8 files changed, 373 insertions, 361 deletions

diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c
index b46e6683f8c9..32dfd6522548 100644
--- a/kernel/rcu/srcutiny.c
+++ b/kernel/rcu/srcutiny.c
@@ -37,30 +37,30 @@ int rcu_scheduler_active __read_mostly;
 static LIST_HEAD(srcu_boot_list);
 static bool srcu_init_done;
 
-static int init_srcu_struct_fields(struct srcu_struct *sp)
+static int init_srcu_struct_fields(struct srcu_struct *ssp)
 {
-	sp->srcu_lock_nesting[0] = 0;
-	sp->srcu_lock_nesting[1] = 0;
-	init_swait_queue_head(&sp->srcu_wq);
-	sp->srcu_cb_head = NULL;
-	sp->srcu_cb_tail = &sp->srcu_cb_head;
-	sp->srcu_gp_running = false;
-	sp->srcu_gp_waiting = false;
-	sp->srcu_idx = 0;
-	INIT_WORK(&sp->srcu_work, srcu_drive_gp);
-	INIT_LIST_HEAD(&sp->srcu_work.entry);
+	ssp->srcu_lock_nesting[0] = 0;
+	ssp->srcu_lock_nesting[1] = 0;
+	init_swait_queue_head(&ssp->srcu_wq);
+	ssp->srcu_cb_head = NULL;
+	ssp->srcu_cb_tail = &ssp->srcu_cb_head;
+	ssp->srcu_gp_running = false;
+	ssp->srcu_gp_waiting = false;
+	ssp->srcu_idx = 0;
+	INIT_WORK(&ssp->srcu_work, srcu_drive_gp);
+	INIT_LIST_HEAD(&ssp->srcu_work.entry);
 	return 0;
 }
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
-int __init_srcu_struct(struct srcu_struct *sp, const char *name,
+int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
 		       struct lock_class_key *key)
 {
 	/* Don't re-initialize a lock while it is held. */
-	debug_check_no_locks_freed((void *)sp, sizeof(*sp));
-	lockdep_init_map(&sp->dep_map, name, key, 0);
-	return init_srcu_struct_fields(sp);
+	debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));
+	lockdep_init_map(&ssp->dep_map, name, key, 0);
+	return init_srcu_struct_fields(ssp);
 }
 EXPORT_SYMBOL_GPL(__init_srcu_struct);
 
@@ -68,15 +68,15 @@ EXPORT_SYMBOL_GPL(__init_srcu_struct);
 
 /*
  * init_srcu_struct - initialize a sleep-RCU structure
- * @sp: structure to initialize.
+ * @ssp: structure to initialize.
  *
  * Must invoke this on a given srcu_struct before passing that srcu_struct
  * to any other function.  Each srcu_struct represents a separate domain
  * of SRCU protection.
  */
-int init_srcu_struct(struct srcu_struct *sp)
+int init_srcu_struct(struct srcu_struct *ssp)
 {
-	return init_srcu_struct_fields(sp);
+	return init_srcu_struct_fields(ssp);
 }
 EXPORT_SYMBOL_GPL(init_srcu_struct);
 
@@ -84,22 +84,22 @@ EXPORT_SYMBOL_GPL(init_srcu_struct);
 
 /*
  * cleanup_srcu_struct - deconstruct a sleep-RCU structure
- * @sp: structure to clean up.
+ * @ssp: structure to clean up.
  *
  * Must invoke this after you are finished using a given srcu_struct that
  * was initialized via init_srcu_struct(), else you leak memory.
  */
-void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced)
+void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
 {
-	WARN_ON(sp->srcu_lock_nesting[0] || sp->srcu_lock_nesting[1]);
+	WARN_ON(ssp->srcu_lock_nesting[0] || ssp->srcu_lock_nesting[1]);
 	if (quiesced)
-		WARN_ON(work_pending(&sp->srcu_work));
+		WARN_ON(work_pending(&ssp->srcu_work));
 	else
-		flush_work(&sp->srcu_work);
-	WARN_ON(sp->srcu_gp_running);
-	WARN_ON(sp->srcu_gp_waiting);
-	WARN_ON(sp->srcu_cb_head);
-	WARN_ON(&sp->srcu_cb_head != sp->srcu_cb_tail);
+		flush_work(&ssp->srcu_work);
+	WARN_ON(ssp->srcu_gp_running);
+	WARN_ON(ssp->srcu_gp_waiting);
+	WARN_ON(ssp->srcu_cb_head);
+	WARN_ON(&ssp->srcu_cb_head != ssp->srcu_cb_tail);
 }
 EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
 
@@ -107,13 +107,13 @@ EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
  * Removes the count for the old reader from the appropriate element of
  * the srcu_struct.
  */
-void __srcu_read_unlock(struct srcu_struct *sp, int idx)
+void __srcu_read_unlock(struct srcu_struct *ssp, int idx)
 {
-	int newval = sp->srcu_lock_nesting[idx] - 1;
+	int newval = ssp->srcu_lock_nesting[idx] - 1;
 
-	WRITE_ONCE(sp->srcu_lock_nesting[idx], newval);
-	if (!newval && READ_ONCE(sp->srcu_gp_waiting))
-		swake_up_one(&sp->srcu_wq);
+	WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval);
+	if (!newval && READ_ONCE(ssp->srcu_gp_waiting))
+		swake_up_one(&ssp->srcu_wq);
 }
 EXPORT_SYMBOL_GPL(__srcu_read_unlock);
 
@@ -127,24 +127,24 @@ void srcu_drive_gp(struct work_struct *wp)
 	int idx;
 	struct rcu_head *lh;
 	struct rcu_head *rhp;
-	struct srcu_struct *sp;
+	struct srcu_struct *ssp;
 
