[PATCH] rcu: Use wrapper for lockdep asserts

Matthew Wilcox
2018-01-17T14:24:34Z

From: Matthew Wilcox <mawilcox@microsoft.com>

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>

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 59c471de342a..30db0a581628 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -360,7 +360,7 @@ 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) \
({ \
@@ -371,6 +371,9 @@ 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 6d5880089ff6..b7bdd3ff4611 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -412,7 +412,7 @@ 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 f9c0ca2ccf0c..aba8dd0cc1f8 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1245,7 +1245,7 @@ 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))
@@ -1712,7 +1712,7 @@ 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.
@@ -1759,7 +1759,7 @@ 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
@@ -1887,7 +1887,7 @@ 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))
@@ -1927,7 +1927,7 @@ 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))
@@ -1955,7 +1955,7 @@ 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 &&
@@ -2380,7 +2380,7 @@ 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
@@ -2442,7 +2442,7 @@ 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);
@@ -2467,7 +2467,7 @@ 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 (;;) {
@@ -2531,7 +2531,7 @@ 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);
@@ -2676,7 +2676,7 @@ 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;
@@ -3697,7 +3697,7 @@ 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 db85ca3975f1..80d29c6fb572 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -181,7 +181,7 @@ 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);

@@ -1043,7 +1043,7 @@ 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;