[PATCH 5.11 095/122] ibmvnic: avoid calling napi_disable() twice

Greg Kroah-Hartman
2021-04-19T13:14:47Z

From: Lijun Pan <lijunp213@gmail.com>

commit 0775ebc4cf8554bdcd2c212669a0868ab68df5c0 upstream.

__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 <tlfalcon@linux.ibm.com>
Signed-off-by: Lijun Pan <lijunp213@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/ibm/ibmvnic.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1180,8 +1180,7 @@ static int __ibmvnic_open(struct net_dev

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;
}