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Wed, 17 Mar 2021 10:21:53 -0700 (PDT) Subject: Re: [RFC PATCH v3 3/3] nvme: wire up support for async passthrough To: Christoph Hellwig Cc: Kanchan Joshi , kbusch@kernel.org, chaitanya.kulkarni@wdc.com, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, anuj20.g@samsung.com, javier.gonz@samsung.com, nj.shetty@samsung.com, selvakuma.s1@samsung.com References: <20210316140126.24900-1-joshi.k@samsung.com> <20210316140126.24900-4-joshi.k@samsung.com> <20210317085258.GA19580@lst.de> <149d2bc7-ec80-2e51-7db1-15765f35a27f@kernel.dk> <20210317165959.GA25097@lst.de> From: Jens Axboe Message-ID: <3b383e8e-b248-b8c4-2eea-6f5708845604@kernel.dk> Date: Wed, 17 Mar 2021 11:21:53 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210317165959.GA25097@lst.de> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210317_172155_762585_6BB100F9 X-CRM114-Status: GOOD ( 24.10 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 3/17/21 10:59 AM, Christoph Hellwig wrote: > On Wed, Mar 17, 2021 at 10:49:28AM -0600, Jens Axboe wrote: >> I will post it soon, only reason I haven't reposted is that I'm not that >> happy with how the sqe split is done (and that it's done in the first >> place). But I'll probably just post the current version for comments, >> and hopefully we can get it to where it needs to be soon. > > Yes, I don't like that at all either. I almost wonder if we should > use an entirely different format after opcode and flags, although > I suspect fd would be nice to have in the same spot as well. Exactly - trying to think of how best to do this. It's somewhat a shame that I didn't place user_data right after fd, or even at the end of the struct. But oh well. One idea would be to have io_uring_sqe_hdr and have that be op/flags/prio/fd as we should have those for anything, and just embed that at the top of both io_uring_sqe (our general command), and io_uring_whatever which is what the passthrough stuff would use. Not sure, I need to dabble in the code a bit and see how we can make it the cleanest. > On a related note: I think it really should have a generic cmd > dispatching mechanism like ioctls have, preferably even enforcing > the _IO* mechanism. Yes, we could certainly do that. I don't want to turn it into a free-for-all and the wild west of passthrough, some notion of coherent definitions would be prudent. -- Jens Axboe _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme