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Wed, 9 Aug 2023 16:02:41 +0900 (KST) Received: from green245 (unknown [107.99.41.245]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20230809070240epsmtip152885e1e42ea27fac825beec2d4565d2~5pQFgnAZy1620916209epsmtip1H; Wed, 9 Aug 2023 07:02:40 +0000 (GMT) Date: Wed, 9 Aug 2023 12:29:20 +0530 From: Kanchan Joshi To: Ming Lei Cc: Christoph Hellwig , Keith Busch , linux-nvme@lists.infradead.org, Sagi Grimberg , Guangwu Zhang , Anuj Gupta Subject: Re: [PATCH] nvme: core: don't hold rcu read lock in nvme_ns_chr_uring_cmd_iopoll Message-ID: <20230809065920.GA19415@green245> MIME-Version: 1.0 In-Reply-To: <20230809020440.174682-1-ming.lei@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprIJsWRmVeSWpSXmKPExsWy7bCmpq6Q1eUUg0PLZSyaJvxltlhyZTeL xcrVR5ksJh26xmgxf9lTdotDk5uZLNa9fs/iwO5x/t5GFo9NqzrZPDYvqffYfbOBzeP9vqts Hn1bVjEGsEVl22SkJqakFimk5iXnp2TmpdsqeQfHO8ebmhkY6hpaWpgrKeQl5qbaKrn4BOi6 ZeYA3aKkUJaYUwoUCkgsLlbSt7Mpyi8tSVXIyC8usVVKLUjJKTAp0CtOzC0uzUvXy0stsTI0 MDAyBSpMyM648Hoie8EKzoqTV/czNTD+Ye9i5OSQEDCRePTnNAuILSSwm1Hi8WIvCPsTo0RP m2UXIxeQ/Y1R4kxDAxNMw75T/WwQib2MEh3/OlggnGeMEtOOvgcbyyKgItH74zZQBwcHm4Cm xIXJpSBhEQElibt3V7OD1DMLXGSUmP5pHStIQlggWmL7+0VgZ/AK6Er8W/ebCcIWlDg58wlY nFPASqJr6R+wuKiAssSBbceZQAZJCHRySPz42sMIcZ6LxOnOC1C2sMSr41ug/pSSeNnfBmUn S1yaeQ7qnRKJx3sOQtn2Eq2n+plBjmYWyJA4uSERJMwswCfR+/sJ2C8SArwSHW1CENWKEvcm PWWFsMUlHs5YAmV7SEy+184OCZNeYAC1vWGawCg3C8k7sxA2zALbYCXR+aGJFSIsLbH8HweE qSmxfpf+AkbWVYySqQXFuempxaYFhnmp5fAYTs7P3cQITptanjsY7z74oHeIkYmD8RCjBAez kgivbfClFCHelMTKqtSi/Pii0pzU4kOMpsDYmcgsJZqcD0zceSXxhiaWBiZmZmYmlsZmhkri vK9b56YICaQnlqRmp6YWpBbB9DFxcEo1MJnfrt6dvy3RZfUjmQdWVa8P8U6JbXj7bln1q/a+ aWsv6fbtuf/y7O5F2Uwzg3apVK41bdiwZ9nPy5vWlBqVPfq7z0bkz5pAO9XZOzybHAK21Yhd n7pd0/qwuaTaUZX7SpM6JLgMz6oHr/x1n5v3+JQsf8u+27I/hefuqv7bfvKQBGej6D+uD+sf W4n7zOEwFk2vsLaettPiQYd15EE2vnvB711z1x5WkktjODJZ45z84apP9veUP8pymhm/duQR cSiu3lz3Y7/BJYdrLHu8ezi0BP4/3MXVf6X+S93r1ZnNOr9XHfjT8G2J16oXrBPXsHUkBXRp dz/5NHN6TseM2D0vpvmz3jvdNjHA691W9kolluKMREMt5qLiRADrAT/fJAQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrELMWRmVeSWpSXmKPExsWy7bCSnK6g1eUUg647yhZNE/4yWyy5spvF YuXqo0wWkw5dY7SYv+wpu8Whyc1MFutev2dxYPc4f28ji8emVZ1sHpuX1HvsvtnA5vF+31U2 j74tqxgD2KK4bFJSczLLUov07RK4Mi63nWQuuMVW0X9gHVMD4wnWLkZODgkBE4l9p/rZuhi5 OIQEdjNKdL2cywSREJdovvaDHcIWllj57zmYLSTwhFFi9QJLEJtFQEWi98dtoHoODjYBTYkL