Re: [PATCH net-next v4 3/3] net/smc: Introduce IPPROTO_SMC

D. Wythe
2024-05-30T03:11:24Z

On 5/29/24 7:12 PM, Dust Li wrote:
> On 2024-05-29 11:59:07, D. Wythe wrote:
>> From: "D. Wythe" <alibuda@linux.alibaba.com>
>>
>> This patch allows to create smc socket via AF_INET,
>> similar to the following code,
>>
>> /* create v4 smc sock */
>> v4 = socket(AF_INET, SOCK_STREAM, IPPROTO_SMC);
>>
>> /* create v6 smc sock */
>> v6 = socket(AF_INET6, SOCK_STREAM, IPPROTO_SMC);
>>
>> There are several reasons why we believe it is appropriate here:
>>
>> 1. For smc sockets, it actually use IPv4 (AF-INET) or IPv6 (AF-INET6)
>> address. There is no AF_SMC address at all.
>>
>> 2. Create smc socket in the AF_INET(6) path, which allows us to reuse
>> the infrastructure of AF_INET(6) path, such as common ebpf hooks.
>> Otherwise, smc have to implement it again in AF_SMC path.
>>
>> Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
>> ---
>> include/uapi/linux/in.h | 2 +
>> net/smc/Makefile | 2 +-
>> net/smc/af_smc.c | 36 ++++++++++++++++
>> net/smc/inet_smc.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++++
>> net/smc/inet_smc.h | 34 +++++++++++++++
>> 5 files changed, 181 insertions(+), 1 deletion(-)
>> create mode 100644 net/smc/inet_smc.c
>> create mode 100644 net/smc/inet_smc.h
>>
>> diff --git a/include/uapi/linux/in.h b/include/uapi/linux/in.h
>> index e682ab6..0c6322b 100644
>> --- a/include/uapi/linux/in.h
>> +++ b/include/uapi/linux/in.h
>> @@ -83,6 +83,8 @@ enum {
>> #define IPPROTO_RAW IPPROTO_RAW
>> IPPROTO_MPTCP = 262, /* Multipath TCP connection */
>> #define IPPROTO_MPTCP IPPROTO_MPTCP
>> + IPPROTO_SMC = 263, /* Shared Memory Communications */
>> +#define IPPROTO_SMC IPPROTO_SMC
>> IPPROTO_MAX
>> };
>> #endif
>> diff --git a/net/smc/Makefile b/net/smc/Makefile
>> index 2c510d54..472b9ee 100644
>> --- a/net/smc/Makefile
>> +++ b/net/smc/Makefile
>> @@ -4,6 +4,6 @@ obj-$(CONFIG_SMC) += smc.o
>> obj-$(CONFIG_SMC_DIAG) += smc_diag.o
>> smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o smc_wr.o smc_llc.o
>> smc-y += smc_cdc.o smc_tx.o smc_rx.o smc_close.o smc_ism.o smc_netlink.o smc_stats.o
>> -smc-y += smc_tracepoint.o
>> +smc-y += smc_tracepoint.o inet_smc.o
>> smc-$(CONFIG_SYSCTL) += smc_sysctl.o
>> smc-$(CONFIG_SMC_LO) += smc_loopback.o
>> diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
>> index 8e3ce76..320624c 100644
>> --- a/net/smc/af_smc.c
>> +++ b/net/smc/af_smc.c
>> @@ -54,6 +54,7 @@
>> #include "smc_tracepoint.h"
>> #include "smc_sysctl.h"
>> #include "smc_loopback.h"
>> +#include "inet_smc.h"
>>
>> static DEFINE_MUTEX(smc_server_lgr_pending); /* serialize link group
>> * creation on server
>> @@ -3594,9 +3595,31 @@ static int __init smc_init(void)
>> goto out_lo;
>> }
>>
>> + rc = proto_register(&smc_inet_prot, 1);
>> + if (rc) {
>> + pr_err("%s: proto_register smc_inet_prot fails with %d\n", __func__, rc);
>> + goto out_ulp;
>> + }
>> + inet_register_protosw(&smc_inet_protosw);
>> +#if IS_ENABLED(CONFIG_IPV6)
>> + rc = proto_register(&smc_inet6_prot, 1);
>> + if (rc) {
>> + pr_err("%s: proto_register smc_inet6_prot fails with %d\n", __func__, rc);
>> + goto out_inet_prot;
>> + }
>> + inet6_register_protosw(&smc_inet6_protosw);
>> +#endif
>> +
> What do you think of moving all those inet initialization code into
> something like smc_inet_init() and move it to smc_inet.c ?
>
Agreed.

