[PATCH 3.16 360/370] mlx4: Invoke softirqs after napi_reschedule

Ben Hutchings
2017-03-10T12:12:01Z

From: Benjamin Poirier <bpoirier@suse.com>

[ Upstream commit bd4ce941c8d5b862b2f83364be5dbe8fc8ab48f8 ]

mlx4 may schedule napi from a workqueue. Afterwards, softirqs are not run
in a deterministic time frame and the following message may be logged:
NOHZ: local_softirq_pending 08

The problem is the same as what was described in commit ec13ee80145c
("virtio_net: invoke softirqs after __napi_schedule") and this patch
applies the same fix to mlx4.

Fixes: 07841f9d94c1 ("net/mlx4_en: Schedule napi when RX buffers allocation fails")
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/ethernet/mellanox/mlx4/en_rx.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -506,8 +506,11 @@ void mlx4_en_recover_from_oom(struct mlx
return;

for (ring = 0; ring < priv->rx_ring_num; ring++) {
- if (mlx4_en_is_ring_empty(priv->rx_ring[ring]))
+ if (mlx4_en_is_ring_empty(priv->rx_ring[ring])) {
+ local_bh_disable();
napi_reschedule(&priv->rx_cq[ring]->napi);
+ local_bh_enable();
+ }
}
}