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{
    "id": 2220583,
    "url": "http://patchwork.ozlabs.org/api/1.1/covers/2220583/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/linux-cifs-client/cover/cover.1775571957.git.metze@samba.org/",
    "project": {
        "id": 12,
        "url": "http://patchwork.ozlabs.org/api/1.1/projects/12/?format=api",
        "name": "Linux CIFS Client",
        "link_name": "linux-cifs-client",
        "list_id": "linux-cifs.vger.kernel.org",
        "list_email": "linux-cifs@vger.kernel.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": ""
    },
    "msgid": "<cover.1775571957.git.metze@samba.org>",
    "date": "2026-04-07T14:46:26",
    "name": "[0/8] smb: add kernel internal IPPROTO_SMBDIRECT",
    "submitter": {
        "id": 8149,
        "url": "http://patchwork.ozlabs.org/api/1.1/people/8149/?format=api",
        "name": "Stefan Metzmacher",
        "email": "metze@samba.org"
    },
    "mbox": "http://patchwork.ozlabs.org/project/linux-cifs-client/cover/cover.1775571957.git.metze@samba.org/mbox/",
    "series": [
        {
            "id": 498990,
            "url": "http://patchwork.ozlabs.org/api/1.1/series/498990/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/linux-cifs-client/list/?series=498990",
            "date": "2026-04-07T14:46:28",
            "name": "smb: add kernel internal IPPROTO_SMBDIRECT",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/498990/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/covers/2220583/comments/",
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        "From": "Stefan Metzmacher <metze@samba.org>",
        "To": "linux-cifs@vger.kernel.org,\n\tsamba-technical@lists.samba.org",
        "Cc": "metze@samba.org,\n\tSteve French <smfrench@gmail.com>,\n\tTom Talpey <tom@talpey.com>,\n\tLong Li <longli@microsoft.com>,\n\tNamjae Jeon <linkinjeon@kernel.org>,\n\tDavid Howells <dhowells@redhat.com>,\n\tHenrique Carvalho <henrique.carvalho@suse.com>,\n\t\"David S . Miller\" <davem@davemloft.net>,\n\tEric Dumazet <edumazet@google.com>,\n\tJakub Kicinski <kuba@kernel.org>,\n\tPaolo Abeni <pabeni@redhat.com>,\n\tSimon Horman <horms@kernel.org>,\n\tKuniyuki Iwashima <kuniyu@google.com>,\n\tWillem de Bruijn <willemb@google.com>,\n\tnetdev@vger.kernel.org,\n\tXin Long <lucien.xin@gmail.com>,\n\tquic@lists.linux.dev,\n\tlinux-rdma@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org,\n\tMark Brown <broonie@kernel.org>,\n\tlinux-next@vger.kernel.org",
        "Subject": "[PATCH 0/8] smb: add kernel internal IPPROTO_SMBDIRECT",
        "Date": "Tue,  7 Apr 2026 16:46:26 +0200",
        "Message-ID": "<cover.1775571957.git.metze@samba.org>",
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        "List-Id": "<linux-cifs.vger.kernel.org>",
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    },
    "content": "Hi,\n\nas the work to unify the smbdirect code\nbetween cifs.ko and ksmbd.ko into an smbdirect.ko\nis in linux-next for a while this is the next\nstep to also share the code with userspace\ne.g. Samba as client and server.\n\nThe SMBDIRECT protocol, defined in [MS-SMBD] by Microsoft.\nIt is used as wrapper around RDMA in order to provide a transport for SMB3,\nbut Microsoft also uses it as transport for other protocols.\n\nSMBDIRECT works over Infiniband, RoCE and iWarp.  RoCEv2 is based on IP/UDP\nand iWarp is based on IP/TCP, so these use IP addresses natively.\nInfiniband and RoCEv1 require IPOIB in order to be used for SMBDIRECT.\n\nSo instead of adding a PF_SMBDIRECT, which would only use AF_INET[6],\nwe use IPPROTO_SMBDIRECT instead, this uses a number not\nallocated from IANA, as it would not appear in an IP header.\n\nThis is similar to IPPROTO_SMC, IPPROTO_MPTCP and IPPROTO_QUIC,\nwhich are linux specific values for the socket() syscall.\n\n  socket(AF_INET, SOCK_STREAM, IPPROTO_SMBDIRECT);\n  socket(AF_INET6, SOCK_STREAM, IPPROTO_SMBDIRECT);\n\nThis will allow the existing smbdirect code used by\ncifs.ko and ksmbd.ko to be moved behind the socket layer [1],\nso that there's less special handling. Only sock_sendmsg()\nsock_recvmsg() are used, so that the main stream handling\nis done all the same for tcp, smbdirect and later also quic.\n\nThe special RDMA read/write handling will be via direct\nfunction calls as they are currently done for the in kernel\nconsumers.\n\nAs a start __sock_create(kern=0)/sk->sk_kern_sock == 0 will\nstill cause a -EPROTONOSUPPORT. So only in kernel consumers\nwill be supported for now.\n\nFor now the core smbdirect code still supports both\nmodes, direct calls in indirect via the socket layer.\nThe core code uses if (sc->sk.sk_family) as indication\nfor the new socket mode. Once cifs.ko and ksmbd.ko\nare converted we can remove the old mode slowly,\nbut I'll deferr that to a future patchset.\n\nThere's still a way to go in order to make this\nas generic as tcp and quic e.g. adding MSG_SPLICE_PAGES support or\nsplice_read/read_sock/read_skb.\n\nBut it's a good start, which will make changes much easier.