Merge branch 'smc-fixes'

Guvenc Gulce says:

====================
net/smc: fixes 2021-08-09

please apply the following patch series for smc to netdev's net tree.
One patch fixes invalid connection counting for links and the other
one fixes an access to an already cleared link.
====================

Signed-off-by: David S. Miller <[e-mail]>

net/smc/af_smc.c

···
 			reason_code = SMC_CLC_DECL_NOSRVLINK;
 			goto connect_abort;
 		}
-		smc->conn.lnk = link;
+		smc_switch_link_and_count(&smc->conn, link);
 	}
 
 	/* create send buffer and rmb */

net/smc/smc_core.c

···
 	return rc;
 }
 
-static void smc_switch_link_and_count(struct smc_connection *conn,
-				      struct smc_link *to_lnk)
+void smc_switch_link_and_count(struct smc_connection *conn,
+			       struct smc_link *to_lnk)
 {
 	atomic_dec(&conn->lnk->conn_cnt);
 	conn->lnk = to_lnk;

net/smc/smc_core.h

···
 	unsigned long		*wr_tx_mask;	/* bit mask of used indexes */
 	u32			wr_tx_cnt;	/* number of WR send buffers */
 	wait_queue_head_t	wr_tx_wait;	/* wait for free WR send buf */
+	atomic_t		wr_tx_refcnt;	/* tx refs to link */
 
 	struct smc_wr_buf	*wr_rx_bufs;	/* WR recv payload buffers */
 	struct ib_recv_wr	*wr_rx_ibs;	/* WR recv meta data */
···
 
 	struct ib_reg_wr	wr_reg;		/* WR register memory region */
 	wait_queue_head_t	wr_reg_wait;	/* wait for wr_reg result */
+	atomic_t		wr_reg_refcnt;	/* reg refs to link */
 	enum smc_wr_reg_state	wr_reg_state;	/* state of wr_reg request */
 
 	u8			gid[SMC_GID_SIZE];/* gid matching used vlan id*/
···
 int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
 		   u8 link_idx, struct smc_init_info *ini);
 void smcr_link_clear(struct smc_link *lnk, bool log);
+void smc_switch_link_and_count(struct smc_connection *conn,
+			       struct smc_link *to_lnk);
 int smcr_buf_map_lgr(struct smc_link *lnk);
 int smcr_buf_reg_lgr(struct smc_link *lnk);
 void smcr_lgr_set_type(struct smc_link_group *lgr, enum smc_lgr_type new_type);

net/smc/smc_llc.c

···
 	if (!rc)
 		goto out;
 out_clear_lnk:
+	lnk_new->state = SMC_LNK_INACTIVE;
 	smcr_link_clear(lnk_new, false);
 out_reject:
 	smc_llc_cli_add_link_reject(qentry);
···
 		goto out_err;
 	return 0;
 out_err:
+	link_new->state = SMC_LNK_INACTIVE;
 	smcr_link_clear(link_new, false);
 	return rc;
 }
···
 	del_llc->reason = 0;
 	smc_llc_send_message(lnk, &qentry->msg); /* response */
 
-	if (smc_link_downing(&lnk_del->state)) {
-		if (smc_switch_conns(lgr, lnk_del, false))
-			smc_wr_tx_wait_no_pending_sends(lnk_del);
-	}
+	if (smc_link_downing(&lnk_del->state))
+		smc_switch_conns(lgr, lnk_del, false);
 	smcr_link_clear(lnk_del, true);
 
 	active_links = smc_llc_active_link_count(lgr);
···
 				    link->smcibdev->ibdev->name, link->ibport);
 	complete(&link->llc_testlink_resp);
 	cancel_delayed_work_sync(&link->llc_testlink_wrk);
-	smc_wr_wakeup_reg_wait(link);
-	smc_wr_wakeup_tx_wait(link);
 }
 
 /* register a new rtoken at the remote peer (for all links) */

net/smc/smc_tx.c

···
 /* Wakeup sndbuf consumers from any context (IRQ or process)
  * since there is more data to transmit; usable snd_wnd as max transmit
  */
-static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
+static int _smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
 {
 	struct smc_cdc_producer_flags *pflags = &conn->local_tx_ctrl.prod_flags;
 	struct smc_link *link = conn->lnk;
···
 
 out_unlock:
 	spin_unlock_bh(&conn->send_lock);
+	return rc;
+}
+
+static int smcr_tx_sndbuf_nonempty(struct smc_connection *conn)
+{
+	struct smc_link *link = conn->lnk;
+	int rc = -ENOLINK;
+
+	if (!link)
+		return rc;
+
+	atomic_inc(&link->wr_tx_refcnt);
+	if (smc_link_usable(link))
+		rc = _smcr_tx_sndbuf_nonempty(conn);
+	if (atomic_dec_and_test(&link->wr_tx_refcnt))
+		wake_up_all(&link->wr_tx_wait);
 	return rc;
 }
 

net/smc/smc_wr.c

···
 	if (rc)
 		return rc;
 
+	atomic_inc(&link->wr_reg_refcnt);
 	rc = wait_event_interruptible_timeout(link->wr_reg_wait,
 					      (link->wr_reg_state != POSTED),
 					      SMC_WR_REG_MR_WAIT_TIME);
+	if (atomic_dec_and_test(&link->wr_reg_refcnt))
+		wake_up_all(&link->wr_reg_wait);
 	if (!rc) {
 		/* timeout - terminate link */
 		smcr_link_down_cond_sched(link);
···
 		return;
 	ibdev = lnk->smcibdev->ibdev;
 
+	smc_wr_wakeup_reg_wait(lnk);
+	smc_wr_wakeup_tx_wait(lnk);
+
 	if (smc_wr_tx_wait_no_pending_sends(lnk))
 		memset(lnk->wr_tx_mask, 0,
 		       BITS_TO_LONGS(SMC_WR_BUF_CNT) *
 						sizeof(*lnk->wr_tx_mask));
+	wait_event(lnk->wr_reg_wait, (!atomic_read(&lnk->wr_reg_refcnt)));
+	wait_event(lnk->wr_tx_wait, (!atomic_read(&lnk->wr_tx_refcnt)));
 
 	if (lnk->wr_rx_dma_addr) {
 		ib_dma_unmap_single(ibdev, lnk->wr_rx_dma_addr,
···
 	memset(lnk->wr_tx_mask, 0,
 	       BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
 	init_waitqueue_head(&lnk->wr_tx_wait);
+	atomic_set(&lnk->wr_tx_refcnt, 0);
 	init_waitqueue_head(&lnk->wr_reg_wait);
+	atomic_set(&lnk->wr_reg_refcnt, 0);
 	return rc;
 
 dma_unmap: