[PATCH net 1/3] ibmvnic: avoid calling napi_disable() twice

[Lijun Pan]

__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: bfc32f297337 ("ibmvnic: Move resource initialization to its own routine")
Suggested-by: Thomas Falcon <tlfal...@linux.ibm.com>
Signed-off-by: Lijun Pan <lijunp...@gmail.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c 
b/drivers/net/ethernet/ibm/ibmvnic.c
index 110a0d0eaabb..2d27f8aa0d4b 100644
--- 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;
        }
-- 
2.23.0