Commit 65e56032 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Paul E. McKenney
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rcu/nocb: Turn enabled/offload states into a common flag 



This commit gathers the rcu_segcblist ->enabled and ->offloaded property
field into a single ->flags bitmask to avoid further proliferation of
individual u8 fields in the structure.  This change prepares for the
state formerly known as ->offloaded state to be modified at runtime.

Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Inspired-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Tested-by: default avatarBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent b4e6039e

include/linux/rcu_segcblist.h

+4 −2
Original line number Diff line number Diff line
@@ -63,6 +63,9 @@ struct rcu_cblist { 
#define RCU_NEXT_TAIL		3

#define RCU_CBLIST_NSEGS	4



#define SEGCBLIST_ENABLED	BIT(0)

#define SEGCBLIST_OFFLOADED	BIT(1)



struct rcu_segcblist {

	struct rcu_head *head;

	struct rcu_head **tails[RCU_CBLIST_NSEGS];
@@ -73,8 +76,7 @@ struct rcu_segcblist { 
	long len;

#endif

	long seglen[RCU_CBLIST_NSEGS];

	u8 enabled;

	u8 offloaded;

	u8 flags;

};



#define RCU_SEGCBLIST_INITIALIZER(n) \

kernel/rcu/rcu_segcblist.c

+3 −3
Original line number Diff line number Diff line
@@ -246,7 +246,7 @@ void rcu_segcblist_init(struct rcu_segcblist *rsclp) 
		rcu_segcblist_set_seglen(rsclp, i, 0);

	}

	rcu_segcblist_set_len(rsclp, 0);

	rsclp->enabled = 1;

	rcu_segcblist_set_flags(rsclp, SEGCBLIST_ENABLED);

}



/*
@@ -257,7 +257,7 @@ void rcu_segcblist_disable(struct rcu_segcblist *rsclp) 
{

	WARN_ON_ONCE(!rcu_segcblist_empty(rsclp));

	WARN_ON_ONCE(rcu_segcblist_n_cbs(rsclp));

	rsclp->enabled = 0;

	rcu_segcblist_clear_flags(rsclp, SEGCBLIST_ENABLED);

}



/*
@@ -266,7 +266,7 @@ void rcu_segcblist_disable(struct rcu_segcblist *rsclp) 
 */

void rcu_segcblist_offload(struct rcu_segcblist *rsclp)

{

	rsclp->offloaded = 1;

	rcu_segcblist_set_flags(rsclp, SEGCBLIST_OFFLOADED);

}



/*

kernel/rcu/rcu_segcblist.h

+21 −2
Original line number Diff line number Diff line
@@ -53,19 +53,38 @@ static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp) 
#endif

}



static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,

					   int flags)

{

	rsclp->flags |= flags;

}



static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,

					     int flags)

{

	rsclp->flags &= ~flags;

}



static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,

					    int flags)

{

	return READ_ONCE(rsclp->flags) & flags;

}



/*

 * Is the specified rcu_segcblist enabled, for example, not corresponding

 * to an offline CPU?

 */

static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)

{

	return rsclp->enabled;

	return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);

}



/* Is the specified rcu_segcblist offloaded?  */

static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)

{

	return IS_ENABLED(CONFIG_RCU_NOCB_CPU) && rsclp->offloaded;

	return IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&

		rcu_segcblist_test_flags(rsclp, SEGCBLIST_OFFLOADED);

}



/*