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Commit 7b2e6011 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Paul E. McKenney
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rcu: Rename ->onofflock to ->orphan_lock 



The ->onofflock field in the rcu_state structure at one time synchronized
CPU-hotplug operations for RCU.  However, its scope has decreased over time
so that it now only protects the lists of orphaned RCU callbacks.  This
commit therefore renames it to ->orphan_lock to reflect its current use.

Signed-off-by: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 48983260

kernel/rcutree.c

+6 −6
Original line number Diff line number Diff line
@@ -70,7 +70,7 @@ static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS]; 
	.fqs_state = RCU_GP_IDLE, \

	.gpnum = -300, \

	.completed = -300, \

	.onofflock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.onofflock), \

	.orphan_lock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.orphan_lock), \

	.orphan_nxttail = &sname##_state.orphan_nxtlist, \

	.orphan_donetail = &sname##_state.orphan_donelist, \

	.barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \
@@ -1573,7 +1573,7 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp) 
/*

 * Send the specified CPU's RCU callbacks to the orphanage.  The

 * specified CPU must be offline, and the caller must hold the

 * ->onofflock.

 * ->orphan_lock.

 */

static void

rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp,
@@ -1623,7 +1623,7 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp, 


/*

 * Adopt the RCU callbacks from the specified rcu_state structure's

 * orphanage.  The caller must hold the ->onofflock.

 * orphanage.  The caller must hold the ->orphan_lock.

 */

static void rcu_adopt_orphan_cbs(struct rcu_state *rsp)

{
@@ -1702,7 +1702,7 @@ static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp) 


	/* Exclude any attempts to start a new grace period. */

	mutex_lock(&rsp->onoff_mutex);

	raw_spin_lock_irqsave(&rsp->onofflock, flags);

	raw_spin_lock_irqsave(&rsp->orphan_lock, flags);



	/* Orphan the dead CPU's callbacks, and adopt them if appropriate. */

	rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp);
@@ -1729,10 +1729,10 @@ static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp) 
	/*

	 * We still hold the leaf rcu_node structure lock here, and

	 * irqs are still disabled.  The reason for this subterfuge is

	 * because invoking rcu_report_unblock_qs_rnp() with ->onofflock

	 * because invoking rcu_report_unblock_qs_rnp() with ->orphan_lock

	 * held leads to deadlock.

	 */

	raw_spin_unlock(&rsp->onofflock); /* irqs remain disabled. */

	raw_spin_unlock(&rsp->orphan_lock); /* irqs remain disabled. */

	rnp = rdp->mynode;

	if (need_report & RCU_OFL_TASKS_NORM_GP)

		rcu_report_unblock_qs_rnp(rnp, flags);

kernel/rcutree.h

+3 −4
Original line number Diff line number Diff line
@@ -383,9 +383,8 @@ struct rcu_state { 


	/* End of fields guarded by root rcu_node's lock. */



	raw_spinlock_t onofflock ____cacheline_internodealigned_in_smp;

						/* exclude on/offline and */

						/*  starting new GP. */

	raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp;

						/* Protect following fields. */

	struct rcu_head *orphan_nxtlist;	/* Orphaned callbacks that */

						/*  need a grace period. */

	struct rcu_head **orphan_nxttail;	/* Tail of above. */
@@ -394,7 +393,7 @@ struct rcu_state { 
	struct rcu_head **orphan_donetail;	/* Tail of above. */

	long qlen_lazy;				/* Number of lazy callbacks. */

	long qlen;				/* Total number of callbacks. */

	/* End of fields guarded by onofflock. */

	/* End of fields guarded by orphan_lock. */



	struct mutex onoff_mutex;		/* Coordinate hotplug & GPs. */

kernel/rcutree_plugin.h

+2 −1
Original line number Diff line number Diff line
@@ -757,7 +757,8 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, 
 * grace period for the specified rcu_node structure.  If there are no such

 * tasks, report it up the rcu_node hierarchy.

 *

 * Caller must hold sync_rcu_preempt_exp_mutex and rsp->onofflock.

 * Caller must hold sync_rcu_preempt_exp_mutex and must exclude

 * CPU hotplug operations.

 */

static void

sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp)