[PATCH net-next 3/4] net/smc: provide fallback reason code

From: Ursula Braun
Date: Wed Jul 25 2018 - 10:36:21 EST

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In reply to: Ursula Braun: "[PATCH net-next 1/4] net/smc: fewer parameters for smc_llc_send_confirm_link()"
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From: Karsten Graul <kgraul@xxxxxxxxxxxxx>

Remember the fallback reason code and the peer diagnosis code for
smc sockets, and provide them in smc_diag.c to the netlink interface.
And add more detailed reason codes.

Signed-off-by: Karsten Graul <kgraul@xxxxxxxxxxxxx>
Signed-off-by: Ursula Braun <ubraun@xxxxxxxxxxxxx>
---
include/uapi/linux/smc_diag.h | 6 +++++
net/smc/af_smc.c | 52 +++++++++++++++++++++++++------------------
net/smc/smc.h | 2 ++
net/smc/smc_clc.c | 6 ++++-
net/smc/smc_clc.h | 18 ++++++++++-----
net/smc/smc_diag.c | 6 +++++
6 files changed, 61 insertions(+), 29 deletions(-)

diff --git a/include/uapi/linux/smc_diag.h b/include/uapi/linux/smc_diag.h
index 48ae3ee22b2d..ac9e8c96d9bd 100644
--- a/include/uapi/linux/smc_diag.h
+++ b/include/uapi/linux/smc_diag.h
@@ -43,6 +43,7 @@ enum {
SMC_DIAG_LGRINFO,
SMC_DIAG_SHUTDOWN,
SMC_DIAG_DMBINFO,
+ SMC_DIAG_FALLBACK,
__SMC_DIAG_MAX,
};

@@ -92,6 +93,11 @@ struct smc_diag_lgrinfo {
__u8 role;
};

+struct smc_diag_fallback {
+ __u32 reason;
+ __u32 peer_diagnosis;
+};
+
struct smcd_diag_dmbinfo { /* SMC-D Socket internals */
__u32 linkid; /* Link identifier */
__u64 peer_gid; /* Peer GID */
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index b81797103260..fce7e4751151 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -344,17 +344,17 @@ static int smc_clnt_conf_first_link(struct smc_sock *smc)

rc = smc_ib_modify_qp_rts(link);
if (rc)
- return SMC_CLC_DECL_INTERR;
+ return SMC_CLC_DECL_ERR_RDYLNK;

smc_wr_remember_qp_attr(link);

if (smc_reg_rmb(link, smc->conn.rmb_desc, false))
- return SMC_CLC_DECL_INTERR;
+ return SMC_CLC_DECL_ERR_REGRMB;

/* send CONFIRM LINK response over RoCE fabric */
rc = smc_llc_send_confirm_link(link, SMC_LLC_RESP);
if (rc < 0)
- return SMC_CLC_DECL_TCL;
+ return SMC_CLC_DECL_TIMEOUT_CL;

/* receive ADD LINK request from server over RoCE fabric */
rest = wait_for_completion_interruptible_timeout(&link->llc_add,
@@ -372,7 +372,7 @@ static int smc_clnt_conf_first_link(struct smc_sock *smc)
link->smcibdev->mac[link->ibport - 1],
link->gid, SMC_LLC_RESP);
if (rc < 0)
- return SMC_CLC_DECL_TCL;
+ return SMC_CLC_DECL_TIMEOUT_AL;

smc_llc_link_active(link, net->ipv4.sysctl_tcp_keepalive_time);

@@ -424,9 +424,10 @@ static void smc_link_save_peer_info(struct smc_link *link,
}

/* fall back during connect */
-static int smc_connect_fallback(struct smc_sock *smc)
+static int smc_connect_fallback(struct smc_sock *smc, int reason_code)
{
smc->use_fallback = true;
+ smc->fallback_rsn = reason_code;
smc_copy_sock_settings_to_clc(smc);
if (smc->sk.sk_state == SMC_INIT)
smc->sk.sk_state = SMC_ACTIVE;
@@ -443,7 +444,7 @@ static int smc_connect_decline_fallback(struct smc_sock *smc, int reason_code)
sock_put(&smc->sk); /* passive closing */
return reason_code;
}
- if (reason_code != SMC_CLC_DECL_REPLY) {
+ if (reason_code != SMC_CLC_DECL_PEERDECL) {
rc = smc_clc_send_decline(smc, reason_code);
if (rc < 0) {
if (smc->sk.sk_state == SMC_INIT)
@@ -451,7 +452,7 @@ static int smc_connect_decline_fallback(struct smc_sock *smc, int reason_code)
return rc;
}
}
- return smc_connect_fallback(smc);
+ return smc_connect_fallback(smc, reason_code);
}