-	sp = container_of(wp, struct srcu_struct, srcu_work);
-	if (sp->srcu_gp_running || !READ_ONCE(sp->srcu_cb_head))
+	ssp = container_of(wp, struct srcu_struct, srcu_work);
+	if (ssp->srcu_gp_running || !READ_ONCE(ssp->srcu_cb_head))
 		return; /* Already running or nothing to do. */
 
 	/* Remove recently arrived callbacks and wait for readers. */
-	WRITE_ONCE(sp->srcu_gp_running, true);
+	WRITE_ONCE(ssp->srcu_gp_running, true);
 	local_irq_disable();
-	lh = sp->srcu_cb_head;
-	sp->srcu_cb_head = NULL;
-	sp->srcu_cb_tail = &sp->srcu_cb_head;
+	lh = ssp->srcu_cb_head;
+	ssp->srcu_cb_head = NULL;
+	ssp->srcu_cb_tail = &ssp->srcu_cb_head;
 	local_irq_enable();
-	idx = sp->srcu_idx;
-	WRITE_ONCE(sp->srcu_idx, !sp->srcu_idx);
-	WRITE_ONCE(sp->srcu_gp_waiting, true);  /* srcu_read_unlock() wakes! */
-	swait_event_exclusive(sp->srcu_wq, !READ_ONCE(sp->srcu_lock_nesting[idx]));
-	WRITE_ONCE(sp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */
+	idx = ssp->srcu_idx;
+	WRITE_ONCE(ssp->srcu_idx, !ssp->srcu_idx);
+	WRITE_ONCE(ssp->srcu_gp_waiting, true);  /* srcu_read_unlock() wakes! */
+	swait_event_exclusive(ssp->srcu_wq, !READ_ONCE(ssp->srcu_lock_nesting[idx]));
+	WRITE_ONCE(ssp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */
 
 	/* Invoke the callbacks we removed above. */
 	while (lh) {
@@ -161,9 +161,9 @@ void srcu_drive_gp(struct work_struct *wp)
 	 * at interrupt level, but the ->srcu_gp_running checks will
 	 * straighten that out.
 	 */
-	WRITE_ONCE(sp->srcu_gp_running, false);
-	if (READ_ONCE(sp->srcu_cb_head))
-		schedule_work(&sp->srcu_work);
+	WRITE_ONCE(ssp->srcu_gp_running, false);
+	if (READ_ONCE(ssp->srcu_cb_head))
+		schedule_work(&ssp->srcu_work);
 }
 EXPORT_SYMBOL_GPL(srcu_drive_gp);
 
@@ -171,7 +171,7 @@ EXPORT_SYMBOL_GPL(srcu_drive_gp);
  * Enqueue an SRCU callback on the specified srcu_struct structure,
  * initiating grace-period processing if it is not already running.
  */
-void call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
+void call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp,
 	       rcu_callback_t func)
 {
 	unsigned long flags;
@@ -179,14 +179,14 @@ void call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
 	rhp->func = func;
 	rhp->next = NULL;
 	local_irq_save(flags);
-	*sp->srcu_cb_tail = rhp;
-	sp->srcu_cb_tail = &rhp->next;
+	*ssp->srcu_cb_tail = rhp;
+	ssp->srcu_cb_tail = &rhp->next;
 	local_irq_restore(flags);
-	if (!READ_ONCE(sp->srcu_gp_running)) {
+	if (!READ_ONCE(ssp->srcu_gp_running)) {
 		if (likely(srcu_init_done))
-			schedule_work(&sp->srcu_work);
-		else if (list_empty(&sp->srcu_work.entry))
-			list_add(&sp->srcu_work.entry, &srcu_boot_list);
+			schedule_work(&ssp->srcu_work);
+		else if (list_empty(&ssp->srcu_work.entry))
+			list_add(&ssp->srcu_work.entry, &srcu_boot_list);
 	}
 }
 EXPORT_SYMBOL_GPL(call_srcu);
@@ -194,13 +194,13 @@ EXPORT_SYMBOL_GPL(call_srcu);
 /*
  * synchronize_srcu - wait for prior SRCU read-side critical-section completion
  */
-void synchronize_srcu(struct srcu_struct *sp)
+void synchronize_srcu(struct srcu_struct *ssp)
 {
 	struct rcu_synchronize rs;
 
 	init_rcu_head_on_stack(&rs.head);
 	init_completion(&rs.completion);
-	call_srcu(sp, &rs.head, wakeme_after_rcu);
+	call_srcu(ssp, &rs.head, wakeme_after_rcu);
 	wait_for_completion(&rs.completion);
 	destroy_rcu_head_on_stack(&rs.head);
 }
@@ -219,13 +219,13 @@ void __init rcu_scheduler_starting(void)
  */
 void __init srcu_init(void)
 {
-	struct srcu_struct *sp;
+	struct srcu_struct *ssp;
 
 	srcu_init_done = true;
 	while (!list_empty(&srcu_boot_list)) {
-		sp = list_first_entry(&srcu_boot_list,
+		ssp = list_first_entry(&srcu_boot_list,
 				      struct srcu_struct, srcu_work.entry);
-		list_del_init(&sp->srcu_work.entry);
-		schedule_work(&sp->srcu_work);
+		list_del_init(&ssp->srcu_work.entry);
+		schedule_work(&ssp->srcu_work);
 	}
 }
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index a8846ed7f352..3600d88d8956 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -56,7 +56,7 @@ static LIST_HEAD(srcu_boot_list);
 static bool __read_mostly srcu_init_done;
 
 static void srcu_invoke_callbacks(struct work_struct *work);
-static void srcu_reschedule(struct srcu_struct *sp, unsigned long delay);
+static void srcu_reschedule(struct srcu_struct *ssp, unsigned long delay);
 static void process_srcu(struct work_struct *work);
 
