netdev - Re: [PATCH v2 iwl-net 3/8] ice: replace synchronize_rcu with synchronize

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Date: Fri, 31 May 2024 16:49:01 -0700
From: "Nelson, Shannon" <shannon.nelson@....com>
To: Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
 intel-wired-lan@...ts.osuosl.org
Cc: netdev@...r.kernel.org, anthony.l.nguyen@...el.com,
 magnus.karlsson@...el.com, michal.kubiak@...el.com, larysa.zaremba@...el.com
Subject: Re: [PATCH v2 iwl-net 3/8] ice: replace synchronize_rcu with
 synchronize_net

On 5/29/2024 4:23 AM, Maciej Fijalkowski wrote:
> 
> Given that ice_qp_dis() is called under rtnl_lock, synchronize_net() can
> be called instead of synchronize_rcu() so that XDP rings can finish its
> job in a faster way. Also let us do this as earlier in XSK queue disable
> flow.
> 
> Additionally, turn off regular Tx queue before disabling irqs and NAPI.
> 
> Fixes: 2d4238f55697 ("ice: Add support for AF_XDP")
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
> ---
>   drivers/net/ethernet/intel/ice/ice_xsk.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
> index 4f606a1055b0..e93cb0ca4106 100644
> --- a/drivers/net/ethernet/intel/ice/ice_xsk.c
> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
> @@ -53,7 +53,6 @@ static void ice_qp_clean_rings(struct ice_vsi *vsi, u16 q_idx)
>   {
>          ice_clean_tx_ring(vsi->tx_rings[q_idx]);
>          if (ice_is_xdp_ena_vsi(vsi)) {
> -               synchronize_rcu();
>                  ice_clean_tx_ring(vsi->xdp_rings[q_idx]);
>          }

With only one statement left in the block you'll probably want to remove 
the {}'s

sln


>          ice_clean_rx_ring(vsi->rx_rings[q_idx]);
> @@ -180,11 +179,12 @@ static int ice_qp_dis(struct ice_vsi *vsi, u16 q_idx)
>                  usleep_range(1000, 2000);
>          }
> 
> +       synchronize_net();
> +       netif_tx_stop_queue(netdev_get_tx_queue(vsi->netdev, q_idx));
> +
>          ice_qvec_dis_irq(vsi, rx_ring, q_vector);
>          ice_qvec_toggle_napi(vsi, q_vector, false);
> 
> -       netif_tx_stop_queue(netdev_get_tx_queue(vsi->netdev, q_idx));
> -
>          ice_fill_txq_meta(vsi, tx_ring, &txq_meta);
>          err = ice_vsi_stop_tx_ring(vsi, ICE_NO_RESET, 0, tx_ring, &txq_meta);
>          if (err)
> --
> 2.34.1
> 
>