+/*
+ * Queue a peer for the attention of the discovery thread. Call with
+ * lnet_net_lock/EX held. Returns 0 if the peer was queued, and
+ * -EALREADY if the peer was already queued.
+ */
+static int lnet_peer_queue_for_discovery(struct lnet_peer *lp)
+{
+ int rc;
+
+ spin_lock(&lp->lp_lock);
+ if (!(lp->lp_state & LNET_PEER_DISCOVERING))
+ lp->lp_state |= LNET_PEER_DISCOVERING;
+ spin_unlock(&lp->lp_lock);
+ if (list_empty(&lp->lp_dc_list)) {
+ lnet_peer_addref_locked(lp);
+ list_add_tail(&lp->lp_dc_list, &the_lnet.ln_dc_request);
+ wake_up(&the_lnet.ln_dc_waitq);
+ rc = 0;
+ } else {
+ rc = -EALREADY;
+ }
+
+ CDEBUG(D_NET, "Queue peer %s: %d\n",
+ libcfs_nid2str(lp->lp_primary_nid), rc);
+
+ return rc;
+}
+
+/*
+ * Discovery of a peer is complete. Wake all waiters on the peer.
+ * Call with lnet_net_lock/EX held.
+ */
+static void lnet_peer_discovery_complete(struct lnet_peer *lp)
+{
+ struct lnet_msg *msg, *tmp;
+ int rc = 0;
+ LIST_HEAD(pending_msgs);
+
+ CDEBUG(D_NET, "Discovery complete. Dequeue peer %s\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+
+ list_del_init(&lp->lp_dc_list);
+ spin_lock(&lp->lp_lock);
+ list_splice_init(&lp->lp_dc_pendq, &pending_msgs);
+ spin_unlock(&lp->lp_lock);
+ wake_up_all(&lp->lp_dc_waitq);
+
+ if (lp->lp_rtr_refcount > 0)
+ lnet_router_discovery_complete(lp);
+
+ lnet_net_unlock(LNET_LOCK_EX);
+
+ /* iterate through all pending messages and send them again */
+ list_for_each_entry_safe(msg, tmp, &pending_msgs, msg_list) {
+ list_del_init(&msg->msg_list);
+ if (lp->lp_dc_error) {
+ lnet_finalize(msg, lp->lp_dc_error);
+ continue;
+ }
+
+ CDEBUG(D_NET, "sending pending message %s to target %s\n",
+ lnet_msgtyp2str(msg->msg_type),
+ libcfs_id2str(msg->msg_target));
+ rc = lnet_send(msg->msg_src_nid_param, msg,
+ msg->msg_rtr_nid_param);
+ if (rc < 0) {
+ CNETERR("Error sending %s to %s: %d\n",
+ lnet_msgtyp2str(msg->msg_type),
+ libcfs_id2str(msg->msg_target), rc);
+ lnet_finalize(msg, rc);
+ }
+ }
+ lnet_net_lock(LNET_LOCK_EX);
+ lnet_peer_decref_locked(lp);
+}
+
+/*
+ * Handle inbound push.
+ * Like any event handler, called with lnet_res_lock/CPT held.
+ */
+void lnet_peer_push_event(struct lnet_event *ev)
+{
+ struct lnet_ping_buffer *pbuf = ev->md.user_ptr;
+ struct lnet_peer *lp;
+
+ /* lnet_find_peer() adds a refcount */
+ lp = lnet_find_peer(ev->source.nid);
+ if (!lp) {
+ CDEBUG(D_NET, "Push Put from unknown %s (source %s). Ignoring...\n",
+ libcfs_nid2str(ev->initiator.nid),
+ libcfs_nid2str(ev->source.nid));
+ return;
+ }
+
+ /* Ensure peer state remains consistent while we modify it. */
+ spin_lock(&lp->lp_lock);
+
+ /*
+ * If some kind of error happened the contents of the message
+ * cannot be used. Clear the NIDS_UPTODATE and set the
+ * FORCE_PING flag to trigger a ping.
+ */
+ if (ev->status) {
+ lp->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
+ lp->lp_state |= LNET_PEER_FORCE_PING;
+ CDEBUG(D_NET, "Push Put error %d from %s (source %s)\n",
+ ev->status,
+ libcfs_nid2str(lp->lp_primary_nid),
+ libcfs_nid2str(ev->source.nid));
+ goto out;
+ }
+
+ /*
+ * A push with invalid or corrupted info. Clear the UPTODATE
+ * flag to trigger a ping.
+ */
+ if (lnet_ping_info_validate(&pbuf->pb_info)) {
+ lp->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
+ lp->lp_state |= LNET_PEER_FORCE_PING;
+ CDEBUG(D_NET, "Corrupted Push from %s\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ goto out;
+ }
+
+ /*
+ * Make sure we'll allocate the correct size ping buffer when
+ * pinging the peer.
+ */
+ if (lp->lp_data_nnis < pbuf->pb_info.pi_nnis)
+ lp->lp_data_nnis = pbuf->pb_info.pi_nnis;
+
+ /*
+ * A non-Multi-Rail peer is not supposed to be capable of
+ * sending a push.
+ */
+ if (!(pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL)) {
+ CERROR("Push from non-Multi-Rail peer %s dropped\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ goto out;
+ }
+
+ /*
+ * Check the MULTIRAIL flag. Complain if the peer was DLC
+ * configured without it.
+ */
+ if (!(lp->lp_state & LNET_PEER_MULTI_RAIL)) {
+ if (lp->lp_state & LNET_PEER_CONFIGURED) {
+ CERROR("Push says %s is Multi-Rail, DLC says not\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ } else {
+ lp->lp_state |= LNET_PEER_MULTI_RAIL;
+ lnet_peer_clr_non_mr_pref_nids(lp);
+ }
+ }
+
+ /*
+ * The peer may have discovery disabled at its end. Set
+ * NO_DISCOVERY as appropriate.
+ */
+ if (!(pbuf->pb_info.pi_features & LNET_PING_FEAT_DISCOVERY)) {
+ CDEBUG(D_NET, "Peer %s has discovery disabled\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ lp->lp_state |= LNET_PEER_NO_DISCOVERY;
+ } else if (lp->lp_state & LNET_PEER_NO_DISCOVERY) {
+ CDEBUG(D_NET, "Peer %s has discovery enabled\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
+ }
+
+ /*
+ * Check for truncation of the Put message. Clear the
+ * NIDS_UPTODATE flag and set FORCE_PING to trigger a ping,
+ * and tell discovery to allocate a bigger buffer.
+ */
+ if (pbuf->pb_nnis < pbuf->pb_info.pi_nnis) {
+ if (the_lnet.ln_push_target_nnis < pbuf->pb_info.pi_nnis)
+ the_lnet.ln_push_target_nnis = pbuf->pb_info.pi_nnis;
+ lp->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
+ lp->lp_state |= LNET_PEER_FORCE_PING;
+ CDEBUG(D_NET, "Truncated Push from %s (%d nids)\n",
+ libcfs_nid2str(lp->lp_primary_nid),
+ pbuf->pb_info.pi_nnis);
+ goto out;
+ }
+
+ /* always assume new data */
+ lp->lp_peer_seqno = LNET_PING_BUFFER_SEQNO(pbuf);
+ lp->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
+
+ /*
+ * If there is data present that hasn't been processed yet,
+ * we'll replace it if the Put contained newer data and it
+ * fits. We're racing with a Ping or earlier Push in this
+ * case.
+ */
+ if (lp->lp_state & LNET_PEER_DATA_PRESENT) {
+ if (LNET_PING_BUFFER_SEQNO(pbuf) >
+ LNET_PING_BUFFER_SEQNO(lp->lp_data) &&
+ pbuf->pb_info.pi_nnis <= lp->lp_data->pb_nnis) {
+ memcpy(&lp->lp_data->pb_info, &pbuf->pb_info,
+ LNET_PING_INFO_SIZE(pbuf->pb_info.pi_nnis));
+ CDEBUG(D_NET, "Ping/Push race from %s: %u vs %u\n",
+ libcfs_nid2str(lp->lp_primary_nid),
+ LNET_PING_BUFFER_SEQNO(pbuf),
+ LNET_PING_BUFFER_SEQNO(lp->lp_data));
+ }
+ goto out;
+ }
+
+ /*
+ * Allocate a buffer to copy the data. On a failure we drop
+ * the Push and set FORCE_PING to force the discovery
+ * thread to fix the problem by pinging the peer.
