smc: connection and link group creation
authorUrsula Braun <ubraun@linux.vnet.ibm.com>
Mon, 9 Jan 2017 15:55:17 +0000 (16:55 +0100)
committerDavid S. Miller <davem@davemloft.net>
Mon, 9 Jan 2017 21:07:39 +0000 (16:07 -0500)
* create smc_connection for SMC-sockets
* determine suitable link group for a connection
* create a new link group if necessary

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/smc/Makefile
net/smc/af_smc.c
net/smc/smc.h
net/smc/smc_clc.c
net/smc/smc_clc.h
net/smc/smc_core.c [new file with mode: 0644]
net/smc/smc_core.h [new file with mode: 0644]

index c0ad5883e8886ddd6a9496412668b72cfc9001b6..cb8bcd9df53e957aef47d68a0f376192b4aed7d8 100644 (file)
@@ -1,2 +1,2 @@
 obj-$(CONFIG_SMC)      += smc.o
-smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o
+smc-y := af_smc.o smc_pnet.o smc_ib.o smc_clc.o smc_core.o
index 05c705a688e520058d77d72c46bbbe53603de486..5fda37decc55d7be8eb3e8ed01c6948f64f4c5e6 100644 (file)
 
 #include "smc.h"
 #include "smc_clc.h"
+#include "smc_core.h"
 #include "smc_ib.h"
 #include "smc_pnet.h"
 
+static DEFINE_MUTEX(smc_create_lgr_pending);   /* serialize link group
+                                                * creation
+                                                */
+
+struct smc_lgr_list smc_lgr_list = {           /* established link groups */
+       .lock = __SPIN_LOCK_UNLOCKED(smc_lgr_list.lock),
+       .list = LIST_HEAD_INIT(smc_lgr_list.list),
+};
+
 static void smc_tcp_listen_work(struct work_struct *);
 
 static void smc_set_keepalive(struct sock *sk, int val)
@@ -235,11 +245,31 @@ out:
        return rc;
 }
 
+static void smc_conn_save_peer_info(struct smc_sock *smc,
+                                   struct smc_clc_msg_accept_confirm *clc)
+{
+       smc->conn.peer_conn_idx = clc->conn_idx;
+}
+
+static void smc_link_save_peer_info(struct smc_link *link,
+                                   struct smc_clc_msg_accept_confirm *clc)
+{
+       link->peer_qpn = ntoh24(clc->qpn);
+       memcpy(link->peer_gid, clc->lcl.gid, SMC_GID_SIZE);
+       memcpy(link->peer_mac, clc->lcl.mac, sizeof(link->peer_mac));
+       link->peer_psn = ntoh24(clc->psn);
+       link->peer_mtu = clc->qp_mtu;
+}
+
 /* setup for RDMA connection of client */
 static int smc_connect_rdma(struct smc_sock *smc)
 {
+       struct sockaddr_in *inaddr = (struct sockaddr_in *)smc->addr;
        struct smc_clc_msg_accept_confirm aclc;
+       int local_contact = SMC_FIRST_CONTACT;
        struct smc_ib_device *smcibdev;
+       struct smc_link *link;
+       u8 srv_first_contact;
        int reason_code = 0;
        int rc = 0;
        u8 ibport;
@@ -278,26 +308,43 @@ static int smc_connect_rdma(struct smc_sock *smc)
        if (reason_code > 0)
                goto decline_rdma;
 
-       /* tbd in follow-on patch: more steps to setup RDMA communcication,
-        * create connection, link group, link
-        */
+       srv_first_contact = aclc.hdr.flag;
+       mutex_lock(&smc_create_lgr_pending);
+       local_contact = smc_conn_create(smc, inaddr->sin_addr.s_addr, smcibdev,
+                                       ibport, &aclc.lcl, srv_first_contact);
+       if (local_contact < 0) {
+               rc = local_contact;
+               if (rc == -ENOMEM)
+                       reason_code = SMC_CLC_DECL_MEM;/* insufficient memory*/
+               else if (rc == -ENOLINK)
+                       reason_code = SMC_CLC_DECL_SYNCERR; /* synchr. error */
+               goto decline_rdma_unlock;
+       }
+       link = &smc->conn.lgr->lnk[SMC_SINGLE_LINK];
 
