rcu: Use wrapper for lockdep asserts

Commits c0b334c5bfa9 and ea9b0c8a26a2 introduced new sparse warnings
by accessing rcu_node->lock directly and ignoring the __private
marker.  Introduce a new wrapper and use it.  Also fix a similar problem
in srcutree.c introduced by a3883df3935e.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

kernel/rcu/rcu.h

@@ -337,7 +337,7 @@ do {									\
 } while (0)
 
 #define raw_spin_unlock_irqrestore_rcu_node(p, flags)			\
-	raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags)	\
+	raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags)
 
 #define raw_spin_trylock_rcu_node(p)					\
 ({									\
@@ -348,6 +348,9 @@ do {									\
 	___locked;							\
 })
 
+#define raw_lockdep_assert_held_rcu_node(p)				\
+	lockdep_assert_held(&ACCESS_PRIVATE(p, lock))
+
 #endif /* #if defined(SRCU) || !defined(TINY_RCU) */
 
 #ifdef CONFIG_TINY_RCU

kernel/rcu/srcutree.c

@@ -439,7 +439,7 @@ static void srcu_gp_start(struct srcu_struct *sp)
 	struct srcu_data *sdp = this_cpu_ptr(sp->sda);
 	int state;
 
-	lockdep_assert_held(&sp->lock);
+	lockdep_assert_held(&ACCESS_PRIVATE(sp, lock));
 	WARN_ON_ONCE(ULONG_CMP_GE(sp->srcu_gp_seq, sp->srcu_gp_seq_needed));
 	rcu_segcblist_advance(&sdp->srcu_cblist,
 			      rcu_seq_current(&sp->srcu_gp_seq));

kernel/rcu/tree.c

@@ -1161,7 +1161,7 @@ static int rcu_is_cpu_rrupt_from_idle(void)
  */
 static void rcu_gpnum_ovf(struct rcu_node *rnp, struct rcu_data *rdp)
 {
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 	if (ULONG_CMP_LT(READ_ONCE(rdp->gpnum) + ULONG_MAX / 4, rnp->gpnum))
 		WRITE_ONCE(rdp->gpwrap, true);
 	if (ULONG_CMP_LT(rdp->rcu_iw_gpnum + ULONG_MAX / 4, rnp->gpnum))
@@ -1629,7 +1629,7 @@ void rcu_cpu_stall_reset(void)
 static unsigned long rcu_cbs_completed(struct rcu_state *rsp,
 				       struct rcu_node *rnp)
 {
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 
 	/*
 	 * If RCU is idle, we just wait for the next grace period.
@@ -1676,7 +1676,7 @@ rcu_start_future_gp(struct rcu_node *rnp, struct rcu_data *rdp,
 	bool ret = false;
 	struct rcu_node *rnp_root = rcu_get_root(rdp->rsp);
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 
 	/*
 	 * Pick up grace-period number for new callbacks.  If this
@@ -1804,7 +1804,7 @@ static bool rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
 {
 	bool ret = false;
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 
 	/* If no pending (not yet ready to invoke) callbacks, nothing to do. */
 	if (!rcu_segcblist_pend_cbs(&rdp->cblist))
@@ -1844,7 +1844,7 @@ static bool rcu_accelerate_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
 static bool rcu_advance_cbs(struct rcu_state *rsp, struct rcu_node *rnp,
 			    struct rcu_data *rdp)
 {
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 
 	/* If no pending (not yet ready to invoke) callbacks, nothing to do. */
 	if (!rcu_segcblist_pend_cbs(&rdp->cblist))
@@ -1872,7 +1872,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp,
 	bool ret;
 	bool need_gp;
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 
 	/* Handle the ends of any preceding grace periods first. */
 	if (rdp->completed == rnp->completed &&
@@ -2297,7 +2297,7 @@ static bool
 rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
 		      struct rcu_data *rdp)
 {
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 	if (!rsp->gp_kthread || !cpu_needs_another_gp(rsp, rdp)) {
 		/*
 		 * Either we have not yet spawned the grace-period
@@ -2359,7 +2359,7 @@ static bool rcu_start_gp(struct rcu_state *rsp)
 static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags)
 	__releases(rcu_get_root(rsp)->lock)
 {
-	lockdep_assert_held(&rcu_get_root(rsp)->lock);
+	raw_lockdep_assert_held_rcu_node(rcu_get_root(rsp));
 	WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
 	WRITE_ONCE(rsp->gp_flags, READ_ONCE(rsp->gp_flags) | RCU_GP_FLAG_FQS);
 	raw_spin_unlock_irqrestore_rcu_node(rcu_get_root(rsp), flags);
@@ -2384,7 +2384,7 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp,
 	unsigned long oldmask = 0;
 	struct rcu_node *rnp_c;
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 
 	/* Walk up the rcu_node hierarchy. */
 	for (;;) {
@@ -2448,7 +2448,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_state *rsp,
 	unsigned long mask;
 	struct rcu_node *rnp_p;
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 	if (rcu_state_p == &rcu_sched_state || rsp != rcu_state_p ||
 	    rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) {
 		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@@ -2593,7 +2593,7 @@ static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf)
 	long mask;
 	struct rcu_node *rnp = rnp_leaf;
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 	if (!IS_ENABLED(CONFIG_HOTPLUG_CPU) ||
 	    rnp->qsmaskinit || rcu_preempt_has_tasks(rnp))
 		return;
@@ -3596,7 +3596,7 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
 	long mask;
 	struct rcu_node *rnp = rnp_leaf;
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 	for (;;) {
 		mask = rnp->grpmask;
 		rnp = rnp->parent;

kernel/rcu/tree_plugin.h

@@ -180,7 +180,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
 			 (rnp->expmask & rdp->grpmask ? RCU_EXP_BLKD : 0);
 	struct task_struct *t = current;
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 	WARN_ON_ONCE(rdp->mynode != rnp);
 	WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1);
 
@@ -1044,7 +1044,7 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
 {
 	struct task_struct *t;
 
-	lockdep_assert_held(&rnp->lock);
+	raw_lockdep_assert_held_rcu_node(rnp);
 	if (!rcu_preempt_blocked_readers_cgp(rnp) && rnp->exp_tasks == NULL) {
 		raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 		return;