Merge branch 'smc-fixes'

Karsten Graul says:

====================
net/smc: fixes 2020-09-03

Please apply the following patch series for smc to netdev's net tree.

Patch 1 fixes the toleration of older SMC implementations. Patch 2
takes care of a problem that happens when SMCR is used after SMCD
initialization failed. Patch 3 fixes a problem with freed send buffers,
and patch 4 corrects refcounting when SMC terminates due to device
removal.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_close.c

@@ -116,7 +116,6 @@ static void smc_close_cancel_work(struct smc_sock *smc)
 	cancel_work_sync(&smc->conn.close_work);
 	cancel_delayed_work_sync(&smc->conn.tx_work);
 	lock_sock(sk);
-	sk->sk_state = SMC_CLOSED;
 }
 
 /* terminate smc socket abnormally - active abort
@@ -134,22 +133,22 @@ void smc_close_active_abort(struct smc_sock *smc)
 	}
 	switch (sk->sk_state) {
 	case SMC_ACTIVE:
-		sk->sk_state = SMC_PEERABORTWAIT;
-		smc_close_cancel_work(smc);
-		sk->sk_state = SMC_CLOSED;
-		sock_put(sk); /* passive closing */
-		break;
 	case SMC_APPCLOSEWAIT1:
 	case SMC_APPCLOSEWAIT2:
+		sk->sk_state = SMC_PEERABORTWAIT;
 		smc_close_cancel_work(smc);
+		if (sk->sk_state != SMC_PEERABORTWAIT)
+			break;
 		sk->sk_state = SMC_CLOSED;
-		sock_put(sk); /* postponed passive closing */
+		sock_put(sk); /* (postponed) passive closing */
 		break;
 	case SMC_PEERCLOSEWAIT1:
 	case SMC_PEERCLOSEWAIT2:
 	case SMC_PEERFINCLOSEWAIT:
 		sk->sk_state = SMC_PEERABORTWAIT;
 		smc_close_cancel_work(smc);
+		if (sk->sk_state != SMC_PEERABORTWAIT)
+			break;
 		sk->sk_state = SMC_CLOSED;
 		smc_conn_free(&smc->conn);
 		release_clcsock = true;
@@ -159,6 +158,8 @@ void smc_close_active_abort(struct smc_sock *smc)
 	case SMC_APPFINCLOSEWAIT:
 		sk->sk_state = SMC_PEERABORTWAIT;
 		smc_close_cancel_work(smc);
+		if (sk->sk_state != SMC_PEERABORTWAIT)
+			break;
 		sk->sk_state = SMC_CLOSED;
 		smc_conn_free(&smc->conn);
 		release_clcsock = true;

net/smc/smc_core.c

@@ -1356,6 +1356,8 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
 	if (ini->is_smcd) {
 		conn->rx_off = sizeof(struct smcd_cdc_msg);
 		smcd_cdc_rx_init(conn); /* init tasklet for this conn */
+	} else {
+		conn->rx_off = 0;
 	}
 #ifndef KERNEL_HAS_ATOMIC64
 	spin_lock_init(&conn->acurs_lock);
@@ -1777,6 +1779,7 @@ int smc_buf_create(struct smc_sock *smc, bool is_smcd)
 		list_del(&smc->conn.sndbuf_desc->list);
 		mutex_unlock(&smc->conn.lgr->sndbufs_lock);
 		smc_buf_free(smc->conn.lgr, false, smc->conn.sndbuf_desc);
+		smc->conn.sndbuf_desc = NULL;
 	}
 	return rc;
 }

net/smc/smc_llc.c

@@ -841,6 +841,9 @@ int smc_llc_cli_add_link(struct smc_link *link, struct smc_llc_qentry *qentry)
 	struct smc_init_info ini;
 	int lnk_idx, rc = 0;
 
+	if (!llc->qp_mtu)
+		goto out_reject;
+
 	ini.vlan_id = lgr->vlan_id;
 	smc_pnet_find_alt_roce(lgr, &ini, link->smcibdev);
 	if (!memcmp(llc->sender_gid, link->peer_gid, SMC_GID_SIZE) &&
@@ -917,10 +920,20 @@ static void smc_llc_cli_add_link_invite(struct smc_link *link,
 	kfree(qentry);
 }
 
+static bool smc_llc_is_empty_llc_message(union smc_llc_msg *llc)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(llc->raw.data); i++)
+		if (llc->raw.data[i])
+			return false;
+	return true;
+}
+
 static bool smc_llc_is_local_add_link(union smc_llc_msg *llc)
 {
 	if (llc->raw.hdr.common.type == SMC_LLC_ADD_LINK &&
-	    !llc->add_link.qp_mtu && !llc->add_link.link_num)
+	    smc_llc_is_empty_llc_message(llc))
 		return true;
 	return false;
 }