Thread (26 messages) flat view 26 messages, 4 authors, 2023-01-07

Re: [PATCH net-next v3 1/9] tsnep: Use spin_lock_bh for TX

From: Alexander Lobakin <hidden>
Date: 2023-01-05 12:40:32

From: Gerhard Engleder <redacted>
Date: Wed Jan 04 2023 20:41:24 GMT+0100
TX processing is done only within process or BH context. Therefore,
_irqsafe variant is not necessary.
NAPI and .ndo_{start,xdp}_xmit are BH-only, where can the process
context happen here?
quoted hunk ↗ jump to hunk
Signed-off-by: Gerhard Engleder <redacted>
---
 drivers/net/ethernet/engleder/tsnep_main.c | 19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
index bf0190e1d2ea..7cc5e2407809 100644
--- a/drivers/net/ethernet/engleder/tsnep_main.c
+++ b/drivers/net/ethernet/engleder/tsnep_main.c
@@ -434,7 +434,6 @@ static int tsnep_tx_unmap(struct tsnep_tx *tx, int index, int count)
 static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
 					 struct tsnep_tx *tx)
 {
-	unsigned long flags;
 	int count = 1;
 	struct tsnep_tx_entry *entry;
 	int length;
@@ -444,7 +443,7 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
 	if (skb_shinfo(skb)->nr_frags > 0)
 		count += skb_shinfo(skb)->nr_frags;
 
-	spin_lock_irqsave(&tx->lock, flags);
+	spin_lock_bh(&tx->lock);
 
 	if (tsnep_tx_desc_available(tx) < count) {
 		/* ring full, shall not happen because queue is stopped if full
@@ -452,7 +451,7 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
 		 */
 		netif_stop_queue(tx->adapter->netdev);
 
-		spin_unlock_irqrestore(&tx->lock, flags);
+		spin_unlock_bh(&tx->lock);
 
 		return NETDEV_TX_BUSY;
 	}
@@ -468,7 +467,7 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
 
 		tx->dropped++;
 
-		spin_unlock_irqrestore(&tx->lock, flags);
+		spin_unlock_bh(&tx->lock);
 
 		netdev_err(tx->adapter->netdev, "TX DMA map failed\n");
 
@@ -496,20 +495,19 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
 		netif_stop_queue(tx->adapter->netdev);
 	}
 
-	spin_unlock_irqrestore(&tx->lock, flags);
+	spin_unlock_bh(&tx->lock);
 
 	return NETDEV_TX_OK;
 }
 
 static bool tsnep_tx_poll(struct tsnep_tx *tx, int napi_budget)
 {
-	unsigned long flags;
 	int budget = 128;
 	struct tsnep_tx_entry *entry;
 	int count;
 	int length;
 
-	spin_lock_irqsave(&tx->lock, flags);
+	spin_lock_bh(&tx->lock);
 
 	do {
 		if (tx->read == tx->write)
@@ -568,18 +566,17 @@ static bool tsnep_tx_poll(struct tsnep_tx *tx, int napi_budget)
 		netif_wake_queue(tx->adapter->netdev);
 	}
 
-	spin_unlock_irqrestore(&tx->lock, flags);
+	spin_unlock_bh(&tx->lock);
 
 	return (budget != 0);
 }
 
 static bool tsnep_tx_pending(struct tsnep_tx *tx)
 {
-	unsigned long flags;
 	struct tsnep_tx_entry *entry;
 	bool pending = false;
 
-	spin_lock_irqsave(&tx->lock, flags);
+	spin_lock_bh(&tx->lock);
 
 	if (tx->read != tx->write) {
 		entry = &tx->entry[tx->read];
@@ -589,7 +586,7 @@ static bool tsnep_tx_pending(struct tsnep_tx *tx)
 			pending = true;
 	}
 
-	spin_unlock_irqrestore(&tx->lock, flags);
+	spin_unlock_bh(&tx->lock);
 
 	return pending;
 }
Thanks,
Olek
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