On Mon, Jul 21, 2025 at 04:33:43PM +0800, Jason Xing wrote: > From: Jason Xing <[email protected]> > > There is no break time in the while() loop, so every time at the end of > igb_xmit_zc(), underflow of nb_pkts will occur, which renders the return > value always false. But theoretically, the result should be set after > calling xsk_tx_peek_release_desc_batch(). We can take i40e_xmit_zc() as > a good example. > > Returning false means we're not done with transmission and we need one > more poll, which is exactly what igb_xmit_zc() always did before this > patch. After this patch, the return value depends on the nb_pkts value. > Two cases might happen then: > 1. if (nb_pkts < budget), it means we process all the possible data, so > return true and no more necessary poll will be triggered because of > this. > 2. if (nb_pkts == budget), it means we might have more data, so return > false to let another poll run again. > > Fixes: f8e284a02afc ("igb: Add AF_XDP zero-copy Tx support") > Signed-off-by: Jason Xing <[email protected]> > --- > drivers/net/ethernet/intel/igb/igb_xsk.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/intel/igb/igb_xsk.c > b/drivers/net/ethernet/intel/igb/igb_xsk.c > index 5cf67ba29269..243f4246fee8 100644 > --- a/drivers/net/ethernet/intel/igb/igb_xsk.c > +++ b/drivers/net/ethernet/intel/igb/igb_xsk.c > @@ -482,7 +482,7 @@ bool igb_xmit_zc(struct igb_ring *tx_ring, struct > xsk_buff_pool *xsk_pool) > if (!nb_pkts) > return true; > > - while (nb_pkts-- > 0) { > + while (i < nb_pkts) {
Hi Jason, FWIIW, I think using a for loop is a more idiomatic way of handling the relationship between i, nb_pkts, and the iterations of this loop. > dma = xsk_buff_raw_get_dma(xsk_pool, descs[i].addr); > xsk_buff_raw_dma_sync_for_device(xsk_pool, dma, descs[i].len); > > -- > 2.41.3 > >
