMXPi7PhkN8mA6BTfTTxUtP5/e8b0mA2m2UIOR86XaqSLGWHvsvP0y+Pajq18giKhA1a13xnxdKgaiRGnb/JYRW6A2Jt6RB3E2YahVulncKsUBq7rUmYrQxqZ8wM1fH7hMJp3CHERgGShFogO9
X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:MN2PR15MB3582.namprd15.prod.outlook.com;PTR:;CAT:NONE;SFS:(376002)(396003)(346002)(39860400002)(136003)(366004)(956004)(2616005)(53546011)(36756003)(7416002)(8936002)(6486002)(186003)(16526019)(33656002)(6916009)(2906002)(52116002)(8676002)(66476007)(66556008)(4326008)(66946007)(86362001)(316002)(54906003)(5660300002)(478600001)(78286007);DIR:OUT;SFP:1102;
X-MS-Exchange-AntiSpam-MessageData: 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
X-MS-Exchange-CrossTenant-Network-Message-Id: 649b3745-3c8b-4014-f79b-08d866d9033f
X-MS-Exchange-CrossTenant-AuthSource: MN2PR15MB3582.namprd15.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Oct 2020 13:42:32.4003
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: GAQNArK7NmQyAyCOUbcs2FCALEaH25eIcUlFcHQgzEfY6PYrMXi0EokvyZ5GaNts
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BLAPR15MB3825
X-OriginatorOrg: fb.com
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687
 definitions=2020-10-02_06:2020-10-02,2020-10-02 signatures=0
X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501
 mlxlogscore=799 impostorscore=0 mlxscore=0 phishscore=0 bulkscore=0
 clxscore=1015 spamscore=0 lowpriorityscore=0 malwarescore=0 adultscore=0
 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2006250000 definitions=main-2010020108
X-FB-Internal: deliver
Precedence: bulk
List-ID: <linux-crypto.vger.kernel.org>
X-Mailing-List: linux-crypto@vger.kernel.org

On 2 Oct 2020, at 2:54, Christoph Hellwig wrote:

> On Wed, Sep 30, 2020 at 08:05:45PM +0000, Nick Terrell wrote:
>>
>>
>>> On Sep 29, 2020, at 11:53 PM, Christoph Hellwig <hch@infradead.org> 
>>> wrote:
>>>
>>> As you keep resend this I keep retelling you that should not do it.
>>> Please provide a proper Linux API, and switch to that.  Versioned 
>>> APIs
>>> have absolutely no business in the Linux kernel.
>>
>> The API is not versioned. We provide a stable ABI for a large section 
>> of our API,
>> and the parts that aren???t ABI stable don???t change in semantics, 
>> and undergo long
>> deprecation periods before being removed.
>>
>> The change of callers is a one-time change to transition from the 
>> existing API
>> in the kernel, which was never upstream's API, to upstream's API.
>
> Again, please transition it to a sane kernel API.  We don't have an
> "upstream" in this case.

The upstream is the zstd project where all this code originates, and 
where the active development takes place.  As Eric Biggers pointed out, 
it also receives a lot of Q/A separate from the kernel.  I think we gain 
a great deal by leveraging the testing and documentation of the zstd 
project in the kernel interfaces we use.

We lose some consistency with the kernel coding style, but we gain the 
ability to search for docs, issues, and fixes directly against the zstd 
project and git repo.

-chris