+/*
+ * 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;
+}
projects / platform / kernel / linux-rpi.git / commitdiff