From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: "Doherty, Declan" <declan.doherty@intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] eal / malloc : alignment parameter check failing due to changes in rte_is_power_of_2
Date: Mon, 19 Jan 2015 10:00:43 +0100 [thread overview]
Message-ID: <3882238.XjXCyuyOGj@xps13> (raw)
In-Reply-To: <345C63BAECC1AD42A2EC8C63AFFC3ADC2747EE3D@IRSMSX101.ger.corp.intel.com>
2015-01-18 19:26, Doherty, Declan:
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> > 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@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)
There is an operator precedence bug here.
Parens are needed after ||.
> > 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.
>
> 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.
So I change to the simpler && form and I add parentheses
after || to correctly check size==0.
Applied with above changes.
Thanks
--
Thomas
prev parent reply other threads:[~2015-01-19 9:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-16 15:10 Declan Doherty
2015-01-16 15:37 ` De Lara Guarch, Pablo
2015-01-16 17:01 ` Thomas Monjalon
2015-01-18 19:26 ` Doherty, Declan
2015-01-19 9:00 ` Thomas Monjalon [this message]
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