/* abort connecting */
@@ -568,7 +569,7 @@ static int smc_connect_rdma(struct smc_sock *smc,
smc_link_save_peer_info(link, aclc);

if (smc_rmb_rtoken_handling(&smc->conn, aclc))
- return smc_connect_abort(smc, SMC_CLC_DECL_INTERR,
+ return smc_connect_abort(smc, SMC_CLC_DECL_ERR_RTOK,
local_contact);

smc_close_init(smc);
@@ -576,12 +577,12 @@ static int smc_connect_rdma(struct smc_sock *smc,

if (local_contact == SMC_FIRST_CONTACT) {
if (smc_ib_ready_link(link))
- return smc_connect_abort(smc, SMC_CLC_DECL_INTERR,
+ return smc_connect_abort(smc, SMC_CLC_DECL_ERR_RDYLNK,
local_contact);
} else {
if (!smc->conn.rmb_desc->reused &&
smc_reg_rmb(link, smc->conn.rmb_desc, true))
- return smc_connect_abort(smc, SMC_CLC_DECL_INTERR,
+ return smc_connect_abort(smc, SMC_CLC_DECL_ERR_REGRMB,
local_contact);
}
smc_rmb_sync_sg_for_device(&smc->conn);
@@ -659,11 +660,11 @@ static int __smc_connect(struct smc_sock *smc)
sock_hold(&smc->sk); /* sock put in passive closing */

if (smc->use_fallback)
- return smc_connect_fallback(smc);
+ return smc_connect_fallback(smc, smc->fallback_rsn);

/* if peer has not signalled SMC-capability, fall back */
if (!tcp_sk(smc->clcsock->sk)->syn_smc)
- return smc_connect_fallback(smc);
+ return smc_connect_fallback(smc, SMC_CLC_DECL_PEERNOSMC);

/* IPSec connections opt out of SMC-R optimizations */
if (using_ipsec(smc))
@@ -693,7 +694,7 @@ static int __smc_connect(struct smc_sock *smc)

/* if neither ISM nor RDMA are supported, fallback */
if (!rdma_supported && !ism_supported)
- return smc_connect_decline_fallback(smc, SMC_CLC_DECL_CNFERR);
+ return smc_connect_decline_fallback(smc, SMC_CLC_DECL_NOSMCDEV);

/* perform CLC handshake */
rc = smc_connect_clc(smc, smc_type, &aclc, ibdev, ibport, gid, ismdev);
@@ -708,7 +709,7 @@ static int __smc_connect(struct smc_sock *smc)
else if (ism_supported && aclc.hdr.path == SMC_TYPE_D)
rc = smc_connect_ism(smc, &aclc, ismdev);
else
- rc = SMC_CLC_DECL_CNFERR;
+ rc = SMC_CLC_DECL_MODEUNSUPP;
if (rc) {
smc_connect_ism_vlan_cleanup(smc, ism_supported, ismdev, vlan);
return smc_connect_decline_fallback(smc, rc);
@@ -946,12 +947,12 @@ static int smc_serv_conf_first_link(struct smc_sock *smc)
link = &lgr->lnk[SMC_SINGLE_LINK];

if (smc_reg_rmb(link, smc->conn.rmb_desc, false))
- return SMC_CLC_DECL_INTERR;
+ return SMC_CLC_DECL_ERR_REGRMB;

/* send CONFIRM LINK request to client over the RoCE fabric */
rc = smc_llc_send_confirm_link(link, SMC_LLC_REQ);
if (rc < 0)
- return SMC_CLC_DECL_TCL;
+ return SMC_CLC_DECL_TIMEOUT_CL;

/* receive CONFIRM LINK response from client over the RoCE fabric */
rest = wait_for_completion_interruptible_timeout(
@@ -973,7 +974,7 @@ static int smc_serv_conf_first_link(struct smc_sock *smc)
link->smcibdev->mac[link->ibport - 1],
link->gid, SMC_LLC_REQ);
if (rc < 0)
- return SMC_CLC_DECL_TCL;
+ return SMC_CLC_DECL_TIMEOUT_AL;

