[PATCH 3.14 052/140] mlx4_en: dont use napi_synchronize inside mlx4_en_netpoll

Greg Kroah-Hartman
2014-05-29T05:28:37Z

From: Chris Mason <clm@fb.com>

commit c98235cb8584a72e95786e17d695a8e5fafcd766 upstream.

The mlx4 driver is triggering schedules while atomic inside
mlx4_en_netpoll:

spin_lock_irqsave(&cq->lock, flags);
napi_synchronize(&cq->napi);
^^^^^ msleep here
mlx4_en_process_rx_cq(dev, cq, 0);
spin_unlock_irqrestore(&cq->lock, flags);

This was part of a patch by Alexander Guller from Mellanox in 2011,
but it still isn't upstream.

Signed-off-by: Chris Mason <clm@fb.com>
Acked-By: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/mellanox/mlx4/en_cq.c | 1 -
drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 6 +-----
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 -
3 files changed, 1 insertion(+), 7 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -66,7 +66,6 @@ int mlx4_en_create_cq(struct mlx4_en_pri

cq->ring = ring;
cq->is_tx = mode;
- spin_lock_init(&cq->lock);

/* Allocate HW buffers on provided NUMA node.
* dev->numa_node is used in mtt range allocation flow.
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -1315,15 +1315,11 @@ static void mlx4_en_netpoll(struct net_d
{
struct mlx4_en_priv *priv = netdev_priv(dev);
struct mlx4_en_cq *cq;
- unsigned long flags;
int i;

for (i = 0; i < priv->rx_ring_num; i++) {
cq = priv->rx_cq[i];
- spin_lock_irqsave(&cq->lock, flags);
- napi_synchronize(&cq->napi);
- mlx4_en_process_rx_cq(dev, cq, 0);
- spin_unlock_irqrestore(&cq->lock, flags);
+ napi_schedule(&cq->napi);
}
}
#endif
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -309,7 +309,6 @@ struct mlx4_en_cq {
struct mlx4_cq mcq;
struct mlx4_hwq_resources wqres;
int ring;
- spinlock_t lock;
struct net_device *dev;
struct napi_struct napi;
int size;