 /* Wrappers for lock acquisition and release, see raw_spin_lock_rcu_node(). */
@@ -92,7 +92,7 @@ do {									\
  * srcu_read_unlock() running against them.  So if the is_static parameter
  * is set, don't initialize ->srcu_lock_count[] and ->srcu_unlock_count[].
  */
-static void init_srcu_struct_nodes(struct srcu_struct *sp, bool is_static)
+static void init_srcu_struct_nodes(struct srcu_struct *ssp, bool is_static)
 {
 	int cpu;
 	int i;
@@ -103,13 +103,13 @@ static void init_srcu_struct_nodes(struct srcu_struct *sp, bool is_static)
 	struct srcu_node *snp_first;
 
 	/* Work out the overall tree geometry. */
-	sp->level[0] = &sp->node[0];
+	ssp->level[0] = &ssp->node[0];
 	for (i = 1; i < rcu_num_lvls; i++)
-		sp->level[i] = sp->level[i - 1] + num_rcu_lvl[i - 1];
+		ssp->level[i] = ssp->level[i - 1] + num_rcu_lvl[i - 1];
 	rcu_init_levelspread(levelspread, num_rcu_lvl);
 
 	/* Each pass through this loop initializes one srcu_node structure. */
-	srcu_for_each_node_breadth_first(sp, snp) {
+	srcu_for_each_node_breadth_first(ssp, snp) {
 		spin_lock_init(&ACCESS_PRIVATE(snp, lock));
 		WARN_ON_ONCE(ARRAY_SIZE(snp->srcu_have_cbs) !=
 			     ARRAY_SIZE(snp->srcu_data_have_cbs));
@@ -120,17 +120,17 @@ static void init_srcu_struct_nodes(struct srcu_struct *sp, bool is_static)
 		snp->srcu_gp_seq_needed_exp = 0;
 		snp->grplo = -1;
 		snp->grphi = -1;
-		if (snp == &sp->node[0]) {
+		if (snp == &ssp->node[0]) {
 			/* Root node, special case. */
 			snp->srcu_parent = NULL;
 			continue;
 		}
 
 		/* Non-root node. */
-		if (snp == sp->level[level + 1])
+		if (snp == ssp->level[level + 1])
 			level++;
-		snp->srcu_parent = sp->level[level - 1] +
-				   (snp - sp->level[level]) /
+		snp->srcu_parent = ssp->level[level - 1] +
+				   (snp - ssp->level[level]) /
 				   levelspread[level - 1];
 	}
 
@@ -141,14 +141,14 @@ static void init_srcu_struct_nodes(struct srcu_struct *sp, bool is_static)
 	WARN_ON_ONCE(ARRAY_SIZE(sdp->srcu_lock_count) !=
 		     ARRAY_SIZE(sdp->srcu_unlock_count));
 	level = rcu_num_lvls - 1;
-	snp_first = sp->level[level];
+	snp_first = ssp->level[level];
 	for_each_possible_cpu(cpu) {
-		sdp = per_cpu_ptr(sp->sda, cpu);
+		sdp = per_cpu_ptr(ssp->sda, cpu);
 		spin_lock_init(&ACCESS_PRIVATE(sdp, lock));
 		rcu_segcblist_init(&sdp->srcu_cblist);
 		sdp->srcu_cblist_invoking = false;
-		sdp->srcu_gp_seq_needed = sp->srcu_gp_seq;
-		sdp->srcu_gp_seq_needed_exp = sp->srcu_gp_seq;
+		sdp->srcu_gp_seq_needed = ssp->srcu_gp_seq;
+		sdp->srcu_gp_seq_needed_exp = ssp->srcu_gp_seq;
 		sdp->mynode = &snp_first[cpu / levelspread[level]];
 		for (snp = sdp->mynode; snp != NULL; snp = snp->srcu_parent) {
 			if (snp->grplo < 0)
@@ -157,7 +157,7 @@ static void init_srcu_struct_nodes(struct srcu_struct *sp, bool is_static)
 		}
 		sdp->cpu = cpu;
 		INIT_DELAYED_WORK(&sdp->work, srcu_invoke_callbacks);
-		sdp->sp = sp;
+		sdp->ssp = ssp;
 		sdp->grpmask = 1 << (cpu - sdp->mynode->grplo);
 		if (is_static)
 			continue;
@@ -176,35 +176,35 @@ static void init_srcu_struct_nodes(struct srcu_struct *sp, bool is_static)
  * parameter is passed through to init_srcu_struct_nodes(), and
  * also tells us that ->sda has already been wired up to srcu_data.
  */
-static int init_srcu_struct_fields(struct srcu_struct *sp, bool is_static)
+static int init_srcu_struct_fields(struct srcu_struct *ssp, bool is_static)
 {
-	mutex_init(&sp->srcu_cb_mutex);
-	mutex_init(&sp->srcu_gp_mutex);
-	sp->srcu_idx = 0;
-	sp->srcu_gp_seq = 0;
-	sp->srcu_barrier_seq = 0;
-	mutex_init(&sp->srcu_barrier_mutex);
-	atomic_set(&sp->srcu_barrier_cpu_cnt, 0);
-	INIT_DELAYED_WORK(&sp->work, process_srcu);
+	mutex_init(&ssp->srcu_cb_mutex);
+	mutex_init(&ssp->srcu_gp_mutex);
+	ssp->srcu_idx = 0;
+	ssp->srcu_gp_seq = 0;
+	ssp->srcu_barrier_seq = 0;
+	mutex_init(&ssp->srcu_barrier_mutex);
+	atomic_set(&ssp->srcu_barrier_cpu_cnt, 0);
+	INIT_DELAYED_WORK(&ssp->work, process_srcu);
 	if (!is_static)
-		sp->sda = alloc_percpu(struct srcu_data);
-	init_srcu_struct_nodes(sp, is_static);
-	sp->srcu_gp_seq_needed_exp = 0;
-	sp->srcu_last_gp_end = ktime_get_mono_fast_ns();
-	smp_store_release(&sp->srcu_gp_seq_needed, 0); /* Init done. */
-	return sp->sda ? 0 : -ENOMEM;
+		ssp->sda = alloc_percpu(struct srcu_data);
+	init_srcu_struct_nodes(ssp, is_static);
+	ssp->srcu_gp_seq_needed_exp = 0;
+	ssp->srcu_last_gp_end = ktime_get_mono_fast_ns();
+	smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */
+	return ssp->sda ? 0 : -ENOMEM;
 }
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
-int __init_srcu_struct(struct srcu_struct *sp, const char *name,
+int __init_srcu_struct(struct srcu_struct *ssp, const char *name,
 		       struct lock_class_key *key)
 {
 	/* Don't re-initialize a lock while it is held. */
-	debug_check_no_locks_freed((void *)sp, sizeof(*sp));
-	lockdep_init_map(&sp->dep_map, name, key, 0);
-	spin_lock_init(&ACCESS_PRIVATE(sp, lock));
-	return init_srcu_struct_fields(sp, false);
+	debug_check_no_locks_freed((void *)ssp, sizeof(*ssp));
+	lockdep_init_map(&ssp->dep_map, name, key, 0);
+	spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
+	return init_srcu_struct_fields(ssp, false);
 }
 EXPORT_SYMBOL_GPL(__init_srcu_struct);
 
