From: Jianbo Liu <jianbo.liu@arm.com>
To: Jia He <hejianet@gmail.com>
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
Subject: Re: [dpdk-dev] [PATCH 1/3] eal/arm64: remove the braces {} for dmb(), dsb()
Date: Thu, 9 Nov 2017 11:21:46 +0800 [thread overview]
Message-ID: <20171109032145.GA26939@arm.com> (raw)
In-Reply-To: <028263d0-44de-bd0c-c495-081588a0ad20@gmail.com>
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.
> >will be like below after precompiling:
> >if (condition)
> > asm volatile("dsb " "ld" : : : "memory");;
> >else
> > anything();
> >Then, the same error - error: 'else' without a previous 'if'
> >
> Ignore my words above，thanks
> sorry for the inconvenience.
> And I've sent out v4 in this mail thread. The ";" has been removed.
> If no more comments, I will send out v5 (2 patch sets for 17 and 18)
>
> --
> Cheers,
> Jia
>
>
> --
> Cheers,
> Jia
>
--
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next prev parent reply other threads:[~2017-11-09 3:22 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-08 6:17 Jia He
2017-11-08 6:17 ` [dpdk-dev] [PATCH 2/3] ring: guarantee load ordering of cons/prod when doing enqueue/dequeue Jia He
2017-11-08 7:27 ` Jerin Jacob
2017-11-08 9:49 ` Ananyev, Konstantin
2017-11-08 6:17 ` [dpdk-dev] [PATCH 3/3] config: support C11 memory model for arm64 Jia He
2017-11-08 7:17 ` [dpdk-dev] [PATCH 1/3] eal/arm64: remove the braces {} for dmb(), dsb() Jerin Jacob
2017-11-08 10:28 ` Bruce Richardson
2017-11-09 1:22 ` Jia He
2017-11-09 3:14 ` Jia He
2017-11-09 3:21 ` Jianbo Liu [this message]
2017-11-09 4:43 ` Jia He
2017-11-09 4:56 ` Jianbo Liu
2017-11-09 9:38 ` Ananyev, Konstantin
2017-11-09 9:58 ` Jianbo Liu
2017-11-09 10:08 ` Ananyev, Konstantin
2017-11-10 2:06 ` Jia He
2017-11-10 3:09 ` Jianbo Liu
2017-11-10 10:06 ` Ananyev, Konstantin
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