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Tue, 28 Mar 2023 14:11:20 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas5p2.samsung.com (KnoxPortal) with ESMTPA id 20230328051120epcas5p23b4a173dadbd6f125c881d3809202d85~QfSnsiGbd1367713677epcas5p2m; Tue, 28 Mar 2023 05:11:20 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20230328051120epsmtrp2790b231483430685416c7b3c303e01a2~QfSnrlTFx0876108761epsmtrp2K; Tue, 28 Mar 2023 05:11:20 +0000 (GMT) X-AuditID: b6c32a4a-6a3ff7000000d97e-be-642276f89e8a Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 39.F9.18071.7F672246; Tue, 28 Mar 2023 14:11:19 +0900 (KST) Received: from green5 (unknown [107.110.206.5]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20230328051117epsmtip1945862bfadb3271bf9b732bc79c0b27f~QfSluiTd_2317323173epsmtip1w; Tue, 28 Mar 2023 05:11:17 +0000 (GMT) Date: Tue, 28 Mar 2023 10:40:37 +0530 From: Kanchan Joshi To: Ming Lei Cc: Jens Axboe , io-uring@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Miklos Szeredi , ZiyangZhang , Xiaoguang Wang , Bernd Schubert , Pavel Begunkov , Stefan Hajnoczi Subject: Re: [PATCH V4 00/17] io_uring/ublk: add IORING_OP_FUSED_CMD Message-ID: <20230328051037.GB8405@green5> MIME-Version: 1.0 In-Reply-To: <20230324135808.855245-1-ming.lei@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrKJsWRmVeSWpSXmKPExsWy7bCmhu6PMqUUgxX9AhZzVm1jtFh9t5/N 4uH7J2wW71rPsVjsvaVtcXnXHDaLQ5ObmSxm9p1hsng96T+rxaa/J5ks2p9OYnTg9pjytI/d Y+esu+wel8+Weux8aOnxft9VNo/Pm+QC2KKybTJSE1NSixRS85LzUzLz0m2VvIPjneNNzQwM dQ0tLcyVFPISc1NtlVx8AnTdMnOAjlNSKEvMKQUKBSQWFyvp29kU5ZeWpCpk5BeX2CqlFqTk FJgU6BUn5haX5qXr5aWWWBkaGBiZAhUmZGe0v3/OVLCTp6Lz7X7GBsZNXF2MnBwSAiYSZ04f ZOti5OIQEtjNKNF/bDEThPOJUWL58q/sEM43RonZS/6ywrR8ffSCGSKxF6jq11Yo5wmjxNM9 jSxdjBwcLAKqEn+WFYKYbAKaEhcml4L0iggoSdy9uxpsKLPATyaJE5+mMoMkhAVcJI7dbACz eQW0JNZt74SyBSVOznzCAmJzClhJzDnUyQRiiwooSxzYdhzsVAmBuRwS9651MENc5yJx/dhC KFtY4tXxLewQtpTE53d72SDsZIlLM88xQdglEo/3HISy7SVaT/WD9TILZEo8OTGNHcLmk+j9 /YQJ5BkJAV6JjjYhiHJFiXuTnkIDRVzi4YwlULaHxKpPj6Eh18socez/T7YJjHKzkPwzC8kK CNtKovNDE+ssoBXMAtISy/9xQJiaEut36S9gZF3FKJlaUJybnlpsWmCUl1oOj+Tk/NxNjOD0 quW1g/Hhgw96hxiZOBgPMUpwMCuJ8G72VkwR4k1JrKxKLcqPLyrNSS0+xGgKjJ6JzFKiyfnA BJ9XEm9oYmlgYmZmZmJpbGaoJM6rbnsyWUggPbEkNTs1tSC1CKaPiYNTqoEpg9Ei/GHRnzlF D8/2KZrbLD9wcHXU32Xmz06I3Jr54/xc5g7LUtPNRbzfbHyTlvCeyGs+l//JWSP2e11WNjvT 0nnrJCs/HFugtvrYwkTTBIMFP21KrZxjDcOEub7vcP2dEct/4+S6X4Z+i1fvNt8euMToZ8GH Bhv1yasenLlq9rut9kKifGd8kv7lT912IQ+jHrXKfV/2+p6zTfy+c9UdMvs//zTjvTjr3r5t JxsvTt55fK+AvFKc4PY9db9Xsz7hmiS2math38ciM9n17o9bNucf9Lp8/fii/qCSbRXSH9Z/ /PiVV3D1sVWsqfeePY0/l77xtFqsrvTGrar/H190dmZwtHl5d8L1dQySyv1zmJVYijMSDbWY i4oTATiZqWc4BAAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrMLMWRmVeSWpSXmKPExsWy7bCSnO73MqUUgyVtFhZzVm1jtFh9t5/N 4uH7J2wW71rPsVjsvaVtcXnXHDaLQ5ObmSxm9p1hsng96T+rxaa/J5ks2p9OYnTg9pjytI/d