[PATCH 3.2 06/34] mlx4_en: don't use napi_synchronize inside mlx4_en_netpoll

From: Ben Hutchings
Date: Fri May 16 2014 - 08:51:04 EST


3.2.59-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: Chris Mason <clm@xxxxxx>

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@xxxxxx>
Acked-By: Amir Vadai <amirv@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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
@@ -58,7 +58,6 @@ int mlx4_en_create_cq(struct mlx4_en_pri

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

err = mlx4_alloc_hwq_res(mdev->dev, &cq->wqres,
cq->buf_size, 2 * PAGE_SIZE);
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -355,15 +355,11 @@ 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
@@ -300,7 +300,6 @@ 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;
/* Per-core Tx cq processing support */

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