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Commit 09e2db37 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Add comment headers to expedited-grace-period counter functions 



These functions (rcu_exp_gp_seq_start(), rcu_exp_gp_seq_end(),
rcu_exp_gp_seq_snap(), and rcu_exp_gp_seq_done() seemed too obvious
to comment when written, but not so much when being documented.
This commit therefore adds header comments to each of them.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJosh Triplett <josh@joshtriplett.org>
parent 630c7ed9

kernel/rcu/tree_exp.h

+17 −1
Original line number Diff line number Diff line
@@ -20,16 +20,26 @@ 
 * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

 */



/* Wrapper functions for expedited grace periods.  */

/*

 * Record the start of an expedited grace period.

 */

static void rcu_exp_gp_seq_start(struct rcu_state *rsp)

{

	rcu_seq_start(&rsp->expedited_sequence);

}



/*

 * Record the end of an expedited grace period.

 */

static void rcu_exp_gp_seq_end(struct rcu_state *rsp)

{

	rcu_seq_end(&rsp->expedited_sequence);

	smp_mb(); /* Ensure that consecutive grace periods serialize. */

}



/*

 * Take a snapshot of the expedited-grace-period counter.

 */

static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)

{

	unsigned long s;
@@ -39,6 +49,12 @@ static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp) 
	trace_rcu_exp_grace_period(rsp->name, s, TPS("snap"));

	return s;

}



/*

 * Given a counter snapshot from rcu_exp_gp_seq_snap(), return true

 * if a full expedited grace period has elapsed since that snapshot

 * was taken.

 */

static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)

{

	return rcu_seq_done(&rsp->expedited_sequence, s);