2024-04-28 13:21:34

by Jules Irenge

Subject: [PATCH] net/mlx5e: Remove NULL check before dev_{put, hold}

Coccinelle reports a warning

WARNING: NULL check before dev_{put, hold} functions is not needed

The reason is the call netdev_{put, hold} of dev_{put,hold} will check NULL
There is no need to check before using dev_{put, hold}

Signed-off-by: Jules Irenge <[email protected]>
---
drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
index 8dfb57f712b0..f23d7116e6d8 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
@@ -68,16 +68,14 @@ static int get_route_and_out_devs(struct mlx5e_priv *priv,
* while holding rcu read lock. Take the net_device for correctness
* sake.
*/
- if (uplink_upper)
- dev_hold(uplink_upper);
+ dev_hold(uplink_upper);
rcu_read_unlock();

dst_is_lag_dev = (uplink_upper &&
netif_is_lag_master(uplink_upper) &&
real_dev == uplink_upper &&
mlx5_lag_is_sriov(priv->mdev));
- if (uplink_upper)
- dev_put(uplink_upper);
+ dev_put(uplink_upper);

/* if the egress device isn't on the same HW e-switch or
* it's a LAG device, use the uplink
--
2.43.2

2024-04-30 13:16:21

by Leon Romanovsky

Subject: Re: [PATCH] net/mlx5e: Remove NULL check before dev_{put, hold}

On Sun, Apr 28, 2024 at 02:21:20PM +0100, Jules Irenge wrote:
> Coccinelle reports a warning
>
> WARNING: NULL check before dev_{put, hold} functions is not needed
>
> The reason is the call netdev_{put, hold} of dev_{put,hold} will check NULL
> There is no need to check before using dev_{put, hold}
>
> Signed-off-by: Jules Irenge <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
> index 8dfb57f712b0..f23d7116e6d8 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
> @@ -68,16 +68,14 @@ static int get_route_and_out_devs(struct mlx5e_priv *priv,
> * while holding rcu read lock. Take the net_device for correctness
> * sake.
> */
> - if (uplink_upper)
> - dev_hold(uplink_upper);
> + dev_hold(uplink_upper);

I see same if (..) dev_hold() in drivers/net/ethernet/mellanox/mlx5/core/lag/lag.c too.

> rcu_read_unlock();
>
> dst_is_lag_dev = (uplink_upper &&
> netif_is_lag_master(uplink_upper) &&
> real_dev == uplink_upper &&
> mlx5_lag_is_sriov(priv->mdev));
> - if (uplink_upper)
> - dev_put(uplink_upper);
> + dev_put(uplink_upper);

This pattern exists in other places in the same file and others too.

Let's change all of them in one patch.

Thanks

>
> /* if the egress device isn't on the same HW e-switch or
> * it's a LAG device, use the uplink
> --
> 2.43.2
>
>