[PATCH v2 3/9] env: correctly handle result in env_init

[Tom Rini]

On Fri, Jun 19, 2020 at 02:14:00PM +0000, Patrick DELAUNAY wrote:
> Hi Tom and Marek,
> 
> > From: Tom Rini <trini at konsulko.com>
> > Sent: jeudi 18 juin 2020 21:16
> > 
> > On Tue, Jun 16, 2020 at 09:40:42AM +0200, Patrick Delaunay wrote:
> > 
> > > Don't return error with ret=-ENOENT when the optional ops drv->init is
> > > absent but only if env_driver_lookup doesn't found driver.
> > >
> > > This patch correct an issue for the code
> > >   if (!env_init())
> > >      env_load()
> > > When only ext4 is supported (CONFIG_ENV_IS_IN_EXT4), as the backend
> > > env/ext4.c doesn't define an ops .init
> > >
> > > Signed-off-by: Patrick Delaunay <patrick.delaunay at st.com>
> > > ---
> > >
> > > (no changes since v1)
> > >
> > >  env/env.c | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/env/env.c b/env/env.c
> > > index dcc25c030b..819c88f729 100644
> > > --- a/env/env.c
> > > +++ b/env/env.c
> > > @@ -295,7 +295,10 @@ int env_init(void)
> > >  	int prio;
> > >
> > >  	for (prio = 0; (drv = env_driver_lookup(ENVOP_INIT, prio)); prio++) {
> > > -		if (!drv->init || !(ret = drv->init()))
> > > +		ret = 0;
> > > +		if (drv->init)
> > > +			ret = drv->init();
> > > +		if (!ret)
> > >  			env_set_inited(drv->location);
> > >
> > >  		debug("%s: Environment %s init done (ret=%d)\n", __func__,
> > 
> > I'm adding in Marek here because this reminds me of similar questions / concerns
> > I had looking in to his series.  At root, I think we're not being consistent in each of
> > our env backing implementations about where flags such as ENV_VALID are set,
> > and return values / checks of functions.
> > 
> > Just outside of the start of the patch context here, we set ret to -ENOENT and just
> > past this, if still -ENOENT we say ENV_VALID and point at the default
> > environment.
> > 
> > But, I don't follow the patch commit message here.  If we don't have
> > drv->init we call env_set_inited(drv->location) but we won't have change
> > ret to 0, which means that later on down the function we go back to default
> > environment.
> 
> The cause of the issue is because the init() ops is optional in "struct env_driver".

Right.

> When this opt is absent, I assume that the initialization is not mandatory but
> this inititialization need to be tagged in gd->env_has_init with the call of
> env_set_inited() function 

So when drv->init isn't set we are already calling env_set_inited(...).
If that's not the case, what's going on?

> And the ENV backend is FOUND (don't return -ENOENT)
> 
> else the next call of env_has_inited(drv->location) always failed : in env_load()
> 
> I see the error  in EXT4 env backend,.all the other backend as a env_init() function
> 
> But some othe backend don't define the .init operation and have the issue
> 
> eeprom.c:235:U_BOOT_ENV_LOCATION(eeprom) = {
> ext4.c:135:U_BOOT_ENV_LOCATION(ext4) = {
> fat.c:128:U_BOOT_ENV_LOCATION(fat) = { 
> mmc.c:393:U_BOOT_ENV_LOCATION(mmc) = {
> onenand.c:108:U_BOOT_ENV_LOCATION(onenand) = {
> sata.c:117:U_BOOT_ENV_LOCATION(sata) = { 
> ubi.c:179:U_BOOT_ENV_LOCATION(ubi) = {
> 
> The other don't have issue:
> 
> flash.c:358:U_BOOT_ENV_LOCATION(flash) = {
> flash.c:368:	.init		= env_flash_init,
> nand.c:382:U_BOOT_ENV_LOCATION(nand) = {
> nand.c:389:	.init		= env_nand_init,
> nowhere.c:30:U_BOOT_ENV_LOCATION(nowhere) = {
> nowhere.c:32:	.init		= env_nowhere_init,
> nvram.c:117:U_BOOT_ENV_LOCATION(nvram) = {
> nvram.c:122:	.init		= env_nvram_init,
> remote.c:54:U_BOOT_ENV_LOCATION(remote) = {
> remote.c:59:	.init		= env_remote_init,
> sf.c:306:U_BOOT_ENV_LOCATION(sf) = {
> sf.c:312:	.init		= env_sf_init,

Right, there should be a problem showing up on a ton of locations, not
just ext4 which is why I'm concerned / confused here.  While ext4 isn't
as widely used yet as I would expect, FAT/MMC are.

> > So isn't this a problem in most environment cases then?  Thanks!
> 
> I don't sure which environment configuration can case issue (only one ENV without drc->init() function)
> But no issue if at least one CONFIG_ENV_IS_ is activated with driver implementing init ops 
> 
> But I see the issue in SANDBOX when I activate EXT4 only target. (CONFIG_ENV_IS_IN_EXT4), 
> And no more issue when I add CONFIG_ENV_IS_NOWHERE.
> 
> PS: no direct issue if env_init result is not checked
>        but I check this result in the sandbox tests in next patches:
> 	if (!env_init())
> 	     env_load()
>  
>        but anyway inconsistent value of gd->env_has_init 
>        which can be a problem for any env_has_inited() calls

Right.  I think there's some bigger inconsistency going on here that
needs to be fixed.  I'm also confused / concerned how you're not seeing
env_set_inite(..) being called.  if (!NULL) is true.  Thanks!

-- 
Tom
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