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. ] Link: https://lore.kernel.org/all/20250721162433.10454-1-paul...@kernel.org Signed-off-by: Paul E. McKenney <paul...@kernel.org> Reviewed-by: Joel Fernandes <joelagn...@nvidia.com> Cc: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> Cc: Steven Rostedt <rost...@goodmis.org> Cc: Sebastian Andrzej Siewior <bige...@linutronix.de> Cc: <b...@vger.kernel.org> --- include/linux/srcu.h | 30 ++++++++++++++++++++++++++++-- include/linux/srcutree.h | 5 +++-- 2 files changed, 31 insertions(+), 4 deletions(-) diff --git a/include/linux/srcu.h b/include/linux/srcu.h index 478c73d067f7d..ec3b8e27d6c5a 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -271,7 +271,7 @@ static inline int srcu_read_lock(struct srcu_struct *ssp) __acquires(ssp) * where RCU is watching, that is, from contexts where it would be legal * to invoke rcu_read_lock(). Otherwise, lockdep will complain. */ -static inline struct srcu_ctr __percpu *srcu_read_lock_fast(struct srcu_struct *ssp) __acquires(ssp) +static inline struct srcu_ctr __percpu notrace *srcu_read_lock_fast(struct srcu_struct *ssp) __acquires(ssp) { struct srcu_ctr __percpu *retval; @@ -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. @@ -385,7 +399,8 @@ static inline void srcu_read_unlock(struct srcu_struct *ssp, int idx) * * Exit a light-weight SRCU read-side critical section. */ -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) __releases(ssp) { srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_FAST); @@ -394,6 +409,17 @@ 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 043b5a67ef71e..4d2fee4d38289 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)) -- 2.40.1