+       smc_conn_save_peer_info(smc, &aclc);
+       if (local_contact == SMC_FIRST_CONTACT)
+               smc_link_save_peer_info(link, &aclc);
        /* tbd in follow-on patch: more steps to setup RDMA communcication,
         * create rmbs, map rmbs, rtoken_handling, modify_qp
         */
 
        rc = smc_clc_send_confirm(smc);
        if (rc)
-               goto out_err;
+               goto out_err_unlock;
 
        /* tbd in follow-on patch: llc_confirm */
 
+       mutex_unlock(&smc_create_lgr_pending);
 out_connected:
        smc_copy_sock_settings_to_clc(smc);
        smc->sk.sk_state = SMC_ACTIVE;
 
-       return rc;
+       return rc ? rc : local_contact;
 
+decline_rdma_unlock:
+       mutex_unlock(&smc_create_lgr_pending);
+       smc_conn_free(&smc->conn);
 decline_rdma:
        /* RDMA setup failed, switch back to TCP */
        smc->use_fallback = true;
@@ -308,6 +355,9 @@ decline_rdma:
        }
        goto out_connected;
 
+out_err_unlock:
+       mutex_unlock(&smc_create_lgr_pending);
+       smc_conn_free(&smc->conn);
 out_err:
        return rc;
 }
@@ -476,10 +526,12 @@ static void smc_listen_work(struct work_struct *work)
        struct socket *newclcsock = new_smc->clcsock;
        struct smc_sock *lsmc = new_smc->listen_smc;
        struct smc_clc_msg_accept_confirm cclc;
+       int local_contact = SMC_REUSE_CONTACT;
        struct sock *newsmcsk = &new_smc->sk;
        struct smc_clc_msg_proposal pclc;
        struct smc_ib_device *smcibdev;
        struct sockaddr_in peeraddr;
+       struct smc_link *link;
        int reason_code = 0;
        int rc = 0, len;
        __be32 subnet;
@@ -527,15 +579,30 @@ static void smc_listen_work(struct work_struct *work)
        /* get address of the peer connected to the internal TCP socket */
        kernel_getpeername(newclcsock, (struct sockaddr *)&peeraddr, &len);
 
-       /* tbd in follow-on patch: more steps to setup RDMA communcication,
-        * create connection, link_group, link
-        */
+       /* allocate connection / link group */
+       mutex_lock(&smc_create_lgr_pending);
+       local_contact = smc_conn_create(new_smc, peeraddr.sin_addr.s_addr,
+                                       smcibdev, ibport, &pclc.lcl, 0);
+       if (local_contact == SMC_REUSE_CONTACT)
+               /* lock no longer needed, free it due to following
+                * smc_clc_wait_msg() call
+                */
+               mutex_unlock(&smc_create_lgr_pending);
+       if (local_contact < 0) {
+               rc = local_contact;
+               if (rc == -ENOMEM)
+                       reason_code = SMC_CLC_DECL_MEM;/* insufficient memory*/
+               else if (rc == -ENOLINK)
+                       reason_code = SMC_CLC_DECL_SYNCERR; /* synchr. error */
+               goto decline_rdma;
+       }
+       link = &new_smc->conn.lgr->lnk[SMC_SINGLE_LINK];
 
        /* tbd in follow-on patch: more steps to setup RDMA communcication,
         * create rmbs, map rmbs
         */
 
-       rc = smc_clc_send_accept(new_smc);
+       rc = smc_clc_send_accept(new_smc, local_contact);
        if (rc)
                goto out_err;
 
@@ -546,6 +613,9 @@ static void smc_listen_work(struct work_struct *work)
                goto out_err;
        if (reason_code > 0)
                goto decline_rdma;
+       smc_conn_save_peer_info(new_smc, &cclc);
+       if (local_contact == SMC_FIRST_CONTACT)
+               smc_link_save_peer_info(link, &cclc);
 
