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

[Nicholas <nicholas.faustini@azcomtech.com>]

On ven, 2018-07-13 at 11:15 +0200, Simon Goldschmidt wrote:
> 
> 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@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@gmx.de>

I didn't notice that.. :blush:
I remove it from gd. 
env_load_prio is actually enough to get the information about the
location if someone will need it.

> 
> > 
> >   }
> >   
> >   
> > @@ -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 */
> >