@@ -212,16 +212,16 @@ EXPORT_SYMBOL_GPL(__init_srcu_struct);
 
 /**
  * init_srcu_struct - initialize a sleep-RCU structure
- * @sp: structure to initialize.
+ * @ssp: structure to initialize.
  *
  * Must invoke this on a given srcu_struct before passing that srcu_struct
  * to any other function.  Each srcu_struct represents a separate domain
  * of SRCU protection.
  */
-int init_srcu_struct(struct srcu_struct *sp)
+int init_srcu_struct(struct srcu_struct *ssp)
 {
-	spin_lock_init(&ACCESS_PRIVATE(sp, lock));
-	return init_srcu_struct_fields(sp, false);
+	spin_lock_init(&ACCESS_PRIVATE(ssp, lock));
+	return init_srcu_struct_fields(ssp, false);
 }
 EXPORT_SYMBOL_GPL(init_srcu_struct);
 
@@ -231,37 +231,37 @@ EXPORT_SYMBOL_GPL(init_srcu_struct);
  * First-use initialization of statically allocated srcu_struct
  * structure.  Wiring up the combining tree is more than can be
  * done with compile-time initialization, so this check is added
- * to each update-side SRCU primitive.  Use sp->lock, which -is-
+ * to each update-side SRCU primitive.  Use ssp->lock, which -is-
  * compile-time initialized, to resolve races involving multiple
  * CPUs trying to garner first-use privileges.
  */
-static void check_init_srcu_struct(struct srcu_struct *sp)
+static void check_init_srcu_struct(struct srcu_struct *ssp)
 {
 	unsigned long flags;
 
 	/* The smp_load_acquire() pairs with the smp_store_release(). */
-	if (!rcu_seq_state(smp_load_acquire(&sp->srcu_gp_seq_needed))) /*^^^*/
+	if (!rcu_seq_state(smp_load_acquire(&ssp->srcu_gp_seq_needed))) /*^^^*/
 		return; /* Already initialized. */
-	spin_lock_irqsave_rcu_node(sp, flags);
-	if (!rcu_seq_state(sp->srcu_gp_seq_needed)) {
-		spin_unlock_irqrestore_rcu_node(sp, flags);
+	spin_lock_irqsave_rcu_node(ssp, flags);
+	if (!rcu_seq_state(ssp->srcu_gp_seq_needed)) {
+		spin_unlock_irqrestore_rcu_node(ssp, flags);
 		return;
 	}
-	init_srcu_struct_fields(sp, true);
-	spin_unlock_irqrestore_rcu_node(sp, flags);
+	init_srcu_struct_fields(ssp, true);
+	spin_unlock_irqrestore_rcu_node(ssp, flags);
 }
 
 /*
  * Returns approximate total of the readers' ->srcu_lock_count[] values
  * for the rank of per-CPU counters specified by idx.
  */
-static unsigned long srcu_readers_lock_idx(struct srcu_struct *sp, int idx)
+static unsigned long srcu_readers_lock_idx(struct srcu_struct *ssp, int idx)
 {
 	int cpu;
 	unsigned long sum = 0;
 
 	for_each_possible_cpu(cpu) {
-		struct srcu_data *cpuc = per_cpu_ptr(sp->sda, cpu);
+		struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu);
 
 		sum += READ_ONCE(cpuc->srcu_lock_count[idx]);
 	}
@@ -272,13 +272,13 @@ static unsigned long srcu_readers_lock_idx(struct srcu_struct *sp, int idx)
  * Returns approximate total of the readers' ->srcu_unlock_count[] values
  * for the rank of per-CPU counters specified by idx.
  */
-static unsigned long srcu_readers_unlock_idx(struct srcu_struct *sp, int idx)
+static unsigned long srcu_readers_unlock_idx(struct srcu_struct *ssp, int idx)
 {
 	int cpu;
 	unsigned long sum = 0;
 
 	for_each_possible_cpu(cpu) {
-		struct srcu_data *cpuc = per_cpu_ptr(sp->sda, cpu);
+		struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu);
 
 		sum += READ_ONCE(cpuc->srcu_unlock_count[idx]);
 	}
@@ -289,11 +289,11 @@ static unsigned long srcu_readers_unlock_idx(struct srcu_struct *sp, int idx)
  * Return true if the number of pre-existing readers is determined to
  * be zero.
  */
-static bool srcu_readers_active_idx_check(struct srcu_struct *sp, int idx)
+static bool srcu_readers_active_idx_check(struct srcu_struct *ssp, int idx)
 {
 	unsigned long unlocks;
 