        /* tbd in follow-on patch: more steps to setup RDMA communcication,
         * rtoken_handling, modify_qp
@@ -555,6 +625,8 @@ out_connected:
        sk_refcnt_debug_inc(newsmcsk);
        newsmcsk->sk_state = SMC_ACTIVE;
 enqueue:
+       if (local_contact == SMC_FIRST_CONTACT)
+               mutex_unlock(&smc_create_lgr_pending);
        lock_sock(&lsmc->sk);
        if (lsmc->sk.sk_state == SMC_LISTEN) {
                smc_accept_enqueue(&lsmc->sk, newsmcsk);
@@ -570,6 +642,7 @@ enqueue:
 
 decline_rdma:
        /* RDMA setup failed, switch back to TCP */
+       smc_conn_free(&new_smc->conn);
        new_smc->use_fallback = true;
        if (reason_code && (reason_code != SMC_CLC_DECL_REPLY)) {
                rc = smc_clc_send_decline(new_smc, reason_code, 0);
@@ -1024,6 +1097,17 @@ out_pnet:
 
 static void __exit smc_exit(void)
 {
+       struct smc_link_group *lgr, *lg;
+       LIST_HEAD(lgr_freeing_list);
+
+       spin_lock_bh(&smc_lgr_list.lock);
+       if (!list_empty(&smc_lgr_list.list))
+               list_splice_init(&smc_lgr_list.list, &lgr_freeing_list);
+       spin_unlock_bh(&smc_lgr_list.lock);
+       list_for_each_entry_safe(lgr, lg, &lgr_freeing_list, list) {
+               list_del_init(&lgr->list);
+               smc_lgr_free(lgr); /* free link group */
+       }
        smc_ib_unregister_client();
        sock_unregister(PF_SMC);
        proto_unregister(&smc_proto);
index 5946aaecdebf5ef730364207512eb1683e434e37..11265bde465538be7648ed10718651a84bef9be4 100644 (file)
@@ -14,6 +14,8 @@
 #include <linux/types.h>
 #include <net/sock.h>
 
+#include "smc_ib.h"
+
 #define SMCPROTO_SMC           0       /* SMC protocol */
 
 #define SMC_MAX_PORTS          2       /* Max # of ports */
@@ -25,9 +27,19 @@ enum smc_state {             /* possible states of an SMC socket */
        SMC_LISTEN      = 10,
 };
 
+struct smc_link_group;
+
+struct smc_connection {
+       struct rb_node          alert_node;
+       struct smc_link_group   *lgr;           /* link group of connection */
+       u32                     alert_token_local; /* unique conn. id */
+       u8                      peer_conn_idx;  /* from tcp handshake */
+};
+
 struct smc_sock {                              /* smc sock container */
        struct sock             sk;
        struct socket           *clcsock;       /* internal tcp socket */
+       struct smc_connection   conn;           /* smc connection */
        struct sockaddr         *addr;          /* inet connect address */
        struct smc_sock         *listen_smc;    /* listen parent */
        struct work_struct      tcp_listen_work;/* handle tcp socket accepts */
@@ -46,6 +58,24 @@ static inline struct smc_sock *smc_sk(const struct sock *sk)
 
 extern u8      local_systemid[SMC_SYSTEMID_LEN]; /* unique system identifier */
 
+/* convert an u32 value into network byte order, store it into a 3 byte field */
+static inline void hton24(u8 *net, u32 host)
+{
+       __be32 t;
+
+       t = cpu_to_be32(host);
+       memcpy(net, ((u8 *)&t) + 1, 3);
+}
+
+/* convert a received 3 byte field into host byte order*/
+static inline u32 ntoh24(u8 *net)
+{
+       __be32 t = 0;
+
+       memcpy(((u8 *)&t) + 1, net, 3);
+       return be32_to_cpu(t);
+}
+
 #ifdef CONFIG_XFRM
 static inline bool using_ipsec(struct smc_sock *smc)
 {
@@ -59,7 +89,13 @@ static inline bool using_ipsec(struct smc_sock *smc)
 }
 #endif
 
+struct smc_clc_msg_local;
+
 int smc_netinfo_by_tcpsk(struct socket *clcsock, __be32 *subnet,
                         u8 *prefix_len);
+void smc_conn_free(struct smc_connection *conn);
+int smc_conn_create(struct smc_sock *smc, __be32 peer_in_addr,
+                   struct smc_ib_device *smcibdev, u8 ibport,
+                   struct smc_clc_msg_local *lcl, int srv_first_contact);
 
 #endif /* __SMC_H */
index b613b866a2ef55bbf996f4b9a88d4f742a6cbc57..f8e47c06d2edb796adbfd42be64cd88400ac1009 100644 (file)
@@ -14,6 +14,7 @@
 #include <net/tcp.h>
 
