Re: [PATCH V2 1/6] PM / OPP: Free resources and properly return error on failure

[Dan Carpenter <dan.carpenter@oracle.com>]

On Tue, Aug 11, 2015 at 04:04:34PM +0530, Viresh Kumar wrote:
> _of_init_opp_table_v2() isn't freeing up resources on some errors and
> the error values returned are also not correct always.
> 
> This fixes following problems:
> - Return -ENOENT, if no entries are found in the table.
> - Use IS_ERR() to properly check return value of _find_device_opp().
> - Return error value with PTR_ERR() in above case.
> - Free table if _find_device_opp() fails.
> 
> Fixes: 274659029c9d ("PM / OPP: Add support to parse operating-points-v2" bindings")
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  drivers/base/power/opp.c | 29 +++++++++++++++--------------
>  1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> index 204c6c945168..bcbd92c3b717 100644
> --- a/drivers/base/power/opp.c
> +++ b/drivers/base/power/opp.c
> @@ -1323,28 +1323,29 @@ static int _of_init_opp_table_v2(struct device *dev,
>  		if (ret) {
>  			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
>  				ret);
> -			break;
> +			goto free_table;
>  		}
>  	}
>  
>  	/* There should be one of more OPP defined */
> -	if (WARN_ON(!count))
> +	if (WARN_ON(!count)) {
> +		ret = -ENOENT;
>  		goto put_opp_np;
> +	}

This is weird to me, because we are going backwards.  What happens if
we goto free_table without adding anything?  I suspect it's fine, but if
it's a bug then this code still has problems.

What about if we only increment count when _opp_add_static_v2()
succeeds, and change it back to the original where we break, check
count, then check ret.  That way we don't need to know the details of
free_table to see that the code is correct.

regards,
dan carpenter