net/smc: do not call dma sync for unmapped memory

The dma related ...sync_sg... functions check the link state before the
dma function is actually called. But the check in smc_link_usable()
allows links in ACTIVATING state which are not yet mapped to dma memory.
Under high load it may happen that the sync_sg functions are called for
such a link which results in an debug output like
   DMA-API: mlx5_core 0002:00:00.0: device driver tries to sync
   DMA memory it has not allocated [device address=0x0000000103370000]
   [size=65536 bytes]
To fix that introduce a helper to check for the link state ACTIVE and
use it where appropriate. And move the link state update to ACTIVATING
to the end of smcr_link_init() when most initial setup is done.

Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Fixes: d854fcb ("net/smc: add new link state and related helpers")
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -352,7 +352,7 @@ static int smcr_lgr_reg_rmbs(struct smc_link *link,
 	 */
 	mutex_lock(&lgr->llc_conf_mutex);
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (lgr->lnk[i].state != SMC_LNK_ACTIVE)
+		if (!smc_link_active(&lgr->lnk[i]))
 			continue;
 		rc = smcr_link_reg_rmb(&lgr->lnk[i], rmb_desc);
 		if (rc)

net/smc/smc_core.c

@@ -318,7 +318,6 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
 
 	get_device(&ini->ib_dev->ibdev->dev);
 	atomic_inc(&ini->ib_dev->lnk_cnt);
-	lnk->state = SMC_LNK_ACTIVATING;
 	lnk->link_id = smcr_next_link_id(lgr);
 	lnk->lgr = lgr;
 	lnk->link_idx = link_idx;
@@ -354,6 +353,7 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
 	rc = smc_wr_create_link(lnk);
 	if (rc)
 		goto destroy_qp;
+	lnk->state = SMC_LNK_ACTIVATING;
 	return 0;
 
 destroy_qp:
@@ -542,8 +542,7 @@ struct smc_link *smc_switch_conns(struct smc_link_group *lgr,
 	smc_wr_wakeup_tx_wait(from_lnk);
 
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (lgr->lnk[i].state != SMC_LNK_ACTIVE ||
-		    i == from_lnk->link_idx)
+		if (!smc_link_active(&lgr->lnk[i]) || i == from_lnk->link_idx)
 			continue;
 		if (is_dev_err && from_lnk->smcibdev == lgr->lnk[i].smcibdev &&
 		    from_lnk->ibport == lgr->lnk[i].ibport) {
@@ -1269,7 +1268,7 @@ static bool smcr_lgr_match(struct smc_link_group *lgr,
 		return false;
 
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (lgr->lnk[i].state != SMC_LNK_ACTIVE)
+		if (!smc_link_active(&lgr->lnk[i]))
 			continue;
 		if ((lgr->role == SMC_SERV || lgr->lnk[i].peer_qpn == clcqpn) &&
 		    !memcmp(lgr->lnk[i].peer_gid, &lcl->gid, SMC_GID_SIZE) &&
@@ -1717,14 +1716,14 @@ static int __smc_buf_create(struct smc_sock *smc, bool is_smcd, bool is_rmb)
 
 void smc_sndbuf_sync_sg_for_cpu(struct smc_connection *conn)
 {
-	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_usable(conn->lnk))
+	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_active(conn->lnk))
 		return;
 	smc_ib_sync_sg_for_cpu(conn->lnk, conn->sndbuf_desc, DMA_TO_DEVICE);
 }
 
 void smc_sndbuf_sync_sg_for_device(struct smc_connection *conn)
 {
-	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_usable(conn->lnk))
+	if (!conn->lgr || conn->lgr->is_smcd || !smc_link_active(conn->lnk))
 		return;
 	smc_ib_sync_sg_for_device(conn->lnk, conn->sndbuf_desc, DMA_TO_DEVICE);
 }
@@ -1736,7 +1735,7 @@ void smc_rmb_sync_sg_for_cpu(struct smc_connection *conn)
 	if (!conn->lgr || conn->lgr->is_smcd)
 		return;
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (!smc_link_usable(&conn->lgr->lnk[i]))
+		if (!smc_link_active(&conn->lgr->lnk[i]))
 			continue;
 		smc_ib_sync_sg_for_cpu(&conn->lgr->lnk[i], conn->rmb_desc,
 				       DMA_FROM_DEVICE);
@@ -1750,7 +1749,7 @@ void smc_rmb_sync_sg_for_device(struct smc_connection *conn)
 	if (!conn->lgr || conn->lgr->is_smcd)
 		return;
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (!smc_link_usable(&conn->lgr->lnk[i]))
+		if (!smc_link_active(&conn->lgr->lnk[i]))
 			continue;
 		smc_ib_sync_sg_for_device(&conn->lgr->lnk[i], conn->rmb_desc,
 					  DMA_FROM_DEVICE);

net/smc/smc_core.h

@@ -349,6 +349,11 @@ static inline bool smc_link_usable(struct smc_link *lnk)
 	return true;
 }
 
+static inline bool smc_link_active(struct smc_link *lnk)
+{
+	return lnk->state == SMC_LNK_ACTIVE;
+}
+
 struct smc_sock;
 struct smc_clc_msg_accept_confirm;
 struct smc_clc_msg_local;

net/smc/smc_llc.c

@@ -428,7 +428,7 @@ static int smc_llc_send_confirm_rkey(struct smc_link *send_link,
 	rtok_ix = 1;
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
 		link = &send_link->lgr->lnk[i];
-		if (link->state == SMC_LNK_ACTIVE && link != send_link) {
+		if (smc_link_active(link) && link != send_link) {
 			rkeyllc->rtoken[rtok_ix].link_id = link->link_id;
 			rkeyllc->rtoken[rtok_ix].rmb_key =
 				htonl(rmb_desc->mr_rx[link->link_idx]->rkey);
@@ -944,7 +944,7 @@ static int smc_llc_active_link_count(struct smc_link_group *lgr)
 	int i, link_count = 0;
 
 	for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
-		if (!smc_link_usable(&lgr->lnk[i]))
+		if (!smc_link_active(&lgr->lnk[i]))
 			continue;
 		link_count++;
 	}
@@ -1622,7 +1622,7 @@ static void smc_llc_rx_response(struct smc_link *link,
 
 	switch (llc_type) {
 	case SMC_LLC_TEST_LINK:
-		if (link->state == SMC_LNK_ACTIVE)
+		if (smc_link_active(link))
 			complete(&link->llc_testlink_resp);
 		break;
 	case SMC_LLC_ADD_LINK:
@@ -1706,7 +1706,7 @@ static void smc_llc_testlink_work(struct work_struct *work)
 	u8 user_data[16] = { 0 };
 	int rc;
 
-	if (link->state != SMC_LNK_ACTIVE)
+	if (!smc_link_active(link))
 		return;		/* don't reschedule worker */
 	expire_time = link->wr_rx_tstamp + link->llc_testlink_time;
 	if (time_is_after_jiffies(expire_time)) {
@@ -1718,7 +1718,7 @@ static void smc_llc_testlink_work(struct work_struct *work)
 	/* receive TEST LINK response over RoCE fabric */
 	rc = wait_for_completion_interruptible_timeout(&link->llc_testlink_resp,
 						       SMC_LLC_WAIT_TIME);
-	if (link->state != SMC_LNK_ACTIVE)
+	if (!smc_link_active(link))
 		return;		/* link state changed */
 	if (rc <= 0) {
 		smcr_link_down_cond_sched(link);