[PATCH net v2 4/4] gve: Make ethtool config changes synchronous

[Harshitha Ramamurthy]

From: Pin-yen Lin <treapking@xxxxxxxxxx>

When modifying device features via ethtool, the driver queues the
carrier status update to its workqueue (gve_wq). This leads to a
short link-down state after running the ethtool command.

Use `gve_turnup_and_check_status()` instead of `gve_turnup()` in
`gve_queues_start()` to update the carrier status before returning to
the userspace.

This was discovered by drivers/net/ping.py selftest. The test calls
ping command right after an ethtool configuration, but the interface
could be down without this fix.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 5f08cd3d6423 ("gve: Alloc before freeing when adjusting queues")
Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxx>
Reviewed-by: Joshua Washington <joshwash@xxxxxxxxxx>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@xxxxxxxxxx>
---
 drivers/net/ethernet/google/gve/gve_main.c | 56 +++++++++++-----------
 1 file changed, 28 insertions(+), 28 deletions(-)

diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c
index 1fec8e1e4821..2c461be12a75 100644
--- a/drivers/net/ethernet/google/gve/gve_main.c
+++ b/drivers/net/ethernet/google/gve/gve_main.c
@@ -1424,6 +1424,33 @@ static void gve_queues_mem_remove(struct gve_priv *priv)
 	priv->rx = NULL;
 }
 
+static void gve_handle_link_status(struct gve_priv *priv, bool link_status)
+{
+	if (!gve_get_napi_enabled(priv))
+		return;
+
+	if (link_status == netif_carrier_ok(priv->dev))
+		return;
+
+	if (link_status) {
+		netdev_info(priv->dev, "Device link is up.\n");
+		netif_carrier_on(priv->dev);
+	} else {
+		netdev_info(priv->dev, "Device link is down.\n");
+		netif_carrier_off(priv->dev);
+	}
+}
+
+static void gve_turnup_and_check_status(struct gve_priv *priv)
+{
+	u32 status;
+
+	gve_turnup(priv);
+	status = ioread32be(&priv->reg_bar0->device_status);
+	gve_handle_link_status(priv,
+			       GVE_DEVICE_STATUS_LINK_STATUS_MASK & status);
+}
+
 /* The passed-in queue memory is stored into priv and the queues are made live.
  * No memory is allocated. Passed-in memory is freed on errors.
  */
@@ -1486,8 +1513,7 @@ static int gve_queues_start(struct gve_priv *priv,
 			  round_jiffies(jiffies +
 				msecs_to_jiffies(priv->stats_report_timer_period)));
 
-	gve_turnup(priv);
-	queue_work(priv->gve_wq, &priv->service_task);
+	gve_turnup_and_check_status(priv);
 	priv->interface_up_cnt++;
 	return 0;
 
@@ -1608,23 +1634,6 @@ static int gve_close(struct net_device *dev)
 	return 0;
 }
 
-static void gve_handle_link_status(struct gve_priv *priv, bool link_status)
-{
-	if (!gve_get_napi_enabled(priv))
-		return;
-
-	if (link_status == netif_carrier_ok(priv->dev))
-		return;
-
-	if (link_status) {
-		netdev_info(priv->dev, "Device link is up.\n");
-		netif_carrier_on(priv->dev);
-	} else {
-		netdev_info(priv->dev, "Device link is down.\n");
-		netif_carrier_off(priv->dev);
-	}
-}
-
 static int gve_configure_rings_xdp(struct gve_priv *priv,
 				   u16 num_xdp_rings)
 {
@@ -2099,15 +2108,6 @@ static void gve_turnup(struct gve_priv *priv)
 	gve_set_napi_enabled(priv);
 }
 
-static void gve_turnup_and_check_status(struct gve_priv *priv)
-{
-	u32 status;
-
-	gve_turnup(priv);
-	status = ioread32be(&priv->reg_bar0->device_status);
-	gve_handle_link_status(priv, GVE_DEVICE_STATUS_LINK_STATUS_MASK & status);
-}
-
 static struct gve_notify_block *gve_get_tx_notify_block(struct gve_priv *priv,
 							unsigned int txqueue)
 {
-- 
2.54.0.545.g6539524ca2-goog