/* receive ADD LINK response from client over the RoCE fabric */
rest = wait_for_completion_interruptible_timeout(&link->llc_add_resp,
@@ -1048,7 +1049,8 @@ static void smc_listen_decline(struct smc_sock *new_smc, int reason_code,
}
smc_conn_free(&new_smc->conn);
new_smc->use_fallback = true;
- if (reason_code && reason_code != SMC_CLC_DECL_REPLY) {
+ new_smc->fallback_rsn = reason_code;
+ if (reason_code && reason_code != SMC_CLC_DECL_PEERDECL) {
if (smc_clc_send_decline(new_smc, reason_code) < 0) {
smc_listen_out_err(new_smc);
return;
@@ -1139,7 +1141,7 @@ static int smc_listen_rdma_reg(struct smc_sock *new_smc, int local_contact)
if (local_contact != SMC_FIRST_CONTACT) {
if (!new_smc->conn.rmb_desc->reused) {
if (smc_reg_rmb(link, new_smc->conn.rmb_desc, true))
- return SMC_CLC_DECL_INTERR;
+ return SMC_CLC_DECL_ERR_REGRMB;
}
}
smc_rmb_sync_sg_for_device(&new_smc->conn);
@@ -1159,13 +1161,13 @@ static void smc_listen_rdma_finish(struct smc_sock *new_smc,
smc_link_save_peer_info(link, cclc);

if (smc_rmb_rtoken_handling(&new_smc->conn, cclc)) {
- reason_code = SMC_CLC_DECL_INTERR;
+ reason_code = SMC_CLC_DECL_ERR_RTOK;
goto decline;
}

if (local_contact == SMC_FIRST_CONTACT) {
if (smc_ib_ready_link(link)) {
- reason_code = SMC_CLC_DECL_INTERR;
+ reason_code = SMC_CLC_DECL_ERR_RDYLNK;
goto decline;
}
/* QP confirmation over RoCE fabric */
@@ -1206,6 +1208,7 @@ static void smc_listen_work(struct work_struct *work)
/* check if peer is smc capable */
if (!tcp_sk(newclcsock->sk)->syn_smc) {
new_smc->use_fallback = true;
+ new_smc->fallback_rsn = SMC_CLC_DECL_PEERNOSMC;
smc_listen_out_connected(new_smc);
return;
}
@@ -1250,7 +1253,8 @@ static void smc_listen_work(struct work_struct *work)
smc_listen_rdma_reg(new_smc, local_contact))) {
/* SMC not supported, decline */
mutex_unlock(&smc_create_lgr_pending);
- smc_listen_decline(new_smc, SMC_CLC_DECL_CNFERR, local_contact);
+ smc_listen_decline(new_smc, SMC_CLC_DECL_MODEUNSUPP,
+ local_contact);
return;
}

@@ -1297,6 +1301,7 @@ static void smc_tcp_listen_work(struct work_struct *work)