Y+esu+wel8+Weux8aOnxft9VNo/Pm+QC2KK4bFJSczLLUov07RK4Mp6f/s9U8IKz4vDb52wN jL/Zuxg5OSQETCS+PnrB3MXIxSEksJtR4lT3V6iEuETztR9QtrDEyn/P2SGKHjFKfF+6m7GL kYODRUBV4s+yQhCTTUBT4sLkUpByEQElibt3V4OVMwv8ZZJ4fOcNK0hCWMBF4tjNBmYQm1dA S2Ld9k6oxb2MEnMuPWSFSAhKnJz5hAXEZhYwk5i3+SEzyAJmAWmJ5f84QMKcAlYScw51MoHY ogLKEge2HWeawCg4C0n3LCTdsxC6FzAyr2KUTC0ozk3PLTYsMMxLLdcrTswtLs1L10vOz93E CI4XLc0djNtXfdA7xMjEwXiIUYKDWUmEd7O3YooQb0piZVVqUX58UWlOavEhRmkOFiVx3gtd J+OFBNITS1KzU1MLUotgskwcnFINTH6n2CYf8zp2sOgn+7mPVSpCkhcPadod5ZQ4/73Vv26p u/P2L3lsXYU5N6wb787avGt35o1VThVdpxM+xfRcbk836KrqyHurzpqwOGB7bOWHyZs+POAr rTwY9ptXlilcZp3ZVN1ladu5d+xl7Tm0qGufXKinWuKZmfc4nfa8qMp5deCme9CxGT58G/0v 837acG9bEbvkGiYe/SmfpQx3bedqmP/vtjbHRaMjYi4z7c7on3p9aVfTlp9WNid6q7eH1vNZ iRueqX/Ql/R8X+PqZUL5u1kkPEpTD76WEfGwb5lzTV1FJPXrIY1igUeR9bq8C/wXGTJe5kle VhqyqKJnTZ2jg4fiz7RvoVtEXA4dUmIpzkg01GIuKk4EANNV18YGAwAA X-CMS-MailID: 20230328051120epcas5p23b4a173dadbd6f125c881d3809202d85 X-Msg-Generator: CA Content-Type: multipart/mixed; boundary="----KU2CxbTk4.ftA7vvsvzLW4bt.-m_7jRTbTuK1k18jgDVn8pS=_11136e_" CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230324135916epcas5p37aad4c49c76c05567a484377d8909092 References: <20230324135808.855245-1-ming.lei@redhat.com> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org ------KU2CxbTk4.ftA7vvsvzLW4bt.-m_7jRTbTuK1k18jgDVn8pS=_11136e_ Content-Type: text/plain; charset="utf-8"; format="flowed" Content-Disposition: inline On Fri, Mar 24, 2023 at 09:57:51PM +0800, Ming Lei wrote: >Hello Jens, > >Add IORING_OP_FUSED_CMD, it is one special URING_CMD, which has to >be SQE128. The 1st SQE(master) is one 64byte URING_CMD, and the 2nd >64byte SQE(slave) is another normal 64byte OP. For any OP which needs >to support slave OP, io_issue_defs[op].fused_slave needs to be set as 1, >and its ->issue() can retrieve/import buffer from master request's >fused_cmd_kbuf. The slave OP is actually submitted from kernel, part of >this idea is from Xiaoguang's ublk ebpf patchset, but this patchset >submits slave OP just like normal OP issued from userspace, that said, >SQE order is kept, and batching handling is done too. > >Please see detailed design in commit log of the 2th patch, and one big >point is how to handle buffer ownership. > >With this way, it is easy to support zero copy for ublk/fuse device. > >Basically userspace can specify any sub-buffer of the ublk block request >buffer from the fused command just by setting 'offset/len' >in the slave SQE for running slave OP. Wondering if this new OP can also be used to do larger IO (than device limit) on nvme-passthrough? For example, 1MB IO on NVMe than has 512k or 256K maximum transfer size. ------KU2CxbTk4.ftA7vvsvzLW4bt.-m_7jRTbTuK1k18jgDVn8pS=_11136e_ Content-Type: text/plain; charset="utf-8" ------KU2CxbTk4.ftA7vvsvzLW4bt.-m_7jRTbTuK1k18jgDVn8pS=_11136e_--