[RFC PATCH v2 net-next 5/6] net/smc: support max links per lgr negotiation in clc handshake

From: Guangguan Wang
Date: Mon Aug 07 2023 - 02:28:02 EST

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Next in thread: Simon Horman: "Re: [RFC PATCH v2 net-next 5/6] net/smc: support max links per lgr negotiation in clc handshake"
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Support max links per lgr negotiation in clc handshake for SMCR v2.1,
which is one of smc v2.1 features.

Signed-off-by: Guangguan Wang <guangguan.wang@xxxxxxxxxxxxxxxxx>
Reviewed-by: Tony Lu <tonylu@xxxxxxxxxxxxxxxxx>
---
net/smc/af_smc.c | 44 +++++++++++++++++++++++++++-----------------
net/smc/smc_clc.c | 16 +++++++++++++++-
net/smc/smc_clc.h | 7 +++++--
net/smc/smc_core.c | 5 +++++
net/smc/smc_core.h | 5 +++++
net/smc/smc_llc.c | 17 +++++++++++++----
6 files changed, 70 insertions(+), 24 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index b95d3fd48c28..23384d08d3f2 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -610,20 +610,22 @@ static int smcr_clnt_conf_first_link(struct smc_sock *smc)
smc_llc_link_active(link);
smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);

- /* optional 2nd link, receive ADD LINK request from server */
- qentry = smc_llc_wait(link->lgr, NULL, SMC_LLC_WAIT_TIME,
- SMC_LLC_ADD_LINK);
- if (!qentry) {
- struct smc_clc_msg_decline dclc;
-
- rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
- SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
- if (rc == -EAGAIN)
- rc = 0; /* no DECLINE received, go with one link */
- return rc;
+ if (link->lgr->max_links > 1) {
+ /* optional 2nd link, receive ADD LINK request from server */
+ qentry = smc_llc_wait(link->lgr, NULL, SMC_LLC_WAIT_TIME,
+ SMC_LLC_ADD_LINK);
+ if (!qentry) {
+ struct smc_clc_msg_decline dclc;
+
+ rc = smc_clc_wait_msg(smc, &dclc, sizeof(dclc),
+ SMC_CLC_DECLINE, CLC_WAIT_TIME_SHORT);
+ if (rc == -EAGAIN)
+ rc = 0; /* no DECLINE received, go with one link */
+ return rc;
+ }
+ smc_llc_flow_qentry_clr(&link->lgr->llc_flow_lcl);
+ smc_llc_cli_add_link(link, qentry);
}
- smc_llc_flow_qentry_clr(&link->lgr->llc_flow_lcl);
- smc_llc_cli_add_link(link, qentry);
return 0;
}

@@ -1215,6 +1217,7 @@ static int smc_connect_rdma(struct smc_sock *smc,
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_RMBS_PER_LGR_MAX;
+ ini->max_links = SMC_LINKS_ADD_LNK_MAX;

reason_code = smc_connect_rdma_v2_prepare(smc, aclc, ini);
if (reason_code)
@@ -1861,10 +1864,12 @@ static int smcr_serv_conf_first_link(struct smc_sock *smc)
smc_llc_link_active(link);
smcr_lgr_set_type(link->lgr, SMC_LGR_SINGLE);

- down_write(&link->lgr->llc_conf_mutex);
- /* initial contact - try to establish second link */
- smc_llc_srv_add_link(link, NULL);
- up_write(&link->lgr->llc_conf_mutex);
+ if (link->lgr->max_links > 1) {
+ down_write(&link->lgr->llc_conf_mutex);
+ /* initial contact - try to establish second link */
+ smc_llc_srv_add_link(link, NULL);
+ up_write(&link->lgr->llc_conf_mutex);
+ }
return 0;
}

@@ -2468,6 +2473,11 @@ static void smc_listen_work(struct work_struct *work)
goto out_decl;
}

