This is a feature that is needed for a follow up patch
in ovs kernel datapath.
Signed-off-by: Yi-Hung Wei <yihung....@gmail.com>
---
acinclude.m4 | 3 +
datapath/linux/Modules.mk | 1 +
datapath/linux/compat/include/linux/static_key.h | 70 ++++++++++++++++++++++++
3 files changed, 74 insertions(+)
create mode 100644 datapath/linux/compat/include/linux/static_key.h
diff --git a/acinclude.m4 b/acinclude.m4
index 96fcad55a7cb..341edbbd70f1 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -467,6 +467,9 @@ AC_DEFUN([OVS_CHECK_LINUX_COMPAT], [
OVS_GREP_IFELSE([$KSRC/include/linux/err.h], [IS_ERR_OR_NULL])
OVS_GREP_IFELSE([$KSRC/include/linux/err.h], [PTR_ERR_OR_ZERO])
+ OVS_GREP_IFELSE([$KSRC/include/linux/jump_label.h],
[DEFINE_STATIC_KEY_FALSE],
+ [OVS_DEFINE([HAVE_UPSTREAM_STATIC_KEY])])
+
OVS_GREP_IFELSE([$KSRC/include/linux/etherdevice.h], [eth_hw_addr_random])
OVS_GREP_IFELSE([$KSRC/include/linux/etherdevice.h], [ether_addr_copy])
diff --git a/datapath/linux/Modules.mk b/datapath/linux/Modules.mk
index f5c3b6580ad7..2fec6500e7c8 100644
--- a/datapath/linux/Modules.mk
+++ b/datapath/linux/Modules.mk
@@ -63,6 +63,7 @@ openvswitch_headers += \
linux/compat/include/linux/reciprocal_div.h \
linux/compat/include/linux/rtnetlink.h \
linux/compat/include/linux/skbuff.h \
+ linux/compat/include/linux/static_key.h \
linux/compat/include/linux/stddef.h \
linux/compat/include/linux/types.h \
linux/compat/include/linux/u64_stats_sync.h \
diff --git a/datapath/linux/compat/include/linux/static_key.h
b/datapath/linux/compat/include/linux/static_key.h
new file mode 100644
index 000000000000..ea59e3e285a1
--- /dev/null
+++ b/datapath/linux/compat/include/linux/static_key.h
@@ -0,0 +1,70 @@
+#ifndef _STATIC_KEY_WRAPPER_H
+#define _STATIC_KEY_WRAPPER_H
+
+#include_next <linux/static_key.h>
+#ifndef HAVE_UPSTREAM_STATIC_KEY
+/*
+ * This backport is based on upstream net-next commit 11276d5306b8
+ * ("locking/static_keys: Add a new static_key interface").
+ *
+ * For kernel that does not support the new static key interface,
+ * we do not backport the jump label support but the fall back version
+ * of static key that is simply a conditional branch.
+ */
+
+struct static_key_true {
+ struct static_key key;
+};
+
+struct static_key_false {
+ struct static_key key;
+};
+
+#define rpl_STATIC_KEY_INIT_TRUE { .enabled = ATOMIC_INIT(1) }
+#define rpl_STATIC_KEY_INIT_FALSE { .enabled = ATOMIC_INIT(0) }
+
+#define STATIC_KEY_TRUE_INIT \
+ (struct static_key_true) { .key = rpl_STATIC_KEY_INIT_TRUE, }
+#define STATIC_KEY_FALSE_INIT \
+ (struct static_key_false){ .key = rpl_STATIC_KEY_INIT_FALSE, }
+
+#define DEFINE_STATIC_KEY_TRUE(name) \
+ struct static_key_true name = STATIC_KEY_TRUE_INIT
+
+#define DEFINE_STATIC_KEY_FALSE(name) \
+ struct static_key_false name = STATIC_KEY_FALSE_INIT
+
+static inline int rpl_static_key_count(struct static_key *key)
+{
+ return atomic_read(&key->enabled);
+}
+
+static inline void rpl_static_key_enable(struct static_key *key)
+{
+ int count = rpl_static_key_count(key);
+
+ WARN_ON_ONCE(count < 0 || count > 1);
+
+ if (!count)
+ static_key_slow_inc(key);
+}
+
+static inline void rpl_static_key_disable(struct static_key *key)
+{
+ int count = rpl_static_key_count(key);
+
+ WARN_ON_ONCE(count < 0 || count > 1);
+
+ if (count)
+ static_key_slow_dec(key);
+}
+
+#define static_branch_likely(x)
likely(static_key_enabled(&(x)->key))
+#define static_branch_unlikely(x) unlikely(static_key_enabled(&(x)->key))
+
+#define static_branch_enable(x) rpl_static_key_enable(&(x)->key)
+#define static_branch_disable(x) rpl_static_key_disable(&(x)->key)
+
+#endif /* HAVE_UPSTREAM_STATIC_KEY */
+
+#endif /* _STATIC_KEY_WRAPPER_H */
--
2.7.4
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