-	unlocks = srcu_readers_unlock_idx(sp, idx);
+	unlocks = srcu_readers_unlock_idx(ssp, idx);
 
 	/*
 	 * Make sure that a lock is always counted if the corresponding
@@ -329,25 +329,25 @@ static bool srcu_readers_active_idx_check(struct srcu_struct *sp, int idx)
 	 * of floor(ULONG_MAX/NR_CPUS/2), which should be sufficient,
 	 * especially on 64-bit systems.
 	 */
-	return srcu_readers_lock_idx(sp, idx) == unlocks;
+	return srcu_readers_lock_idx(ssp, idx) == unlocks;
 }
 
 /**
  * srcu_readers_active - returns true if there are readers. and false
  *                       otherwise
- * @sp: which srcu_struct to count active readers (holding srcu_read_lock).
+ * @ssp: which srcu_struct to count active readers (holding srcu_read_lock).
  *
  * Note that this is not an atomic primitive, and can therefore suffer
  * severe errors when invoked on an active srcu_struct.  That said, it
  * can be useful as an error check at cleanup time.
  */
-static bool srcu_readers_active(struct srcu_struct *sp)
+static bool srcu_readers_active(struct srcu_struct *ssp)
 {
 	int cpu;
 	unsigned long sum = 0;
 
 	for_each_possible_cpu(cpu) {
-		struct srcu_data *cpuc = per_cpu_ptr(sp->sda, cpu);
+		struct srcu_data *cpuc = per_cpu_ptr(ssp->sda, cpu);
 
 		sum += READ_ONCE(cpuc->srcu_lock_count[0]);
 		sum += READ_ONCE(cpuc->srcu_lock_count[1]);
@@ -363,44 +363,44 @@ static bool srcu_readers_active(struct srcu_struct *sp)
  * Return grace-period delay, zero if there are expedited grace
  * periods pending, SRCU_INTERVAL otherwise.
  */
-static unsigned long srcu_get_delay(struct srcu_struct *sp)
+static unsigned long srcu_get_delay(struct srcu_struct *ssp)
 {
-	if (ULONG_CMP_LT(READ_ONCE(sp->srcu_gp_seq),
-			 READ_ONCE(sp->srcu_gp_seq_needed_exp)))
+	if (ULONG_CMP_LT(READ_ONCE(ssp->srcu_gp_seq),
+			 READ_ONCE(ssp->srcu_gp_seq_needed_exp)))
 		return 0;
 	return SRCU_INTERVAL;
 }
 
 /* Helper for cleanup_srcu_struct() and cleanup_srcu_struct_quiesced(). */
-void _cleanup_srcu_struct(struct srcu_struct *sp, bool quiesced)
+void _cleanup_srcu_struct(struct srcu_struct *ssp, bool quiesced)
 {
 	int cpu;
 
-	if (WARN_ON(!srcu_get_delay(sp)))
+	if (WARN_ON(!srcu_get_delay(ssp)))
 		return; /* Just leak it! */
-	if (WARN_ON(srcu_readers_active(sp)))
+	if (WARN_ON(srcu_readers_active(ssp)))
 		return; /* Just leak it! */
 	if (quiesced) {
-		if (WARN_ON(delayed_work_pending(&sp->work)))
+		if (WARN_ON(delayed_work_pending(&ssp->work)))
 			return; /* Just leak it! */
 	} else {
-		flush_delayed_work(&sp->work);
+		flush_delayed_work(&ssp->work);
 	}
 	for_each_possible_cpu(cpu)
 		if (quiesced) {
-			if (WARN_ON(delayed_work_pending(&per_cpu_ptr(sp->sda, cpu)->work)))
+			if (WARN_ON(delayed_work_pending(&per_cpu_ptr(ssp->sda, cpu)->work)))
 				return; /* Just leak it! */
 		} else {
-			flush_delayed_work(&per_cpu_ptr(sp->sda, cpu)->work);
+			flush_delayed_work(&per_cpu_ptr(ssp->sda, cpu)->work);
 		}
-	if (WARN_ON(rcu_seq_state(READ_ONCE(sp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
-	    WARN_ON(srcu_readers_active(sp))) {
+	if (WARN_ON(rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)) != SRCU_STATE_IDLE) ||
+	    WARN_ON(srcu_readers_active(ssp))) {
 		pr_info("%s: Active srcu_struct %p state: %d\n",
-			__func__, sp, rcu_seq_state(READ_ONCE(sp->srcu_gp_seq)));
+			__func__, ssp, rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq)));
 		return; /* Caller forgot to stop doing call_srcu()? */
 	}
-	free_percpu(sp->sda);
-	sp->sda = NULL;
+	free_percpu(ssp->sda);
+	ssp->sda = NULL;
 }
 EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
 
@@ -409,12 +409,12 @@ EXPORT_SYMBOL_GPL(_cleanup_srcu_struct);
  * srcu_struct.
  * Returns an index that must be passed to the matching srcu_read_unlock().
  */
-int __srcu_read_lock(struct srcu_struct *sp)
+int __srcu_read_lock(struct srcu_struct *ssp)
 {
 	int idx;
 
-	idx = READ_ONCE(sp->srcu_idx) & 0x1;
-	this_cpu_inc(sp->sda->srcu_lock_count[idx]);
+	idx = READ_ONCE(ssp->srcu_idx) & 0x1;
+	this_cpu_inc(ssp->sda->srcu_lock_count[idx]);
 	smp_mb(); /* B */  /* Avoid leaking the critical section. */
 	return idx;
 }
@@ -425,10 +425,10 @@ EXPORT_SYMBOL_GPL(__srcu_read_lock);
  * element of the srcu_struct.  Note that this may well be a different
  * CPU than that which was incremented by the corresponding srcu_read_lock().
  */
-void __srcu_read_unlock(struct srcu_struct *sp, int idx)
+void __srcu_read_unlock(struct srcu_struct *ssp, int idx)
 {
 	smp_mb(); /* C */  /* Avoid leaking the critical section. */
-	this_cpu_inc(sp->sda->srcu_unlock_count[idx]);
+	this_cpu_inc(ssp->sda->srcu_unlock_count[idx]);
 }
 EXPORT_SYMBOL_GPL(__srcu_read_unlock);
 
