[PATCH V2 4/7] env: Fix invalid env handling in env_init()

[Tom Rini]

On Tue, Jul 07, 2020 at 08:51:36PM +0200, Marek Vasut wrote:

> This fixes the case where there are multiple environment drivers, one of
> them is the default environment one, and it is followed by an environment
> driver which does not implement .init() callback. The default environment
> driver sets gd->env_valid to ENV_INVALID and returns 0 from its .init()
> callback implementation, which is valid behavior for default environment.
> 
> Since the subsequent environment driver does not implement .init(), it
> also does not modify the $ret variable in the loop. Therefore, the loop
> is exited with gd->env_valid=ENV_INVALID and ret=0, which means that the
> code further down in env_init() will not reset the environment to the
> default one, which is incorrect.
> 
> This patch sets the $ret variable back to -ENOENT in case the env_valid
> is set to ENV_INVALID by an environment driver, so that the environment
> would be correctly reset back to default one, unless a subsequent driver
> loads a valid environment.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> ---
> V2: Reword commit message
> ---
>  env/env.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/env/env.c b/env/env.c
> index dcc25c030b..024d36fdbe 100644
> --- a/env/env.c
> +++ b/env/env.c
> @@ -300,6 +300,9 @@ int env_init(void)
>  
>  		debug("%s: Environment %s init done (ret=%d)\n", __func__,
>  		      drv->name, ret);
> +
> +		if (gd->env_valid == ENV_INVALID)
> +			ret = -ENOENT;
>  	}
>  
>  	if (!prio)

So, I am not sure about this change.  Given the whole thread that ends
in https://lists.denx.de/pipermail/u-boot/2020-June/417433.html this
particular part of the function is being too clever.  I think it's
intentionally not doing what you're adding right here for some use
cases.  I think that to cleanly achieve the goals of your series we need
to stop letting drv->init be optional so that we then stop doing the
particular we're doing with "ENOENT means runs this common code path for
many envs".  We may also need to make sure the link order in
env/Makefile has nowhere first in all cases, rather than just most cases
like it does now, with a big comment on why.

-- 
Tom
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