From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jianbo Liu <jianbo.liu@arm.com>
Subject: Re: [PATCH 1/3] eal/arm64: remove the braces {} for
	dmb(), dsb()
Date: Thu, 9 Nov 2017 12:56:03 +0800
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Cc: Bruce Richardson <bruce.richardson@intel.com>,
 jerin.jacob@caviumnetworks.com, dev@dpdk.org,
 olivier.matz@6wind.com, konstantin.ananyev@intel.com,
 hemant.agrawal@nxp.com, jia.he@hxt-semitech.com
To: Jia He <hejianet@gmail.com>
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The 11/09/2017 12:43, Jia He wrote:
> Hi Jianbo
>
>
> On 11/9/2017 11:21 AM, Jianbo Liu Wrote:
> >The 11/09/2017 11:14, Jia He wrote:
> >>
> >>On 11/9/2017 9:22 AM, Jia He Wrote:
> >>>Hi Bruce
> >>>
> >>>
> >>>On 11/8/2017 6:28 PM, Bruce Richardson Wrote:
> >>>>On Wed, Nov 08, 2017 at 06:17:10AM +0000, Jia He wrote:
> >>>>>for the code as follows:
> >>>>>if (condition)
> >>>>>     rte_smp_rmb();
> >>>>>else
> >>>>>     rte_smp_wmb();
> >>>>>Without this patch, compiler will report this error:
> >>>>>error: 'else' without a previous 'if'
> >>>>>
> >>>>>Signed-off-by: Jia He <hejianet@gmail.com>
> >>>>>Signed-off-by: jia.he@hxt-semitech.com
> >>>>>---
> >>>>>   lib/librte_eal/common/include/arch/arm/rte_atomic_64.h | 4 ++--
> >>>>>   1 file changed, 2 insertions(+), 2 deletions(-)
> >>>>>
> >>>>>diff --git
> >>>>>a/lib/librte_eal/common/include/arch/arm/rte_atomic_64.h
> >>>>>b/lib/librte_eal/common/include/arch/arm/rte_atomic_64.h
> >>>>>index 0b70d62..38c3393 100644
> >>>>>--- a/lib/librte_eal/common/include/arch/arm/rte_atomic_64.h
> >>>>>+++ b/lib/librte_eal/common/include/arch/arm/rte_atomic_64.h
> >>>>>@@ -43,8 +43,8 @@ extern "C" {
> >>>>>     #include "generic/rte_atomic.h"
> >>>>>   -#define dsb(opt)  { asm volatile("dsb " #opt : : : "memory"); }
> >>>>>-#define dmb(opt)  { asm volatile("dmb " #opt : : : "memory"); }
> >>>>>+#define dsb(opt) asm volatile("dsb " #opt : : : "memory");
> >>>>>+#define dmb(opt) asm volatile("dmb " #opt : : : "memory");
> >>>>Need to remove the trailing ";" I too I think.
> >>>>Alternatively, to keep the braces, the standard practice is to use
> >>>>do { ... } while(0)
> >>>If trailing ";" is not removed
> >>>the code:
> >>>if (condition)
> >>>     rte_smp_rmb();
> >>>else
> >>>     anything();
> >>>
> >Sorry, why not use two different functions as your conditions passed in
> >are fixed in the calling functions.
> Do you mean to split update_tail() into update_tail_enqueue() and
> update_tail_dequeue()?

Yes. So it's not need to change dsb/dmb.

Jianbo
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