Thread (13 messages) 13 messages, 1 author, 7d ago
COOLING7d

[PATCH net-next 03/12] net: dsa: qca8k: dsa_inband_request: More normal return values

From: Luke Howard <hidden>
Date: 2026-07-03 07:30:49
Also in: lkml
Subsystem: networking drivers, networking [dsa], networking [general], the rest · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Vladimir Oltean, Linus Torvalds

From: Andrew Lunn <andrew@lunn.ch>

wait_for_completion_timeout() has unusual return values. If it times
out, it returns 0, and on success it returns the number of remaining
jiffies for the timeout.

For the use case here, the remaining time is not needed. All that is
really interesting is, it succeeded and returns 0, or a timeout.
Massage the return value to fit this, and modify the callers to the
more usual pattern of ret < 0 is an error.

Sending the clear message is expected to fail, so don't check the
return value, and add a comment about this.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
v2
Remove check on the clear message.
wait_for_completion_timeout() does not return negative values
---
 drivers/net/dsa/qca/qca8k-8xxx.c | 24 +++++++++++-------------
 net/dsa/dsa.c                    |  6 +++++-
 2 files changed, 16 insertions(+), 14 deletions(-)
diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c
index 4da6094552f1e..b0cbe72c15b4c 100644
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
@@ -348,8 +348,8 @@ static int qca8k_read_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len)
 
 	mutex_unlock(&mgmt_eth_data->mutex);
 
-	if (ret <= 0)
-		return -ETIMEDOUT;
+	if (ret)
+		return ret;
 
 	if (!ack)
 		return -EINVAL;
@@ -392,8 +392,8 @@ static int qca8k_write_eth(struct qca8k_priv *priv, u32 reg, u32 *val, int len)
 
 	mutex_unlock(&mgmt_eth_data->mutex);
 
-	if (ret <= 0)
-		return -ETIMEDOUT;
+	if (ret)
+		return ret;
 
 	if (!ack)
 		return -EINVAL;
@@ -596,8 +596,8 @@ qca8k_phy_eth_busy_wait(struct qca8k_mgmt_eth_data *mgmt_eth_data,
 
 	ack = mgmt_eth_data->ack;
 
-	if (ret <= 0)
-		return -ETIMEDOUT;
+	if (ret)
+		return ret;
 
 	if (!ack)
 		return -EINVAL;
@@ -694,8 +694,7 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 
 	ack = mgmt_eth_data->ack;
 
-	if (ret <= 0) {
-		ret = -ETIMEDOUT;
+	if (ret) {
 		kfree_skb(read_skb);
 		goto exit;
 	}
@@ -727,10 +726,8 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 
 		ack = mgmt_eth_data->ack;
 
-		if (ret <= 0) {
-			ret = -ETIMEDOUT;
+		if (ret)
 			goto exit;
-		}
 
 		if (!ack) {
 			ret = -EINVAL;
@@ -747,8 +744,9 @@ qca8k_phy_eth_command(struct qca8k_priv *priv, bool read, int phy,
 	qca8k_mdio_header_fill_seq_num(clear_skb, mgmt_eth_data->seq);
 	mgmt_eth_data->ack = false;
 
-	dsa_inband_wait_for_completion(&mgmt_eth_data->inband,
-				       QCA8K_ETHERNET_TIMEOUT);
+	/* This is expected to fail sometimes, so don't check return value. */
+	dsa_inband_request(&mgmt_eth_data->inband, clear_skb,
+			   QCA8K_ETHERNET_TIMEOUT);
 
 	mutex_unlock(&mgmt_eth_data->mutex);
 	mutex_unlock(&priv->bus->mdio_lock);
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 534e391fac7b5..f6ae11b06b4ab 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -1878,12 +1878,16 @@ int dsa_inband_request(struct dsa_inband *inband, struct sk_buff *skb,
 		       int timeout_ms)
 {
 	unsigned long jiffies = msecs_to_jiffies(timeout_ms);
+	int ret;
 
 	reinit_completion(&inband->completion);
 
 	dev_queue_xmit(skb);
 
-	return wait_for_completion_timeout(&inband->completion, jiffies);
+	ret = wait_for_completion_timeout(&inband->completion, jiffies);
+	if (ret == 0)
+		return -ETIMEDOUT;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(dsa_inband_request);
 
-- 
2.43.0
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