+ */
+ lp->lp_data = lnet_ping_buffer_alloc(lp->lp_data_nnis, GFP_ATOMIC);
+ if (!lp->lp_data) {
+ lp->lp_state |= LNET_PEER_FORCE_PING;
+ CDEBUG(D_NET, "Cannot allocate Push buffer for %s %u\n",
+ libcfs_nid2str(lp->lp_primary_nid),
+ LNET_PING_BUFFER_SEQNO(pbuf));
+ goto out;
+ }
+
+ /* Success */
+ memcpy(&lp->lp_data->pb_info, &pbuf->pb_info,
+ LNET_PING_INFO_SIZE(pbuf->pb_info.pi_nnis));
+ lp->lp_state |= LNET_PEER_DATA_PRESENT;
+ CDEBUG(D_NET, "Received Push %s %u\n",
+ libcfs_nid2str(lp->lp_primary_nid),
+ LNET_PING_BUFFER_SEQNO(pbuf));
+
+out:
+ /*
+ * Queue the peer for discovery if not done, force it on the request
+ * queue and wake the discovery thread if the peer was already queued,
+ * because its status changed.
+ */
+ spin_unlock(&lp->lp_lock);
+ lnet_net_lock(LNET_LOCK_EX);
+ if (!lnet_peer_is_uptodate(lp) && lnet_peer_queue_for_discovery(lp)) {
+ list_move(&lp->lp_dc_list, &the_lnet.ln_dc_request);
+ wake_up(&the_lnet.ln_dc_waitq);
+ }
+ /* Drop refcount from lookup */
+ lnet_peer_decref_locked(lp);
+ lnet_net_unlock(LNET_LOCK_EX);
+}
+
+/*
+ * Clear the discovery error state, unless we're already discovering
+ * this peer, in which case the error is current.
+ */
+static void lnet_peer_clear_discovery_error(struct lnet_peer *lp)
+{
+ spin_lock(&lp->lp_lock);
+ if (!(lp->lp_state & LNET_PEER_DISCOVERING))
+ lp->lp_dc_error = 0;
+ spin_unlock(&lp->lp_lock);
+}
+
+/*
+ * Peer discovery slow path. The ln_api_mutex is held on entry, and
+ * dropped/retaken within this function. An lnet_peer_ni is passed in
+ * because discovery could tear down an lnet_peer.
+ */
+int
+lnet_discover_peer_locked(struct lnet_peer_ni *lpni, int cpt, bool block)
+{
+ DEFINE_WAIT(wait);
+ struct lnet_peer *lp;
+ int rc = 0;
+ int count = 0;
+
+again:
+ lnet_net_unlock(cpt);
+ lnet_net_lock(LNET_LOCK_EX);
+ lp = lpni->lpni_peer_net->lpn_peer;
+ lnet_peer_clear_discovery_error(lp);
+
+ /*
+ * We're willing to be interrupted. The lpni can become a
+ * zombie if we race with DLC, so we must check for that.
+ */
+ for (;;) {
+ /* Keep lp alive when the lnet_net_lock is unlocked */
+ lnet_peer_addref_locked(lp);
+ prepare_to_wait(&lp->lp_dc_waitq, &wait, TASK_INTERRUPTIBLE);
+ if (signal_pending(current))
+ break;
+ if (the_lnet.ln_dc_state != LNET_DC_STATE_RUNNING)
+ break;
+ /*
+ * Don't repeat discovery if discovery is disabled. This is
+ * done to ensure we can use discovery as a standard ping as
+ * well for backwards compatibility with routers which do not
+ * have discovery or have discovery disabled
+ */
+ if (lnet_is_discovery_disabled(lp) && count > 0)
+ break;
+ if (lp->lp_dc_error)
+ break;
+ if (lnet_peer_is_uptodate(lp))
+ break;
+ lnet_peer_queue_for_discovery(lp);
+ count++;
+ CDEBUG(D_NET, "Discovery attempt # %d\n", count);
+
+ /*
+ * If caller requested a non-blocking operation then
+ * return immediately. Once discovery is complete any
+ * pending messages that were stopped due to discovery
+ * will be transmitted.
+ */
+ if (!block)
+ break;
+
+ lnet_net_unlock(LNET_LOCK_EX);
+ schedule();
+ finish_wait(&lp->lp_dc_waitq, &wait);
+ lnet_net_lock(LNET_LOCK_EX);
+ lnet_peer_decref_locked(lp);
+ /* Peer may have changed */
+ lp = lpni->lpni_peer_net->lpn_peer;
+ }
+ finish_wait(&lp->lp_dc_waitq, &wait);
+
+ lnet_net_unlock(LNET_LOCK_EX);
+ lnet_net_lock(cpt);
+ lnet_peer_decref_locked(lp);
+ /*
+ * The peer may have changed, so re-check and rediscover if that turns
+ * out to have been the case. The reference count on lp ensured that
+ * even if it was unlinked from lpni the memory could not be recycled.
+ * Thus the check below is sufficient to determine whether the peer
+ * changed. If the peer changed, then lp must not be dereferenced.
+ */
+ if (lp != lpni->lpni_peer_net->lpn_peer)
+ goto again;
+
+ if (signal_pending(current))
+ rc = -EINTR;
+ else if (the_lnet.ln_dc_state != LNET_DC_STATE_RUNNING)
+ rc = -ESHUTDOWN;
+ else if (lp->lp_dc_error)
+ rc = lp->lp_dc_error;
+ else if (!block)
+ CDEBUG(D_NET, "non-blocking discovery\n");
+ else if (!lnet_peer_is_uptodate(lp) && !lnet_is_discovery_disabled(lp))
+ goto again;
+
+ CDEBUG(D_NET, "peer %s NID %s: %d. %s\n",
+ (lp ? libcfs_nid2str(lp->lp_primary_nid) : "(none)"),
+ libcfs_nid2str(lpni->lpni_nid), rc,
+ (!block) ? "pending discovery" : "discovery complete");
+
+ return rc;
+}
+
+/* Handle an incoming ack for a push. */
+static void
+lnet_discovery_event_ack(struct lnet_peer *lp, struct lnet_event *ev)
+{
+ struct lnet_ping_buffer *pbuf;
+
+ pbuf = LNET_PING_INFO_TO_BUFFER(ev->md.start);
+ spin_lock(&lp->lp_lock);
+ lp->lp_state &= ~LNET_PEER_PUSH_SENT;
+ lp->lp_push_error = ev->status;
+ if (ev->status)
+ lp->lp_state |= LNET_PEER_PUSH_FAILED;
+ else
+ lp->lp_node_seqno = LNET_PING_BUFFER_SEQNO(pbuf);
+ spin_unlock(&lp->lp_lock);
+
+ CDEBUG(D_NET, "peer %s ev->status %d\n",
+ libcfs_nid2str(lp->lp_primary_nid), ev->status);
+}
+
+/* Handle a Reply message. This is the reply to a Ping message. */
+static void
+lnet_discovery_event_reply(struct lnet_peer *lp, struct lnet_event *ev)
+{
+ struct lnet_ping_buffer *pbuf;
+ int rc;
+
+ spin_lock(&lp->lp_lock);
+
+ /*
+ * If some kind of error happened the contents of message
+ * cannot be used. Set PING_FAILED to trigger a retry.
+ */
+ if (ev->status) {
+ lp->lp_state |= LNET_PEER_PING_FAILED;
+ lp->lp_ping_error = ev->status;
+ CDEBUG(D_NET, "Ping Reply error %d from %s (source %s)\n",
+ ev->status,
+ libcfs_nid2str(lp->lp_primary_nid),
+ libcfs_nid2str(ev->source.nid));
+ goto out;
+ }
+
+ pbuf = LNET_PING_INFO_TO_BUFFER(ev->md.start);
+ if (pbuf->pb_info.pi_magic == __swab32(LNET_PROTO_PING_MAGIC))
+ lnet_swap_pinginfo(pbuf);
+
+ /*
+ * A reply with invalid or corrupted info. Set PING_FAILED to
+ * trigger a retry.