@@ -444,20 +444,22 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock);
 /*
  * Start an SRCU grace period.
  */
-static void srcu_gp_start(struct srcu_struct *sp)
+static void srcu_gp_start(struct srcu_struct *ssp)
 {
-	struct srcu_data *sdp = this_cpu_ptr(sp->sda);
+	struct srcu_data *sdp = this_cpu_ptr(ssp->sda);
 	int state;
 
-	lockdep_assert_held(&ACCESS_PRIVATE(sp, lock));
-	WARN_ON_ONCE(ULONG_CMP_GE(sp->srcu_gp_seq, sp->srcu_gp_seq_needed));
+	lockdep_assert_held(&ACCESS_PRIVATE(ssp, lock));
+	WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed));
+	spin_lock_rcu_node(sdp);  /* Interrupts already disabled. */
 	rcu_segcblist_advance(&sdp->srcu_cblist,
-			      rcu_seq_current(&sp->srcu_gp_seq));
+			      rcu_seq_current(&ssp->srcu_gp_seq));
 	(void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
-				       rcu_seq_snap(&sp->srcu_gp_seq));
+				       rcu_seq_snap(&ssp->srcu_gp_seq));
+	spin_unlock_rcu_node(sdp);  /* Interrupts remain disabled. */
 	smp_mb(); /* Order prior store to ->srcu_gp_seq_needed vs. GP start. */
-	rcu_seq_start(&sp->srcu_gp_seq);
-	state = rcu_seq_state(READ_ONCE(sp->srcu_gp_seq));
+	rcu_seq_start(&ssp->srcu_gp_seq);
+	state = rcu_seq_state(READ_ONCE(ssp->srcu_gp_seq));
 	WARN_ON_ONCE(state != SRCU_STATE_SCAN1);
 }
 
@@ -511,7 +513,7 @@ static void srcu_schedule_cbs_sdp(struct srcu_data *sdp, unsigned long delay)
  * just-completed grace period, the one corresponding to idx.  If possible,
  * schedule this invocation on the corresponding CPUs.
  */
-static void srcu_schedule_cbs_snp(struct srcu_struct *sp, struct srcu_node *snp,
+static void srcu_schedule_cbs_snp(struct srcu_struct *ssp, struct srcu_node *snp,
 				  unsigned long mask, unsigned long delay)
 {
 	int cpu;
@@ -519,7 +521,7 @@ static void srcu_schedule_cbs_snp(struct srcu_struct *sp, struct srcu_node *snp,
 	for (cpu = snp->grplo; cpu <= snp->grphi; cpu++) {
 		if (!(mask & (1 << (cpu - snp->grplo))))
 			continue;
-		srcu_schedule_cbs_sdp(per_cpu_ptr(sp->sda, cpu), delay);
+		srcu_schedule_cbs_sdp(per_cpu_ptr(ssp->sda, cpu), delay);
 	}
 }
 
@@ -532,7 +534,7 @@ static void srcu_schedule_cbs_snp(struct srcu_struct *sp, struct srcu_node *snp,
  * are initiating callback invocation.  This allows the ->srcu_have_cbs[]
  * array to have a finite number of elements.
  */
-static void srcu_gp_end(struct srcu_struct *sp)
+static void srcu_gp_end(struct srcu_struct *ssp)
 {
 	unsigned long cbdelay;
 	bool cbs;
@@ -546,28 +548,28 @@ static void srcu_gp_end(struct srcu_struct *sp)
 	struct srcu_node *snp;
 
 	/* Prevent more than one additional grace period. */
-	mutex_lock(&sp->srcu_cb_mutex);
+	mutex_lock(&ssp->srcu_cb_mutex);
 
 	/* End the current grace period. */
-	spin_lock_irq_rcu_node(sp);
-	idx = rcu_seq_state(sp->srcu_gp_seq);
+	spin_lock_irq_rcu_node(ssp);
+	idx = rcu_seq_state(ssp->srcu_gp_seq);
 	WARN_ON_ONCE(idx != SRCU_STATE_SCAN2);
-	cbdelay = srcu_get_delay(sp);
-	sp->srcu_last_gp_end = ktime_get_mono_fast_ns();
-	rcu_seq_end(&sp->srcu_gp_seq);
-	gpseq = rcu_seq_current(&sp->srcu_gp_seq);
-	if (ULONG_CMP_LT(sp->srcu_gp_seq_needed_exp, gpseq))
-		sp->srcu_gp_seq_needed_exp = gpseq;
-	spin_unlock_irq_rcu_node(sp);
-	mutex_unlock(&sp->srcu_gp_mutex);
+	cbdelay = srcu_get_delay(ssp);
+	ssp->srcu_last_gp_end = ktime_get_mono_fast_ns();
+	rcu_seq_end(&ssp->srcu_gp_seq);
+	gpseq = rcu_seq_current(&ssp->srcu_gp_seq);
+	if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, gpseq))
+		ssp->srcu_gp_seq_needed_exp = gpseq;
+	spin_unlock_irq_rcu_node(ssp);
+	mutex_unlock(&ssp->srcu_gp_mutex);
 	/* A new grace period can start at this point.  But only one. */
 
