Commit f3949408 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

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



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: default avatarPaul E. McKenney <paulmck@kernel.org>
Reviewed-by: default avatarJoel 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>
parent 61399e0c

include/linux/srcu.h

+4 −0
Original line number Diff line number Diff line
@@ -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().");

}



/**

include/linux/srcutree.h

+0 −2
Original line number Diff line number Diff line
@@ -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);