 #include "smc.h"
+#include "smc_core.h"
 #include "smc_clc.h"
 #include "smc_ib.h"
 
@@ -89,8 +90,13 @@ int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
                reason_code = -EPROTO;
                goto out;
        }
-       if (clcm->type == SMC_CLC_DECLINE)
+       if (clcm->type == SMC_CLC_DECLINE) {
                reason_code = SMC_CLC_DECL_REPLY;
+               if (ntohl(((struct smc_clc_msg_decline *)buf)->peer_diagnosis)
+                       == SMC_CLC_DECL_SYNCERR)
+                       smc->conn.lgr->sync_err = true;
+       }
+
 out:
        return reason_code;
 }
@@ -175,12 +181,15 @@ int smc_clc_send_proposal(struct smc_sock *smc,
 /* send CLC CONFIRM message across internal TCP socket */
 int smc_clc_send_confirm(struct smc_sock *smc)
 {
+       struct smc_connection *conn = &smc->conn;
        struct smc_clc_msg_accept_confirm cclc;
+       struct smc_link *link;
        int reason_code = 0;
        struct msghdr msg;
        struct kvec vec;
        int len;
 
+       link = &conn->lgr->lnk[SMC_SINGLE_LINK];
        /* send SMC Confirm CLC msg */
        memset(&cclc, 0, sizeof(cclc));
        memcpy(cclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
@@ -188,12 +197,18 @@ int smc_clc_send_confirm(struct smc_sock *smc)
        cclc.hdr.length = htons(sizeof(cclc));
        cclc.hdr.version = SMC_CLC_V1;          /* SMC version */
        memcpy(cclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
-
-       /* tbd in follow-on patch: fill in link-related values */
+       memcpy(&cclc.lcl.gid, &link->smcibdev->gid[link->ibport - 1],
+              SMC_GID_SIZE);
+       memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1],
+              sizeof(link->smcibdev->mac));
 
        /* tbd in follow-on patch: fill in rmb-related values */
 
+       hton24(cclc.qpn, link->roce_qp->qp_num);
        cclc.conn_idx = 1; /* for now: 1 RMB = 1 RMBE */
+       cclc.rmbe_alert_token = htonl(conn->alert_token_local);
+       cclc.qp_mtu = min(link->path_mtu, link->peer_mtu);
+       hton24(cclc.psn, link->psn_initial);
 
        memcpy(cclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 
@@ -214,26 +229,37 @@ int smc_clc_send_confirm(struct smc_sock *smc)
 }
 
 /* send CLC ACCEPT message across internal TCP socket */
-int smc_clc_send_accept(struct smc_sock *new_smc)
+int smc_clc_send_accept(struct smc_sock *new_smc, int srv_first_contact)
 {
+       struct smc_connection *conn = &new_smc->conn;
        struct smc_clc_msg_accept_confirm aclc;
+       struct smc_link *link;
        struct msghdr msg;
        struct kvec vec;
        int rc = 0;
        int len;
 
+       link = &conn->lgr->lnk[SMC_SINGLE_LINK];
        memset(&aclc, 0, sizeof(aclc));
        memcpy(aclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
        aclc.hdr.type = SMC_CLC_ACCEPT;
        aclc.hdr.length = htons(sizeof(aclc));
        aclc.hdr.version = SMC_CLC_V1;          /* SMC version */
+       if (srv_first_contact)
+               aclc.hdr.flag = 1;
        memcpy(aclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
-
-       /* tbd in follow-on patch: fill in link-related values */
+       memcpy(&aclc.lcl.gid, &link->smcibdev->gid[link->ibport - 1],
+              SMC_GID_SIZE);
+       memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1],
+              sizeof(link->smcibdev->mac[link->ibport - 1]));
 
