[src/trunk]: src/sys/external/bsd/common/include/linux Simplify rcu_* definit...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0162c3dadd2a
branches:  trunk
changeset: 1028352:0162c3dadd2a
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Dec 19 10:47:19 2021 +0000

description:
Simplify rcu_* definitions with atomic_load/store_*.

diffstat:

 sys/external/bsd/common/include/linux/rcupdate.h |  21 ++++-----------------
 1 files changed, 4 insertions(+), 17 deletions(-)

diffs (42 lines):

diff -r d0331db2300f -r 0162c3dadd2a sys/external/bsd/common/include/linux/rcupdate.h
--- a/sys/external/bsd/common/include/linux/rcupdate.h  Sun Dec 19 10:47:13 2021 +0000
+++ b/sys/external/bsd/common/include/linux/rcupdate.h  Sun Dec 19 10:47:19 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: rcupdate.h,v 1.3 2021/12/19 09:48:29 riastradh Exp $   */
+/*     $NetBSD: rcupdate.h,v 1.4 2021/12/19 10:47:19 riastradh Exp $   */
 
 /*-
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -42,17 +42,9 @@
 
 #define        RCU_INIT_POINTER(P, V)  ((P) = (V))
 
-#define        rcu_assign_pointer(P, V) do {                                         \
-       __typeof__(*(P)) *__rcu_assign_pointer_tmp = (V);                     \
-       membar_exit();                                                        \
-       (P) = __rcu_assign_pointer_tmp;                                       \
-} while (0)
-
-#define        rcu_dereference(P) ({                                                 \
-       __typeof__(*(P)) *__rcu_dereference_tmp = (P);                        \
-       membar_datadep_consumer();                                            \
-       __rcu_dereference_tmp;                                                \
-})
+#define        rcu_assign_pointer(P,V) atomic_store_release(&(P), (V))
+#define        rcu_dereference(P)      atomic_load_consume(&(P))
+#define        rcu_access_pointer(P)   atomic_load_relaxed(&(P))
 
 #define        rcu_dereference_raw     rcu_dereference
 
@@ -61,11 +53,6 @@
        (P);                                                                  \
 })
 
-#define        rcu_access_pointer(P) ({                                              \
-       __typeof__(*(P)) *__rcu_access_pointer_tmp = (P);                     \
-       __insn_barrier();                                                     \
-       __rcu_access_pointer_tmp;                                             \
-})
 
 /* kill_dependency */
 #define        rcu_pointer_handoff(P)  (P)