From 36a782fdcc2bfe39265ac4640f29404493b52a55 Mon Sep 17 00:00:00 2001
From: Thomas Falcon <tlfalcon@linux.ibm.com>
Date: Mon, 31 Aug 2020 11:59:57 -0500
Subject: [PATCH] ibmvnic: Harden device Command Response Queue handshake

References: bsc#1184114 ltc#192237 bsc#1179243 ltc#189290
Patch-mainline: v5.10-rc1
Git-commit: 36a782fdcc2bfe39265ac4640f29404493b52a55

In some cases, the device or firmware may be busy when the
driver attempts to perform the CRQ initialization handshake.
If the partner is busy, the hypervisor will return the H_CLOSED
return code. The aim of this patch is that, if the device is not
ready, to query the device a number of times, with a small wait
time in between queries. If all initialization requests fail,
the driver will remain in a dormant state, awaiting a signal
from the device that it is ready for operation.

Signed-off-by: Thomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 86a83e53dce5..994358689de9 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -3566,14 +3566,31 @@ static int ibmvnic_send_crq(struct ibmvnic_adapter *adapter,
 
 static int ibmvnic_send_crq_init(struct ibmvnic_adapter *adapter)
 {
+	struct device *dev = &adapter->vdev->dev;
 	union ibmvnic_crq crq;
+	int retries = 100;
+	int rc;
 
 	memset(&crq, 0, sizeof(crq));
 	crq.generic.first = IBMVNIC_CRQ_INIT_CMD;
 	crq.generic.cmd = IBMVNIC_CRQ_INIT;
 	netdev_dbg(adapter->netdev, "Sending CRQ init\n");
 
-	return ibmvnic_send_crq(adapter, &crq);
+	do {
+		rc = ibmvnic_send_crq(adapter, &crq);
+		if (rc != H_CLOSED)
+			break;
+		retries--;
+		msleep(50);
+
+	} while (retries > 0);
+
+	if (rc) {
+		dev_err(dev, "Failed to send init request, rc = %d\n", rc);
+		return rc;
+	}
+
+	return 0;
 }
 
 static int send_version_xchg(struct ibmvnic_adapter *adapter)
-- 
2.26.2