Subject: Re: [PATCH net-next 1/2] dpaa2-eth: defer probe on object allocate

From: Andrew Lunn <[email-masked]>
Date: Thu, 8 Nov 2018 19:25:07 +0100

On Thu, Nov 08, 2018 at 01:17:47PM +0000, Ioana Ciornei wrote:
> The fsl_mc_object_allocate function can fail because not all allocatable
> objects are probed by the fsl_mc_allocator at the call time. Defer the
> dpaa2-eth probe when this happens.
> 
> Signed-off-by: Ioana Ciornei <[email-masked]>
> ---
>  drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 30 +++++++++++++++++-------
>  1 file changed, 21 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> index 88f7acc..71f5cd4 100644
> --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
> @@ -1434,8 +1434,11 @@ static struct fsl_mc_device *setup_dpcon(struct dpaa2_eth_priv *priv)
>  	err = fsl_mc_object_allocate(to_fsl_mc_device(dev),
>  				     FSL_MC_POOL_DPCON, &dpcon);
>  	if (err) {
> -		dev_info(dev, "Not enough DPCONs, will go on as-is\n");
> -		return NULL;
> +		if (err == -ENXIO)
> +			err = -EPROBE_DEFER;
> +		else
> +			dev_info(dev, "Not enough DPCONs, will go on as-is\n");
> +		return ERR_PTR(err);
>  	}
>  
>  	err = dpcon_open(priv->mc_io, 0, dpcon->obj_desc.id, &dpcon->mc_handle);
> @@ -1493,8 +1496,10 @@ static void free_dpcon(struct dpaa2_eth_priv *priv,
>  		return NULL;
>  
>  	channel->dpcon = setup_dpcon(priv);
> -	if (!channel->dpcon)
> +	if (IS_ERR_OR_NULL(channel->dpcon)) {
> +		err = PTR_ERR(channel->dpcon);
>  		goto err_setup;
> +	}

Hi Ioana

You need to be careful with IS_ERR_OR_NULL(). If it is a NULL,
PTR_ERR() is going to return 0. You then jump to the error cleanup
code, but return 0, meaning everything is O.K.

      Andrew