Re: [PATCH net-next v2 4/6] net/smc: support max connections per lgr negotiation

Jan Karcher
2023-08-18T19:43:28Z

On 17/08/2023 15:20, Guangguan Wang wrote:
> Support max connections per lgr negotiation for SMCR v2.1,
> which is one of smc v2.1 features. Server makes decision for
> the final value of max conns based on the client preferred
> max conns and self-preferred max conns. Here use the minimum
> value of client preferred max conns and server preferred max
> conns.
>
> Client Server
> Proposal(max conns(client preferred))
> ------------------------------------>
>
> Accept(max conns(accepted value))
> accepted value=min(client preferred, server preferred)
> <-----------------------------------
>
> Confirm(max conns(accepted value))
> ----------------------------------->
>
> Signed-off-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
> Reviewed-by: Tony Lu <tonylu@linux.alibaba.com>

Thank you for your contribution, Guangguan.

Reviewed-by: Jan Karcher <jaka@linux.ibm.com>

> ---
> net/smc/af_smc.c | 1 +
> net/smc/smc_clc.c | 38 ++++++++++++++++++++++++++++++++++++--
> net/smc/smc_clc.h | 7 +++++--
> net/smc/smc_core.c | 4 +++-
> net/smc/smc_core.h | 12 ++++++++++++
> net/smc/smc_llc.c | 6 +++++-
> 6 files changed, 62 insertions(+), 6 deletions(-)
>
> diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
> index 9174dedd9b3b..8f041e871ddd 100644
> --- a/net/smc/af_smc.c
> +++ b/net/smc/af_smc.c
> @@ -1211,6 +1211,7 @@ static int smc_connect_rdma(struct smc_sock *smc,
> memcpy(ini->peer_systemid, aclc->r0.lcl.id_for_peer, SMC_SYSTEMID_LEN);
> memcpy(ini->peer_gid, aclc->r0.lcl.gid, SMC_GID_SIZE);
> memcpy(ini->peer_mac, aclc->r0.lcl.mac, ETH_ALEN);
> + ini->max_conns = SMC_CONN_PER_LGR_MAX;
>
> reason_code = smc_connect_rdma_v2_prepare(smc, aclc, ini);
> if (reason_code)
> diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
> index d3c892ee7177..60cfe37625b8 100644
> --- a/net/smc/smc_clc.c
> +++ b/net/smc/smc_clc.c
> @@ -427,9 +427,17 @@ static int smc_clc_fill_fce(struct smc_clc_first_contact_ext_v2x *fce,
> fce->fce_v2_base.os_type = SMC_CLC_OS_LINUX;
> fce->fce_v2_base.release = ini->release_nr;
> memcpy(fce->fce_v2_base.hostname, smc_hostname, sizeof(smc_hostname));
> - if (ini->is_smcd && ini->release_nr < SMC_RELEASE_1)
> + if (ini->is_smcd && ini->release_nr < SMC_RELEASE_1) {
> ret = sizeof(struct smc_clc_first_contact_ext);
> + goto out;
> + }
> +
> + if (ini->release_nr >= SMC_RELEASE_1) {
> + if (!ini->is_smcd)
> + fce->max_conns = ini->max_conns;
> + }
>
> +out:
> return ret;
> }
>
> @@ -931,8 +939,10 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
> sizeof(struct smc_clc_smcd_gid_chid);
> }
> }
> - if (smcr_indicated(ini->smc_type_v2))
> + if (smcr_indicated(ini->smc_type_v2)) {
> memcpy(v2_ext->roce, ini->smcrv2.ib_gid_v2, SMC_GID_SIZE);
> + v2_ext->max_conns = SMC_CONN_PER_LGR_PREFER;
> + }
>
> pclc_base->hdr.length = htons(plen);
> memcpy(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