 	/* Initiate callback invocation as needed. */
 	idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
-	srcu_for_each_node_breadth_first(sp, snp) {
+	srcu_for_each_node_breadth_first(ssp, snp) {
 		spin_lock_irq_rcu_node(snp);
 		cbs = false;
-		last_lvl = snp >= sp->level[rcu_num_lvls - 1];
+		last_lvl = snp >= ssp->level[rcu_num_lvls - 1];
 		if (last_lvl)
 			cbs = snp->srcu_have_cbs[idx] == gpseq;
 		snp->srcu_have_cbs[idx] = gpseq;
@@ -578,12 +580,12 @@ static void srcu_gp_end(struct srcu_struct *sp)
 		snp->srcu_data_have_cbs[idx] = 0;
 		spin_unlock_irq_rcu_node(snp);
 		if (cbs)
-			srcu_schedule_cbs_snp(sp, snp, mask, cbdelay);
+			srcu_schedule_cbs_snp(ssp, snp, mask, cbdelay);
 
 		/* Occasionally prevent srcu_data counter wrap. */
 		if (!(gpseq & counter_wrap_check) && last_lvl)
 			for (cpu = snp->grplo; cpu <= snp->grphi; cpu++) {
-				sdp = per_cpu_ptr(sp->sda, cpu);
+				sdp = per_cpu_ptr(ssp->sda, cpu);
 				spin_lock_irqsave_rcu_node(sdp, flags);
 				if (ULONG_CMP_GE(gpseq,
 						 sdp->srcu_gp_seq_needed + 100))
@@ -596,18 +598,18 @@ static void srcu_gp_end(struct srcu_struct *sp)
 	}
 
 	/* Callback initiation done, allow grace periods after next. */
-	mutex_unlock(&sp->srcu_cb_mutex);
+	mutex_unlock(&ssp->srcu_cb_mutex);
 
 	/* Start a new grace period if needed. */
-	spin_lock_irq_rcu_node(sp);
-	gpseq = rcu_seq_current(&sp->srcu_gp_seq);
+	spin_lock_irq_rcu_node(ssp);
+	gpseq = rcu_seq_current(&ssp->srcu_gp_seq);
 	if (!rcu_seq_state(gpseq) &&
-	    ULONG_CMP_LT(gpseq, sp->srcu_gp_seq_needed)) {
-		srcu_gp_start(sp);
-		spin_unlock_irq_rcu_node(sp);
-		srcu_reschedule(sp, 0);
+	    ULONG_CMP_LT(gpseq, ssp->srcu_gp_seq_needed)) {
+		srcu_gp_start(ssp);
+		spin_unlock_irq_rcu_node(ssp);
+		srcu_reschedule(ssp, 0);
 	} else {
-		spin_unlock_irq_rcu_node(sp);
+		spin_unlock_irq_rcu_node(ssp);
 	}
 }
 
@@ -618,13 +620,13 @@ static void srcu_gp_end(struct srcu_struct *sp)
  * but without expediting.  To start a completely new grace period,
  * whether expedited or not, use srcu_funnel_gp_start() instead.
  */
-static void srcu_funnel_exp_start(struct srcu_struct *sp, struct srcu_node *snp,
+static void srcu_funnel_exp_start(struct srcu_struct *ssp, struct srcu_node *snp,
 				  unsigned long s)
 {
 	unsigned long flags;
 
 	for (; snp != NULL; snp = snp->srcu_parent) {
-		if (rcu_seq_done(&sp->srcu_gp_seq, s) ||
+		if (rcu_seq_done(&ssp->srcu_gp_seq, s) ||
 		    ULONG_CMP_GE(READ_ONCE(snp->srcu_gp_seq_needed_exp), s))
 			return;
 		spin_lock_irqsave_rcu_node(snp, flags);
@@ -635,10 +637,10 @@ static void srcu_funnel_exp_start(struct srcu_struct *sp, struct srcu_node *snp,
 		WRITE_ONCE(snp->srcu_gp_seq_needed_exp, s);
 		spin_unlock_irqrestore_rcu_node(snp, flags);
 	}
-	spin_lock_irqsave_rcu_node(sp, flags);
-	if (ULONG_CMP_LT(sp->srcu_gp_seq_needed_exp, s))
-		sp->srcu_gp_seq_needed_exp = s;
-	spin_unlock_irqrestore_rcu_node(sp, flags);
+	spin_lock_irqsave_rcu_node(ssp, flags);
+	if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, s))
+		ssp->srcu_gp_seq_needed_exp = s;
+	spin_unlock_irqrestore_rcu_node(ssp, flags);
 }
 
 /*
@@ -651,7 +653,7 @@ static void srcu_funnel_exp_start(struct srcu_struct *sp, struct srcu_node *snp,
  * Note that this function also does the work of srcu_funnel_exp_start(),
  * in some cases by directly invoking it.
  */
-static void srcu_funnel_gp_start(struct srcu_struct *sp, struct srcu_data *sdp,
+static void srcu_funnel_gp_start(struct srcu_struct *ssp, struct srcu_data *sdp,
 				 unsigned long s, bool do_norm)
 {
 	unsigned long flags;
@@ -661,7 +663,7 @@ static void srcu_funnel_gp_start(struct srcu_struct *sp, struct srcu_data *sdp,
 
 	/* Each pass through the loop does one level of the srcu_node tree. */
 	for (; snp != NULL; snp = snp->srcu_parent) {
-		if (rcu_seq_done(&sp->srcu_gp_seq, s) && snp != sdp->mynode)
+		if (rcu_seq_done(&ssp->srcu_gp_seq, s) && snp != sdp->mynode)
 			return; /* GP already done and CBs recorded. */
 		spin_lock_irqsave_rcu_node(snp, flags);
 		if (ULONG_CMP_GE(snp->srcu_have_cbs[idx], s)) {
@@ -676,7 +678,7 @@ static void srcu_funnel_gp_start(struct srcu_struct *sp, struct srcu_data *sdp,
 				return;
 			}
 			if (!do_norm)
-				srcu_funnel_exp_start(sp, snp, s);
+				srcu_funnel_exp_start(ssp, snp, s);
 			return;
 		}
 		snp->srcu_have_cbs[idx] = s;
@@ -688,29 +690,29 @@ static void srcu_funnel_gp_start(struct srcu_struct *sp, struct srcu_data *sdp,
 	}
 
