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srcu: Move rcu_is_watching() checks to srcu_read_{,un}lock_fast()

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The rcu_is_watching() warnings are currently in the SRCU-tree
implementations of __srcu_read_lock_fast() and __srcu_read_unlock_fast().
However, this makes it difficult to create _notrace variants of
srcu_read_lock_fast() and srcu_read_unlock_fast().  This commit therefore
moves these checks to srcu_read_lock_fast(), srcu_read_unlock_fast(),
srcu_down_read_fast(), and srcu_up_read_fast().

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>
This commit is contained in:
Paul E. McKenney 2025-07-15 21:09:13 -07:00
parent 61399e0c54
commit f39494089a
2 changed files with 4 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/srcu.h
View File

@ -275,6 +275,7 @@ static inline struct srcu_ctr __percpu *srcu_read_lock_fast(struct srcu_struct *
{
struct srcu_ctr __percpu *retval;
RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_lock_fast().");
srcu_check_read_flavor_force(ssp, SRCU_READ_FLAVOR_FAST);
retval = __srcu_read_lock_fast(ssp);
rcu_try_lock_acquire(&ssp->dep_map);
@ -295,6 +296,7 @@ static inline struct srcu_ctr __percpu *srcu_read_lock_fast(struct srcu_struct *
static inline struct srcu_ctr __percpu *srcu_down_read_fast(struct srcu_struct *ssp) __acquires(ssp)
{
WARN_ON_ONCE(IS_ENABLED(CONFIG_PROVE_RCU) && in_nmi());
RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_down_read_fast().");
srcu_check_read_flavor_force(ssp, SRCU_READ_FLAVOR_FAST);
return __srcu_read_lock_fast(ssp);
}
@ -389,6 +391,7 @@ static inline void srcu_read_unlock_fast(struct srcu_struct *ssp, struct srcu_ct
srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_FAST);
srcu_lock_release(&ssp->dep_map);
__srcu_read_unlock_fast(ssp, scp);
RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_unlock_fast().");
}
/**
@ -405,6 +408,7 @@ static inline void srcu_up_read_fast(struct srcu_struct *ssp, struct srcu_ctr __
WARN_ON_ONCE(IS_ENABLED(CONFIG_PROVE_RCU) && in_nmi());
srcu_check_read_flavor(ssp, SRCU_READ_FLAVOR_FAST);
__srcu_read_unlock_fast(ssp, scp);
RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_up_read_fast().");
}
/**

2
include/linux/srcutree.h
View File

@ -244,7 +244,6 @@ static inline struct srcu_ctr __percpu *__srcu_read_lock_fast(struct srcu_struct
{
struct srcu_ctr __percpu *scp = READ_ONCE(ssp->srcu_ctrp);
RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_lock_fast().");
if (!IS_ENABLED(CONFIG_NEED_SRCU_NMI_SAFE))
this_cpu_inc(scp->srcu_locks.counter); /* Y */
else
@ -275,7 +274,6 @@ static inline void __srcu_read_unlock_fast(struct srcu_struct *ssp, struct srcu_
this_cpu_inc(scp->srcu_unlocks.counter); /* Z */
else
atomic_long_inc(raw_cpu_ptr(&scp->srcu_unlocks)); /* Z */
RCU_LOCKDEP_WARN(!rcu_is_watching(), "RCU must be watching srcu_read_unlock_fast().");
}
void __srcu_check_read_flavor(struct srcu_struct *ssp, int read_flavor);