[U-Boot] [PATCH v2] common: env_nand: Ensure that we have nand_info[0] prior to use

[Tom Rini]

On Mon, Aug 15, 2016 at 11:48:31AM -0500, Scott Wood wrote:
> On Mon, 2016-08-15 at 11:56 -0400, Tom Rini wrote:
> > Now that nand_info[] is an array of pointers we need to ensure that it's
> > been populated prior to use.  We may for example have ENV in NAND set in
> > configurations that run on boards with and without NAND (where default
> > env is fine enough, such as omap3_beagle and beagleboard (NAND) vs
> > beagle xM (no NAND)).
> > 
> > Fixes: b616d9b0a708 ("nand: Embed mtd_info in struct nand_chip")
> > Cc: Scott Wood <oss at buserror.net>
> > Signed-off-by: Tom Rini <trini at konsulko.com>
> > ---
> > Changes in v2:
> > - Oops, move check on the saveenv side in to erase_and_write_env
> > ---
> >  common/env_nand.c | 9 +++++++--
> >  1 file changed, 7 insertions(+), 2 deletions(-)
> > 
> > diff --git a/common/env_nand.c b/common/env_nand.c
> > index fc99a5e3fc0d..96a1020b5e79 100644
> > --- a/common/env_nand.c
> > +++ b/common/env_nand.c
> > @@ -163,6 +163,9 @@ static int erase_and_write_env(const struct env_location
> > *location,
> >  {
> >  	int ret = 0;
> >  
> > +	if (!nand_info[0])
> > +		return 1;
> > +
> >  	printf("Erasing %s...\n", location->name);
> >  	if (nand_erase_opts(nand_info[0], &location->erase_opts))
> >  		return 1;
> > @@ -244,10 +247,12 @@ static int readenv(size_t offset, u_char *buf)
> >  {
> >  	size_t end = offset + CONFIG_ENV_RANGE;
> >  	size_t amount_loaded = 0;
> > -	size_t blocksize, len;
> > +	size_t blocksize = 0, len;
> >  	u_char *char_ptr;
> >  
> > -	blocksize = nand_info[0]->erasesize;
> > +	if (nand_info[0])
> > +		blocksize = nand_info[0]->erasesize;
> > +
> >  	if (!blocksize)
> >  		return 1;
> >  
> 
> Messing around with blocksize rather than directly returning is awkward -- it
> makes it look as if you could proceed with blocksize zero until you read the
> next statement.  And is there ever a case where blocksize can be zero, now
> that uninitialized NAND devices will simply have a NULL pointer?

OK, I can see how that reads awkwardly now.  And I suspect that no,
blocksize could never be valid and zero.  I'll re-work for a v3.

-- 
Tom
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