[dpdk-dev] [PATCH 1/3] eal/arm64: remove the braces {} for dmb(), dsb()

[Jia He]

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 at gmail.com>
>>> Signed-off-by: jia.he at 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();
>
> 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