+ /* fce smc release version is needed in smc_listen_rdma_finish,
+ * so save fce info here.
+ */
+ smc_conn_save_peer_info_fce(new_smc, cclc);
+
/* finish worker */
if (!ini->is_smcd) {
rc = smc_listen_rdma_finish(new_smc, cclc,
diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index e2b224063dcc..84c47cb1e779 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -433,8 +433,10 @@ static int smc_clc_fill_fce(struct smc_clc_first_contact_ext_v2x *fce,
}

if (ini->release_ver >= SMC_RELEASE_1) {
- if (!ini->is_smcd)
+ if (!ini->is_smcd) {
fce->max_conns = ini->max_conns;
+ fce->max_links = ini->max_links;
+ }
}

out:
@@ -942,6 +944,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
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_MAX;
+ v2_ext->max_links = SMC_LINKS_PER_LGR_MAX_PREFER;
}

pclc_base->hdr.length = htons(plen);
@@ -1177,6 +1180,7 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
* which is the default value in smc v1 and v2.0.
*/
ini->max_conns = SMC_RMBS_PER_LGR_MAX;
+ ini->max_links = SMC_LINKS_ADD_LNK_MAX;

if ((!(ini->smcd_version & SMC_V2) && !(ini->smcr_version & SMC_V2)) ||
ini->release_ver < SMC_RELEASE_1)
@@ -1190,6 +1194,10 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
ini->max_conns = min_t(u8, pclc_v2_ext->max_conns, SMC_CONN_PER_LGR_MAX);
if (ini->max_conns < SMC_CONN_PER_LGR_MIN)
return SMC_CLC_DECL_MAXCONNERR;
+
+ ini->max_links = min_t(u8, pclc_v2_ext->max_links, SMC_LINKS_PER_LGR_MAX_PREFER);
+ if (!ini->max_links)
+ return SMC_CLC_DECL_MAXLINKERR;
}

return 0;
@@ -1208,6 +1216,10 @@ int smc_clc_cli_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
if (fce_v2x->max_conns < SMC_CONN_PER_LGR_MIN)
return SMC_CLC_DECL_MAXCONNERR;
ini->max_conns = fce_v2x->max_conns;
+
+ if (fce_v2x->max_links > SMC_LINKS_ADD_LNK_MAX)
+ return SMC_CLC_DECL_MAXLINKERR;
+ ini->max_links = fce_v2x->max_links;
}

return 0;
@@ -1236,6 +1248,8 @@ int smc_clc_v2x_features_confirm_check(struct smc_clc_msg_accept_confirm *cclc,
if (!ini->is_smcd) {
if (fce_v2x->max_conns != ini->max_conns)
return SMC_CLC_DECL_MAXCONNERR;
+ if (fce_v2x->max_links != ini->max_links)
+ return SMC_CLC_DECL_MAXLINKERR;
}

return 0;
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
index 54077e50c368..53fb20d7c14d 100644
--- a/net/smc/smc_clc.h
+++ b/net/smc/smc_clc.h
@@ -47,6 +47,7 @@
#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_MAXLINKERR 0x0303000b /* max links 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 */
@@ -136,7 +137,8 @@ struct smc_clc_v2_extension {
struct smc_clnt_opts_area_hdr hdr;
u8 roce[16]; /* RoCEv2 GID */
u8 max_conns;
- u8 reserved[15];
+ u8 max_links;
+ u8 reserved[14];
u8 user_eids[][SMC_MAX_EID_LEN];
};

@@ -239,7 +241,8 @@ struct smc_clc_first_contact_ext {
struct smc_clc_first_contact_ext_v2x {
struct smc_clc_first_contact_ext fce_v20;
u8 max_conns; /* for SMC-R only */
- u8 reserved3[3];
+ u8 max_links; /* for SMC-R only */
+ u8 reserved3[2];
__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 5de1fbaa6e28..d5967826bcdf 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -896,10 +896,12 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
memcpy(lgr->nexthop_mac, ini->smcrv2.nexthop_mac,
ETH_ALEN);
lgr->max_conns = ini->max_conns;
+ lgr->max_links = ini->max_links;
} else {
ibdev = ini->ib_dev;
ibport = ini->ib_port;
lgr->max_conns = SMC_RMBS_PER_LGR_MAX;
+ lgr->max_links = SMC_LINKS_ADD_LNK_MAX;
}
memcpy(lgr->pnet_id, ibdev->pnetid[ibport - 1],
SMC_MAX_PNETID_LEN);
@@ -1667,6 +1669,9 @@ void smcr_port_add(struct smc_ib_device *smcibdev, u8 ibport)
!rdma_dev_access_netns(smcibdev->ibdev, lgr->net))
continue;

