[PATCH v2 15/16] mbuf: use previous value atomic fetch operations

[Tyler Retzlaff]

Use __atomic_fetch_{add,and,or,sub,xor} instead of
__atomic_{add,and,or,sub,xor}_fetch adding the necessary code to
allow consumption of the resulting value.

Signed-off-by: Tyler Retzlaff <roret...@linux.microsoft.com>
---
 lib/mbuf/rte_mbuf.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/mbuf/rte_mbuf.h b/lib/mbuf/rte_mbuf.h
index 3a82eb1..e5ab4a4 100644
--- a/lib/mbuf/rte_mbuf.h
+++ b/lib/mbuf/rte_mbuf.h
@@ -381,8 +381,8 @@ struct rte_pktmbuf_pool_private {
 static inline uint16_t
 __rte_mbuf_refcnt_update(struct rte_mbuf *m, int16_t value)
 {
-       return __atomic_add_fetch(&m->refcnt, (uint16_t)value,
-                                __ATOMIC_ACQ_REL);
+       return __atomic_fetch_add(&m->refcnt, value,
+                                __ATOMIC_ACQ_REL) + value;
 }
 
 /**
@@ -502,8 +502,8 @@ struct rte_pktmbuf_pool_private {
                return (uint16_t)value;
        }
 
-       return __atomic_add_fetch(&shinfo->refcnt, (uint16_t)value,
-                                __ATOMIC_ACQ_REL);
+       return __atomic_fetch_add(&shinfo->refcnt, value,
+                                __ATOMIC_ACQ_REL) + value;
 }
 
 /** Mbuf prefetch */
@@ -1315,8 +1315,8 @@ static inline int 
__rte_pktmbuf_pinned_extbuf_decref(struct rte_mbuf *m)
         * Direct usage of add primitive to avoid
         * duplication of comparing with one.
         */
-       if (likely(__atomic_add_fetch(&shinfo->refcnt, (uint16_t)-1,
-                                    __ATOMIC_ACQ_REL)))
+       if (likely(__atomic_fetch_add(&shinfo->refcnt, -1,
+                                    __ATOMIC_ACQ_REL) - 1))
                return 1;
 
        /* Reinitialize counter before mbuf freeing. */
-- 
1.8.3.1