This is a note to let you know that I've just added the patch titled
mlx4: handle non-napi callers to napi_poll
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mlx4-handle-non-napi-callers-to-napi_poll.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Sat Oct 17 12:48:24 PM CEST 2020
From: Jonathan Lemon <bsd@xxxxxx>
Date: Thu, 8 Oct 2020 11:45:26 -0700
Subject: mlx4: handle non-napi callers to napi_poll
From: Jonathan Lemon <bsd@xxxxxx>
[ 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@xxxxxxxxx>
Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -945,6 +945,9 @@ 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);
Patches currently in stable-queue which might be from bsd@xxxxxx are
queue-4.19/mlx4-handle-non-napi-callers-to-napi_poll.patch