+ if (lgr->type == SMC_LGR_SINGLE && lgr->max_links <= 1)
+ continue;
+
/* trigger local add link processing */
link = smc_llc_usable_link(lgr);
if (link)
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index f4f7299c810a..b327ef01c838 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -166,6 +166,8 @@ struct smc_link {
*/
#define SMC_LINKS_PER_LGR_MAX 3
#define SMC_SINGLE_LINK 0
+#define SMC_LINKS_PER_LGR_MAX_PREFER 2 /* prefer 2 links max per lgr */
+#define SMC_LINKS_ADD_LNK_MAX 2

/* tx/rx buffer list element for sndbufs list and rmbs list of a lgr */
struct smc_buf_desc {
@@ -335,6 +337,8 @@ struct smc_link_group {
struct net *net;
u8 max_conns;
/* max conn can be assigned to lgr */
+ u8 max_links;
+ /* max links can be added in lgr */
};
struct { /* SMC-D */
u64 peer_gid;
@@ -380,6 +384,7 @@ struct smc_init_info {
u8 smc_type_v2;
u8 release_ver;
u8 max_conns;
+ u8 max_links;
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 5347b62f1518..41e5e149edf3 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -59,8 +59,6 @@ struct smc_llc_msg_confirm_link { /* type 0x01 */
#define SMC_LLC_FLAG_ADD_LNK_REJ 0x40
#define SMC_LLC_REJ_RSN_NO_ALT_PATH 1

-#define SMC_LLC_ADD_LNK_MAX_LINKS 2
-
struct smc_llc_msg_add_link { /* type 0x02 */
struct smc_llc_hdr hd;
u8 sender_mac[ETH_ALEN];
@@ -472,10 +470,12 @@ int smc_llc_send_confirm_link(struct smc_link *link,
hton24(confllc->sender_qp_num, link->roce_qp->qp_num);
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;
+ confllc->max_links = SMC_LINKS_ADD_LNK_MAX;
if (link->lgr->smc_version == SMC_V2 &&
- link->lgr->peer_smc_release >= SMC_RELEASE_1)
+ link->lgr->peer_smc_release >= SMC_RELEASE_1) {
confllc->max_conns = link->lgr->max_conns;
+ confllc->max_links = link->lgr->max_links;
+ }
/* send llc message */
rc = smc_wr_tx_send(link, pend);
put_out:
@@ -1045,6 +1045,9 @@ int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry)
goto out_reject;
}

+ if (lgr->type == SMC_LGR_SINGLE && lgr->max_links <= 1)
+ goto out_reject;
+
ini->vlan_id = lgr->vlan_id;
if (lgr->smc_version == SMC_V2) {
ini->check_smcrv2 = true;
@@ -1169,6 +1172,9 @@ static void smc_llc_cli_add_link_invite(struct smc_link *link,
lgr->type == SMC_LGR_ASYMMETRIC_PEER)
goto out;

+ if (lgr->type == SMC_LGR_SINGLE && lgr->max_links <= 1)
+ goto out;
+
ini = kzalloc(sizeof(*ini), GFP_KERNEL);
if (!ini)
goto out;
@@ -1414,6 +1420,9 @@ int smc_llc_srv_add_link(struct smc_link *link,
goto out;
}

+ if (lgr->type == SMC_LGR_SINGLE && lgr->max_links <= 1)
+ goto out;
+
/* ignore client add link recommendation, start new flow */
ini->vlan_id = lgr->vlan_id;
if (lgr->smc_version == SMC_V2) {
--
2.24.3 (Apple Git-128)

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