[dpdk-dev] [PATCH v3 08/24] rte_ring_generic.h: stack declarations before code
Andy Green
andy at warmcat.com
Mon May 14 01:21:52 CEST 2018
On 05/14/2018 12:47 AM, Thomas Monjalon wrote:
> 12/05/2018 03:59, Andy Green:
>> /projects/lagopus/src/dpdk/build/include/rte_ring_generic.h:
>> In function '__rte_ring_move_prod_head':
>> /projects/lagopus/src/dpdk/build/include/rte_ring_generic.h:76:3:
>> warning: ISO C90 forbids mixed declarations and code
>> [-Wdeclaration-after-statement]
>> const uint32_t cons_tail = r->cons.tail;
>> ^~~~~
>> /projects/lagopus/src/dpdk/build/include/rte_ring_generic.h:
>> In function '__rte_ring_move_cons_head':
>> /projects/lagopus/src/dpdk/build/include/rte_ring_generic.h:147:3:
>> warning: ISO C90 forbids mixed declarations and code
>> [-Wdeclaration-after-statement]
>> const uint32_t prod_tail = r->prod.tail;
>
> The fix line is:
> Fixes: 0dfc98c507b1 ("ring: separate out head index manipulation")
OK... people can just use git blame at the time they want to know this
though.
> But I wonder why it was done like this. Maybe there is a hidden reason.
> Bruce? Olivier?
It's not crazy to do it for clarity, or when you thought there'd be more
uses of the calculation. At any rate, I don't see any openings for it
to affect the code changing it.
-Andy
>> Signed-off-by: Andy Green <andy at warmcat.com>
> [...]
>> --- a/lib/librte_ring/rte_ring_generic.h
>> +++ b/lib/librte_ring/rte_ring_generic.h
>> @@ -73,14 +73,13 @@ __rte_ring_move_prod_head(struct rte_ring *r, int is_sp,
>> */
>> rte_smp_rmb();
>>
>> - const uint32_t cons_tail = r->cons.tail;
>> /*
>> * The subtraction is done between two unsigned 32bits value
>> * (the result is always modulo 32 bits even if we have
>> * *old_head > cons_tail). So 'free_entries' is always between 0
>> * and capacity (which is < size).
>> */
>> - *free_entries = (capacity + cons_tail - *old_head);
>> + *free_entries = (capacity + r->cons.tail - *old_head);
>
>
>
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