> @@ -1163,6 +1173,8 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
> {
> struct smc_clc_v2_extension *pclc_v2_ext;
>
> + ini->max_conns = SMC_CONN_PER_LGR_MAX;
> +
> if ((!(ini->smcd_version & SMC_V2) && !(ini->smcr_version & SMC_V2)) ||
> ini->release_nr < SMC_RELEASE_1)
> return 0;
> @@ -1171,15 +1183,30 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
> if (!pclc_v2_ext)
> return SMC_CLC_DECL_NOV2EXT;
>
> + if (ini->smcr_version & SMC_V2) {
> + ini->max_conns = min_t(u8, pclc_v2_ext->max_conns, SMC_CONN_PER_LGR_PREFER);
> + if (ini->max_conns < SMC_CONN_PER_LGR_MIN)
> + return SMC_CLC_DECL_MAXCONNERR;
> + }
> +
> return 0;
> }
>
> int smc_clc_clnt_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
> struct smc_init_info *ini)
> {
> + struct smc_clc_first_contact_ext_v2x *fce_v2x =
> + (struct smc_clc_first_contact_ext_v2x *)fce;
> +
> if (ini->release_nr < SMC_RELEASE_1)
> return 0;
>
> + if (!ini->is_smcd) {
> + if (fce_v2x->max_conns < SMC_CONN_PER_LGR_MIN)
> + return SMC_CLC_DECL_MAXCONNERR;
> + ini->max_conns = fce_v2x->max_conns;
> + }
> +
> return 0;
> }
>
> @@ -1190,6 +1217,8 @@ int smc_clc_v2x_features_confirm_check(struct smc_clc_msg_accept_confirm *cclc,
> (struct smc_clc_msg_accept_confirm_v2 *)cclc;
> struct smc_clc_first_contact_ext *fce =
> smc_get_clc_first_contact_ext(clc_v2, ini->is_smcd);
> + struct smc_clc_first_contact_ext_v2x *fce_v2x =
> + (struct smc_clc_first_contact_ext_v2x *)fce;
>
> if (cclc->hdr.version == SMC_V1 ||
> !(cclc->hdr.typev2 & SMC_FIRST_CONTACT_MASK))
> @@ -1201,6 +1230,11 @@ int smc_clc_v2x_features_confirm_check(struct smc_clc_msg_accept_confirm *cclc,
> if (fce->release < SMC_RELEASE_1)
> return 0;
>
> + if (!ini->is_smcd) {
> + if (fce_v2x->max_conns != ini->max_conns)
> + return SMC_CLC_DECL_MAXCONNERR;
> + }
> +
> return 0;
> }
>
> diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
> index 552d0656252c..464b93b46047 100644
> --- a/net/smc/smc_clc.h
> +++ b/net/smc/smc_clc.h
> @@ -46,6 +46,7 @@
> #define SMC_CLC_DECL_NOSMCD2DEV 0x03030007 /* no SMC-Dv2 device found */
> #define SMC_CLC_DECL_NOUEID 0x03030008 /* peer sent no UEID */
> #define SMC_CLC_DECL_RELEASEERR 0x03030009 /* release version negotiate failed */
> +#define SMC_CLC_DECL_MAXCONNERR 0x0303000a /* max connections negotiate failed */
> #define SMC_CLC_DECL_MODEUNSUPP 0x03040000 /* smc modes do not match (R or D)*/
> #define SMC_CLC_DECL_RMBE_EC 0x03050000 /* peer has eyecatcher in RMBE */
> #define SMC_CLC_DECL_OPTUNSUPP 0x03060000 /* fastopen sockopt not supported */
> @@ -134,7 +135,8 @@ struct smc_clc_smcd_gid_chid {
> struct smc_clc_v2_extension {
> struct smc_clnt_opts_area_hdr hdr;
> u8 roce[16]; /* RoCEv2 GID */
> - u8 reserved[16];
> + u8 max_conns;
> + u8 reserved[15];
> u8 user_eids[][SMC_MAX_EID_LEN];
> };
>
> @@ -236,7 +238,8 @@ struct smc_clc_first_contact_ext {
>
> struct smc_clc_first_contact_ext_v2x {
> struct smc_clc_first_contact_ext fce_v2_base;
> - u8 reserved3[4];
> + u8 max_conns; /* for SMC-R only */
> + u8 reserved3[3];
> __be32 vendor_exp_options;
