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Content-Language: en-US To: Sagi Grimberg , Kanchan Joshi Cc: Kanchan Joshi , Christoph Hellwig , Keith Busch , Pavel Begunkov , io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, sbates@raithlin.com, logang@deltatee.com, Pankaj Raghav , =?UTF-8?Q?Javier_Gonz=c3=a1lez?= , Luis Chamberlain , Adam Manzanares , Anuj Gupta References: <20220308152105.309618-1-joshi.k@samsung.com> <20220308152105.309618-6-joshi.k@samsung.com> <7a123895-1102-4b36-2d6e-1e00e978d03d@grimberg.me> <8f45a761-5ecb-5911-1064-9625a285c93d@grimberg.me> <20220316092153.GA4885@test-zns> <11f9e933-cfc8-2e3b-c815-c49a4b7db4ec@grimberg.me> <3ed01280-5487-7206-a326-0cd110118b65@grimberg.me> From: Jens Axboe In-Reply-To: <3ed01280-5487-7206-a326-0cd110118b65@grimberg.me> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 3/16/22 7:52 AM, Sagi Grimberg wrote: > >>>>>>> No one cares that this has no multipathing capabilities what-so-ever? >>>>>>> despite being issued on the mpath device node? >>>>>>> >>>>>>> I know we are not doing multipathing for userspace today, but this >>>>>>> feels like an alternative I/O interface for nvme, seems a bit cripled >>>>>>> with zero multipathing capabilities... > > [...] > >> Got it, thanks. Passthrough (sync or async) just returns the failure >> to user-space if that fails. >> No attempt to retry/requeue as the block path does. > > I know, and that was my original question, no one cares that this > interface completely lacks this capability? Maybe it is fine, but > it is not a trivial assumption given that this is designed to be more > than an interface to send admin/vs commands to the controller... Most people don't really care about or use multipath, so it's not a primary goal. For passthrough, most of request types should hit the exact target, I would suggest that if someone cares about multipath for specific commands, that they be flagged as such. -- Jens Axboe