        /* tbd in follow-on patch: fill in rmb-related values */
 
+       hton24(aclc.qpn, link->roce_qp->qp_num);
        aclc.conn_idx = 1;                      /* as long as 1 RMB = 1 RMBE */
+       aclc.rmbe_alert_token = htonl(conn->alert_token_local);
+       aclc.qp_mtu = link->path_mtu;
+       hton24(aclc.psn, link->psn_initial);
        memcpy(aclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 
        memset(&msg, 0, sizeof(msg));
index 60bfc8bd8d896d28f67669bc787ec91400cd4891..5924d998b5ca311471bcda37a9a771c47f5b30db 100644 (file)
@@ -109,6 +109,6 @@ int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info,
 int smc_clc_send_proposal(struct smc_sock *smc, struct smc_ib_device *smcibdev,
                          u8 ibport);
 int smc_clc_send_confirm(struct smc_sock *smc);
-int smc_clc_send_accept(struct smc_sock *smc);
+int smc_clc_send_accept(struct smc_sock *smc, int srv_first_contact);
 
 #endif
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
new file mode 100644 (file)
index 0000000..b88a829
--- /dev/null
@@ -0,0 +1,336 @@
+/*
+ *  Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ *  Basic Transport Functions exploiting Infiniband API
+ *
+ *  Copyright IBM Corp. 2016
+ *
+ *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
+ */
+
+#include <linux/socket.h>
+#include <linux/if_vlan.h>
+#include <linux/random.h>
+#include <linux/workqueue.h>
+#include <net/tcp.h>
+#include <net/sock.h>
+#include <rdma/ib_verbs.h>
+
+#include "smc.h"
+#include "smc_clc.h"
+#include "smc_core.h"
+#include "smc_ib.h"
+
+#define SMC_LGR_FREE_DELAY     (600 * HZ)
+
+/* Register connection's alert token in our lookup structure.
+ * To use rbtrees we have to implement our own insert core.
+ * Requires @conns_lock
+ * @smc                connection to register
+ * Returns 0 on success, != otherwise.
+ */
+static void smc_lgr_add_alert_token(struct smc_connection *conn)
+{
+       struct rb_node **link, *parent = NULL;
+       u32 token = conn->alert_token_local;
+
+       link = &conn->lgr->conns_all.rb_node;
+       while (*link) {
+               struct smc_connection *cur = rb_entry(*link,
+                                       struct smc_connection, alert_node);
+
+               parent = *link;
+               if (cur->alert_token_local > token)
+                       link = &parent->rb_left;
+               else
+                       link = &parent->rb_right;
+       }
+       /* Put the new node there */
+       rb_link_node(&conn->alert_node, parent, link);
+       rb_insert_color(&conn->alert_node, &conn->lgr->conns_all);
+}
+
+/* Register connection in link group by assigning an alert token
+ * registered in a search tree.
+ * Requires @conns_lock
+ * Note that '0' is a reserved value and not assigned.
+ */
+static void smc_lgr_register_conn(struct smc_connection *conn)
+{
+       struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
+       static atomic_t nexttoken = ATOMIC_INIT(0);
+
+       /* find a new alert_token_local value not yet used by some connection
+        * in this link group
+        */
+       sock_hold(&smc->sk); /* sock_put in smc_lgr_unregister_conn() */
+       while (!conn->alert_token_local) {
+               conn->alert_token_local = atomic_inc_return(&nexttoken);
+               if (smc_lgr_find_conn(conn->alert_token_local, conn->lgr))
+                       conn->alert_token_local = 0;
+       }
+       smc_lgr_add_alert_token(conn);
+       conn->lgr->conns_num++;
+}
+
+/* Unregister connection and reset the alert token of the given connection<
+ */
+static void __smc_lgr_unregister_conn(struct smc_connection *conn)
+{
+       struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
+       struct smc_link_group *lgr = conn->lgr;
+
+       rb_erase(&conn->alert_node, &lgr->conns_all);
+       lgr->conns_num--;
+       conn->alert_token_local = 0;
+       conn->lgr = NULL;
+       sock_put(&smc->sk); /* sock_hold in smc_lgr_register_conn() */
+}
+
+/* Unregister connection and trigger lgr freeing if applicable
+ */
+static void smc_lgr_unregister_conn(struct smc_connection *conn)
+{
+       struct smc_link_group *lgr = conn->lgr;
