[dpdk-dev] [PATCH v3 08/24] rte_ring_generic.h: stack declarations before code
Thomas Monjalon
thomas at monjalon.net
Sun May 13 18:47:15 CEST 2018
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")
But I wonder why it was done like this. Maybe there is a hidden reason.
Bruce? Olivier?
> 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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