> u8 reserved4[8];
> } __packed; /* format defined in
> diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
> index 6aa3db47a956..a8091a3e6cdd 100644
> --- a/net/smc/smc_core.c
> +++ b/net/smc/smc_core.c
> @@ -895,9 +895,11 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
> lgr->uses_gateway = ini->smcrv2.uses_gateway;
> memcpy(lgr->nexthop_mac, ini->smcrv2.nexthop_mac,
> ETH_ALEN);
> + lgr->max_conns = ini->max_conns;
> } else {
> ibdev = ini->ib_dev;
> ibport = ini->ib_port;
> + lgr->max_conns = SMC_CONN_PER_LGR_MAX;
> }
> memcpy(lgr->pnet_id, ibdev->pnetid[ibport - 1],
> SMC_MAX_PNETID_LEN);
> @@ -1890,7 +1892,7 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
> (ini->smcd_version == SMC_V2 ||
> lgr->vlan_id == ini->vlan_id) &&
> (role == SMC_CLNT || ini->is_smcd ||
> - (lgr->conns_num < SMC_RMBS_PER_LGR_MAX &&
> + (lgr->conns_num < lgr->max_conns &&
> !bitmap_full(lgr->rtokens_used_mask, SMC_RMBS_PER_LGR_MAX)))) {
> /* link group found */
> ini->first_contact_local = 0;
> diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
> index b6c68db61f23..32b199477ef3 100644
> --- a/net/smc/smc_core.h
> +++ b/net/smc/smc_core.h
> @@ -22,6 +22,15 @@
> #include "smc_ib.h"
>
> #define SMC_RMBS_PER_LGR_MAX 255 /* max. # of RMBs per link group */
> +#define SMC_CONN_PER_LGR_MIN 16 /* min. # of connections per link group */
> +#define SMC_CONN_PER_LGR_MAX 255 /* max. # of connections per link group,
> + * also is the default value for SMC-R v1 and v2.0
> + */
> +#define SMC_CONN_PER_LGR_PREFER 255 /* Preferred connections per link group used for
> + * SMC-R v2.1 and later negotiation, vendors or
> + * distrubutions may modify it to a value between
> + * 16-255 as needed.
> + */
>
> struct smc_lgr_list { /* list of link group definition */
> struct list_head list;
> @@ -331,6 +340,8 @@ struct smc_link_group {
> __be32 saddr;
> /* net namespace */
> struct net *net;
> + u8 max_conns;
> + /* max conn can be assigned to lgr */
> };
> struct { /* SMC-D */
> u64 peer_gid;
> @@ -375,6 +386,7 @@ struct smc_init_info {
> u8 smc_type_v1;
> u8 smc_type_v2;
> u8 release_nr;
> + u8 max_conns;
> u8 first_contact_peer;
> u8 first_contact_local;
> unsigned short vlan_id;
> diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
> index 90f0b60b196a..5347b62f1518 100644
> --- a/net/smc/smc_llc.c
> +++ b/net/smc/smc_llc.c
> @@ -52,7 +52,8 @@ struct smc_llc_msg_confirm_link { /* type 0x01 */
> u8 link_num;
> u8 link_uid[SMC_LGR_ID_SIZE];
> u8 max_links;
> - u8 reserved[9];
> + u8 max_conns;
> + u8 reserved[8];
> };
>
> #define SMC_LLC_FLAG_ADD_LNK_REJ 0x40
> @@ -472,6 +473,9 @@ int smc_llc_send_confirm_link(struct smc_link *link,
> confllc->link_num = link->link_id;
> memcpy(confllc->link_uid, link->link_uid, SMC_LGR_ID_SIZE);
> confllc->max_links = SMC_LLC_ADD_LNK_MAX_LINKS;
> + if (link->lgr->smc_version == SMC_V2 &&
> + link->lgr->peer_smc_release >= SMC_RELEASE_1)
> + confllc->max_conns = link->lgr->max_conns;
> /* send llc message */
> rc = smc_wr_tx_send(link, pend);