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authorPaul E. McKenney <paulmck@kernel.org>2025-07-16 09:12:16 -0700
committerPaul E. McKenney <paulmck@kernel.org>2025-08-14 15:25:48 -0700
commit7e2a2d060da4860af37e1000dc62a30a1551d9e8 (patch)
treecfe2cc80c193e94c392a00b9db384dc51f4dc609
parentf39494089aaa1022008eee245fb83ef1ae911b6d (diff)
srcu: Add srcu_read_lock_fast_notrace() and srcu_read_unlock_fast_notrace()
This commit adds no-trace variants of the srcu_read_lock_fast() and srcu_read_unlock_fast() functions for tracing use. [ paulmck: Apply notrace feedback from Joel Fernandes, Steven Rostedt, and Mathieu Desnoyers. ] [ paulmck: Apply excess-notrace feedback from Boqun Feng. ] Link: https://lore.kernel.org/all/20250721162433.10454-1-paulmck@kernel.org Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: <bpf@vger.kernel.org>
-rw-r--r--include/linux/srcu.h25
-rw-r--r--include/linux/srcutree.h5
2 files changed, 28 insertions, 2 deletions
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 478c73d067f7..7a692bf8f99b 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -282,6 +282,20 @@ static inline struct srcu_ctr __percpu *srcu_read_lock_fast(struct srcu_struct *
return retval;
}
+/*
+ * Used by tracing, cannot be traced and cannot call lockdep.
+ * See srcu_read_lock_fast() for more information.
+ */
+static inline struct srcu_ctr __percpu *srcu_read_lock_fast_notrace(struct srcu_struct *ssp)
+ __acquires(ssp)
+{
+ struct srcu_ctr __percpu *retval;
+
+ srcu_check_read_flavor_force(ssp, SRCU_READ_FLAVOR_FAST);
+ retval = __srcu_read_lock_fast(ssp);
+ return retval;
+}
+
/**
* srcu_down_read_fast - register a new reader for an SRCU-protected structure.
* @ssp: srcu_struct in which to register the new reader.
@@ -394,6 +408,17 @@ static inline void srcu_read_unlock_fast(struct srcu_struct *ssp, struct srcu_ct
RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_unlock_fast().");
}
+/*
+ * Used by tracing, cannot be traced and cannot call lockdep.
+ * See srcu_read_unlock_fast() for more information.
+ */
+static inline void srcu_read_unlock_fast_notrace(struct srcu_struct *ssp,
+ struct srcu_ctr __percpu *scp) __releases(ssp)
+{
+ srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_FAST);
+ __srcu_read_unlock_fast(ssp, scp);
+}
+
/**
* srcu_up_read_fast - unregister a old reader from an SRCU-protected structure.
* @ssp: srcu_struct in which to unregister the old reader.
diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
index 043b5a67ef71..4d2fee4d3828 100644
--- a/include/linux/srcutree.h
+++ b/include/linux/srcutree.h
@@ -240,7 +240,7 @@ static inline struct srcu_ctr __percpu *__srcu_ctr_to_ptr(struct srcu_struct *ss
* on architectures that support NMIs but do not supply NMI-safe
* implementations of this_cpu_inc().
*/
-static inline struct srcu_ctr __percpu *__srcu_read_lock_fast(struct srcu_struct *ssp)
+static inline struct srcu_ctr __percpu notrace *__srcu_read_lock_fast(struct srcu_struct *ssp)
{
struct srcu_ctr __percpu *scp = READ_ONCE(ssp->srcu_ctrp);
@@ -267,7 +267,8 @@ static inline struct srcu_ctr __percpu *__srcu_read_lock_fast(struct srcu_struct
* on architectures that support NMIs but do not supply NMI-safe
* implementations of this_cpu_inc().
*/
-static inline void __srcu_read_unlock_fast(struct srcu_struct *ssp, struct srcu_ctr __percpu *scp)
+static inline void notrace
+__srcu_read_unlock_fast(struct srcu_struct *ssp, struct srcu_ctr __percpu *scp)
{
barrier(); /* Avoid leaking the critical section. */
if (!IS_ENABLED(CONFIG_NEED_SRCU_NMI_SAFE))