[U-Boot] [RFC PATCH v2] u-boot: remove driver lookup loop from env_save()

[Simon Goldschmidt]

On 12.07.2018 12:52, Nicholas Faustini wrote:
> When called with ENVOP_SAVE, env_get_location() only returns the
> gd->env_load_location variable without actually checking for
> the environment location and priority.
> 
> This behaviour causes env_save() to fall into an infinite loop when
> the low-level drv->save() call fails.
> 
> The env_save() function should not loop through the environment
> location list but it should save the environment into the location
> stored in gd->env_load_location by the last env_load() call.
> 
> Signed-off-by: Nicholas Faustini <nicholas.faustini at azcomtech.com>
> ---
> 
> Changes in v2:
> - Restore gd->env_load_location to the highest priority location when
>    env_load() fails
> 
>   env/env.c | 10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/env/env.c b/env/env.c
> index 5c0842a..18eb78d 100644
> --- a/env/env.c
> +++ b/env/env.c
> @@ -205,22 +205,24 @@ int env_load(void)
>   			return 0;
>   	}
>   
> +	env_get_location(ENVOP_LOAD, 0);

A comment why this is required would be good, I guess.

> +
>   	return -ENODEV;
>   }
>   
>   int env_save(void)
>   {
>   	struct env_driver *drv;
> -	int prio;
>   
> -	for (prio = 0; (drv = env_driver_lookup(ENVOP_SAVE, prio)); prio++) {
> +	drv = env_driver_lookup(ENVOP_SAVE, 0);

Thinking again about this, would it make more sense to store 
'env_load_prio' in 'gd' after successful load? That way, 
'env_get_location()' would be more straightforward (no special case for 
ENVOP_SAVE) and here in 'env_save()' we could just write something like 
this:

drv = env_driver_lookup(ENVOP_SAVE, gd->env_load_prio);


Simon

> +	if (drv) {
>   		int ret;
>   
>   		if (!drv->save)
> -			continue;
> +			return -ENODEV;
>   
>   		if (!env_has_inited(drv->location))
> -			continue;
> +			return -ENODEV;
>   
>   		printf("Saving Environment to %s... ", drv->name);
>   		ret = drv->save();
>