+ */
+ rc = lnet_ping_info_validate(&pbuf->pb_info);
+ if (rc) {
+ lp->lp_state |= LNET_PEER_PING_FAILED;
+ lp->lp_ping_error = 0;
+ CDEBUG(D_NET, "Corrupted Ping Reply from %s: %d\n",
+ libcfs_nid2str(lp->lp_primary_nid), rc);
+ goto out;
+ }
+
+
+ /*
+ * The peer may have discovery disabled at its end. Set
+ * NO_DISCOVERY as appropriate.
+ */
+ if ((pbuf->pb_info.pi_features & LNET_PING_FEAT_DISCOVERY) &&
+ !lnet_peer_discovery_disabled) {
+ CDEBUG(D_NET, "Peer %s has discovery enabled\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
+ } else {
+ CDEBUG(D_NET, "Peer %s has discovery disabled\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ lp->lp_state |= LNET_PEER_NO_DISCOVERY;
+ }
+
+ /*
+ * Update the MULTI_RAIL flag based on the reply. If the peer
+ * was configured with DLC then the setting should match what
+ * DLC put in.
+ */
+ if (pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL) {
+ if (lp->lp_state & LNET_PEER_MULTI_RAIL) {
+ CDEBUG(D_NET, "peer %s(%p) is MR\n",
+ libcfs_nid2str(lp->lp_primary_nid), lp);
+ } else if (lp->lp_state & LNET_PEER_CONFIGURED) {
+ CWARN("Reply says %s is Multi-Rail, DLC says not\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ } else if (lnet_peer_discovery_disabled) {
+ CDEBUG(D_NET,
+ "peer %s(%p) not MR: DD disabled locally\n",
+ libcfs_nid2str(lp->lp_primary_nid), lp);
+ } else if (lp->lp_state & LNET_PEER_NO_DISCOVERY) {
+ CDEBUG(D_NET,
+ "peer %s(%p) not MR: DD disabled remotely\n",
+ libcfs_nid2str(lp->lp_primary_nid), lp);
+ } else {
+ CDEBUG(D_NET, "peer %s(%p) is MR capable\n",
+ libcfs_nid2str(lp->lp_primary_nid), lp);
+ lp->lp_state |= LNET_PEER_MULTI_RAIL;
+ lnet_peer_clr_non_mr_pref_nids(lp);
+ }
+ } else if (lp->lp_state & LNET_PEER_MULTI_RAIL) {
+ if (lp->lp_state & LNET_PEER_CONFIGURED) {
+ CWARN("DLC says %s is Multi-Rail, Reply says not\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ } else {
+ CERROR("Multi-Rail state vanished from %s\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ lp->lp_state &= ~LNET_PEER_MULTI_RAIL;
+ }
+ }
+
+ /*
+ * Make sure we'll allocate the correct size ping buffer when
+ * pinging the peer.
+ */
+ if (lp->lp_data_nnis < pbuf->pb_info.pi_nnis)
+ lp->lp_data_nnis = pbuf->pb_info.pi_nnis;
+
+ /*
+ * Check for truncation of the Reply. Clear PING_SENT and set
+ * PING_FAILED to trigger a retry.
+ */
+ if (pbuf->pb_nnis < pbuf->pb_info.pi_nnis) {
+ if (the_lnet.ln_push_target_nnis < pbuf->pb_info.pi_nnis)
+ the_lnet.ln_push_target_nnis = pbuf->pb_info.pi_nnis;
+ lp->lp_state |= LNET_PEER_PING_FAILED;
+ lp->lp_ping_error = 0;
+ CDEBUG(D_NET, "Truncated Reply from %s (%d nids)\n",
+ libcfs_nid2str(lp->lp_primary_nid),
+ pbuf->pb_info.pi_nnis);
+ goto out;
+ }
+
+ /*
+ * Check the sequence numbers in the reply. These are only
+ * available if the reply came from a Multi-Rail peer.
+ */
+ if (pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL &&
+ pbuf->pb_info.pi_nnis > 1 &&
+ lp->lp_primary_nid == pbuf->pb_info.pi_ni[1].ns_nid) {
+ if (LNET_PING_BUFFER_SEQNO(pbuf) < lp->lp_peer_seqno)
+ CDEBUG(D_NET, "peer %s: seq# got %u have %u. peer rebooted?\n",
+ libcfs_nid2str(lp->lp_primary_nid),
+ LNET_PING_BUFFER_SEQNO(pbuf),
+ lp->lp_peer_seqno);
+
+ lp->lp_peer_seqno = LNET_PING_BUFFER_SEQNO(pbuf);
+ }
+
+ /* We're happy with the state of the data in the buffer. */
+ CDEBUG(D_NET, "peer %s data present %u. state = 0x%x\n",
+ libcfs_nid2str(lp->lp_primary_nid), lp->lp_peer_seqno, lp->lp_state);
+ if (lp->lp_state & LNET_PEER_DATA_PRESENT)
+ lnet_ping_buffer_decref(lp->lp_data);
+ else
+ lp->lp_state |= LNET_PEER_DATA_PRESENT;
+ lnet_ping_buffer_addref(pbuf);
+ lp->lp_data = pbuf;
+out:
+ lp->lp_state &= ~LNET_PEER_PING_SENT;
+ spin_unlock(&lp->lp_lock);
+
+ lnet_net_lock(LNET_LOCK_EX);
+ /*
+ * If this peer is a gateway, call the routing callback to
+ * handle the ping reply
+ */
+ if (lp->lp_rtr_refcount > 0)
+ lnet_router_discovery_ping_reply(lp);
+ lnet_net_unlock(LNET_LOCK_EX);
+}
+
+/*
+ * Send event handling. Only matters for error cases, where we clean
+ * up state on the peer and peer_ni that would otherwise be updated in
+ * the REPLY event handler for a successful Ping, and the ACK event
+ * handler for a successful Push.
+ */
+static int
+lnet_discovery_event_send(struct lnet_peer *lp, struct lnet_event *ev)
+{
+ int rc = 0;
+
+ if (!ev->status)
+ goto out;
+
+ spin_lock(&lp->lp_lock);
+ if (ev->msg_type == LNET_MSG_GET) {
+ lp->lp_state &= ~LNET_PEER_PING_SENT;
+ lp->lp_state |= LNET_PEER_PING_FAILED;
+ lp->lp_ping_error = ev->status;
+ } else { /* ev->msg_type == LNET_MSG_PUT */
+ lp->lp_state &= ~LNET_PEER_PUSH_SENT;
+ lp->lp_state |= LNET_PEER_PUSH_FAILED;
+ lp->lp_push_error = ev->status;
+ }
+ spin_unlock(&lp->lp_lock);
+ rc = LNET_REDISCOVER_PEER;
+out:
+ CDEBUG(D_NET, "%s Send to %s: %d\n",
+ (ev->msg_type == LNET_MSG_GET ? "Ping" : "Push"),
+ libcfs_nid2str(ev->target.nid), rc);
+ return rc;
+}
+
+/*
+ * Unlink event handling. This event is only seen if a call to
+ * LNetMDUnlink() caused the event to be unlinked. If this call was
+ * made after the event was set up in LNetGet() or LNetPut() then we
+ * assume the Ping or Push timed out.
+ */
+static void
+lnet_discovery_event_unlink(struct lnet_peer *lp, struct lnet_event *ev)
+{
+ spin_lock(&lp->lp_lock);
+ /* We've passed through LNetGet() */
+ if (lp->lp_state & LNET_PEER_PING_SENT) {
+ lp->lp_state &= ~LNET_PEER_PING_SENT;
+ lp->lp_state |= LNET_PEER_PING_FAILED;
+ lp->lp_ping_error = -ETIMEDOUT;
+ CDEBUG(D_NET, "Ping Unlink for message to peer %s\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ }
+ /* We've passed through LNetPut() */
+ if (lp->lp_state & LNET_PEER_PUSH_SENT) {
+ lp->lp_state &= ~LNET_PEER_PUSH_SENT;
+ lp->lp_state |= LNET_PEER_PUSH_FAILED;
+ lp->lp_push_error = -ETIMEDOUT;
+ CDEBUG(D_NET, "Push Unlink for message to peer %s\n",
+ libcfs_nid2str(lp->lp_primary_nid));
+ }
+ spin_unlock(&lp->lp_lock);
+}
+
+/*
+ * Event handler for the discovery EQ.
+ *
+ * Called with lnet_res_lock(cpt) held. The cpt is the
+ * lnet_cpt_of_cookie() of the md handle cookie.
