linux-kernel - Re: [PATCH 1/2 v3] drivers: reorganize do-while loops

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Date: Wed, 1 May 2024 12:04:04 +0100
From: Sudeep Holla <sudeep.holla@....com>
To: Vincenzo Mezzela <vincenzo.mezzela@...il.com>
Cc: gregkh@...uxfoundation.org, javier.carrasco.cruz@...il.com,
	Sudeep Holla <sudeep.holla@....com>, julia.lawall@...ia.fr,
	linux-kernel@...r.kernel.org, rafael@...nel.org,
	skhan@...uxfoundation.org
Subject: Re: [PATCH 1/2 v3] drivers: reorganize do-while loops

Hi,

$subject seems to be too generic. Please change it to something like
drivers: arch_topology: Refactor do-while loops

On Wed, May 01, 2024 at 11:43:12AM +0200, Vincenzo Mezzela wrote:
> Test c = of_get_child_by_name() failures using "if(!c) break;" instead of
> having the body of the loop all within the "if(c){ }" body.
>

Drop the above description which is clear from the code.

Just mention it as refactor do-while look to move the break condition
inside the loop.

> This modification is required

s/required/in preparation/

> to move the declaration of the device_node
> directly within the loop and take advantage of the automatic cleanup
> feature provided by the __free(device_node) attribute.
> 
> Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@...il.com>
> ---
>  drivers/base/arch_topology.c | 107 ++++++++++++++++++-----------------
>  1 file changed, 55 insertions(+), 52 deletions(-)
> 
> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index 024b78a0cfc1..ea8836f0bb4b 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c

[...]

> @@ -599,48 +600,48 @@ static int __init parse_cluster(struct device_node *cluster, int package_id,
>  	do {
>  		snprintf(name, sizeof(name), "cluster%d", i);
>  		c = of_get_child_by_name(cluster, name);
> -		if (c) {
> -			leaf = false;
> -			ret = parse_cluster(c, package_id, i, depth + 1);
> -			if (depth > 0)
> -				pr_warn("Topology for clusters of clusters not yet supported\n");
> -			of_node_put(c);
> -			if (ret != 0)
> -				return ret;
> -		}
> +		if (!c)
> +			break;
> +
> +		leaf = false;
> +		ret = parse_cluster(c, package_id, i, depth + 1);
> +		if (depth > 0)
> +			pr_warn("Topology for clusters of clusters not yet supported\n");
> +		of_node_put(c);
> +		if (ret != 0)
> +			return ret;
>  		i++;
> -	} while (c);
> +	} while (1);
>  
>  	/* Now check for cores */
>  	i = 0;
>  	do {
>  		snprintf(name, sizeof(name), "core%d", i);
>  		c = of_get_child_by_name(cluster, name);
> -		if (c) {
> -			has_cores = true;
> -
> -			if (depth == 0) {
> -				pr_err("%pOF: cpu-map children should be clusters\n",
> -				       c);
> -				of_node_put(c);
> -				return -EINVAL;
> -			}
> +		if (!c)
> +			break;
>  
> -			if (leaf) {
> -				ret = parse_core(c, package_id, cluster_id,
> -						 core_id++);
> -			} else {
> -				pr_err("%pOF: Non-leaf cluster with core %s\n",
> -				       cluster, name);
> -				ret = -EINVAL;
> -			}
> +		has_cores = true;
>  
> +		if (depth == 0) {
> +			pr_err("%pOF: cpu-map children should be clusters\n", c);
>  			of_node_put(c);
> -			if (ret != 0)
> -				return ret;
> +			return -EINVAL;
>  		}
> +
> +		if (leaf) {
> +			ret = parse_core(c, package_id, cluster_id, core_id++);
> +		} else {
> +			pr_err("%pOF: Non-leaf cluster with core %s\n",
> +				cluster, name);

Extra space before 'cluster' ? checkpatch must have complain if I am not
reading this correctly.

--
Regards,
Sudeep