[dpdk-dev] [PATCH v3 4/4] ethdev: use C11 atomic builtins for link status update

[Phil Yang]

Since rte_atomicXX APIs are not allowed to be used, use C11 atomic
builtins for link status update.

Signed-off-by: Phil Yang <phil.y...@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
Acked-by: Andrew Rybchenko <arybche...@solarflare.com>
---
 lib/librte_ethdev/rte_ethdev_driver.h | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/lib/librte_ethdev/rte_ethdev_driver.h 
b/lib/librte_ethdev/rte_ethdev_driver.h
index 23cc1e0..04ac8e9 100644
--- a/lib/librte_ethdev/rte_ethdev_driver.h
+++ b/lib/librte_ethdev/rte_ethdev_driver.h
@@ -920,8 +920,7 @@ static inline int
 rte_eth_linkstatus_set(struct rte_eth_dev *dev,
                       const struct rte_eth_link *new_link)
 {
-       volatile uint64_t *dev_link
-                = (volatile uint64_t *)&(dev->data->dev_link);
+       uint64_t *dev_link = (uint64_t *)&(dev->data->dev_link);
        union {
                uint64_t val64;
                struct rte_eth_link link;
@@ -929,8 +928,8 @@ rte_eth_linkstatus_set(struct rte_eth_dev *dev,
 
        RTE_BUILD_BUG_ON(sizeof(*new_link) != sizeof(uint64_t));
 
-       orig.val64 = rte_atomic64_exchange(dev_link,
-                                          *(const uint64_t *)new_link);
+       orig.val64 = __atomic_exchange_n(dev_link, *(const uint64_t *)new_link,
+                                       __ATOMIC_SEQ_CST);
 
        return (orig.link.link_status == new_link->link_status) ? -1 : 0;
 }
@@ -948,20 +947,12 @@ static inline void
 rte_eth_linkstatus_get(const struct rte_eth_dev *dev,
                       struct rte_eth_link *link)
 {
-       volatile uint64_t *src = (uint64_t *)&(dev->data->dev_link);
+       uint64_t *src = (uint64_t *)&(dev->data->dev_link);
        uint64_t *dst = (uint64_t *)link;
 
        RTE_BUILD_BUG_ON(sizeof(*link) != sizeof(uint64_t));
 
-#ifdef __LP64__
-       /* if cpu arch has 64 bit unsigned lon then implicitly atomic */
-       *dst = *src;
-#else
-       /* can't use rte_atomic64_read because it returns signed int */
-       do {
-               *dst = *src;
-       } while (!rte_atomic64_cmpset(src, *dst, *dst));
-#endif
+       *dst = __atomic_load_n(src, __ATOMIC_SEQ_CST);
 }
 
 /**
-- 
2.7.4