Re: [PATCH v2] regulator: wm831x-dcdc: Use pointer after NULL check

[Charles Keepax <ckeepax@opensource.wolfsonmicro.com>]

On Thu, Jul 02, 2015 at 11:02:54AM +0000, Maninder Singh wrote:
> Hello charles,
> >> pdata is used before NULL check, so it looks misleading.
> >> If pdata validation is required then we have to
> >> first check for pdata validation, then calculate id,
> >> and then second check for pdata->dcdc[id].
> >> 
> >> and it is better to use !pointer than (pointer == NULL)
> >> 
> >> Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
> >> ---
> 
> >The patch basically looks fine, but it feels a bit like needless
> >churn. The current code is perfectly correct and feels clear
> >enough to me.
> 
> Reason for patch is we are checking a pointer which is already dereferenced 
> before NULL check, which looks misleading.
> If we know code is working correctly, Then we may simply drop NULL check,
> rather than these changes. 

You can't drop the NULL check because then we might dereference a
NULL pointer. ARRAY_SIZE(pdata->dcdc) is perfectly save because
sizeof only works on types so no actual dereference takes place.

Thanks,
Charles