napi->poll can be called with budget 0, e.g. in netpoll scenarios where the caller only wants to poll TX rings (poll_one_napi@net/core/netpoll.c).
The below commit changed RX polling from "while" loop to "do {} while", which caused to ignore the initial budget and handle at least one RX packet. This fixes the following warning: [ 2852.049194] mlx5e_napi_poll+0x0/0x260 [mlx5_core] exceeded budget in poll [ 2852.049195] ------------[ cut here ]------------ [ 2852.049195] WARNING: CPU: 0 PID: 25691 at net/core/netpoll.c:171 netpoll_poll_dev+0x18a/0x1a0 Fixes: 4b7dfc992514 ("net/mlx5e: Early-return on empty completion queues") Signed-off-by: Saeed Mahameed <sae...@mellanox.com> Reviewed-by: Tariq Toukan <tar...@mellanox.com> Reported-by: Martin KaFai Lau <ka...@fb.com> Tested-by: Martin KaFai Lau <ka...@fb.com> Cc: kernel-t...@fb.com Signed-off-by: Saeed Mahameed <sae...@mellanox.com> --- drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c index e906b754415c..ab92298eafc3 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c @@ -49,7 +49,7 @@ int mlx5e_napi_poll(struct napi_struct *napi, int budget) struct mlx5e_channel *c = container_of(napi, struct mlx5e_channel, napi); bool busy = false; - int work_done; + int work_done = 0; int i; for (i = 0; i < c->num_tc; i++) @@ -58,15 +58,17 @@ int mlx5e_napi_poll(struct napi_struct *napi, int budget) if (c->xdp) busy |= mlx5e_poll_xdpsq_cq(&c->rq.xdpsq.cq); - work_done = mlx5e_poll_rx_cq(&c->rq.cq, budget); - busy |= work_done == budget; + if (likely(budget)) { /* budget=0 means: don't poll rx rings */ + work_done = mlx5e_poll_rx_cq(&c->rq.cq, budget); + busy |= work_done == budget; + } busy |= c->rq.post_wqes(&c->rq); if (busy) { if (likely(mlx5e_channel_no_affinity_change(c))) return budget; - if (work_done == budget) + if (budget && work_done == budget) work_done--; } -- 2.13.6