 	/* Top of tree, must ensure the grace period will be started. */
-	spin_lock_irqsave_rcu_node(sp, flags);
-	if (ULONG_CMP_LT(sp->srcu_gp_seq_needed, s)) {
+	spin_lock_irqsave_rcu_node(ssp, flags);
+	if (ULONG_CMP_LT(ssp->srcu_gp_seq_needed, s)) {
 		/*
 		 * Record need for grace period s.  Pair with load
 		 * acquire setting up for initialization.
 		 */
-		smp_store_release(&sp->srcu_gp_seq_needed, s); /*^^^*/
+		smp_store_release(&ssp->srcu_gp_seq_needed, s); /*^^^*/
 	}
-	if (!do_norm && ULONG_CMP_LT(sp->srcu_gp_seq_needed_exp, s))
-		sp->srcu_gp_seq_needed_exp = s;
+	if (!do_norm && ULONG_CMP_LT(ssp->srcu_gp_seq_needed_exp, s))
+		ssp->srcu_gp_seq_needed_exp = s;
 
 	/* If grace period not already done and none in progress, start it. */
-	if (!rcu_seq_done(&sp->srcu_gp_seq, s) &&
-	    rcu_seq_state(sp->srcu_gp_seq) == SRCU_STATE_IDLE) {
-		WARN_ON_ONCE(ULONG_CMP_GE(sp->srcu_gp_seq, sp->srcu_gp_seq_needed));
-		srcu_gp_start(sp);
+	if (!rcu_seq_done(&ssp->srcu_gp_seq, s) &&
+	    rcu_seq_state(ssp->srcu_gp_seq) == SRCU_STATE_IDLE) {
+		WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_gp_seq, ssp->srcu_gp_seq_needed));
+		srcu_gp_start(ssp);
 		if (likely(srcu_init_done))
-			queue_delayed_work(rcu_gp_wq, &sp->work,
-					   srcu_get_delay(sp));
-		else if (list_empty(&sp->work.work.entry))
-			list_add(&sp->work.work.entry, &srcu_boot_list);
+			queue_delayed_work(rcu_gp_wq, &ssp->work,
+					   srcu_get_delay(ssp));
+		else if (list_empty(&ssp->work.work.entry))
+			list_add(&ssp->work.work.entry, &srcu_boot_list);
 	}
-	spin_unlock_irqrestore_rcu_node(sp, flags);
+	spin_unlock_irqrestore_rcu_node(ssp, flags);
 }
 
 /*
@@ -718,12 +720,12 @@ static void srcu_funnel_gp_start(struct srcu_struct *sp, struct srcu_data *sdp,
  * loop an additional time if there is an expedited grace period pending.
  * The caller must ensure that ->srcu_idx is not changed while checking.
  */
-static bool try_check_zero(struct srcu_struct *sp, int idx, int trycount)
+static bool try_check_zero(struct srcu_struct *ssp, int idx, int trycount)
 {
 	for (;;) {
-		if (srcu_readers_active_idx_check(sp, idx))
+		if (srcu_readers_active_idx_check(ssp, idx))
 			return true;
-		if (--trycount + !srcu_get_delay(sp) <= 0)
+		if (--trycount + !srcu_get_delay(ssp) <= 0)
 			return false;
 		udelay(SRCU_RETRY_CHECK_DELAY);
 	}
@@ -734,7 +736,7 @@ static bool try_check_zero(struct srcu_struct *sp, int idx, int trycount)
  * use the other rank of the ->srcu_(un)lock_count[] arrays.  This allows
  * us to wait for pre-existing readers in a starvation-free manner.
  */
-static void srcu_flip(struct srcu_struct *sp)
+static void srcu_flip(struct srcu_struct *ssp)
 {
 	/*
 	 * Ensure that if this updater saw a given reader's increment
@@ -746,7 +748,7 @@ static void srcu_flip(struct srcu_struct *sp)
 	 */
 	smp_mb(); /* E */  /* Pairs with B and C. */
 
-	WRITE_ONCE(sp->srcu_idx, sp->srcu_idx + 1);
+	WRITE_ONCE(ssp->srcu_idx, ssp->srcu_idx + 1);
 
 	/*
 	 * Ensure that if the updater misses an __srcu_read_unlock()
@@ -779,7 +781,7 @@ static void srcu_flip(struct srcu_struct *sp)
  * negligible when amoritized over that time period, and the extra latency
  * of a needlessly non-expedited grace period is similarly negligible.
  */
-static bool srcu_might_be_idle(struct srcu_struct *sp)
+static bool srcu_might_be_idle(struct srcu_struct *ssp)
 {
 	unsigned long curseq;
 	unsigned long flags;
@@ -788,7 +790,7 @@ static bool srcu_might_be_idle(struct srcu_struct *sp)
 
 	/* If the local srcu_data structure has callbacks, not idle.  */
 	local_irq_save(flags);
-	sdp = this_cpu_ptr(sp->sda);
+	sdp = this_cpu_ptr(ssp->sda);
 	if (rcu_segcblist_pend_cbs(&sdp->srcu_cblist)) {
 		local_irq_restore(flags);
 		return false; /* Callbacks already present, so not idle. */
@@ -804,17 +806,17 @@ static bool srcu_might_be_idle(struct srcu_struct *sp)
 	/* First, see if enough time has passed since the last GP. */
 	t = ktime_get_mono_fast_ns();
 	if (exp_holdoff == 0 ||
-	    time_in_range_open(t, sp->srcu_last_gp_end,
-			       sp->srcu_last_gp_end + exp_holdoff))
+	    time_in_range_open(t, ssp->srcu_last_gp_end,
+			       ssp->srcu_last_gp_end + exp_holdoff))