net/smc: provide fallback reason code

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@linux.ibm.com>
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 55 insertions, 29 deletions

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;