+ */
+static void lnet_discovery_event_handler(struct lnet_event *event)
+{
+ struct lnet_peer *lp = event->md.user_ptr;
+ struct lnet_ping_buffer *pbuf;
+ int rc;
+
+ /* discovery needs to take another look */
+ rc = LNET_REDISCOVER_PEER;
+
+ CDEBUG(D_NET, "Received event: %d\n", event->type);
+
+ switch (event->type) {
+ case LNET_EVENT_ACK:
+ lnet_discovery_event_ack(lp, event);
+ break;
+ case LNET_EVENT_REPLY:
+ lnet_discovery_event_reply(lp, event);
+ break;
+ case LNET_EVENT_SEND:
+ /* Only send failure triggers a retry. */
+ rc = lnet_discovery_event_send(lp, event);
+ break;
+ case LNET_EVENT_UNLINK:
+ /* LNetMDUnlink() was called */
+ lnet_discovery_event_unlink(lp, event);
+ break;
+ default:
+ /* Invalid events. */
+ LBUG();
+ }
+ lnet_net_lock(LNET_LOCK_EX);
+ if (event->unlinked) {
+ pbuf = LNET_PING_INFO_TO_BUFFER(event->md.start);
+ lnet_ping_buffer_decref(pbuf);
+ lnet_peer_decref_locked(lp);
+ }
+
+ /* put peer back at end of request queue, if discovery not already
+ * done */
+ if (rc == LNET_REDISCOVER_PEER && !lnet_peer_is_uptodate(lp)) {
+ list_move_tail(&lp->lp_dc_list, &the_lnet.ln_dc_request);
+ wake_up(&the_lnet.ln_dc_waitq);
+ }
+ lnet_net_unlock(LNET_LOCK_EX);
+}
+
+/*
+ * Build a peer from incoming data.
+ *
+ * The NIDs in the incoming data are supposed to be structured as follows:
+ * - loopback
+ * - primary NID
+ * - other NIDs in same net
+ * - NIDs in second net
+ * - NIDs in third net
+ * - ...
+ * This due to the way the list of NIDs in the data is created.
+ *
+ * Note that this function will mark the peer uptodate unless an
+ * ENOMEM is encontered. All other errors are due to a conflict
+ * between the DLC configuration and what discovery sees. We treat DLC
+ * as binding, and therefore set the NIDS_UPTODATE flag to prevent the
+ * peer from becoming stuck in discovery.
+ */
+static int lnet_peer_merge_data(struct lnet_peer *lp,
+ struct lnet_ping_buffer *pbuf)
+{
+ struct lnet_peer_ni *lpni;
+ lnet_nid_t *curnis = NULL;
+ struct lnet_ni_status *addnis = NULL;
+ lnet_nid_t *delnis = NULL;
+ unsigned flags;
+ int ncurnis;
+ int naddnis;
+ int ndelnis;
+ int nnis = 0;
+ int i;
+ int j;
+ int rc;
+
+ flags = LNET_PEER_DISCOVERED;
+ if (pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL)
+ flags |= LNET_PEER_MULTI_RAIL;
+
+ /*
+ * Cache the routing feature for the peer; whether it is enabled
+ * for disabled as reported by the remote peer.
+ */
+ spin_lock(&lp->lp_lock);
+ if (!(pbuf->pb_info.pi_features & LNET_PING_FEAT_RTE_DISABLED))
+ lp->lp_state |= LNET_PEER_ROUTER_ENABLED;
+ else
+ lp->lp_state &= ~LNET_PEER_ROUTER_ENABLED;
+ spin_unlock(&lp->lp_lock);
+
+ nnis = max_t(int, lp->lp_nnis, pbuf->pb_info.pi_nnis);
+ LIBCFS_ALLOC(curnis, nnis * sizeof(*curnis));
+ LIBCFS_ALLOC(addnis, nnis * sizeof(*addnis));
+ LIBCFS_ALLOC(delnis, nnis * sizeof(*delnis));
+ if (!curnis || !addnis || !delnis) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ ncurnis = 0;
+ naddnis = 0;
+ ndelnis = 0;
+
+ /* Construct the list of NIDs present in peer. */
+ lpni = NULL;
+ while ((lpni = lnet_get_next_peer_ni_locked(lp, NULL, lpni)) != NULL)
+ curnis[ncurnis++] = lpni->lpni_nid;
+
+ /*
+ * Check for NIDs in pbuf not present in curnis[].
+ * The loop starts at 1 to skip the loopback NID.
+ */
+ for (i = 1; i < pbuf->pb_info.pi_nnis; i++) {
+ for (j = 0; j < ncurnis; j++)
+ if (pbuf->pb_info.pi_ni[i].ns_nid == curnis[j])
+ break;
+ if (j == ncurnis)
+ addnis[naddnis++] = pbuf->pb_info.pi_ni[i];
+ }
+ /*
+ * Check for NIDs in curnis[] not present in pbuf.
+ * The nested loop starts at 1 to skip the loopback NID.
+ *
+ * But never add the loopback NID to delnis[]: if it is
+ * present in curnis[] then this peer is for this node.
+ */
+ for (i = 0; i < ncurnis; i++) {
+ if (LNET_NETTYP(LNET_NIDNET(curnis[i])) == LOLND)
+ continue;
+ for (j = 1; j < pbuf->pb_info.pi_nnis; j++) {
+ if (curnis[i] == pbuf->pb_info.pi_ni[j].ns_nid) {
+ /*
+ * update the information we cache for the
+ * peer with the latest information we
+ * received
+ */
+ lpni = lnet_find_peer_ni_locked(curnis[i]);
+ if (lpni) {
+ lpni->lpni_ns_status = pbuf->pb_info.pi_ni[j].ns_status;
+ lnet_peer_ni_decref_locked(lpni);
+ }
+ break;
+ }
+ }
+ if (j == pbuf->pb_info.pi_nnis)
+ delnis[ndelnis++] = curnis[i];
+ }
+
+ /*
+ * If we get here and the discovery is disabled then we don't want
+ * to add or delete any NIs. We just updated the ones we have some
+ * information on, and call it a day
+ */
+ rc = 0;
+ if (lnet_is_discovery_disabled(lp))
+ goto out;
+
+ for (i = 0; i < naddnis; i++) {
+ rc = lnet_peer_add_nid(lp, addnis[i].ns_nid, flags);
+ if (rc) {
+ CERROR("Error adding NID %s to peer %s: %d\n",
+ libcfs_nid2str(addnis[i].ns_nid),
+ libcfs_nid2str(lp->lp_primary_nid), rc);
+ if (rc == -ENOMEM)
+ goto out;
+ }
+ lpni = lnet_find_peer_ni_locked(addnis[i].ns_nid);
+ if (lpni) {
+ lpni->lpni_ns_status = addnis[i].ns_status;
+ lnet_peer_ni_decref_locked(lpni);
+ }
+ }
+
+ for (i = 0; i < ndelnis; i++) {
+ /*
+ * for routers it's okay to delete the primary_nid because
+ * the upper layers don't really rely on it. So if we're
+ * being told that the router changed its primary_nid
+ * then it's okay to delete it.
+ */
+ if (lp->lp_rtr_refcount > 0)
+ flags |= LNET_PEER_RTR_NI_FORCE_DEL;
+ rc = lnet_peer_del_nid(lp, delnis[i], flags);
+ if (rc) {
+ CERROR("Error deleting NID %s from peer %s: %d\n",
+ libcfs_nid2str(delnis[i]),
+ libcfs_nid2str(lp->lp_primary_nid), rc);
+ if (rc == -ENOMEM)
+ goto out;
+ }
+ }
+ /*
+ * Errors other than -ENOMEM are due to peers having been
+ * configured with DLC. Ignore these because DLC overrides
+ * Discovery.
+ */
+ rc = 0;
+out:
+ LIBCFS_FREE(curnis, nnis * sizeof(*curnis));
+ LIBCFS_FREE(addnis, nnis * sizeof(*addnis));
+ LIBCFS_FREE(delnis, nnis * sizeof(*delnis));
+ lnet_ping_buffer_decref(pbuf);
+ CDEBUG(D_NET, "peer %s (%p): %d\n", libcfs_nid2str(lp->lp_primary_nid), lp, rc);
+
+ if (rc) {
+ spin_lock(&lp->lp_lock);
+ lp->lp_state &= ~LNET_PEER_NIDS_UPTODATE;
+ lp->lp_state |= LNET_PEER_FORCE_PING;
+ spin_unlock(&lp->lp_lock);
+ }
+ return rc;
+}
+
+/*
+ * The data in pbuf says lp is its primary peer, but the data was
+ * received by a different peer. Try to update lp with the data.
