From dff515a3e71dc8ab3b9dcc2e23a9b5fca88b3c18 Mon Sep 17 00:00:00 2001
From: Thomas Falcon <tlfalcon@linux.ibm.com>
Date: Mon, 15 Jun 2020 10:29:23 -0500
Subject: [PATCH] ibmvnic: Harden device login requests

References: bsc#1170011 ltc#183538
Patch-mainline: v5.8 or v5.8-rc2 (next release)
Git-commit: dff515a3e71dc8ab3b9dcc2e23a9b5fca88b3c18

The VNIC driver's "login" command sequence is the final step
in the driver's initialization process with device firmware,
confirming the available device queue resources to be utilized
by the driver. Under high system load, firmware may not respond
to the request in a timely manner or may abort the request. In
such cases, the driver should reattempt the login command
sequence. In case of a device error, the number of retries
is bounded.

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 | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 1b4d04e4474b..2baf7b3ff4cb 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -842,12 +842,13 @@ static int ibmvnic_login(struct net_device *netdev)
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
 	unsigned long timeout = msecs_to_jiffies(30000);
 	int retry_count = 0;
+	int retries = 10;
 	bool retry;
 	int rc;
 
 	do {
 		retry = false;
-		if (retry_count > IBMVNIC_MAX_QUEUES) {
+		if (retry_count > retries) {
 			netdev_warn(netdev, "Login attempts exceeded\n");
 			return -1;
 		}
@@ -862,11 +863,23 @@ static int ibmvnic_login(struct net_device *netdev)
 
 		if (!wait_for_completion_timeout(&adapter->init_done,
 						 timeout)) {
-			netdev_warn(netdev, "Login timed out\n");
-			return -1;
+			netdev_warn(netdev, "Login timed out, retrying...\n");
+			retry = true;
+			adapter->init_done_rc = 0;
+			retry_count++;
+			continue;
 		}
 
-		if (adapter->init_done_rc == PARTIALSUCCESS) {
+		if (adapter->init_done_rc == ABORTED) {
+			netdev_warn(netdev, "Login aborted, retrying...\n");
+			retry = true;
+			adapter->init_done_rc = 0;
+			retry_count++;
+			/* FW or device may be busy, so
+			 * wait a bit before retrying login
+			 */
+			msleep(500);
+		} else if (adapter->init_done_rc == PARTIALSUCCESS) {
 			retry_count++;
 			release_sub_crqs(adapter, 1);
 
-- 
2.26.2