[PATCH net 2/2] ibmvnic: fix race with multiple open/close

[Sukadev Bhattiprolu <sukadev@linux.ibm.com>]

If two or more instances of 'ip link set' commands race and first one
already brings the interface up (or down), the subsequent instances
can simply return without redoing the up/down operation.

Fixes: ed651a10875f ("ibmvnic: Updated reset handling")
Reported-by: Abdul Haleem <abdhalee@in.ibm.com>
Tested-by: Abdul Haleem <abdhalee@in.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index cb7ddfefb03e..84b772921f35 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1219,6 +1219,13 @@ static int ibmvnic_open(struct net_device *netdev)
 		goto out;
 	}
 
+	/* If adapter is already open, we don't have to do anything. */
+	if (adapter->state == VNIC_OPEN) {
+		netdev_dbg(netdev, "[S:%d] adapter already open\n",
+			   adapter->state);
+		return 0;
+	}
+
 	if (adapter->state != VNIC_CLOSED) {
 		rc = ibmvnic_login(netdev);
 		if (rc)
@@ -1392,6 +1399,12 @@ static int ibmvnic_close(struct net_device *netdev)
 		return 0;
 	}
 
+	/* If adapter is already closed, we don't have to do anything. */
+	if (adapter->state == VNIC_CLOSED) {
+		netdev_dbg(netdev, "[S:%d] adapter already closed\n",
+			   adapter->state);
+		return 0;
+	}
 	rc = __ibmvnic_close(netdev);
 	ibmvnic_cleanup(netdev);
 
-- 
2.26.2