+ */
+static int
+lnet_peer_set_primary_data(struct lnet_peer *lp, struct lnet_ping_buffer *pbuf)
+{
+ struct lnet_handle_md mdh;
+
+ /* Queue lp for discovery, and force it on the request queue. */
+ lnet_net_lock(LNET_LOCK_EX);
+ if (lnet_peer_queue_for_discovery(lp))
+ list_move(&lp->lp_dc_list, &the_lnet.ln_dc_request);
+ lnet_net_unlock(LNET_LOCK_EX);
+
+ LNetInvalidateMDHandle(&mdh);
+
+ /*
+ * Decide whether we can move the peer to the DATA_PRESENT state.
+ *
+ * We replace stale data for a multi-rail peer, repair PING_FAILED
+ * status, and preempt FORCE_PING.
+ *
+ * If after that we have DATA_PRESENT, we merge it into this peer.
+ */
+ spin_lock(&lp->lp_lock);
+ if (lp->lp_state & LNET_PEER_MULTI_RAIL) {
+ if (lp->lp_peer_seqno < LNET_PING_BUFFER_SEQNO(pbuf)) {
+ lp->lp_peer_seqno = LNET_PING_BUFFER_SEQNO(pbuf);
+ } else if (lp->lp_state & LNET_PEER_DATA_PRESENT) {
+ lp->lp_state &= ~LNET_PEER_DATA_PRESENT;
+ lnet_ping_buffer_decref(pbuf);
+ pbuf = lp->lp_data;
+ lp->lp_data = NULL;
+ }
+ }
+ if (lp->lp_state & LNET_PEER_DATA_PRESENT) {
+ lnet_ping_buffer_decref(lp->lp_data);
+ lp->lp_data = NULL;
+ lp->lp_state &= ~LNET_PEER_DATA_PRESENT;
+ }
+ if (lp->lp_state & LNET_PEER_PING_FAILED) {
+ mdh = lp->lp_ping_mdh;
+ LNetInvalidateMDHandle(&lp->lp_ping_mdh);
+ lp->lp_state &= ~LNET_PEER_PING_FAILED;
+ lp->lp_ping_error = 0;
+ }
+ if (lp->lp_state & LNET_PEER_FORCE_PING)
+ lp->lp_state &= ~LNET_PEER_FORCE_PING;
+ lp->lp_state |= LNET_PEER_NIDS_UPTODATE;
+ spin_unlock(&lp->lp_lock);
+
+ if (!LNetMDHandleIsInvalid(mdh))
+ LNetMDUnlink(mdh);
+
+ if (pbuf)
+ return lnet_peer_merge_data(lp, pbuf);
+
+ CDEBUG(D_NET, "peer %s\n", libcfs_nid2str(lp->lp_primary_nid));
+ return 0;
+}
+
+static bool lnet_is_nid_in_ping_info(lnet_nid_t nid, struct lnet_ping_info *pinfo)
+{
+ int i;
+
+ for (i = 0; i < pinfo->pi_nnis; i++) {
+ if (pinfo->pi_ni[i].ns_nid == nid)
+ return true;
+ }
+
+ return false;
+}
+
+/*
+ * Update a peer using the data received.
+ */
+static int lnet_peer_data_present(struct lnet_peer *lp)
+__must_hold(&lp->lp_lock)
+{
+ struct lnet_ping_buffer *pbuf;
+ struct lnet_peer_ni *lpni;
+ lnet_nid_t nid = LNET_NID_ANY;
+ unsigned flags;
+ int rc = 0;
+
+ pbuf = lp->lp_data;
+ lp->lp_data = NULL;
+ lp->lp_state &= ~LNET_PEER_DATA_PRESENT;
+ lp->lp_state |= LNET_PEER_NIDS_UPTODATE;
+ spin_unlock(&lp->lp_lock);
+
+ /*
+ * Modifications of peer structures are done while holding the
+ * ln_api_mutex. A global lock is required because we may be
+ * modifying multiple peer structures, and a mutex greatly
+ * simplifies memory management.
+ *
+ * The actual changes to the data structures must also protect
+ * against concurrent lookups, for which the lnet_net_lock in
+ * LNET_LOCK_EX mode is used.
+ */
+ mutex_lock(&the_lnet.ln_api_mutex);
+ if (the_lnet.ln_state != LNET_STATE_RUNNING) {
+ rc = -ESHUTDOWN;
+ goto out;
+ }
+
+ /*
+ * If this peer is not on the peer list then it is being torn
+ * down, and our reference count may be all that is keeping it
+ * alive. Don't do any work on it.
+ */
+ if (list_empty(&lp->lp_peer_list))
+ goto out;
+
+ flags = LNET_PEER_DISCOVERED;
+ if (pbuf->pb_info.pi_features & LNET_PING_FEAT_MULTI_RAIL)
+ flags |= LNET_PEER_MULTI_RAIL;
+
+ /*
+ * Check whether the primary NID in the message matches the
+ * primary NID of the peer. If it does, update the peer, if
+ * it it does not, check whether there is already a peer with
+ * that primary NID. If no such peer exists, try to update
+ * the primary NID of the current peer (allowed if it was
+ * created due to message traffic) and complete the update.
+ * If the peer did exist, hand off the data to it.
+ *
+ * The peer for the loopback interface is a special case: this
+ * is the peer for the local node, and we want to set its
+ * primary NID to the correct value here. Moreover, this peer
+ * can show up with only the loopback NID in the ping buffer.
+ */
+ if (pbuf->pb_info.pi_nnis <= 1)
+ goto out;
+ nid = pbuf->pb_info.pi_ni[1].ns_nid;
+ if (LNET_NETTYP(LNET_NIDNET(lp->lp_primary_nid)) == LOLND) {
+ rc = lnet_peer_set_primary_nid(lp, nid, flags);
+ if (!rc)
+ rc = lnet_peer_merge_data(lp, pbuf);
+ /*
+ * if the primary nid of the peer is present in the ping info returned
+ * from the peer, but it's not the local primary peer we have
+ * cached and discovery is disabled, then we don't want to update
+ * our local peer info, by adding or removing NIDs, we just want
+ * to update the status of the nids that we currently have
+ * recorded in that peer.
+ */
+ } else if (lp->lp_primary_nid == nid ||
+ (lnet_is_nid_in_ping_info(lp->lp_primary_nid, &pbuf->pb_info) &&
+ lnet_is_discovery_disabled(lp))) {
+ rc = lnet_peer_merge_data(lp, pbuf);
+ } else {
+ lpni = lnet_find_peer_ni_locked(nid);
+ if (!lpni) {
+ rc = lnet_peer_set_primary_nid(lp, nid, flags);
+ if (rc) {
+ CERROR("Primary NID error %s versus %s: %d\n",
+ libcfs_nid2str(lp->lp_primary_nid),
+ libcfs_nid2str(nid), rc);
+ } else {
+ rc = lnet_peer_merge_data(lp, pbuf);
+ }
+ } else {
+ struct lnet_peer *new_lp;
+ new_lp = lpni->lpni_peer_net->lpn_peer;
+ /*
+ * if lp has discovery/MR enabled that means new_lp
+ * should have discovery/MR enabled as well, since
+ * it's the same peer, which we're about to merge
+ */
+ if (!(lp->lp_state & LNET_PEER_NO_DISCOVERY))
+ new_lp->lp_state &= ~LNET_PEER_NO_DISCOVERY;
+ if (lp->lp_state & LNET_PEER_MULTI_RAIL)
+ new_lp->lp_state |= LNET_PEER_MULTI_RAIL;
+
+ rc = lnet_peer_set_primary_data(new_lp, pbuf);
+ lnet_consolidate_routes_locked(lp, new_lp);
+ lnet_peer_ni_decref_locked(lpni);
+ }
+ }
+out:
+ CDEBUG(D_NET, "peer %s(%p): %d. state = 0x%x\n", libcfs_nid2str(lp->lp_primary_nid), lp, rc,
+ lp->lp_state);
+ mutex_unlock(&the_lnet.ln_api_mutex);
+
+ spin_lock(&lp->lp_lock);
+ /* Tell discovery to re-check the peer immediately. */
+ if (!rc)
+ rc = LNET_REDISCOVER_PEER;
+ return rc;
+}
+
+/*
+ * A ping failed. Clear the PING_FAILED state and set the
+ * FORCE_PING state, to ensure a retry even if discovery is
+ * disabled. This avoids being left with incorrect state.
