ibmvnic: avoid calling napi_disable() twice

Lijun Pan · davem330 · commit 0775ebc4cf85 · 2021-04-14T13:10:58.000-07:00
__ibmvnic_open calls napi_disable without checking whether NAPI polling has already been disabled or not. This could cause napi_disable being called twice, which could generate deadlock. For example, the first napi_disable will spin until NAPI_STATE_SCHED is cleared by napi_complete_done, then set it again. When napi_disable is called the second time, it will loop infinitely because no dev->poll will be running to clear NAPI_STATE_SCHED. To prevent above scenario from happening, call ibmvnic_napi_disable() which checks if napi is disabled or not before calling napi_disable. Fixes: bfc32f2 ("ibmvnic: Move resource initialization to its own routine") Suggested-by: Thomas Falcon <tlfalcon@linux.ibm.com> Signed-off-by: Lijun Pan <lijunp213@gmail.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
@@ -1149,8 +1149,7 @@ static int __ibmvnic_open(struct net_device *netdev)
 
 	rc = set_link_state(adapter, IBMVNIC_LOGICAL_LNK_UP);
 	if (rc) {
-		for (i = 0; i < adapter->req_rx_queues; i++)
-			napi_disable(&adapter->napi[i]);
+		ibmvnic_napi_disable(adapter);
 		release_resources(adapter);
 		return rc;
 	}

Original file line number	Diff line number	Diff line change
`@@ -1149,8 +1149,7 @@ static int __ibmvnic_open(struct net_device *netdev)`
`1149`	`1149`
`1150`	`1150`	`rc = set_link_state(adapter, IBMVNIC_LOGICAL_LNK_UP);`
`1151`	`1151`	`if (rc) {`
`1152`		`- for (i = 0; i < adapter->req_rx_queues; i++)`
`1153`		`- napi_disable(&adapter->napi[i]);`
	`1152`	`+ ibmvnic_napi_disable(adapter);`
`1154`	`1153`	`release_resources(adapter);`
`1155`	`1154`	`return rc;`
`1156`	`1155`	`}`