From ffc385b95adb0e601f6858b06401adabedf59f81 Mon Sep 17 00:00:00 2001
From: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Date: Sun, 18 Feb 2018 10:08:41 -0600
Subject: [PATCH] ibmvnic: Keep track of supplementary TX descriptors

References: bsc#1081491
Patch-mainline: v4.17-rc1
Git-commit: ffc385b95adb0e601f6858b06401adabedf59f81

Supplementary TX descriptors were not being accounted for, which
was resulting in an overflow of the hardware device's transmit
queue. Keep track of those descriptors now when determining
how many entries remain on the TX queue.

Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 8 ++++++--
 drivers/net/ethernet/ibm/ibmvnic.h | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 996f47568f9e..64770a1c406d 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1467,6 +1467,7 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 	if ((*hdrs >> 7) & 1) {
 		build_hdr_descs_arr(tx_buff, &num_entries, *hdrs);
 		tx_crq.v1.n_crq_elem = num_entries;
+		tx_buff->num_entries = num_entries;
 		tx_buff->indir_arr[0] = tx_crq;
 		tx_buff->indir_dma = dma_map_single(dev, tx_buff->indir_arr,
 						    sizeof(tx_buff->indir_arr),
@@ -1515,7 +1516,7 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 		goto out;
 	}
 
-	if (atomic_inc_return(&tx_scrq->used)
+	if (atomic_add_return(num_entries, &tx_scrq->used)
 					>= adapter->req_tx_entries_per_subcrq) {
 		netdev_info(netdev, "Stopping queue %d\n", queue_num);
 		netif_stop_subqueue(netdev, queue_num);
@@ -2468,6 +2469,7 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
 restart_loop:
 	while (pending_scrq(adapter, scrq)) {
 		unsigned int pool = scrq->pool_index;
+		int num_entries = 0;
 
 		next = ibmvnic_next_scrq(adapter, scrq);
 		for (i = 0; i < next->tx_comp.num_comps; i++) {
@@ -2498,6 +2500,8 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
 				txbuff->skb = NULL;
 			}
 
+			num_entries += txbuff->num_entries;
+
 			adapter->tx_pool[pool].free_map[adapter->tx_pool[pool].
 						     producer_index] = index;
 			adapter->tx_pool[pool].producer_index =
@@ -2507,7 +2511,7 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter,
 		/* remove tx_comp scrq*/
 		next->tx_comp.first = 0;
 
-		if (atomic_sub_return(next->tx_comp.num_comps, &scrq->used) <=
+		if (atomic_sub_return(num_entries, &scrq->used) <=
 		    (adapter->req_tx_entries_per_subcrq / 2) &&
 		    __netif_subqueue_stopped(adapter->netdev,
 					     scrq->pool_index)) {
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index fe21a6e2ddae..2f51458ccdc3 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -909,6 +909,7 @@ struct ibmvnic_tx_buff {
 	union sub_crq indir_arr[6];
 	u8 hdr_data[140];
 	dma_addr_t indir_dma;
+	int num_entries;
 };
 
 struct ibmvnic_tx_pool {
-- 
2.13.6