Re: [PATCH v2 4/7] nvmem: simplify locking with guard()

[Johan Hovold <johan@kernel.org>]

On Mon, Feb 23, 2026 at 11:57:05AM +0100, Bartosz Golaszewski wrote:
> Use lock guards from cleanup.h to simplify locking. While at it: add the
> missing mutex.h include.
 
> @@ -1335,7 +1326,7 @@ nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
>  
>  	dev_id = dev_name(dev);
>  
> -	mutex_lock(&nvmem_lookup_mutex);
> +	guard(mutex)(&nvmem_mutex);
>  
>  	list_for_each_entry(lookup, &nvmem_lookup_list, node) {
>  		if ((strcmp(lookup->dev_id, dev_id) == 0) &&
> @@ -1343,11 +1334,9 @@ nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
>  			/* This is the right entry. */
>  			nvmem = __nvmem_device_get((void *)lookup->nvmem_name,
>  						   device_match_name);
> -			if (IS_ERR(nvmem)) {
> +			if (IS_ERR(nvmem))
>  				/* Provider may not be registered yet. */
> -				cell = ERR_CAST(nvmem);
> -				break;
> -			}
> +				return ERR_CAST(nvmem);

Please keep the brackets here for readability.

>  
>  			cell_entry = nvmem_find_cell_entry_by_name(nvmem,
>  								   lookup->cell_name);
> @@ -1363,7 +1352,6 @@ nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
>  		}
>  	}
>  
> -	mutex_unlock(&nvmem_lookup_mutex);
>  	return cell;
>  }
>  
> @@ -1379,14 +1367,14 @@ nvmem_find_cell_entry_by_node(struct nvmem_device *nvmem, struct device_node *np
>  {
>  	struct nvmem_cell_entry *iter, *cell = NULL;
>  
> -	mutex_lock(&nvmem_mutex);
> +	guard(mutex)(&nvmem_mutex);
> +
>  	list_for_each_entry(iter, &nvmem->cells, node) {
>  		if (np == iter->np) {
>  			cell = iter;
>  			break;

Shouldn't you return cell here now?

>  		}
>  	}
> -	mutex_unlock(&nvmem_mutex);
>  
>  	return cell;
>  }

And explicit NULL here (dropping the initialisation above)?

Johan