netdev - Re: [PATCH net V1 4/6] net/mlx4_core: Do not BUG

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Date:	Thu, 18 Feb 2016 15:45:40 +0300
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Or Gerlitz <ogerlitz@...lanox.com>,
	"David S. Miller" <davem@...emloft.net>
Cc:	netdev@...r.kernel.org, Eran Ben Elisha <eranbe@...lanox.com>,
	Yishai Hadas <yishaih@...lanox.com>,
	Daniel Jurgens <danielj@...lanox.com>
Subject: Re: [PATCH net V1 4/6] net/mlx4_core: Do not BUG_ON during reset when
 PCI is offline

Hello.

On 2/17/2016 6:24 PM, Or Gerlitz wrote:

> From: Daniel Jurgens <danielj@...lanox.com>
>
> The PCI channel could go offline during reset due to EEH.  Don't bug on in
> this case, the error is recoverable.
>
> Fixes: f6bc11e42646 ('net/mlx4_core: Enhance the catas flow to support device reset')
> Signed-off-by: Daniel Jurgens <danielj@...lanox.com>
> Reviewed-by: Yishai Hadas <yishaih@...lanox.com>
> ---
>   drivers/net/ethernet/mellanox/mlx4/catas.c | 11 +++++++++--
>   1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx4/catas.c b/drivers/net/ethernet/mellanox/mlx4/catas.c
> index 715de8a..c7e9399 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/catas.c
> +++ b/drivers/net/ethernet/mellanox/mlx4/catas.c
> @@ -182,10 +182,17 @@ void mlx4_enter_error_state(struct mlx4_dev_persistent *persist)
>   		err = mlx4_reset_slave(dev);
>   	else
>   		err = mlx4_reset_master(dev);
> -	BUG_ON(err != 0);
>
> +	if (!err) {

    Grr, couldn't you add your new code just *instead* of BUG_ON()? There's 
really no need for empty line before the *if*.

> +		mlx4_err(dev, "device was reset successfully\n");
> +	} else {
> +		/* EEH could have disabled the PCI channel during reset. That's
> +		 * recoverable and the PCI error flow will handle it.
> +		 */
> +		if (!pci_channel_offline(dev->persist->pdev))
> +			BUG_ON(1);
> +	}
>   	dev->persist->state |= MLX4_DEVICE_STATE_INTERNAL_ERROR;
> -	mlx4_err(dev, "device was reset successfully\n");
>   	mutex_unlock(&persist->device_state_mutex);
>
>   	/* At that step HW was already reset, now notify clients */

MBR, Sergei