From 0775ebc4cf8554bdcd2c212669a0868ab68df5c0 Mon Sep 17 00:00:00 2001
From: Lijun Pan <lijunp213@gmail.com>
Date: Wed, 14 Apr 2021 02:46:14 -0500
Subject: [PATCH] ibmvnic: avoid calling napi_disable() twice

References: bsc#1065729
Patch-mainline: v5.12-rc8
Git-commit: 0775ebc4cf8554bdcd2c212669a0868ab68df5c0

__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>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 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;
 	}
-- 
2.26.2