RE: [PATCH net-next v14 06/13] rtase: Implement .ndo_start_xmit function

JustinLai0215
2023-12-14T13:01:00Z

>
> On Fri, 8 Dec 2023 17:47:26 +0800 Justin Lai wrote:
> > +static int tx_handler(struct rtase_ring *ring, int budget)
>
> I don't see how this is called, the way you split the submission makes it a bit
> hard to review, oh well. Anyway - if you pass the NAPI budget here - that's not
> right, it may be 0, and you'd loop forever.
> For Tx - you should try to reap some fixed number of packets, say 128, the
> budget is for Rx, not for Tx.

Even if the budget is 0, this function will not loop forever, it will just run all tx_left.
Or what changes would you like us to make?
>
> > + const struct rtase_private *tp = ring->ivec->tp;
> > + struct net_device *dev = tp->dev;
> > + int workdone = 0;
> > + u32 dirty_tx;
> > + u32 tx_left;
> > +
> > + dirty_tx = ring->dirty_idx;
> > + tx_left = READ_ONCE(ring->cur_idx) - dirty_tx;
> > +
> > + while (tx_left > 0) {
> > + u32 entry = dirty_tx % NUM_DESC;
> > + struct tx_desc *desc = ring->desc +
> > + sizeof(struct tx_desc) * entry;
> > + u32 len = ring->mis.len[entry];
> > + u32 status;
> > +
> > + status = le32_to_cpu(desc->opts1);
> > +
> > + if (status & DESC_OWN)
> > + break;
> > +
> > + rtase_unmap_tx_skb(tp->pdev, len, desc);
> > + ring->mis.len[entry] = 0;
> > + if (ring->skbuff[entry]) {
> > + dev_consume_skb_any(ring->skbuff[entry]);
>
> napi_consume_skb, assuming you call this from NAPI

Ok, I will modify it.
>
> > + ring->skbuff[entry] = NULL;
> > + }
> > +
> > + dev->stats.tx_bytes += len;
> > + dev->stats.tx_packets++;
> > + dirty_tx++;
> > + tx_left--;
> > + workdone++;
> > +
> > + if (workdone == budget)
> > + break;
> > + }
> > +
> > + if (ring->dirty_idx != dirty_tx) {
> > + WRITE_ONCE(ring->dirty_idx, dirty_tx);
> > +
> > + if (__netif_subqueue_stopped(dev, ring->index) &&
> > + rtase_tx_avail(ring))
> > + netif_start_subqueue(dev, ring->index);
>
> Please use the start / stop macros from include/net/netdev_queues.h I'm
> pretty sure the current code is racy.
>

Ok, I will use the macros from include/net/netdev_queues.h.