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Wed, 17 May 2023 13:16:29 -0700 (PDT) Received: from [192.168.8.100] ([85.255.236.195]) by smtp.gmail.com with ESMTPSA id h14-20020adffd4e000000b00304aba2cfcbsm3762683wrs.7.2023.05.17.13.16.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 May 2023 13:16:29 -0700 (PDT) Message-ID: Date: Wed, 17 May 2023 21:11:55 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH for-next 2/2] nvme: optimise io_uring passthrough completion Content-Language: en-US To: Christoph Hellwig Cc: linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, io-uring@vger.kernel.org, axboe@kernel.dk, kbusch@kernel.org, sagi@grimberg.me, joshi.k@samsung.com References: <20230517072314.GC27026@lst.de> <9367cc09-c8b4-a56c-a61a-d2c776c05a1c@gmail.com> <20230517123921.GA19835@lst.de> <61787b53-3c16-8cdb-eaad-6c724315435b@gmail.com> <20230517135344.GA26147@lst.de> From: Pavel Begunkov In-Reply-To: <20230517135344.GA26147@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230517_131633_251170_5C03DBD2 X-CRM114-Status: GOOD ( 16.08 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 5/17/23 14:53, Christoph Hellwig wrote: > On Wed, May 17, 2023 at 02:30:47PM +0100, Pavel Begunkov wrote: >> Aside that you decided to ignore the third point, that's a >> generic interface, not nvme specific, there are patches for >> net cmds, someone even tried to use it for drm. How do you >> think new users are supposed to appear if the only helper >> doing the job can hang the userspace for their use case? >> Well, then maybe it'll remain nvme/ublk specific with such >> an approach. > > New users can add new code when it's actualy needed. We don't > bloat the kernel for maybe in the future crap as a policy. Let me put it for you this way, it's an absolutely horrendous idea to leave the old innocently looking name, i.e. io_uring_cmd_complete_in_task(), and add there a bunch of restrictions no new user would care about, that's called shooting yourself in the leg. So, we need to rename the function, which, again, for absolutely no reason adds dependency on ublk. Why doing that instead of waiting until ublk is converted? That's a big mystery. -- Pavel Begunkov