+ */
+static int lnet_peer_ping_failed(struct lnet_peer *lp)
+__must_hold(&lp->lp_lock)
+{
+ struct lnet_handle_md mdh;
+ int rc;
+
+ mdh = lp->lp_ping_mdh;
+ LNetInvalidateMDHandle(&lp->lp_ping_mdh);
+ lp->lp_state &= ~LNET_PEER_PING_FAILED;
+ lp->lp_state |= LNET_PEER_FORCE_PING;
+ rc = lp->lp_ping_error;
+ lp->lp_ping_error = 0;
+ spin_unlock(&lp->lp_lock);
+
+ if (!LNetMDHandleIsInvalid(mdh))
+ LNetMDUnlink(mdh);
+
+ CDEBUG(D_NET, "peer %s:%d\n",
+ libcfs_nid2str(lp->lp_primary_nid), rc);
+
+ spin_lock(&lp->lp_lock);
+ return rc ? rc : LNET_REDISCOVER_PEER;
+}
+
+/*
+ * Select NID to send a Ping or Push to.
+ */
+static lnet_nid_t lnet_peer_select_nid(struct lnet_peer *lp)
+{
+ struct lnet_peer_ni *lpni;
+
+ /* Look for a direct-connected NID for this peer. */
+ lpni = NULL;
+ while ((lpni = lnet_get_next_peer_ni_locked(lp, NULL, lpni)) != NULL) {
+ if (!lnet_get_net_locked(lpni->lpni_peer_net->lpn_net_id))
+ continue;
+ break;
+ }
+ if (lpni)
+ return lpni->lpni_nid;
+
+ /* Look for a routed-connected NID for this peer. */
+ lpni = NULL;
+ while ((lpni = lnet_get_next_peer_ni_locked(lp, NULL, lpni)) != NULL) {
+ if (!lnet_find_rnet_locked(lpni->lpni_peer_net->lpn_net_id))
+ continue;
+ break;
+ }
+ if (lpni)
+ return lpni->lpni_nid;
+
+ return LNET_NID_ANY;
+}
+
+/* Active side of ping. */
+static int lnet_peer_send_ping(struct lnet_peer *lp)
+__must_hold(&lp->lp_lock)
+{
+ lnet_nid_t pnid;
+ int nnis;
+ int rc;
+ int cpt;
+
+ lp->lp_state |= LNET_PEER_PING_SENT;
+ lp->lp_state &= ~LNET_PEER_FORCE_PING;
+ spin_unlock(&lp->lp_lock);
+
+ cpt = lnet_net_lock_current();
+ /* Refcount for MD. */
+ lnet_peer_addref_locked(lp);
+ pnid = lnet_peer_select_nid(lp);
+ lnet_net_unlock(cpt);
+
+ nnis = max(lp->lp_data_nnis, LNET_INTERFACES_MIN);
+
+ rc = lnet_send_ping(pnid, &lp->lp_ping_mdh, nnis, lp,
+ the_lnet.ln_dc_eqh, false);
+
+ /*
+ * if LNetMDBind in lnet_send_ping fails we need to decrement the
+ * refcount on the peer, otherwise LNetMDUnlink will be called
+ * which will eventually do that.
+ */
+ if (rc > 0) {
+ lnet_net_lock(cpt);
+ lnet_peer_decref_locked(lp);
+ lnet_net_unlock(cpt);
+ rc = -rc; /* change the rc to negative value */
+ goto fail_error;
+ } else if (rc < 0) {
+ goto fail_error;
+ }
+
+ CDEBUG(D_NET, "peer %s\n", libcfs_nid2str(lp->lp_primary_nid));
+
+ spin_lock(&lp->lp_lock);
+ return 0;
+
+fail_error:
+ CDEBUG(D_NET, "peer %s: %d\n", libcfs_nid2str(lp->lp_primary_nid), rc);
+ /*
+ * The errors that get us here are considered hard errors and
+ * cause Discovery to terminate. So we clear PING_SENT, but do
+ * not set either PING_FAILED or FORCE_PING. In fact we need
+ * to clear PING_FAILED, because the unlink event handler will
+ * have set it if we called LNetMDUnlink() above.
+ */
+ spin_lock(&lp->lp_lock);
+ lp->lp_state &= ~(LNET_PEER_PING_SENT | LNET_PEER_PING_FAILED);
+ return rc;
+}
+
+/*
+ * This function exists because you cannot call LNetMDUnlink() from an
+ * event handler.
+ */
+static int lnet_peer_push_failed(struct lnet_peer *lp)
+__must_hold(&lp->lp_lock)
+{
+ struct lnet_handle_md mdh;
+ int rc;
+
+ mdh = lp->lp_push_mdh;
+ LNetInvalidateMDHandle(&lp->lp_push_mdh);
+ lp->lp_state &= ~LNET_PEER_PUSH_FAILED;
+ rc = lp->lp_push_error;
+ lp->lp_push_error = 0;
+ spin_unlock(&lp->lp_lock);
+
+ if (!LNetMDHandleIsInvalid(mdh))
+ LNetMDUnlink(mdh);
+
+ CDEBUG(D_NET, "peer %s\n", libcfs_nid2str(lp->lp_primary_nid));
+ spin_lock(&lp->lp_lock);
+ return rc ? rc : LNET_REDISCOVER_PEER;
+}
+
+/* Active side of push. */
+static int lnet_peer_send_push(struct lnet_peer *lp)
+__must_hold(&lp->lp_lock)
+{
+ struct lnet_ping_buffer *pbuf;
+ struct lnet_process_id id;
+ struct lnet_md md;
+ int cpt;
+ int rc;
+
+ /* Don't push to a non-multi-rail peer. */
+ if (!(lp->lp_state & LNET_PEER_MULTI_RAIL)) {
+ lp->lp_state &= ~LNET_PEER_FORCE_PUSH;
+ return 0;
+ }
+
+ lp->lp_state |= LNET_PEER_PUSH_SENT;
+ lp->lp_state &= ~LNET_PEER_FORCE_PUSH;
+ spin_unlock(&lp->lp_lock);
+
+ cpt = lnet_net_lock_current();
+ pbuf = the_lnet.ln_ping_target;
+ lnet_ping_buffer_addref(pbuf);
+ lnet_net_unlock(cpt);
+
+ /* Push source MD */
+ md.start = &pbuf->pb_info;
+ md.length = LNET_PING_INFO_SIZE(pbuf->pb_nnis);
+ md.threshold = 2; /* Put/Ack */
+ md.max_size = 0;
+ md.options = 0;
+ md.eq_handle = the_lnet.ln_dc_eqh;
+ md.user_ptr = lp;
+
+ rc = LNetMDBind(md, LNET_UNLINK, &lp->lp_push_mdh);
+ if (rc) {
+ lnet_ping_buffer_decref(pbuf);
+ CERROR("Can't bind push source MD: %d\n", rc);
+ goto fail_error;
+ }
+ cpt = lnet_net_lock_current();
+ /* Refcount for MD. */
+ lnet_peer_addref_locked(lp);
+ id.pid = LNET_PID_LUSTRE;
+ id.nid = lnet_peer_select_nid(lp);
+ lnet_net_unlock(cpt);
+
+ if (id.nid == LNET_NID_ANY) {
+ rc = -EHOSTUNREACH;
+ goto fail_unlink;
+ }
+
+ rc = LNetPut(LNET_NID_ANY, lp->lp_push_mdh,
+ LNET_ACK_REQ, id, LNET_RESERVED_PORTAL,
+ LNET_PROTO_PING_MATCHBITS, 0, 0);
+
+ if (rc)
+ goto fail_unlink;
+
+ CDEBUG(D_NET, "peer %s\n", libcfs_nid2str(lp->lp_primary_nid));
+
+ spin_lock(&lp->lp_lock);
+ return 0;
+
+fail_unlink:
+ LNetMDUnlink(lp->lp_push_mdh);
+ LNetInvalidateMDHandle(&lp->lp_push_mdh);
+fail_error:
+ CDEBUG(D_NET, "peer %s(%p): %d\n", libcfs_nid2str(lp->lp_primary_nid), lp, rc);
+ /*
+ * The errors that get us here are considered hard errors and
+ * cause Discovery to terminate. So we clear PUSH_SENT, but do
+ * not set PUSH_FAILED. In fact we need to clear PUSH_FAILED,
+ * because the unlink event handler will have set it if we
+ * called LNetMDUnlink() above.
