From: Brian King <brking@linux.vnet.ibm.com>
Date: Wed, 19 Apr 2017 17:44:47 +0000 (-0400)
Subject: ibmvnic: Fixup atomic API usage
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=58c8c0c096611f6a1d43ed24e320494bf894a66e;p=openwrt%2Fstaging%2Fblogic.git

ibmvnic: Fixup atomic API usage

Replace a couple of modifications of an atomic followed
by a read of the atomic, which is no longer atomic, to
use atomic_XX_return variants to avoid race conditions.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index c10bae7823e0..b5871dfff1b7 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -962,9 +962,8 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 		goto out;
 	}
 
-	atomic_inc(&tx_scrq->used);
-
-	if (atomic_read(&tx_scrq->used) >= adapter->req_tx_entries_per_subcrq) {
+	if (atomic_inc_return(&tx_scrq->used)
+					>= adapter->req_tx_entries_per_subcrq) {
 		netdev_info(netdev, "Stopping queue %d\n", queue_num);
 		netif_stop_subqueue(netdev, queue_num);
 	}
@@ -1499,9 +1498,8 @@ restart_loop:
 			}
 
 			if (txbuff->last_frag) {
-				atomic_dec(&scrq->used);
-
-				if (atomic_read(&scrq->used) <=
+				if (atomic_sub_return(next->tx_comp.num_comps,
+						      &scrq->used) <=
 				    (adapter->req_tx_entries_per_subcrq / 2) &&
 				    netif_subqueue_stopped(adapter->netdev,
 							   txbuff->skb)) {