netdev - [PATCH net] ibmvnic: Harden device login requests

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Message-Id: <1591986699-19484-1-git-send-email-tlfalcon@linux.ibm.com>
Date:   Fri, 12 Jun 2020 13:31:39 -0500
From:   Thomas Falcon <tlfalcon@...ux.ibm.com>
To:     netdev@...r.kernel.org
Cc:     linuxppc-dev@...ts.ozlabs.org, danymadden@...ibm.com,
        Thomas Falcon <tlfalcon@...ux.ibm.com>
Subject: [PATCH net] ibmvnic: Harden device login requests

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@...ux.ibm.com>
---
 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 197dc5b2c090..1cb2b7f3b2cb 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -841,13 +841,14 @@ static int ibmvnic_login(struct net_device *netdev)
 {
 	struct ibmvnic_adapter *adapter = netdev_priv(netdev);
 	unsigned long timeout = msecs_to_jiffies(30000);
+	int retries = 10;
 	int retry_count = 0;
 	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);
 
-- 
2.18.1