\n\nThis patchset is based on top of the smbdirect.ko patches\nin ksmbd-for-next and it's also based on netdev-next\nbecause it needs this commit from there:\n8341c989ac77d712c7d6e2bce29e8a4bcb2eeae4\n\"net: remove addr_len argument of recvmsg() handlers\"\n\nPatches 1-4 are some preparation fixes for the\nexisting smbdirect.ko patchset. We may\nsquash them into the existing patches before\nsending them to Linus. But for now I kept\nthem separately. I also don't cc the network and rdma\npeople on these...\n\nPatch 5 defines IPPROTO_SMBDIRECT and SOL_SMBDIRECT\nconstants (and also reserve the number 288 for SOL_QUIC\nas applications are already using that and we don't\nwant to conflict)\n\nPatch 6 adds basic IPPROTO_SMBDIRECT layering\non top of the existing smbdirect code.\nThis is just enough in order to let cifs.ko\nand ksmbd.ko use it in the following commits,\nso userspace still sees -EPROTONOSUPPORT.\n\nPatch 7 converts cifs.ko to use IPPROTO_SMBDIRECT\nas much as currently possible.\nUsing sock_sendmsg is not yet possible, because of the\ntcp_sock_set_cork usage, but that will change in future.\n\nPatch 8 converts ksmbd.ko to use IPPROTO_SMBDIRECT.\n\nBecause of the need for netdev-next commit\n8341c989ac77d712c7d6e2bce29e8a4bcb2eeae4\n\"net: remove addr_len argument of recvmsg() handlers\"\nit's a bit tricky to prepare something that would not\ncause problems in linux-next.\n\nWe could merge in netdev-next completely,\nbut I saw commit 00f03539e3d97af925abf42992d8c46167d54243\nin next-20260406, indicates some resolved conflicts\nwith (at least) the rdma tree, which comes\njust before netdev-next, while ksmbd-for-next is merged\nbefore all of them. So merging netdev-next into\nksmbd-for-next changes the order of netdev-next vs. rdma.\n\nOr we add a new branch smbdirect-for-next that's\nmerged into linux-next after netdev-next.\n\nOr a bit hacky but likely easier, ksmbd-for-next\njust cherry-picks 8341c989ac77d712c7d6e2bce29e8a4bcb2eeae4\n\"net: remove addr_len argument of recvmsg() handlers\"\nand that cherry picked commit is reverted as\nlast commit in ksmbd-for-next, or only in linux-next\nright before netdev-next is merged.\n\nFor now I have the patches in a branch with a\ncherry picked version of the needed commit only, see\nfor-7.1/ipproto-smbdirect-20260407-v1 at commit:\ne1972e6f1fda9842c5724b7daf4a2aa7779901a5\ngit fetch https://git.samba.org/metze/linux/wip.git for-7.1/ipproto-smbdirect-20260407-v1\nhttps://git.samba.org/?p=metze/linux/wip.git;a=shortlog;h=refs/heads/for-7.1/ipproto-smbdirect-20260407-v1\n\nIt would be great to get this somehow into linux-next soon :-)\n\nStefan Metzmacher (8):\n  smb: smbdirect: change\n    smbdirect_socket_parameters.{initiator_depth,responder_resources} to\n    __u16\n  smb: smbdirect: fix copyright header of smbdirect.h\n  smb: smbdirect: fix the logic in smbdirect_socket_destroy_sync()\n    without an error\n  smb: smbdirect: let smbdirect_connection_deregister_mr_io unlock while\n    waiting\n  net: define IPPROTO_SMBDIRECT and SOL_SMBDIRECT constants\n  smb: smbdirect: add in kernel only support for IPPROTO_SMBDIRECT\n  smb: client: make use of IPPROTO_SMBDIRECT sockets\n  smb: server: make use of IPPROTO_SMBDIRECT sockets\n\n fs/smb/client/cifs_debug.c                    |    2 +-\n fs/smb/client/cifsfs.c                        |    2 +-\n fs/smb/client/cifsglob.h                      |    7 +-\n fs/smb/client/connect.c                       |  123 +-\n fs/smb/client/file.c                          |    8 +-\n fs/smb/client/sess.c                          |    4 +-\n fs/smb/client/smb2ops.c                       |    8 +-\n fs/smb/client/smb2pdu.c                       |   10 +-\n fs/smb/client/smbdirect.c                     |  275 +--\n fs/smb/client/smbdirect.h                     |   27 +-\n fs/smb/client/transport.c                     |    2 +-\n fs/smb/common/smbdirect/Makefile              |    1 +\n fs/smb/common/smbdirect/smbdirect.h           |   69 +-\n fs/smb/common/smbdirect/smbdirect_accept.c    |   14 +-\n .../common/smbdirect/smbdirect_connection.c   |   58 +\n fs/smb/common/smbdirect/smbdirect_devices.c   |    2 +-\n fs/smb/common/smbdirect/smbdirect_internal.h  |   59 +-\n fs/smb/common/smbdirect/smbdirect_listen.c    |   49 +-\n fs/smb/common/smbdirect/smbdirect_main.c      |   45 +\n fs/smb/common/smbdirect/smbdirect_mr.c        |   18 +\n fs/smb/common/smbdirect/smbdirect_proto.c     | 1549 +++++++++++++++++\n fs/smb/common/smbdirect/smbdirect_public.h    |    3 +\n fs/smb/common/smbdirect/smbdirect_rw.c        |   29 +-\n fs/smb/common/smbdirect/smbdirect_socket.c    |  180 +-\n fs/smb/common/smbdirect/smbdirect_socket.h    |   26 +-\n fs/smb/server/transport_rdma.c                |  119 +-\n include/linux/socket.h                        |    2 +\n include/uapi/linux/in.h                       |    2 +\n 28 files changed, 2320 insertions(+), 373 deletions(-)\n create mode 100644 fs/smb/common/smbdirect/smbdirect_proto.c"
}