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Tue, 12 Jul 2022 20:38:30 +0900 (KST) Received: from epsmtrp1.samsung.com (unknown [182.195.40.13]) by epcas5p4.samsung.com (KnoxPortal) with ESMTPA id 20220712113829epcas5p450d873c7e596124b079f17595fc42e9f~BEftvBJyZ2337223372epcas5p44; Tue, 12 Jul 2022 11:38:29 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp1.samsung.com (KnoxPortal) with ESMTP id 20220712113829epsmtrp1b6a97dd9a13941a3024487eca20a16a3~BEftuNYIr0581305813epsmtrp1D; Tue, 12 Jul 2022 11:38:29 +0000 (GMT) X-AuditID: b6c32a4a-b8dff7000000255e-75-62cd5d360378 Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 63.31.08905.53D5DC26; Tue, 12 Jul 2022 20:38:29 +0900 (KST) Received: from test-zns (unknown [107.110.206.5]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20220712113827epsmtip16c82cf0b4509137dd52e2cd1092c0b23~BEfsJMP7o1734017340epsmtip11; Tue, 12 Jul 2022 11:38:27 +0000 (GMT) Date: Tue, 12 Jul 2022 17:03:04 +0530 From: Kanchan Joshi To: Christoph Hellwig Cc: sagi@grimberg.me, kbusch@kernel.org, axboe@kernel.dk, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, asml.silence@gmail.com, joshiiitr@gmail.com, anuj20.g@samsung.com, gost.dev@samsung.com Subject: Re: [PATCH for-next 4/4] nvme-multipath: add multipathing for uring-passthrough commands Message-ID: <20220712113304.GA4465@test-zns> MIME-Version: 1.0 In-Reply-To: <20220712065250.GA6574@lst.de> User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrPJsWRmVeSWpSXmKPExsWy7bCmlq5Z7Nkkg09TuSyaJvxltpizahuj xeq7/WwWNw/sZLJYufook8W71nMsFuffHmaymHToGqPF3lvaFvOXPWW3WPf6PYsDt8fOWXfZ Pc7f28jicflsqcemVZ1sHpuX1HvsvtnA5tG3ZRWjx+dNcgEcUdk2GamJKalFCql5yfkpmXnp tkrewfHO8aZmBoa6hpYW5koKeYm5qbZKLj4Bum6ZOUBnKimUJeaUAoUCEouLlfTtbIryS0tS FTLyi0tslVILUnIKTAr0ihNzi0vz0vXyUkusDA0MjEyBChOyM96cPsxW8IajomvCOaYGxtPs XYycHBICJhLrmk+zdjFycQgJ7GaU+PrgMQuE84lR4suEDmYI5xujxLLH69hgWuZtuMQOkdjL KPH+2gqo/meMEk+3nWMEqWIRUJVo6ugDSnBwsAloSlyYXAoSFhFQknj66ixYCbPAO0aJKe9y QGxhgWSJTU8mMYHYvAI6Es/7FrBD2IISJ2c+YQGxOQW0JT4veAp2hKiAssSBbceZQPZKCKzk kNg4ZRszxHUuEv9fzmOCsIUlXh3fAvWolMTL/jYoO1ni0sxzUDUlEo/3HISy7SVaT/UzQxyX ITG3r5MVwuaT6P39hAnkFwkBXomONiGIckWJe5OeskLY4hIPZyyBsj0kPs5vhgbQHUaJ4/9n ME9glJuF5J9ZSFZA2FYSnR+agGwOIFtaYvk/DghTU2L9Lv0FjKyrGCVTC4pz01OLTQuM8lLL 4ZGcnJ+7iRGccrW8djA+fPBB7xAjEwfjIUYJDmYlEd4/Z08lCfGmJFZWpRblxxeV5qQWH2I0 BUbPRGYp0eR8YNLPK4k3NLE0MDEzMzOxNDYzVBLn9bq6KUlIID2xJDU7NbUgtQimj4mDU6qB yXrqtb+/HVc65wksD/i+Jz9Cft0h8U1VzZdV89fIFtjLXUoU74zL/RDncMJutuXFT47ZsVrd 93/cyrwzXypwpUebiqLWz6sWLLMfdwe3JRb9NMmfIv9Wv9wuT+1xeCJ7x6ez1he/J8g+6Nr+ pfmCnzNTnNu8hmven1bWbtBxW5wzl3H2/G9T9k2R1oqYso3dK2K1OEfTC8FlfIU9jQ9M2VW4 wz2DOnvfPVl7LCbbX/2/nuZM0eS0tyelpgqkyRjzRoQbJBiqrdptUOdr77bLi8vtuGS329MI