netdev - Re: [PATCH] net: macb: Only disable NAPI on the actual error path

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Date:   Mon, 15 Jun 2020 16:51:15 +0200
From:   LABBE Corentin <clabbe@...libre.com>
To:     Charles Keepax <ckeepax@...nsource.cirrus.com>
Cc:     davem@...emloft.net, nicolas.ferre@...rochip.com, kuba@...nel.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH] net: macb: Only disable NAPI on the actual error path

On Mon, Jun 15, 2020 at 02:18:54PM +0100, Charles Keepax wrote:
> A recent change added a disable to NAPI into macb_open, this was
> intended to only happen on the error path but accidentally applies
> to all paths. This causes NAPI to be disabled on the success path, which
> leads to the network to no longer functioning.
> 
> Fixes: 014406babc1f ("net: cadence: macb: disable NAPI on error")
> Signed-off-by: Charles Keepax <ckeepax@...nsource.cirrus.com>
> ---
>  drivers/net/ethernet/cadence/macb_main.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 5b9d7c60eebc0..67933079aeea5 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -2565,15 +2565,14 @@ static int macb_open(struct net_device *dev)
>  	if (bp->ptp_info)
>  		bp->ptp_info->ptp_init(dev);
>  
> +	return 0;
> +
>  napi_exit:
>  	for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue)
>  		napi_disable(&queue->napi);
>  pm_exit:
> -	if (err) {
> -		pm_runtime_put_sync(&bp->pdev->dev);
> -		return err;
> -	}
> -	return 0;
> +	pm_runtime_put_sync(&bp->pdev->dev);
> +	return err;
>  }
>  
>  static int macb_close(struct net_device *dev)
> -- 
> 2.11.0
> 

Shame on me to not have see this.

With the fix it works.
Tested-by: Corentin Labbe <clabbe@...libre.com>
Tested-on: qemu-xilinx-zynq-a9