[dpdk-dev] [PATCH] eal / malloc : alignment parameter check failing due to changes in rte_is_power_of_2

[Doherty, Declan]

> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> Sent: Friday, January 16, 2015 5:02 PM
> To: Doherty, Declan
> Cc: dev at dpdk.org; De Lara Guarch, Pablo
> Subject: Re: [dpdk-dev] [PATCH] eal / malloc : alignment parameter check failing
> due to changes in rte_is_power_of_2
> 
> 2015-01-16 15:10, Declan Doherty:
> > In commit 2fc8d6d the behaviour of function rte_is_power_of_2 was
> > changed to not return true for 0. memzone_reserve_aligned_thread_unsafe
> > and rte_malloc_socket both make the assumption that for align = 0
> > !rte_is_power_of_2(align) will return false. This patch adds a check
> > that align parameter is non-zero before doing the power of 2 check
> >
> > Signed-off-by: Declan Doherty <declan.doherty at intel.com>
> [...]
> > -	if (!rte_is_power_of_2(align)) {
> > +	if (align ? !rte_is_power_of_2(align) : 0) {
> [...]
> > -	if (size == 0 || !rte_is_power_of_2(align))
> > +	if (size == 0 || align ? !rte_is_power_of_2(align) : 0)
> 
> I don't understand why you write "align ? !rte_is_power_of_2(align) : 0"
> instead of the more readable "align && !rte_is_power_of_2(align)" ?
> 
> Pablo acked it so I guess there is something obvious I'm missing.
> 
> --
> Thomas

No there's nothing you're missing, this is just the way I saw the logic, if align is none
zero, then test the power of 2 condition otherwise return 0. I have no problem with
your suggestion in you prefer that, at the end of the day the logic test works out equivalent.