+       int reduced = 0;
+
+       write_lock_bh(&lgr->conns_lock);
+       if (conn->alert_token_local) {
+               reduced = 1;
+               __smc_lgr_unregister_conn(conn);
+       }
+       write_unlock_bh(&lgr->conns_lock);
+       if (reduced && !lgr->conns_num)
+               schedule_delayed_work(&lgr->free_work, SMC_LGR_FREE_DELAY);
+}
+
+static void smc_lgr_free_work(struct work_struct *work)
+{
+       struct smc_link_group *lgr = container_of(to_delayed_work(work),
+                                                 struct smc_link_group,
+                                                 free_work);
+       bool conns;
+
+       spin_lock_bh(&smc_lgr_list.lock);
+       read_lock_bh(&lgr->conns_lock);
+       conns = RB_EMPTY_ROOT(&lgr->conns_all);
+       read_unlock_bh(&lgr->conns_lock);
+       if (!conns) { /* number of lgr connections is no longer zero */
+               spin_unlock_bh(&smc_lgr_list.lock);
+               return;
+       }
+       list_del_init(&lgr->list); /* remove from smc_lgr_list */
+       spin_unlock_bh(&smc_lgr_list.lock);
+       smc_lgr_free(lgr);
+}
+
+/* create a new SMC link group */
+static int smc_lgr_create(struct smc_sock *smc, __be32 peer_in_addr,
+                         struct smc_ib_device *smcibdev, u8 ibport,
+                         char *peer_systemid, unsigned short vlan_id)
+{
+       struct smc_link_group *lgr;
+       struct smc_link *lnk;
+       u8 rndvec[3];
+       int rc = 0;
+
+       lgr = kzalloc(sizeof(*lgr), GFP_KERNEL);
+       if (!lgr) {
+               rc = -ENOMEM;
+               goto out;
+       }
+       lgr->role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
+       lgr->sync_err = false;
+       lgr->daddr = peer_in_addr;
+       memcpy(lgr->peer_systemid, peer_systemid, SMC_SYSTEMID_LEN);
+       lgr->vlan_id = vlan_id;
+       INIT_DELAYED_WORK(&lgr->free_work, smc_lgr_free_work);
+       lgr->conns_all = RB_ROOT;
+
+       lnk = &lgr->lnk[SMC_SINGLE_LINK];
+       /* initialize link */
+       lnk->smcibdev = smcibdev;
+       lnk->ibport = ibport;
+       lnk->path_mtu = smcibdev->pattr[ibport - 1].active_mtu;
+       get_random_bytes(rndvec, sizeof(rndvec));
+       lnk->psn_initial = rndvec[0] + (rndvec[1] << 8) + (rndvec[2] << 16);
+
+       smc->conn.lgr = lgr;
+       rwlock_init(&lgr->conns_lock);
+       spin_lock_bh(&smc_lgr_list.lock);
+       list_add(&lgr->list, &smc_lgr_list.list);
+       spin_unlock_bh(&smc_lgr_list.lock);
+out:
+       return rc;
+}
+
+/* remove a finished connection from its link group */
+void smc_conn_free(struct smc_connection *conn)
+{
+       struct smc_link_group *lgr = conn->lgr;
+
+       if (!lgr)
+               return;
+       smc_lgr_unregister_conn(conn);
+}
+
+static void smc_link_clear(struct smc_link *lnk)
+{
+       lnk->peer_qpn = 0;
+}
+
+/* remove a link group */
+void smc_lgr_free(struct smc_link_group *lgr)
+{
+       smc_link_clear(&lgr->lnk[SMC_SINGLE_LINK]);
+       kfree(lgr);
+}
+
+/* terminate linkgroup abnormally */
+void smc_lgr_terminate(struct smc_link_group *lgr)
+{
+       struct smc_connection *conn;
+       struct rb_node *node;
+
+       spin_lock_bh(&smc_lgr_list.lock);
+       if (list_empty(&lgr->list)) {
+               /* termination already triggered */
+               spin_unlock_bh(&smc_lgr_list.lock);
+               return;
+       }
+       /* do not use this link group for new connections */
+       list_del_init(&lgr->list);
+       spin_unlock_bh(&smc_lgr_list.lock);
+
+       write_lock_bh(&lgr->conns_lock);
+       node = rb_first(&lgr->conns_all);
+       while (node) {
+               conn = rb_entry(node, struct smc_connection, alert_node);
+               __smc_lgr_unregister_conn(conn);
+               node = rb_first(&lgr->conns_all);
+       }
+       write_unlock_bh(&lgr->conns_lock);
+       schedule_delayed_work(&lgr->free_work, SMC_LGR_FREE_DELAY);
+}
+
+/* Determine vlan of internal TCP socket.
+ * @vlan_id: address to store the determined vlan id into
+ */
+static int smc_vlan_by_tcpsk(struct socket *clcsock, unsigned short *vlan_id)
+{
+       struct dst_entry *dst = sk_dst_get(clcsock->sk);
