netdev - [PATCH net-next v5 1/9] tsnep: Replace TX spin_lock with __netif_tx

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Message-Id: <20230116202458.56677-2-gerhard@engleder-embedded.com>
Date:   Mon, 16 Jan 2023 21:24:50 +0100
From:   Gerhard Engleder <gerhard@...leder-embedded.com>
To:     netdev@...r.kernel.org, alexander.duyck@...il.com
Cc:     davem@...emloft.net, kuba@...nel.org, edumazet@...gle.com,
        pabeni@...hat.com, Gerhard Engleder <gerhard@...leder-embedded.com>
Subject: [PATCH net-next v5 1/9] tsnep: Replace TX spin_lock with __netif_tx_lock

TX spin_lock can be eliminated, because the normal TX path is already
protected with __netif_tx_lock and this lock can be used for access to
queue outside of normal TX path too.

Signed-off-by: Gerhard Engleder <gerhard@...leder-embedded.com>
---
 drivers/net/ethernet/engleder/tsnep.h      |  2 --
 drivers/net/ethernet/engleder/tsnep_main.c | 29 ++++++++--------------
 2 files changed, 10 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/engleder/tsnep.h b/drivers/net/ethernet/engleder/tsnep.h
index f93ba48bac3f..48910cb1bd8a 100644
--- a/drivers/net/ethernet/engleder/tsnep.h
+++ b/drivers/net/ethernet/engleder/tsnep.h
@@ -78,8 +78,6 @@ struct tsnep_tx {
 	void *page[TSNEP_RING_PAGE_COUNT];
 	dma_addr_t page_dma[TSNEP_RING_PAGE_COUNT];
 
-	/* TX ring lock */
-	spinlock_t lock;
 	struct tsnep_tx_entry entry[TSNEP_RING_SIZE];
 	int write;
 	int read;
diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
index bf0190e1d2ea..c182c40277dd 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;
@@ -444,16 +443,12 @@ 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);
-
 	if (tsnep_tx_desc_available(tx) < count) {
 		/* ring full, shall not happen because queue is stopped if full
 		 * below
 		 */
 		netif_stop_queue(tx->adapter->netdev);
 
-		spin_unlock_irqrestore(&tx->lock, flags);
-
 		return NETDEV_TX_BUSY;
 	}
 
@@ -468,8 +463,6 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
 
 		tx->dropped++;
 
-		spin_unlock_irqrestore(&tx->lock, flags);
-
 		netdev_err(tx->adapter->netdev, "TX DMA map failed\n");
 
 		return NETDEV_TX_OK;
@@ -496,20 +489,19 @@ static netdev_tx_t tsnep_xmit_frame_ring(struct sk_buff *skb,
 		netif_stop_queue(tx->adapter->netdev);
 	}
 
-	spin_unlock_irqrestore(&tx->lock, flags);
-
 	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;
+	struct netdev_queue *nq;
+	int budget = 128;
 	int length;
+	int count;
 
-	spin_lock_irqsave(&tx->lock, flags);
+	nq = netdev_get_tx_queue(tx->adapter->netdev, tx->queue_index);
+	__netif_tx_lock(nq, smp_processor_id());
 
 	do {
 		if (tx->read == tx->write)
@@ -568,18 +560,19 @@ static bool tsnep_tx_poll(struct tsnep_tx *tx, int napi_budget)
 		netif_wake_queue(tx->adapter->netdev);
 	}
 
-	spin_unlock_irqrestore(&tx->lock, flags);
+	__netif_tx_unlock(nq);
 
 	return (budget != 0);
 }
 
 static bool tsnep_tx_pending(struct tsnep_tx *tx)
 {
-	unsigned long flags;
 	struct tsnep_tx_entry *entry;
+	struct netdev_queue *nq;
 	bool pending = false;
 
-	spin_lock_irqsave(&tx->lock, flags);
+	nq = netdev_get_tx_queue(tx->adapter->netdev, tx->queue_index);
+	__netif_tx_lock(nq, smp_processor_id());
 
 	if (tx->read != tx->write) {
 		entry = &tx->entry[tx->read];
@@ -589,7 +582,7 @@ static bool tsnep_tx_pending(struct tsnep_tx *tx)
 			pending = true;
 	}
 
-	spin_unlock_irqrestore(&tx->lock, flags);
+	__netif_tx_unlock(nq);
 
 	return pending;
 }
@@ -615,8 +608,6 @@ static int tsnep_tx_open(struct tsnep_adapter *adapter, void __iomem *addr,
 	tx->owner_counter = 1;
 	tx->increment_owner_counter = TSNEP_RING_SIZE - 1;
 
-	spin_lock_init(&tx->lock);
-
 	return 0;
 }
 
-- 
2.30.2