[PATCH net] gve: Add adminq lock for creating and destroying multiple queues

[Harshitha Ramamurthy <hramamurthy@google.com>]

From: Ziwei Xiao <ziweixiao@google.com>

The original adminq lock is only protecting the gve_adminq_execute_cmd
which is aimed for sending out single adminq command. However, there are
other callers of gve_adminq_kick_and_wait and gve_adminq_issue_cmd that
need to take the mutex lock for mutual exclusion between them, which are
creating and destroying rx/tx queues. Add the adminq lock for those
unprotected callers.

Also this patch cleans up the error handling code of
gve_adminq_destroy_tx_queue.

Cc: stable@vger.kernel.org
Fixes: 1108566ca509 ("gve: Add adminq mutex lock")
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
Signed-off-by: Harshitha Ramamurthy <hramamurthy@google.com>
---
 drivers/net/ethernet/google/gve/gve_adminq.c | 54 ++++++++++++++------
 1 file changed, 37 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c
index 3e8fc33cc11f..659460812276 100644
--- a/drivers/net/ethernet/google/gve/gve_adminq.c
+++ b/drivers/net/ethernet/google/gve/gve_adminq.c
@@ -442,6 +442,8 @@ static int gve_adminq_kick_and_wait(struct gve_priv *priv)
 	int tail, head;
 	int i;
 
+	lockdep_assert_held(&priv->adminq_lock);
+
 	tail = ioread32be(&priv->reg_bar0->adminq_event_counter);
 	head = priv->adminq_prod_cnt;
 
@@ -467,9 +469,6 @@ static int gve_adminq_kick_and_wait(struct gve_priv *priv)
 	return 0;
 }
 
-/* This function is not threadsafe - the caller is responsible for any
- * necessary locks.
- */
 static int gve_adminq_issue_cmd(struct gve_priv *priv,
 				union gve_adminq_command *cmd_orig)
 {
@@ -477,6 +476,8 @@ static int gve_adminq_issue_cmd(struct gve_priv *priv,
 	u32 opcode;
 	u32 tail;
 
+	lockdep_assert_held(&priv->adminq_lock);
+
 	tail = ioread32be(&priv->reg_bar0->adminq_event_counter);
 
 	// Check if next command will overflow the buffer.
@@ -709,13 +710,19 @@ int gve_adminq_create_tx_queues(struct gve_priv *priv, u32 start_id, u32 num_que
 	int err;
 	int i;
 
+	mutex_lock(&priv->adminq_lock);
+
 	for (i = start_id; i < start_id + num_queues; i++) {
 		err = gve_adminq_create_tx_queue(priv, i);
 		if (err)
-			return err;
+			goto out;
 	}
 
-	return gve_adminq_kick_and_wait(priv);
+	err = gve_adminq_kick_and_wait(priv);
+
+out:
+	mutex_unlock(&priv->adminq_lock);
+	return err;
 }
 
 static void gve_adminq_get_create_rx_queue_cmd(struct gve_priv *priv,
@@ -788,19 +795,24 @@ int gve_adminq_create_rx_queues(struct gve_priv *priv, u32 num_queues)
 	int err;
 	int i;
 
+	mutex_lock(&priv->adminq_lock);
+
 	for (i = 0; i < num_queues; i++) {
 		err = gve_adminq_create_rx_queue(priv, i);
 		if (err)
-			return err;
+			goto out;
 	}
 
-	return gve_adminq_kick_and_wait(priv);
+	err = gve_adminq_kick_and_wait(priv);
+
+out:
+	mutex_unlock(&priv->adminq_lock);
+	return err;
 }
 
 static int gve_adminq_destroy_tx_queue(struct gve_priv *priv, u32 queue_index)
 {
 	union gve_adminq_command cmd;
-	int err;
 
 	memset(&cmd, 0, sizeof(cmd));
 	cmd.opcode = cpu_to_be32(GVE_ADMINQ_DESTROY_TX_QUEUE);
@@ -808,11 +820,7 @@ static int gve_adminq_destroy_tx_queue(struct gve_priv *priv, u32 queue_index)
 		.queue_id = cpu_to_be32(queue_index),
 	};
 
-	err = gve_adminq_issue_cmd(priv, &cmd);
-	if (err)
-		return err;
-
-	return 0;
+	return gve_adminq_issue_cmd(priv, &cmd);
 }
 
 int gve_adminq_destroy_tx_queues(struct gve_priv *priv, u32 start_id, u32 num_queues)
@@ -820,13 +828,19 @@ int gve_adminq_destroy_tx_queues(struct gve_priv *priv, u32 start_id, u32 num_qu
 	int err;
 	int i;
 
+	mutex_lock(&priv->adminq_lock);
+
 	for (i = start_id; i < start_id + num_queues; i++) {
 		err = gve_adminq_destroy_tx_queue(priv, i);
 		if (err)
-			return err;
+			goto out;
 	}
 
-	return gve_adminq_kick_and_wait(priv);
+	err = gve_adminq_kick_and_wait(priv);
+
+out:
+	mutex_unlock(&priv->adminq_lock);
+	return err;
 }
 
 static void gve_adminq_make_destroy_rx_queue_cmd(union gve_adminq_command *cmd,
@@ -861,13 +875,19 @@ int gve_adminq_destroy_rx_queues(struct gve_priv *priv, u32 num_queues)
 	int err;
 	int i;
 
+	mutex_lock(&priv->adminq_lock);
+
 	for (i = 0; i < num_queues; i++) {
 		err = gve_adminq_destroy_rx_queue(priv, i);
 		if (err)
-			return err;
+			goto out;
 	}
 
-	return gve_adminq_kick_and_wait(priv);
+	err = gve_adminq_kick_and_wait(priv);
+
+out:
+	mutex_unlock(&priv->adminq_lock);
+	return err;
 }
 
 static void gve_set_default_desc_cnt(struct gve_priv *priv,
-- 
2.49.0.777.g153de2bbd5-goog