>> static_branch_enable(&tcp_have_smc);
>> return 0;
>>
>> +#if IS_ENABLED(CONFIG_IPV6)
>> +out_inet_prot:
>> + inet_unregister_protosw(&smc_inet_protosw);
>> + proto_unregister(&smc_inet_prot);
>> +#endif
>> +out_ulp:
>> + tcp_unregister_ulp(&smc_ulp_ops);
>> out_lo:
>> smc_loopback_exit();
>> out_ib:
>> @@ -3633,6 +3656,10 @@ static int __init smc_init(void)
>> static void __exit smc_exit(void)
>> {
>> static_branch_disable(&tcp_have_smc);
>> + inet_unregister_protosw(&smc_inet_protosw);
>> +#if IS_ENABLED(CONFIG_IPV6)
>> + inet6_unregister_protosw(&smc_inet6_protosw);
>> +#endif
>> tcp_unregister_ulp(&smc_ulp_ops);
>> sock_unregister(PF_SMC);
>> smc_core_exit();
>> @@ -3644,6 +3671,10 @@ static void __exit smc_exit(void)
>> destroy_workqueue(smc_hs_wq);
>> proto_unregister(&smc_proto6);
>> proto_unregister(&smc_proto);
>> + proto_unregister(&smc_inet_prot);
>> +#if IS_ENABLED(CONFIG_IPV6)
>> + proto_unregister(&smc_inet6_prot);
>> +#endif
>> smc_pnet_exit();
>> smc_nl_exit();
>> smc_clc_exit();
>> @@ -3660,4 +3691,9 @@ static void __exit smc_exit(void)
>> MODULE_LICENSE("GPL");
>> MODULE_ALIAS_NETPROTO(PF_SMC);
>> MODULE_ALIAS_TCP_ULP("smc");
>> +/* 263 for IPPROTO_SMC and 1 for SOCK_STREAM */
>> +MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 263, 1);
>> +#if IS_ENABLED(CONFIG_IPV6)
>> +MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET6, 263, 1);
>> +#endif
>> MODULE_ALIAS_GENL_FAMILY(SMC_GENL_FAMILY_NAME);
>> diff --git a/net/smc/inet_smc.c b/net/smc/inet_smc.c
>> new file mode 100644
>> index 00000000..1ba73d7
>> --- /dev/null
>> +++ b/net/smc/inet_smc.c
>> @@ -0,0 +1,108 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Shared Memory Communications over RDMA (SMC-R) and RoCE
>> + *
>> + * Definitions for the IPPROTO_SMC (socket related)
>> + *
>> + * Copyright IBM Corp. 2016, 2018
>> + * Copyright (c) 2024, Alibaba Inc.
>> + *
>> + * Author: D. Wythe <alibuda@linux.alibaba.com>
>> + */
>> +
>> +#include "inet_smc.h"
>> +#include "smc.h"
>> +
>> +struct proto smc_inet_prot = {
>> + .name = "INET_SMC",
>> + .owner = THIS_MODULE,
>> + .init = smc_inet_init_sock,
>> + .hash = smc_hash_sk,
>> + .unhash = smc_unhash_sk,
>> + .release_cb = smc_release_cb,
>> + .obj_size = sizeof(struct smc_sock),
>> + .h.smc_hash = &smc_v4_hashinfo,
>> + .slab_flags = SLAB_TYPESAFE_BY_RCU,
>> +};
>> +
>> +const struct proto_ops smc_inet_stream_ops = {
>> + .family = PF_INET,
>> + .owner = THIS_MODULE,
>> + .release = smc_release,
>> + .bind = smc_bind,
>> + .connect = smc_connect,
>> + .socketpair = sock_no_socketpair,
>> + .accept = smc_accept,
>> + .getname = smc_getname,
>> + .poll = smc_poll,
>> + .ioctl = smc_ioctl,
>> + .listen = smc_listen,
>> + .shutdown = smc_shutdown,
>> + .setsockopt = smc_setsockopt,
>> + .getsockopt = smc_getsockopt,
>> + .sendmsg = smc_sendmsg,
>> + .recvmsg = smc_recvmsg,
>> + .mmap = sock_no_mmap,
>> + .splice_read = smc_splice_read,
>> +};
>> +
>> +struct inet_protosw smc_inet_protosw = {
>> + .type = SOCK_STREAM,
>> + .protocol = IPPROTO_SMC,
>> + .prot = &smc_inet_prot,
>> + .ops = &smc_inet_stream_ops,
>> + .flags = INET_PROTOSW_ICSK,
>> +};
>> +
>> +#if IS_ENABLED(CONFIG_IPV6)
>> +struct proto smc_inet6_prot = {
>> + .name = "INET6_SMC",
>> + .owner = THIS_MODULE,
>> + .init = smc_inet_init_sock,
>> + .hash = smc_hash_sk,
>> + .unhash = smc_unhash_sk,
>> + .release_cb = smc_release_cb,
>> + .obj_size = sizeof(struct smc_sock),
>> + .h.smc_hash = &smc_v6_hashinfo,
>> + .slab_flags = SLAB_TYPESAFE_BY_RCU,
>> +};
>> +
>> +const struct proto_ops smc_inet6_stream_ops = {
>> + .family = PF_INET6,
>> + .owner = THIS_MODULE,
>> + .release = smc_release,
>> + .bind = smc_bind,
>> + .connect = smc_connect,
>> + .socketpair = sock_no_socketpair,
>> + .accept = smc_accept,
>> + .getname = smc_getname,
>> + .poll = smc_poll,
>> + .ioctl = smc_ioctl,
>> + .listen = smc_listen,
>> + .shutdown = smc_shutdown,
>> + .setsockopt = smc_setsockopt,
>> + .getsockopt = smc_getsockopt,
>> + .sendmsg = smc_sendmsg,
>> + .recvmsg = smc_recvmsg,
>> + .mmap = sock_no_mmap,
>> + .splice_read = smc_splice_read,
>> +};
>> +
>> +struct inet_protosw smc_inet6_protosw = {
>> + .type = SOCK_STREAM,
>> + .protocol = IPPROTO_SMC,
>> + .prot = &smc_inet6_prot,
>> + .ops = &smc_inet6_stream_ops,
>> + .flags = INET_PROTOSW_ICSK,
>> +};
>> +#endif
>> +
>> +int smc_inet_init_sock(struct sock *sk)
>> +{
>> + struct net *net = sock_net(sk);
>> +
>> + /* init common smc sock */
>> + smc_sk_init(net, sk, IPPROTO_SMC);
>> + /* create clcsock */
>> + return smc_create_clcsk(net, sk, sk->sk_family);
>> +}
>> diff --git a/net/smc/inet_smc.h b/net/smc/inet_smc.h
>> new file mode 100644
>> index 00000000..c55345d
>> --- /dev/null
>> +++ b/net/smc/inet_smc.h
>> @@ -0,0 +1,34 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Shared Memory Communications over RDMA (SMC-R) and RoCE
>> + *
>> + * Definitions for the IPPROTO_SMC (socket related)
>> +
>> + * Copyright IBM Corp. 2016
>> + * Copyright (c) 2024, Alibaba Inc.
>> + *
>> + * Author: D. Wythe <alibuda@linux.alibaba.com>
>> + */
>> +#ifndef __INET_SMC
>> +#define __INET_SMC
>> +
>> +#include <net/protocol.h>
>> +#include <net/sock.h>
>> +#include <net/tcp.h>
> Why not put those 'include's in the .c file ?

Agreed.  But I think that  <net/protocol. h> is needed to ensure that
the header file itself is complete.

>> +
>> +extern struct proto smc_inet_prot;
>> +extern const struct proto_ops smc_inet_stream_ops;
>> +extern struct inet_protosw smc_inet_protosw;
>> +
>> +#if IS_ENABLED(CONFIG_IPV6)
>> +#include <net/ipv6.h>
>> +/* MUST after net/tcp.h or warning */
>> +#include <net/transp_v6.h>
>> +extern struct proto smc_inet6_prot;
>> +extern const struct proto_ops smc_inet6_stream_ops;
>> +extern struct inet_protosw smc_inet6_protosw;
>> +#endif
>> +
>> +int smc_inet_init_sock(struct sock *sk);
> Seems smc_inet_init_sock() is only used in smc_inet.c,
> why not defined it as a static function ?
>
> Best regards,
> Dust

That's true, I will fix it.

Best wishes,
D. Wythe

>> +
>> +#endif /* __INET_SMC */
>> --
>> 1.8.3.1
>>