[U-Boot] [PATCH v3] u-boot: remove driver lookup loop from env_save()

[Simon Goldschmidt]

On 13.07.2018 11:03, 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 v3:
> - Add comment when env_load() fails and the env location is restored
> - Introduce env_load_prio into gd struct. It stores the current
>    priority of the environment location. Refactor of env_get_location()
>    which acts the same on all the 'env_operation'
> 
> Changes in v2:
> - Restore gd->env_load_location to the highest priority location when
>    env_load() fails
> 
>   env/env.c                         | 35 +++++++++++++++++------------------
>   include/asm-generic/global_data.h |  1 +
>   2 files changed, 18 insertions(+), 18 deletions(-)
> 
> diff --git a/env/env.c b/env/env.c
> index 5c0842a..ba13ba8 100644
> --- a/env/env.c
> +++ b/env/env.c
> @@ -119,21 +119,13 @@ static void env_set_inited(enum env_location location)
>    */
>   __weak enum env_location env_get_location(enum env_operation op, int prio)
>   {
> -	switch (op) {
> -	case ENVOP_GET_CHAR:
> -	case ENVOP_INIT:
> -	case ENVOP_LOAD:
> -		if (prio >= ARRAY_SIZE(env_locations))
> -			return ENVL_UNKNOWN;
> -
> -		gd->env_load_location = env_locations[prio];
> -		return gd->env_load_location;
> -
> -	case ENVOP_SAVE:
> -		return gd->env_load_location;
> -	}
> +	if (prio >= ARRAY_SIZE(env_locations))
> +		return ENVL_UNKNOWN;
> +
> +	gd->env_load_location = env_locations[prio];
> +	gd->env_load_prio = prio;
>   
> -	return ENVL_UNKNOWN;
> +	return gd->env_load_location;

Ehrm, I just saw gd->env_load_location is now unused...
Other than that:

Reviewed-by: Simon Goldschmidt <goldsimon at gmx.de>

>   }
>   
>   
> @@ -205,22 +197,29 @@ int env_load(void)
>   			return 0;
>   	}
>   
> +	/*
> +	 * In case of invalid environment, we set the 'default' env location
> +	 * to the highest priority. In this way, next calls to env_save()
> +	 * will restore the environment at the right place.
> +	 */
> +	env_get_location(ENVOP_LOAD, 0);
> +
>   	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, gd->env_load_prio);
> +	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();
> diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
> index 2d451f8..319810a 100644
> --- a/include/asm-generic/global_data.h
> +++ b/include/asm-generic/global_data.h
> @@ -51,6 +51,7 @@ typedef struct global_data {
>   	unsigned long env_valid;	/* Environment valid? enum env_valid */
>   	unsigned long env_has_init;	/* Bitmask of boolean of struct env_location offsets */
>   	int env_load_location;
> +	int env_load_prio;
>   
>   	unsigned long ram_top;		/* Top address of RAM used by U-Boot */
>   	unsigned long relocaddr;	/* Start address of U-Boot in RAM */
>