Re: [PATCH net] bnxt_en: Prevent queue stop with deferred completions

[Joe Damato <joe@dama.to>]

On Sat, Aug 29, 2026 at 02:57:59PM +0530, Pavan Chebbi wrote:
> >         if (unlikely(bnxt_tx_avail(bp, txr) < bds_needed)) {
> >                 netif_txq_try_stop(txq, bnxt_tx_avail(bp, txr),
> >                                    bp->tx_wake_thresh);
> > -               return NETDEV_TX_BUSY;
> > +               goto tx_busy;
> >         }
> >
> >         /* BD backpressure alone cannot prevent overwriting in-flight
> > @@ -77,7 +77,7 @@ netdev_tx_t bnxt_sw_udp_gso_xmit(struct bnxt *bp,
> >          */
> >         if (!netif_txq_maybe_stop(txq, bnxt_inline_avail(txr),
> >                                   num_segs, num_segs))
> > -               return NETDEV_TX_BUSY;
> > +               goto tx_busy;
> >
> >         if (unlikely(tso_dma_map_init(&map, &pdev->dev, skb, hdr_len)))
> >                 goto drop;
> > @@ -235,4 +235,17 @@ netdev_tx_t bnxt_sw_udp_gso_xmit(struct bnxt *bp,
> >         dev_kfree_skb_any(skb);
> >         dev_core_stats_tx_dropped_inc(bp->dev);
> >         return NETDEV_TX_OK;
> > +
> > +tx_busy:
> > +       if (txr->kick_pending) {
> > +               u16 kick_prod = txr->kick_prod;
> > +               struct tx_bd *txbd0;
> > +
> > +               txbd0 = &txr->tx_desc_ring[TX_RING(bp, kick_prod)]
> > +                                         [TX_IDX(kick_prod)];
> > +               txbd0->tx_bd_len_flags_type &=
> > +                       cpu_to_le32(~TX_BD_FLAGS_NO_CMPL);
> 
> Should we not do a bnxt_txr_db_kick() also? It maybe a good idea to do
> it in success case also instead of bnxt_db_write..

When this function returns, the caller writes the doorbell, so we should be
good.