[PATCH net v2] ibmvnic: Harden device login requests

[PATCH net v2] ibmvnic: Harden device login requests

[Thomas Falcon]

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>
---
v2: declare variables in Reverse Christmas tree format
---
 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 1b4d04e..2baf7b3 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);
 
-- 
1.8.3.1

Re: [PATCH net v2] ibmvnic: Harden device login requests

[David Miller]

From: Thomas Falcon <tlfalcon@linux.ibm.com>
Date: Mon, 15 Jun 2020 10:29:23 -0500

> 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>
> ---
> v2: declare variables in Reverse Christmas tree format

Applied, thanks.