[patch V4 part 1 30/36] lockdep: Always inline lockdep_{off,on}()

Thomas Gleixner
2020-05-05T14:14:17Z

From: Peter Zijlstra <peterz@infradead.org>

These functions are called {early,late} in nmi_{enter,exit} and should
not be traced or probed. They are also puny, so 'inline' them.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
include/linux/lockdep.h | 23 +++++++++++++++++++++--
kernel/locking/lockdep.c | 19 -------------------
2 files changed, 21 insertions(+), 21 deletions(-)

--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -308,8 +308,27 @@ extern void lockdep_set_selftest_task(st

extern void lockdep_init_task(struct task_struct *task);

-extern void lockdep_off(void);
-extern void lockdep_on(void);
+/*
+ * Split the recrursion counter in two to readily detect 'off' vs recursion.
+ */
+#define LOCKDEP_RECURSION_BITS 16
+#define LOCKDEP_OFF (1U << LOCKDEP_RECURSION_BITS)
+#define LOCKDEP_RECURSION_MASK (LOCKDEP_OFF - 1)
+
+/*
+ * lockdep_{off,on}() are macros to avoid tracing and kprobes; not inlines due
+ * to header dependencies.
+ */
+
+#define lockdep_off() \
+do { \
+ current->lockdep_recursion += LOCKDEP_OFF; \
+} while (0)
+
+#define lockdep_on() \
+do { \
+ current->lockdep_recursion -= LOCKDEP_OFF; \
+} while (0)

extern void lockdep_register_key(struct lock_class_key *key);
extern void lockdep_unregister_key(struct lock_class_key *key);
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -393,25 +393,6 @@ void lockdep_init_task(struct task_struc
task->lockdep_recursion = 0;
}

-/*
- * Split the recrursion counter in two to readily detect 'off' vs recursion.
- */
-#define LOCKDEP_RECURSION_BITS 16
-#define LOCKDEP_OFF (1U << LOCKDEP_RECURSION_BITS)
-#define LOCKDEP_RECURSION_MASK (LOCKDEP_OFF - 1)
-
-void lockdep_off(void)
-{
- current->lockdep_recursion += LOCKDEP_OFF;
-}
-EXPORT_SYMBOL(lockdep_off);
-
-void lockdep_on(void)
-{
- current->lockdep_recursion -= LOCKDEP_OFF;
-}
-EXPORT_SYMBOL(lockdep_on);
-
static inline void lockdep_recursion_finish(void)
{
if (WARN_ON_ONCE(--current->lockdep_recursion))