Re: [Intel-wired-lan] [PATCH iwl-net v6] igb: Fix trigger of incorrect irq in igb_xsk_wakeup

[Maciej Fijalkowski <maciej.fijalkowski@intel.com>]

On Sat, Jan 17, 2026 at 03:51:12PM +0100, Vivek Behera wrote:
> The current implementation in the igb_xsk_wakeup expects
> the Rx and Tx queues to share the same irq. This would lead
> to triggering of incorrect irq in split irq configuration.
> This patch addresses this issue which could impact environments
> with 2 active cpu cores
> or when the number of queues is reduced to 2 or less
> 
> cat /proc/interrupts | grep eno2
>  167:          0          0          0          0 IR-PCI-MSIX-0000:08:00.0
>  0-edge      eno2
>  168:          0          0          0          0 IR-PCI-MSIX-0000:08:00.0
>  1-edge      eno2-rx-0
>  169:          0          0          0          0 IR-PCI-MSIX-0000:08:00.0
>  2-edge      eno2-rx-1
>  170:          0          0          0          0 IR-PCI-MSIX-0000:08:00.0
>  3-edge      eno2-tx-0
>  171:          0          0          0          0 IR-PCI-MSIX-0000:08:00.0
>  4-edge      eno2-tx-1
> 
> Furthermore it uses the flags input argument to trigger either rx, tx or
> both rx and tx irqs as specified in the ndo_xsk_wakeup api documentation
> 
> Fixes: 80f6ccf9f116 ("igb: Introduce XSK data structures and helpers")
> Signed-off-by: Vivek Behera <vivek.behera@siemens.com>
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
> Suggested-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
> ---
> v1: https://lore.kernel.org/intel-wired-lan/20251212131454.124116-1-vivek.behera@siemens.com/
> v2: https://lore.kernel.org/intel-wired-lan/20251215115416.410619-1-vivek.behera@siemens.com/
> v3: https://lore.kernel.org/intel-wired-lan/20251220114936.140473-1-vivek.behera@siemens.com/
> v4: https://lore.kernel.org/intel-wired-lan/20251222115747.230521-1-vivek.behera@siemens.com/
> v5: https://lore.kernel.org/intel-wired-lan/20260112130349.1737901-1-vivek.behera@siemens.com/
> 
> changelog:
> v1
> - Initial description of the Bug and fixes made in the patch
> 
> v1 -> v2
> - Handling of RX and TX Wakeup in igc_xsk_wakeup for a split IRQ configuration
> - Review suggestions by Aleksander: Modified sequence to complete all
>   error checks for rx and tx before updating napi states and triggering irqs
> - Corrected trigger of TX and RX interrupts over E1000_ICS (non msix use case)
> - Added define for Tx interrupt trigger bit mask for E1000_ICS
> 
> v2 -> v3
> - Included applicable feedback and suggestions from igc patch
> - Fixed logic in updating eics value when  both TX and RX need wakeup
> 
> v3 -> v4
> - Added comments to explain trigerring of both TX and RX with active queue pairs
> - Fixed check of xsk pools in if statement
> 
> v4 -> v5
> - Introduced a simplified logic for sequential check for RX and TX
> 
> v5 -> v6
> - Further simplifications suggested by Maciej
> - Included review suggestions from reviewers
> ---
>  drivers/net/ethernet/intel/igb/igb_xsk.c | 31 ++++++++++++++++++++----
>  1 file changed, 26 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igb/igb_xsk.c b/drivers/net/ethernet/intel/igb/igb_xsk.c
> index 30ce5fbb5b77..f8bddb7a2af8 100644
> --- a/drivers/net/ethernet/intel/igb/igb_xsk.c
> +++ b/drivers/net/ethernet/intel/igb/igb_xsk.c
> @@ -524,6 +524,16 @@ bool igb_xmit_zc(struct igb_ring *tx_ring, struct xsk_buff_pool *xsk_pool)
>  	return nb_pkts < budget;
>  }
>  
> +static u32 igb_sw_irq_prep(struct igb_q_vector *q_vector)
> +{
> +	u32 eics = 0;
> +
> +	if (!napi_if_scheduled_mark_missed(&q_vector->napi))
> +		eics = q_vector->eims_value;
> +
> +	return eics;
> +}
> +
>  int igb_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags)
>  {
>  	struct igb_adapter *adapter = netdev_priv(dev);
> @@ -542,16 +552,27 @@ int igb_xsk_wakeup(struct net_device *dev, u32 qid, u32 flags)
>  
>  	ring = adapter->tx_ring[qid];
>  
> -	if (test_bit(IGB_RING_FLAG_TX_DISABLED, &ring->flags))
> -		return -ENETDOWN;
> -
>  	if (!READ_ONCE(ring->xsk_pool))
>  		return -EINVAL;
>  
> -	if (!napi_if_scheduled_mark_missed(&ring->q_vector->napi)) {
> +	if (flags & XDP_WAKEUP_TX) {
> +		if (test_bit(IGB_RING_FLAG_TX_DISABLED, &ring->flags))
> +			return -ENETDOWN;
> +
> +		eics |= igb_sw_irq_prep(ring->q_vector);
> +	}
> +
> +	if (flags & XDP_WAKEUP_RX) {
> +		/* for IGB_FLAG_QUEUE_PAIRS, this will be NOP as NAPI has
> +		 * been already marked with NAPIF_STATE_MISSED
> +		 */
> +		ring = adapter->rx_ring[qid];
> +		eics |= igb_sw_irq_prep(ring->q_vector);
> +	}
> +
> +	if (eics) {
>  		/* Cause software interrupt */
>  		if (adapter->flags & IGB_FLAG_HAS_MSIX) {

braces are redundant now as we have single line bodies of branches.
Besides:

Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>

Thanks for co-op!

> -			eics |= ring->q_vector->eims_value;
>  			wr32(E1000_EICS, eics);
>  		} else {
>  			wr32(E1000_ICS, E1000_ICS_RXDMT0);
> -- 
> 2.34.1
>