[PATCH v4 04/27] bpf: use C11 atomics in BPF_ST_ATOMIC_REG

[Stephen Hemminger]

The BPF_ST_ATOMIC_REG macro generated code with deprecated
rte_atomicNN_add and rte_atomicNN_exchange.

Replace this with the equivalent rte_stdatomic definitions.
Use memory order seq_cst to preserve the previous behavior of
rte_atomicNN_add() / rte_atomicNN_exchange() and matches
the Linux kernel BPF interpreter for these opcodes.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 lib/bpf/bpf_exec.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/lib/bpf/bpf_exec.c b/lib/bpf/bpf_exec.c
index 18013753b1..ee6ec7516f 100644
--- a/lib/bpf/bpf_exec.c
+++ b/lib/bpf/bpf_exec.c
@@ -10,6 +10,7 @@
 #include <rte_log.h>
 #include <rte_debug.h>
 #include <rte_byteorder.h>
+#include <rte_stdatomic.h>
 
 #include "bpf_impl.h"
 
@@ -65,16 +66,16 @@
 		(type)(reg)[(ins)->src_reg])
 
 #define BPF_ST_ATOMIC_REG(reg, ins, tp)	do { \
+	RTE_ATOMIC(uint##tp##_t) *dst = (RTE_ATOMIC(uint##tp##_t) *) \
+		(uintptr_t)((reg)[(ins)->dst_reg] + (ins)->off); \
 	switch (ins->imm) { \
 	case BPF_ATOMIC_ADD: \
-		rte_atomic##tp##_add((rte_atomic##tp##_t *) \
-			(uintptr_t)((reg)[(ins)->dst_reg] + (ins)->off), \
-			(reg)[(ins)->src_reg]); \
+		rte_atomic_fetch_add_explicit(dst, \
+			(reg)[(ins)->src_reg], rte_memory_order_seq_cst); \
 		break; \
 	case BPF_ATOMIC_XCHG: \
-		(reg)[(ins)->src_reg] = rte_atomic##tp##_exchange((uint##tp##_t *) \
-			(uintptr_t)((reg)[(ins)->dst_reg] + (ins)->off), \
-			(reg)[(ins)->src_reg]); \
+		(reg)[(ins)->src_reg] = rte_atomic_exchange_explicit(dst, \
+			(reg)[(ins)->src_reg], rte_memory_order_seq_cst); \
 		break; \
 	default: \
 		/* this should be caught by validator and never reach here */ \
-- 
2.53.0