QzeVlxWL2Zhsd557cMf8+oW9Llwps7u/tM3S+lFrXunTF7CO84l/wYYvk+OMZ89jN5zhN0+J pTgj0VCLuag4EQCxsYW2QgQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrHLMWRmVeSWpSXmKPExsWy7bCSnK5p7Nkkg9e7hSyaJvxltpizahuj xeq7/WwWNw/sZLJYufook8W71nMsFuffHmaymHToGqPF3lvaFvOXPWW3WPf6PYsDt8fOWXfZ Pc7f28jicflsqcemVZ1sHpuX1HvsvtnA5tG3ZRWjx+dNcgEcUVw2Kak5mWWpRfp2CVwZBz6e YyqYx1Zx6dxt9gbG6axdjJwcEgImEvM2XGLvYuTiEBLYzSjRtfoZO0RCXKL52g8oW1hi5b/n UEVPGCU6Vk8BS7AIqEo0dfQBTeLgYBPQlLgwuRQkLCKgJPH01VlGkHpmgXeMEk3zullAEsIC yRKbnkxiArF5BXQknvctgBp6j1Gi7dEzFoiEoMTJmU/AbGYBM4l5mx8ygyxgFpCWWP6PAyTM KaAt8XnBUzYQW1RAWeLAtuNMExgFZyHpnoWkexZC9wJG5lWMkqkFxbnpucWGBYZ5qeV6xYm5 xaV56XrJ+bmbGMFRpKW5g3H7qg96hxiZOBgPMUpwMCuJ8P45eypJiDclsbIqtSg/vqg0J7X4 EKM0B4uSOO+FrpPxQgLpiSWp2ampBalFMFkmDk6pBqboN1tfvsybvsLvf8SC/Y7znV2S8l1e iFt+YzUWXWRdvuHR3mRXp7qt9v/X7P/xSo8js5DBp29K2LFQhu7CDgFx/1sPtGSdDWO0dkj/ rlvZyiuXOI8nKPW3ytnz09dnvjc5NzeRxy8jZOuC7xOmO+rpmRu/nKMZza5g1eKiJnIrRO0R 0zmZScsvvJJbdWP3kqwC47D5Ul8mzrLncmH6U7lWZJrUm6pnjbVhB1jPK4QeOrDHintP+C2h 9Jxt3T8k2Is956lyPjned05FMHLuu8f9Ufr9kh0/V2/aIrznhANLnLPtWhmHBJGmNxN/u7BE FYnN93zVczomaG0VU5KXUKRTaQHPsftKK76XfhPvVWIpzkg01GIuKk4EAKwPXvURAwAA X-CMS-MailID: 20220712113829epcas5p450d873c7e596124b079f17595fc42e9f X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----OEEzMZle2oafIX2psGkTvPl59BrXC3apHO-sLjJPJT1qP5Pe=_81827_" CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20220711110827epcas5p3fd81f142f55ca3048abc38a9ef0d0089 References: <20220711110155.649153-1-joshi.k@samsung.com> <20220711110155.649153-5-joshi.k@samsung.com> <20220712065250.GA6574@lst.de> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org ------OEEzMZle2oafIX2psGkTvPl59BrXC3apHO-sLjJPJT1qP5Pe=_81827_ Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Disposition: inline On Tue, Jul 12, 2022 at 08:52:50AM +0200, Christoph Hellwig wrote: >Hmm, I'm a little confused on what this is trying to archive. > >The io_uring passthrough already does support multipathing, it picks >an available path in nvme_ns_head_chr_uring_cmd and uses that. > >What this does is adding support for requeing on failure or the >lack of an available path. Which very strongly is against our >passthrough philosophy both in SCSI and NVMe where error handling >is left entirely to the userspace program issuing the I/O. > >So this does radically change behavior in a very unexpected way. >Why? I think ask has been to add requeue/failover support for async-passthrough. This came up here - https://lore.kernel.org/linux-nvme/88827a86-1304-e699-ec11-2718e280f9ad@grimberg.me/ ------OEEzMZle2oafIX2psGkTvPl59BrXC3apHO-sLjJPJT1qP5Pe=_81827_ Content-Type: text/plain; charset="utf-8" ------OEEzMZle2oafIX2psGkTvPl59BrXC3apHO-sLjJPJT1qP5Pe=_81827_--