k0tBwiICShJ3765mB5nJLHCZUWLmjb1gy4QFoiW2v1/EAmLzCuhK/Fv3mwlicS+jxNajp1kh EoISJ2c+AStiFjCTmLf5ITPIAmYBaYnl/zhAwpwCVhJdS/+A3SkqoCxxYNtxpgmMgrOQdM9C 0j0LoXsBI/MqRsnUguLc9NxkwwLDvNRyveLE3OLSvHS95PzcTYzgaNDS2MF4b/4/vUOMTByM hxglOJiVRHhtgy+lCPGmJFZWpRblxxeV5qQWH2KU5mBREuc1nDE7RUggPbEkNTs1tSC1CCbL xMEp1cDEbStU8SozJezsYpeNh28wet/anxDa/Zb//ZPNLw8emqTjXecfpbM25POezXJH3mbH hmqtYGVcadR5ebWvwcVeXZsm5esmv05cMk+dzLH7WElG/kb+Aw/2PUoMcxC+ZML8t8XISEMx 5YJQJR9fcuH9LNfUOVy20YWTalayJXw6yrT9YqdKyeGKz9eFVn6L44zpm7npvL/MzYznYrvn rz6+f2NV5rX9X5+d5jrs/0Te1/7thB814l4pza+enlu+S6rW8tfCUPZL7zUea4j+/Lzs0ryJ K625r4sUHag8vLeO+fbX0jn86VKLJ8nOjfy21/rAibQipb4D+YIW35u1dz2e0+1ycfbr66k6 yw5L+UkWK7EUZyQaajEXFScCAPYkT/v1AgAA X-CMS-MailID: 20230809070241epcas5p35e30b2fc1abfcd5abd1bde5ba37ab427 X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----Ax27aEWlRRTyCTKvLJGz44CsYuK4yEI58Kfkn8Ic_yMAot59=_3d5ae_" CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230809020844epcas5p30e520491fa59ab8c20836d4275931e8f References: <20230809020440.174682-1-ming.lei@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230809_000252_614684_09DBCE2A X-CRM114-Status: GOOD ( 14.03 ) 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 ------Ax27aEWlRRTyCTKvLJGz44CsYuK4yEI58Kfkn8Ic_yMAot59=_3d5ae_ Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Disposition: inline On Wed, Aug 09, 2023 at 10:04:40AM +0800, Ming Lei wrote: >Now nvme_ns_chr_uring_cmd_iopoll() has switched to request based io >polling, and the associated NS is guaranteed to be live in case of >io polling, so request is guaranteed to be valid because blk-mq uses >pre-allocated request pool. > >Remove the rcu read lock in nvme_ns_chr_uring_cmd_iopoll(), which >isn't needed any more after switching to request based io polling. >Fix "BUG: sleeping function called from invalid context" because >set_page_dirty_lock() from blk_rq_unmap_user() may sleep. > >Fixes: 585079b6e425 ("nvme: wire up async polling for io passthrough commands") >Reported-by: Guangwu Zhang Thanks Ming. Looks fine, but any link to this report? I don't see this breaking in my tests. So I wonder how to reproduce and improve the coverage. ------Ax27aEWlRRTyCTKvLJGz44CsYuK4yEI58Kfkn8Ic_yMAot59=_3d5ae_ Content-Type: text/plain; charset="utf-8" ------Ax27aEWlRRTyCTKvLJGz44CsYuK4yEI58Kfkn8Ic_yMAot59=_3d5ae_--