+       int rc = 0;
+
+       *vlan_id = 0;
+       if (!dst) {
+               rc = -ENOTCONN;
+               goto out;
+       }
+       if (!dst->dev) {
+               rc = -ENODEV;
+               goto out_rel;
+       }
+
+       if (is_vlan_dev(dst->dev))
+               *vlan_id = vlan_dev_vlan_id(dst->dev);
+
+out_rel:
+       dst_release(dst);
+out:
+       return rc;
+}
+
+/* determine the link gid matching the vlan id of the link group */
+static int smc_link_determine_gid(struct smc_link_group *lgr)
+{
+       struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK];
+       struct ib_gid_attr gattr;
+       union ib_gid gid;
+       int i;
+
+       if (!lgr->vlan_id) {
+               lnk->gid = lnk->smcibdev->gid[lnk->ibport - 1];
+               return 0;
+       }
+
+       for (i = 0; i < lnk->smcibdev->pattr[lnk->ibport - 1].gid_tbl_len;
+            i++) {
+               if (ib_query_gid(lnk->smcibdev->ibdev, lnk->ibport, i, &gid,
+                                &gattr))
+                       continue;
+               if (gattr.ndev &&
+                   (vlan_dev_vlan_id(gattr.ndev) == lgr->vlan_id)) {
+                       lnk->gid = gid;
+                       return 0;
+               }
+       }
+       return -ENODEV;
+}
+
+/* create a new SMC connection (and a new link group if necessary) */
+int smc_conn_create(struct smc_sock *smc, __be32 peer_in_addr,
+                   struct smc_ib_device *smcibdev, u8 ibport,
+                   struct smc_clc_msg_local *lcl, int srv_first_contact)
+{
+       struct smc_connection *conn = &smc->conn;
+       struct smc_link_group *lgr;
+       unsigned short vlan_id;
+       enum smc_lgr_role role;
+       int local_contact = SMC_FIRST_CONTACT;
+       int rc = 0;
+
+       role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
+       rc = smc_vlan_by_tcpsk(smc->clcsock, &vlan_id);
+       if (rc)
+               return rc;
+
+       if ((role == SMC_CLNT) && srv_first_contact)
+               /* create new link group as well */
+               goto create;
+
+       /* determine if an existing link group can be reused */
+       spin_lock_bh(&smc_lgr_list.lock);
+       list_for_each_entry(lgr, &smc_lgr_list.list, list) {
+               write_lock_bh(&lgr->conns_lock);
+               if (!memcmp(lgr->peer_systemid, lcl->id_for_peer,
+                           SMC_SYSTEMID_LEN) &&
+                   !memcmp(lgr->lnk[SMC_SINGLE_LINK].peer_gid, &lcl->gid,
+                           SMC_GID_SIZE) &&
+                   !memcmp(lgr->lnk[SMC_SINGLE_LINK].peer_mac, lcl->mac,
+                           sizeof(lcl->mac)) &&
+                   !lgr->sync_err &&
+                   (lgr->role == role) &&
+                   (lgr->vlan_id == vlan_id)) {
+                       /* link group found */
+                       local_contact = SMC_REUSE_CONTACT;
+                       conn->lgr = lgr;
+                       smc_lgr_register_conn(conn); /* add smc conn to lgr */
+                       write_unlock_bh(&lgr->conns_lock);
+                       break;
+               }
+               write_unlock_bh(&lgr->conns_lock);
+       }
+       spin_unlock_bh(&smc_lgr_list.lock);
+
+       if (role == SMC_CLNT && !srv_first_contact &&
+           (local_contact == SMC_FIRST_CONTACT)) {
+               /* Server reuses a link group, but Client wants to start
+                * a new one
+                * send out_of_sync decline, reason synchr. error
+                */
+               return -ENOLINK;
+       }
+
+create:
+       if (local_contact == SMC_FIRST_CONTACT) {
+               rc = smc_lgr_create(smc, peer_in_addr, smcibdev, ibport,
+                                   lcl->id_for_peer, vlan_id);
+               if (rc)
+                       goto out;
+               smc_lgr_register_conn(conn); /* add smc conn to lgr */
+               rc = smc_link_determine_gid(conn->lgr);
+       }
+
+out:
+       return rc ? rc : local_contact;
+}
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
new file mode 100644 (file)
index 0000000..14b787a
--- /dev/null
@@ -0,0 +1,106 @@
+/*
+ * Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ *  Definitions for SMC Connections, Link Groups and Links
+ *
+ *  Copyright IBM Corp. 2016
+ *
+ *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
+ */
+
+#ifndef _SMC_CORE_H
+#define _SMC_CORE_H
+
+#include <rdma/ib_verbs.h>
+
+#include "smc.h"
+#include "smc_ib.h"
+
+struct smc_lgr_list {                  /* list of link group definition */
+       struct list_head        list;
+       spinlock_t              lock;   /* protects list of link groups */
+};
+
+extern struct smc_lgr_list     smc_lgr_list; /* list of link groups */
+
+enum smc_lgr_role {            /* possible roles of a link group */
+       SMC_CLNT,       /* client */
+       SMC_SERV        /* server */
+};
+
+struct smc_link {
+       struct smc_ib_device    *smcibdev;      /* ib-device */
+       u8                      ibport;         /* port - values 1 | 2 */
+       struct ib_qp            *roce_qp;       /* IB queue pair */
+       struct ib_qp_attr       qp_attr;        /* IB queue pair attributes */
+       union ib_gid            gid;            /* gid matching used vlan id */
+       u32                     peer_qpn;       /* QP number of peer */
+       enum ib_mtu             path_mtu;       /* used mtu */
+       enum ib_mtu             peer_mtu;       /* mtu size of peer */
+       u32                     psn_initial;    /* QP tx initial packet seqno */
+       u32                     peer_psn;       /* QP rx initial packet seqno */
+       u8                      peer_mac[ETH_ALEN];     /* = gid[8:10||13:15] */
+       u8                      peer_gid[sizeof(union ib_gid)]; /* gid of peer*/
+};
+
+/* For now we just allow one parallel link per link group. The SMC protocol
+ * allows more (up to 8).
+ */
+#define SMC_LINKS_PER_LGR_MAX  1
+#define SMC_SINGLE_LINK                0
+
+#define SMC_FIRST_CONTACT      1               /* first contact to a peer */
+#define SMC_REUSE_CONTACT      0               /* follow-on contact to a peer*/
+
+struct smc_link_group {
+       struct list_head        list;
+       enum smc_lgr_role       role;           /* client or server */
+       __be32                  daddr;          /* destination ip address */
+       struct smc_link         lnk[SMC_LINKS_PER_LGR_MAX];     /* smc link */
+       char                    peer_systemid[SMC_SYSTEMID_LEN];
+                                               /* unique system_id of peer */
+       struct rb_root          conns_all;      /* connection tree */
+       rwlock_t                conns_lock;     /* protects conns_all */
+       unsigned int            conns_num;      /* current # of connections */
+       unsigned short          vlan_id;        /* vlan id of link group */
+       struct delayed_work     free_work;      /* delayed freeing of an lgr */
+       bool                    sync_err;       /* lgr no longer fits to peer */
+};
+
+/* Find the connection associated with the given alert token in the link group.
+ * To use rbtrees we have to implement our own search core.
+ * Requires @conns_lock
+ * @token      alert token to search for
+ * @lgr                 link group to search in
+ * Returns connection associated with token if found, NULL otherwise.
+ */
+static inline struct smc_connection *smc_lgr_find_conn(
+       u32 token, struct smc_link_group *lgr)
+{
+       struct smc_connection *res = NULL;
+       struct rb_node *node;
+
+       node = lgr->conns_all.rb_node;
+       while (node) {
+               struct smc_connection *cur = rb_entry(node,
+                                       struct smc_connection, alert_node);
+
+               if (cur->alert_token_local > token) {
+                       node = node->rb_left;
+               } else {
+                       if (cur->alert_token_local < token) {
+                               node = node->rb_right;
+                       } else {
+                               res = cur;
+                               break;
+                       }
+               }
+       }
+
+       return res;
+}
+
+void smc_lgr_free(struct smc_link_group *lgr);
+void smc_lgr_terminate(struct smc_link_group *lgr);
+
+#endif