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

From: Jan Karcher
Date: Thu Aug 17 2023 - 02:42:51 EST

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In reply to: Guangguan Wang: "[PATCH net-next 4/6] net/smc: support max connections per lgr negotiation"
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On 16/08/2023 10:33, 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@xxxxxxxxxxxxxxxxx>
Reviewed-by: Tony Lu <tonylu@xxxxxxxxxxxxxxxxx>
---
net/smc/af_smc.c | 1 +
net/smc/smc_clc.c | 41 +++++++++++++++++++++++++++++++++++++++--
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, 65 insertions(+), 6 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 65c02b48331f..f7174135c74a 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -1212,6 +1212,7 @@ 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 f71b22e50be5..6609b06f000f 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_v20.os_type = SMC_CLC_OS_LINUX;
fce->fce_v20.release = ini->release_nr;
memcpy(fce->fce_v20.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 +1173,11 @@ int smc_clc_srv_v2x_features_validate(struct smc_clc_msg_proposal *pclc,
{
struct smc_clc_v2_extension *pclc_v2_ext;
+ /* default max conn is SMC_CONN_PER_LGR_MAX(255),
+ * which is the default value in smc v1 and v2.0.
+ */

I'm afraid this comment is not going to age well. You already put this to the define itself so i plea to remove it here.

Thank you.
- Jan

+ 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 +1186,30 @@ 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_cli_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 +1220,8 @@ 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 +1233,11 @@ 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 66932bfdc6d0..54077e50c368 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_v20;
- 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);
put_out:

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In reply to: Guangguan Wang: "[PATCH net-next 4/6] net/smc: support max connections per lgr negotiation"
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