[PATCH 4.14 004/191] mlx4: handle non-napi callers to napi_poll

Greg Kroah-Hartman
2020-10-27T18:17:02Z

From: Jonathan Lemon <bsd@fb.com>

[ Upstream commit b2b8a92733b288128feb57ffa694758cf475106c ]

netcons calls napi_poll with a budget of 0 to transmit packets.
Handle this by:
- skipping RX processing
- do not try to recycle TX packets to the RX cache

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx4/en_rx.c | 3 +++
drivers/net/ethernet/mellanox/mlx4/en_tx.c | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -948,6 +948,9 @@ int mlx4_en_poll_rx_cq(struct napi_struc
bool clean_complete = true;
int done;

+ if (!budget)
+ return 0;
+
if (priv->tx_ring_num[TX_XDP]) {
xdp_tx_cq = priv->tx_cq[TX_XDP][cq->ring];
if (xdp_tx_cq->xdp_busy) {
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -343,7 +343,7 @@ u32 mlx4_en_recycle_tx_desc(struct mlx4_
.dma = tx_info->map0_dma,
};

- if (!mlx4_en_rx_recycle(ring->recycle_ring, &frame)) {
+ if (!napi_mode || !mlx4_en_rx_recycle(ring->recycle_ring, &frame)) {
dma_unmap_page(priv->ddev, tx_info->map0_dma,
PAGE_SIZE, priv->dma_dir);
put_page(tx_info->page);