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From: Alexander Lobakin <alexandr.lobakin@intel•com>
To: Gerhard Engleder <gerhard@engleder-embedded•com>
Cc: <davem@davemloft•net>, <kuba@kernel•org>, <edumazet@google•com>,
	<pabeni@redhat•com>, <netdev@vger•kernel.org>
Subject: Re: [PATCH net-next v3 1/9] tsnep: Use spin_lock_bh for TX
Date: Thu, 5 Jan 2023 13:40:17 +0100	[thread overview]
Message-ID: <79d2e66a-3633-ff3a-bdfd-656c735c85e0@intel.com> (raw)
In-Reply-To: <20230104194132.24637-2-gerhard@engleder-embedded.com>

From: Gerhard Engleder <gerhard@engleder-embedded•com>
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?

> 
> Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded•com>
> ---
>  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

  reply	other threads:[~2023-01-05 12:40 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-04 19:41 [PATCH net-next v3 0/9] tsnep: XDP support Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 1/9] tsnep: Use spin_lock_bh for TX Gerhard Engleder
2023-01-05 12:40   ` Alexander Lobakin [this message]
2023-01-05 19:48     ` Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 2/9] tsnep: Do not print DMA mapping error Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 3/9] tsnep: Add adapter down state Gerhard Engleder
2023-01-05 12:44   ` Alexander Lobakin
2023-01-05 19:54     ` Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 4/9] tsnep: Add XDP TX support Gerhard Engleder
2023-01-05 13:01   ` Alexander Lobakin
2023-01-05 21:13     ` Gerhard Engleder
2023-01-06 22:13       ` Jakub Kicinski
2023-01-06 23:34         ` Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 5/9] tsnep: Substract TSNEP_RX_INLINE_METADATA_SIZE once Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 6/9] tsnep: Support XDP BPF program setup Gerhard Engleder
2023-01-05 17:24   ` Alexander Lobakin
2023-01-05 22:09     ` Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 7/9] tsnep: Prepare RX buffer for XDP support Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 8/9] tsnep: Add RX queue info " Gerhard Engleder
2023-01-05 17:35   ` Alexander Lobakin
2023-01-05 22:28     ` Gerhard Engleder
2023-01-04 19:41 ` [PATCH net-next v3 9/9] tsnep: Add XDP RX support Gerhard Engleder
2023-01-05 17:52   ` Alexander Lobakin
2023-01-05 23:22     ` Gerhard Engleder
2023-01-07  8:46   ` Dan Carpenter
2023-01-07 20:12     ` Gerhard Engleder

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