netdev - [PATCH net v3] ibmvnic: Continue with reset if set link down failed

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Message-Id: <20210504191142.2872696-1-drt@linux.ibm.com>
Date:   Tue,  4 May 2021 15:11:42 -0400
From:   Dany Madden <drt@...ux.ibm.com>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     drt@...ux.ibm.com, sukadev@...ux.ibm.com, tlfalcon@...ux.ibm.com,
        mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
        netdev@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH net v3] ibmvnic: Continue with reset if set link down failed

When ibmvnic gets a FATAL error message from the vnicserver, it marks
the Command Respond Queue (CRQ) inactive and resets the adapter. If this
FATAL reset fails and a transmission timeout reset follows, the CRQ is
still inactive, ibmvnic's attempt to set link down will also fail. If
ibmvnic abandons the reset because of this failed set link down and this
is the last reset in the workqueue, then this adapter will be left in an
inoperable state.

Instead, make the driver ignore this link down failure and continue to
free and re-register CRQ so that the adapter has an opportunity to
recover.

Fixes: ed651a10875f ("ibmvnic: Updated reset handling")
Signed-off-by: Dany Madden <drt@...ux.ibm.com>
Reviewed-by: Rick Lindsley <ricklind@...ux.ibm.com>
Reviewed-by: Sukadev Bhattiprolu <sukadev@...ux.ibm.com>
---
Changes in V2:
- Update description to clarify background for the patch
- Include Reviewed-by tags
Changes in V3:
- Add comment above the code change
---
 drivers/net/ethernet/ibm/ibmvnic.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 5788bb956d73..9e005a08d43b 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2017,8 +2017,15 @@ static int do_reset(struct ibmvnic_adapter *adapter,
 			rtnl_unlock();
 			rc = set_link_state(adapter, IBMVNIC_LOGICAL_LNK_DN);
 			rtnl_lock();
-			if (rc)
-				goto out;
+
+			/* Attempted to set the link down. It could fail if the
+			 * vnicserver has already torn down the CRQ. We will
+			 * note it and continue with reset to reinit the CRQ.
+			 */
+			if (rc) {
+				netdev_dbg(netdev,
+					   "Setting link down failed rc=%d. Continue anyway\n", rc);
+			}
 
 			if (adapter->state == VNIC_OPEN) {
 				/* When we dropped rtnl, ibmvnic_open() got
-- 
2.18.2