Subject: Re: [PATCH 2/4] igb: Introduce txrx ring enable/disable functions

From: Maciej Fijalkowski <[email-masked]>
Date: Tue, 4 Jul 2023 17:38:56 +0200

On Tue, Jul 04, 2023 at 11:59:13AM +0200, Sriram Yagnaraman wrote:
> Add enable/disable functions for TX and RX rings, will be used in later
> patches when AF_XDP zero-copy support is added.
> 
> Signed-off-by: Sriram Yagnaraman <[email-masked]>
> ---
>  drivers/net/ethernet/intel/igb/igb.h      |  5 ++-
>  drivers/net/ethernet/intel/igb/igb_main.c | 41 +++++++++++++++++++++++
>  2 files changed, 45 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/igb/igb.h b/drivers/net/ethernet/intel/igb/igb.h
> index 94440af6cf4b..5fa011c6ef2f 100644
> --- a/drivers/net/ethernet/intel/igb/igb.h
> +++ b/drivers/net/ethernet/intel/igb/igb.h
> @@ -384,7 +384,8 @@ enum e1000_ring_flags_t {
>  	IGB_RING_FLAG_RX_SCTP_CSUM,
>  	IGB_RING_FLAG_RX_LB_VLAN_BSWAP,
>  	IGB_RING_FLAG_TX_CTX_IDX,
> -	IGB_RING_FLAG_TX_DETECT_HANG
> +	IGB_RING_FLAG_TX_DETECT_HANG,
> +	IGB_RING_FLAG_TX_DISABLED
>  };
>  
>  #define ring_uses_large_buffer(ring) \
> @@ -735,6 +736,8 @@ void igb_free_tx_resources(struct igb_ring *);
>  void igb_free_rx_resources(struct igb_ring *);
>  void igb_configure_tx_ring(struct igb_adapter *, struct igb_ring *);
>  void igb_configure_rx_ring(struct igb_adapter *, struct igb_ring *);
> +void igb_txrx_ring_disable(struct igb_adapter *adapter, u16 qid);
> +void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid);
>  void igb_setup_tctl(struct igb_adapter *);
>  void igb_setup_rctl(struct igb_adapter *);
>  void igb_setup_srrctl(struct igb_adapter *, struct igb_ring *);
> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> index dadc3d423cfd..391c0eb136d9 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -4856,6 +4856,47 @@ static void igb_configure_rx(struct igb_adapter *adapter)
>  	}
>  }
>  
> +void igb_txrx_ring_disable(struct igb_adapter *adapter, u16 qid)

they could be static funcs defined in igb_xsk.c i believe? I'll review the
rest after you address the things I have requested on cover letter
response.

> +{
> +	struct e1000_hw *hw = &adapter->hw;
> +	struct igb_ring *tx_ring = adapter->tx_ring[qid];
> +	struct igb_ring *rx_ring = adapter->rx_ring[qid];
> +
> +	set_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags);
> +
> +	wr32(E1000_TXDCTL(tx_ring->reg_idx), 0);
> +	wr32(E1000_RXDCTL(rx_ring->reg_idx), 0);
> +
> +	/* Rx/Tx share the same napi context. */
> +	napi_disable(&rx_ring->q_vector->napi);
> +
> +	igb_clean_tx_ring(tx_ring);
> +	igb_clean_rx_ring(rx_ring);
> +
> +	memset(&rx_ring->rx_stats, 0, sizeof(rx_ring->rx_stats));
> +	memset(&tx_ring->tx_stats, 0, sizeof(tx_ring->tx_stats));
> +}
> +
> +void igb_txrx_ring_enable(struct igb_adapter *adapter, u16 qid)
> +{
> +	struct igb_ring *tx_ring = adapter->tx_ring[qid];
> +	struct igb_ring *rx_ring = adapter->rx_ring[qid];
> +
> +	/* Rx/Tx share the same napi context. */
> +	napi_enable(&rx_ring->q_vector->napi);
> +
> +	igb_configure_tx_ring(adapter, tx_ring);
> +	igb_configure_rx_ring(adapter, rx_ring);
> +
> +	/* call igb_desc_unused which always leaves
> +	 * at least 1 descriptor unused to make sure
> +	 * next_to_use != next_to_clean
> +	 */
> +	igb_alloc_rx_buffers(rx_ring, igb_desc_unused(rx_ring));
> +
> +	clear_bit(IGB_RING_FLAG_TX_DISABLED, &tx_ring->flags);
> +}
> +
>  /**
>   *  igb_free_tx_resources - Free Tx Resources per Queue
>   *  @tx_ring: Tx descriptor ring for a specific queue
> -- 
> 2.34.1
> 
>