On 07/21, Jason Xing wrote: > From: Jason Xing <[email protected]> > > The issue can happen when the budget number of descs are consumed. As > long as the budget is decreased to zero, it will again go into > while (budget-- > 0) statement and get decreased by one, so the > underflow issue can happen. It will lead to returning true whereas the > expected value should be false. > > In this case where all the budget are used up, it means zc function > should return false to let the poll run again because normally we > might have more data to process. > > Fixes: 132c32ee5bc0 ("net: stmmac: Add TX via XDP zero-copy socket") > Signed-off-by: Jason Xing <[email protected]> > --- > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > index f350a6662880..ea5541f9e9a6 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -2596,7 +2596,7 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv > *priv, u32 queue, u32 budget) > > budget = min(budget, stmmac_tx_avail(priv, queue)); > > - while (budget-- > 0) { > + while (budget > 0) {
There is a continue on line 2621. Should we do 'for (; budget > 0; budget--)' instead? And maybe the same for ixgbe [0]? 0: https://lore.kernel.org/netdev/[email protected]/