new_smc->listen_smc = lsmc;
new_smc->use_fallback = lsmc->use_fallback;
+ new_smc->fallback_rsn = lsmc->fallback_rsn;
sock_hold(lsk); /* sock_put in smc_listen_work */
INIT_WORK(&new_smc->smc_listen_work, smc_listen_work);
smc_copy_sock_settings_to_smc(new_smc);
@@ -1451,6 +1456,7 @@ static int smc_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
if (msg->msg_flags & MSG_FASTOPEN) {
if (sk->sk_state == SMC_INIT) {
smc->use_fallback = true;
+ smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP;
} else {
rc = -EINVAL;
goto out;
@@ -1648,6 +1654,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
/* option not supported by SMC */
if (sk->sk_state == SMC_INIT) {
smc->use_fallback = true;
+ smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP;
} else {
if (!smc->use_fallback)
rc = -EINVAL;
@@ -1885,6 +1892,7 @@ static int smc_create(struct net *net, struct socket *sock, int protocol,
/* create internal TCP socket for CLC handshake and fallback */
smc = smc_sk(sk);
smc->use_fallback = false; /* assume rdma capability first */
+ smc->fallback_rsn = 0;
rc = sock_create_kern(net, family, SOCK_STREAM, IPPROTO_TCP,
&smc->clcsock);
if (rc) {
diff --git a/net/smc/smc.h b/net/smc/smc.h
index be20acd7b5ab..08786ace6010 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -208,6 +208,8 @@ struct smc_sock { /* smc sock container */
struct list_head accept_q; /* sockets to be accepted */
spinlock_t accept_q_lock; /* protects accept_q */
bool use_fallback; /* fallback to tcp */
+ int fallback_rsn; /* reason for fallback */
+ u32 peer_diagnosis; /* decline reason from peer */
int sockopt_defer_accept;
/* sockopt TCP_DEFER_ACCEPT
* value
diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 78d74938a9d9..83aba9ade060 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -334,7 +334,11 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
goto out;
}
if (clcm->type == SMC_CLC_DECLINE) {
- reason_code = SMC_CLC_DECL_REPLY;
+ struct smc_clc_msg_decline *dclc;
+
+ dclc = (struct smc_clc_msg_decline *)clcm;
+ reason_code = SMC_CLC_DECL_PEERDECL;
+ smc->peer_diagnosis = ntohl(dclc->peer_diagnosis);
if (((struct smc_clc_msg_decline *)buf)->hdr.flag) {
smc->conn.lgr->sync_err = 1;
smc_lgr_terminate(smc->conn.lgr);
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
index 6bdc63352d6a..18da89b681c2 100644
--- a/net/smc/smc_clc.h
+++ b/net/smc/smc_clc.h
@@ -28,15 +28,21 @@
#define SMC_TYPE_B 3 /* SMC-R and SMC-D */
#define CLC_WAIT_TIME (6 * HZ) /* max. wait time on clcsock */
#define SMC_CLC_DECL_MEM 0x01010000 /* insufficient memory resources */
-#define SMC_CLC_DECL_TIMEOUT 0x02000000 /* timeout */
+#define SMC_CLC_DECL_TIMEOUT_CL 0x02010000 /* timeout w4 QP confirm link */
+#define SMC_CLC_DECL_TIMEOUT_AL 0x02020000 /* timeout w4 QP add link */
#define SMC_CLC_DECL_CNFERR 0x03000000 /* configuration error */
-#define SMC_CLC_DECL_IPSEC 0x03030000 /* IPsec usage */
+#define SMC_CLC_DECL_PEERNOSMC 0x03010000 /* peer did not indicate SMC */
+#define SMC_CLC_DECL_IPSEC 0x03020000 /* IPsec usage */
+#define SMC_CLC_DECL_NOSMCDEV 0x03030000 /* no SMC device found */
+#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 */
#define SMC_CLC_DECL_SYNCERR 0x04000000 /* synchronization error */
-#define SMC_CLC_DECL_REPLY 0x06000000 /* reply to a received decline */
+#define SMC_CLC_DECL_PEERDECL 0x05000000 /* peer declined during handshake */
#define SMC_CLC_DECL_INTERR 0x99990000 /* internal error */
-#define SMC_CLC_DECL_TCL 0x02040000 /* timeout w4 QP confirm */
-#define SMC_CLC_DECL_SEND 0x07000000 /* sending problem */
-#define SMC_CLC_DECL_RMBE_EC 0x08000000 /* peer has eyecatcher in RMBE */
+#define SMC_CLC_DECL_ERR_RTOK 0x99990001 /* rtoken handling failed */
+#define SMC_CLC_DECL_ERR_RDYLNK 0x99990002 /* ib ready link failed */
+#define SMC_CLC_DECL_ERR_REGRMB 0x99990003 /* reg rmb failed */

struct smc_clc_msg_hdr { /* header1 of clc messages */
u8 eyecatcher[4]; /* eye catcher */
diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c
index a3cf7313a2d3..dbf64a93d68a 100644
--- a/net/smc/smc_diag.c
+++ b/net/smc/smc_diag.c
@@ -79,6 +79,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
struct nlattr *bc)
{
struct smc_sock *smc = smc_sk(sk);
+ struct smc_diag_fallback fallback;
struct user_namespace *user_ns;
struct smc_diag_msg *r;
struct nlmsghdr *nlh;
@@ -101,6 +102,11 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
if (smc_diag_msg_attrs_fill(sk, skb, r, user_ns))
goto errout;

+ fallback.reason = smc->fallback_rsn;
+ fallback.peer_diagnosis = smc->peer_diagnosis;
+ if (nla_put(skb, SMC_DIAG_FALLBACK, sizeof(fallback), &fallback) < 0)
+ goto errout;
+
if ((req->diag_ext & (1 << (SMC_DIAG_CONNINFO - 1))) &&
smc->conn.alert_token_local) {
struct smc_connection *conn = &smc->conn;
--
2.16.4

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