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: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index ac8aed8..8914886 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -70,7 +70,7 @@
.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 @@
/*
* 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 @@
/*
* 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 @@
/* 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 @@
/*
* 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);
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index a240f03..a7c945d 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -383,9 +383,8 @@
/* 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_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. */
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index f921154..2b281cf0 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -757,7 +757,8 @@
* 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)
