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

D. Wythe
2024-05-30T02:35:04Z

On 5/30/24 3:55 AM, Zhu Yanjun wrote:
> 在 2024/5/29 5:59, D. Wythe 写道:
>> 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
>> +
>>       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>
>> +
>> +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
>
> If we append /* CONFIG_IPV6 */ to #endif to indicate that it is the
> end of CONFIG_IPV6, it is a good habit. When browsing the source code,
> it is easy for us to know that it is the end of CONFIG_IPV6.
> Just my 2 cent suggestions. It is a trivial problem. You can ignore it.
> But if you fix it, it can make the source code more readable.
>
> Zhu Yanjun

I really like the style you said, I will use it in the next version.

Best wishes,
D. Wythe

>
>> +
>> +int smc_inet_init_sock(struct sock *sk);
>> +
>> +#endif /* __INET_SMC */