[PATCH tip/core/rcu 14/20] rcu: Use wrapper for lockdep asserts

From: Paul E. McKenney
Date: Mon Feb 26 2018 - 16:55:06 EST


From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/rcu.h | 5 ++++-
kernel/rcu/srcutree.c | 2 +-
kernel/rcu/tree.c | 24 ++++++++++++------------
kernel/rcu/tree_plugin.h | 4 ++--
4 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index c90812673d54..5d13f651cf08 100644
--- a/kernel/rcu/rcu.h
+++ b/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
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index d5cea81378cc..9c6e0eaab4d5 100644
--- a/kernel/rcu/srcutree.c
+++ b/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));
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 4d7c727020f0..99d404c6bbbb 100644
--- a/kernel/rcu/tree.c
+++ b/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;
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 1c2d58a85511..84fbee4686d3 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/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;
--
2.5.2