+ */
+ spin_lock(&lp->lp_lock);
+ lp->lp_state &= ~(LNET_PEER_PUSH_SENT | LNET_PEER_PUSH_FAILED);
+ return rc;
+}
+
+/*
+ * An unrecoverable error was encountered during discovery.
+ * Set error status in peer and abort discovery.
+ */
+static void lnet_peer_discovery_error(struct lnet_peer *lp, int error)
+{
+ CDEBUG(D_NET, "Discovery error %s: %d\n",
+ libcfs_nid2str(lp->lp_primary_nid), error);
+
+ spin_lock(&lp->lp_lock);
+ lp->lp_dc_error = error;
+ lp->lp_state &= ~LNET_PEER_DISCOVERING;
+ lp->lp_state |= LNET_PEER_REDISCOVER;
+ spin_unlock(&lp->lp_lock);
+}
+
+/*
+ * Mark the peer as discovered.
+ */
+static int lnet_peer_discovered(struct lnet_peer *lp)
+__must_hold(&lp->lp_lock)
+{
+ lp->lp_state |= LNET_PEER_DISCOVERED;
+ lp->lp_state &= ~(LNET_PEER_DISCOVERING |
+ LNET_PEER_REDISCOVER);
+
+ CDEBUG(D_NET, "peer %s\n", libcfs_nid2str(lp->lp_primary_nid));
+
+ return 0;
+}
+
+
+/*
+ * Discovering this peer is taking too long. Cancel any Ping or Push
+ * that discovery is waiting on by unlinking the relevant MDs. The
+ * lnet_discovery_event_handler() will proceed from here and complete
+ * the cleanup.
+ */
+static void lnet_peer_cancel_discovery(struct lnet_peer *lp)
+{
+ struct lnet_handle_md ping_mdh;
+ struct lnet_handle_md push_mdh;
+
+ LNetInvalidateMDHandle(&ping_mdh);
+ LNetInvalidateMDHandle(&push_mdh);
+
+ spin_lock(&lp->lp_lock);
+ if (lp->lp_state & LNET_PEER_PING_SENT) {
+ ping_mdh = lp->lp_ping_mdh;
+ LNetInvalidateMDHandle(&lp->lp_ping_mdh);
+ }
+ if (lp->lp_state & LNET_PEER_PUSH_SENT) {
+ push_mdh = lp->lp_push_mdh;
+ LNetInvalidateMDHandle(&lp->lp_push_mdh);
+ }
+ spin_unlock(&lp->lp_lock);
+
+ if (!LNetMDHandleIsInvalid(ping_mdh))
+ LNetMDUnlink(ping_mdh);
+ if (!LNetMDHandleIsInvalid(push_mdh))
+ LNetMDUnlink(push_mdh);
+}
+
+/*
+ * Wait for work to be queued or some other change that must be
+ * attended to. Returns non-zero if the discovery thread should shut
+ * down.
+ */
+static int lnet_peer_discovery_wait_for_work(void)
+{
+ int cpt;
+ int rc = 0;
+
+ DEFINE_WAIT(wait);
+
+ cpt = lnet_net_lock_current();
+ for (;;) {
+ prepare_to_wait(&the_lnet.ln_dc_waitq, &wait,
+ TASK_INTERRUPTIBLE);
+ if (the_lnet.ln_dc_state == LNET_DC_STATE_STOPPING)
+ break;
+ if (lnet_push_target_resize_needed())
+ break;
+ if (!list_empty(&the_lnet.ln_dc_request))
+ break;
+ if (!list_empty(&the_lnet.ln_msg_resend))
+ break;
+ lnet_net_unlock(cpt);
+
+ /*
+ * wakeup max every second to check if there are peers that
+ * have been stuck on the working queue for greater than
+ * the peer timeout.
+ */
+ schedule_timeout(cfs_time_seconds(1));
+ finish_wait(&the_lnet.ln_dc_waitq, &wait);
+ cpt = lnet_net_lock_current();
+ }
+ finish_wait(&the_lnet.ln_dc_waitq, &wait);
+
+ if (the_lnet.ln_dc_state == LNET_DC_STATE_STOPPING)
+ rc = -ESHUTDOWN;
+
+ lnet_net_unlock(cpt);
+
+ CDEBUG(D_NET, "woken: %d\n", rc);
+
+ return rc;
+}
+
+/*
+ * Messages that were pending on a destroyed peer will be put on a global
+ * resend list. The message resend list will be checked by
+ * the discovery thread when it wakes up, and will resend messages. These
+ * messages can still be sendable in the case the lpni which was the initial
+ * cause of the message re-queue was transfered to another peer.
+ *
+ * It is possible that LNet could be shutdown while we're iterating
+ * through the list. lnet_shudown_lndnets() will attempt to access the
+ * resend list, but will have to wait until the spinlock is released, by
+ * which time there shouldn't be any more messages on the resend list.
+ * During shutdown lnet_send() will fail and lnet_finalize() will be called
+ * for the messages so they can be released. The other case is that
+ * lnet_shudown_lndnets() can finalize all the messages before this
+ * function can visit the resend list, in which case this function will be
+ * a no-op.
+ */
+static void lnet_resend_msgs(void)
+{
+ struct lnet_msg *msg, *tmp;
+ LIST_HEAD(resend);
+ int rc;
+
+ spin_lock(&the_lnet.ln_msg_resend_lock);
+ list_splice(&the_lnet.ln_msg_resend, &resend);
+ spin_unlock(&the_lnet.ln_msg_resend_lock);
+
+ list_for_each_entry_safe(msg, tmp, &resend, msg_list) {
+ list_del_init(&msg->msg_list);
+ rc = lnet_send(msg->msg_src_nid_param, msg,
+ msg->msg_rtr_nid_param);
+ if (rc < 0) {
+ CNETERR("Error sending %s to %s: %d\n",
+ lnet_msgtyp2str(msg->msg_type),
+ libcfs_id2str(msg->msg_target), rc);
+ lnet_finalize(msg, rc);
+ }
+ }
+}
+
+/* The discovery thread. */
+static int lnet_peer_discovery(void *arg)
+{
+ struct lnet_peer *lp;
+ int rc;
+
+ wait_for_completion(&the_lnet.ln_started);
+
+ CDEBUG(D_NET, "started\n");
+ cfs_block_allsigs();
+
+ for (;;) {
+ if (lnet_peer_discovery_wait_for_work())
+ break;
+
+ lnet_resend_msgs();
+
+ if (lnet_push_target_resize_needed())
+ lnet_push_target_resize();
+
+ lnet_net_lock(LNET_LOCK_EX);
+ if (the_lnet.ln_dc_state == LNET_DC_STATE_STOPPING)
+ break;
+
+ /*
+ * Process all incoming discovery work requests. When
+ * discovery must wait on a peer to change state, it
+ * is added to the tail of the ln_dc_working queue. A
+ * timestamp keeps track of when the peer was added,
+ * so we can time out discovery requests that take too
+ * long.
+ */
+ while (!list_empty(&the_lnet.ln_dc_request)) {
+ lp = list_first_entry(&the_lnet.ln_dc_request,
+ struct lnet_peer, lp_dc_list);
+ list_move(&lp->lp_dc_list, &the_lnet.ln_dc_working);
+ /*
+ * set the time the peer was put on the dc_working
+ * queue. It shouldn't remain on the queue
+ * forever, in case the GET message (for ping)
+ * doesn't get a REPLY or the PUT message (for
+ * push) doesn't get an ACK.
+ */
+ lp->lp_last_queued = ktime_get_real_seconds();
+ lnet_net_unlock(LNET_LOCK_EX);
+
+ /*
+ * Select an action depending on the state of
+ * the peer and whether discovery is disabled.
+ * The check whether discovery is disabled is
+ * done after the code that handles processing
+ * for arrived data, cleanup for failures, and
+ * forcing a Ping or Push.
