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 <a...@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);