+ */
+ spin_lock(&lp->lp_lock);
+ CDEBUG(D_NET, "peer %s(%p) state %#x\n",
+ libcfs_nid2str(lp->lp_primary_nid), lp,
+ lp->lp_state);
+ if (lp->lp_state & LNET_PEER_DATA_PRESENT)
+ rc = lnet_peer_data_present(lp);
+ else if (lp->lp_state & LNET_PEER_PING_FAILED)
+ rc = lnet_peer_ping_failed(lp);
+ else if (lp->lp_state & LNET_PEER_PUSH_FAILED)
+ rc = lnet_peer_push_failed(lp);
+ else if (lp->lp_state & LNET_PEER_FORCE_PING)
+ rc = lnet_peer_send_ping(lp);
+ else if (lp->lp_state & LNET_PEER_FORCE_PUSH)
+ rc = lnet_peer_send_push(lp);
+ else if (!(lp->lp_state & LNET_PEER_NIDS_UPTODATE))
+ rc = lnet_peer_send_ping(lp);
+ else if (lnet_peer_needs_push(lp))
+ rc = lnet_peer_send_push(lp);
+ else
+ rc = lnet_peer_discovered(lp);
+ CDEBUG(D_NET, "peer %s(%p) state %#x rc %d\n",
+ libcfs_nid2str(lp->lp_primary_nid), lp,
+ lp->lp_state, rc);
+ spin_unlock(&lp->lp_lock);
+
+ lnet_net_lock(LNET_LOCK_EX);
+ if (rc == LNET_REDISCOVER_PEER) {
+ list_move(&lp->lp_dc_list,
+ &the_lnet.ln_dc_request);
+ } else if (rc) {
+ lnet_peer_discovery_error(lp, rc);
+ }
+ if (!(lp->lp_state & LNET_PEER_DISCOVERING))
+ lnet_peer_discovery_complete(lp);
+ if (the_lnet.ln_dc_state == LNET_DC_STATE_STOPPING)
+ break;
+ }
+
+ lnet_net_unlock(LNET_LOCK_EX);
+ }
+
+ CDEBUG(D_NET, "stopping\n");
+ /*
+ * Clean up before telling lnet_peer_discovery_stop() that
+ * we're done. Use wake_up() below to somewhat reduce the
+ * size of the thundering herd if there are multiple threads
+ * waiting on discovery of a single peer.
+ */
+
+ /* Queue cleanup 1: stop all pending pings and pushes. */
+ lnet_net_lock(LNET_LOCK_EX);
+ while (!list_empty(&the_lnet.ln_dc_working)) {
+ lp = list_first_entry(&the_lnet.ln_dc_working,
+ struct lnet_peer, lp_dc_list);
+ list_move(&lp->lp_dc_list, &the_lnet.ln_dc_expired);
+ lnet_net_unlock(LNET_LOCK_EX);
+ lnet_peer_cancel_discovery(lp);
+ lnet_net_lock(LNET_LOCK_EX);
+ }
+ lnet_net_unlock(LNET_LOCK_EX);
+
+ /* Queue cleanup 2: wait for the expired queue to clear. */
+ while (!list_empty(&the_lnet.ln_dc_expired))
+ schedule_timeout_uninterruptible(cfs_time_seconds(1));
+
+ /* Queue cleanup 3: clear the request queue. */
+ lnet_net_lock(LNET_LOCK_EX);
+ while (!list_empty(&the_lnet.ln_dc_request)) {
+ lp = list_first_entry(&the_lnet.ln_dc_request,
+ struct lnet_peer, lp_dc_list);
+ lnet_peer_discovery_error(lp, -ESHUTDOWN);
+ lnet_peer_discovery_complete(lp);
+ }
+ lnet_net_unlock(LNET_LOCK_EX);
+
+ LNetEQFree(the_lnet.ln_dc_eqh);
+ LNetInvalidateEQHandle(&the_lnet.ln_dc_eqh);
+
+ the_lnet.ln_dc_state = LNET_DC_STATE_SHUTDOWN;
+ wake_up(&the_lnet.ln_dc_waitq);
+
+ CDEBUG(D_NET, "stopped\n");
+
+ return 0;
+}
+
+/* ln_api_mutex is held on entry. */
+int lnet_peer_discovery_start(void)
+{
+ struct task_struct *task;
+ int rc;
+
+ if (the_lnet.ln_dc_state != LNET_DC_STATE_SHUTDOWN)
+ return -EALREADY;
+
+ rc = LNetEQAlloc(0, lnet_discovery_event_handler, &the_lnet.ln_dc_eqh);
+ if (rc != 0) {
+ CERROR("Can't allocate discovery EQ: %d\n", rc);
+ return rc;
+ }
+
+ the_lnet.ln_dc_state = LNET_DC_STATE_RUNNING;
+ task = kthread_run(lnet_peer_discovery, NULL, "lnet_discovery");
+ if (IS_ERR(task)) {
+ rc = PTR_ERR(task);
+ CERROR("Can't start peer discovery thread: %d\n", rc);
+
+ LNetEQFree(the_lnet.ln_dc_eqh);
+ LNetInvalidateEQHandle(&the_lnet.ln_dc_eqh);
+
+ the_lnet.ln_dc_state = LNET_DC_STATE_SHUTDOWN;
+ }
+
+ CDEBUG(D_NET, "discovery start: %d\n", rc);
+
+ return rc;
+}
+
+/* ln_api_mutex is held on entry. */
+void lnet_peer_discovery_stop(void)
+{
+ if (the_lnet.ln_dc_state == LNET_DC_STATE_SHUTDOWN)
+ return;
+
+ LASSERT(the_lnet.ln_dc_state == LNET_DC_STATE_RUNNING);
+ the_lnet.ln_dc_state = LNET_DC_STATE_STOPPING;
+
+ /* In the LNetNIInit() path we may be stopping discovery before it
+ * entered its work loop
+ */
+ if (!completion_done(&the_lnet.ln_started))
+ complete(&the_lnet.ln_started);
+ else
+ wake_up(&the_lnet.ln_dc_waitq);
+
+ wait_event(the_lnet.ln_dc_waitq,
+ the_lnet.ln_dc_state == LNET_DC_STATE_SHUTDOWN);
+
+ LASSERT(list_empty(&the_lnet.ln_dc_request));
+ LASSERT(list_empty(&the_lnet.ln_dc_working));
+ LASSERT(list_empty(&the_lnet.ln_dc_expired));
+
+ CDEBUG(D_NET, "discovery stopped\n");
+}
+
+/* Debugging */
+
+void
+lnet_debug_peer(lnet_nid_t nid)
+{
+ char *aliveness = "NA";
+ struct lnet_peer_ni *lp;
+ int cpt;
+
+ cpt = lnet_cpt_of_nid(nid, NULL);
+ lnet_net_lock(cpt);
+
+ lp = lnet_nid2peerni_locked(nid, LNET_NID_ANY, cpt);
+ if (IS_ERR(lp)) {
+ lnet_net_unlock(cpt);
+ CDEBUG(D_WARNING, "No peer %s\n", libcfs_nid2str(nid));
+ return;
+ }
+
+ if (lnet_isrouter(lp) || lnet_peer_aliveness_enabled(lp))
+ aliveness = (lnet_is_peer_ni_alive(lp)) ? "up" : "down";
+
+ CDEBUG(D_WARNING, "%-24s %4d %5s %5d %5d %5d %5d %5d %ld\n",
+ libcfs_nid2str(lp->lpni_nid), atomic_read(&lp->lpni_refcount),
+ aliveness, lp->lpni_net->net_tunables.lct_peer_tx_credits,
+ lp->lpni_rtrcredits, lp->lpni_minrtrcredits,
+ lp->lpni_txcredits, lp->lpni_mintxcredits, lp->lpni_txqnob);
+
+ lnet_peer_ni_decref_locked(lp);
+
+ lnet_net_unlock(cpt);
+}
+
+/* Gathering information for userspace. */
+
+int lnet_get_peer_ni_info(__u32 peer_index, __u64 *nid,
+ char aliveness[LNET_MAX_STR_LEN],
+ __u32 *cpt_iter, __u32 *refcount,
+ __u32 *ni_peer_tx_credits, __u32 *peer_tx_credits,
+ __u32 *peer_rtr_credits, __u32 *peer_min_rtr_credits,
+ __u32 *peer_tx_qnob)