[PATCH 2/2] drivers: base: power: wakeup.c: Use built-in RCU list checking

From: madhuparnabhowmik10
Date: Tue Mar 03 2020 - 14:42:22 EST


From: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>

Pass cond argument to list_for_each_entry_rcu() to fix the
following false positive lockdep warning and other uses of
list_for_each_entry_rcu() in wakeup.c.
(CONFIG_PROVE_RCU_LIST = y)

[ 331.934648] =============================
[ 331.934650] WARNING: suspicious RCU usage
[ 331.934653] 5.6.0-rc1+ #5 Not tainted
[ 331.934655] -----------------------------
[ 331.934657] drivers/base/power/wakeup.c:408 RCU-list traversed in non-reader section!!

[ 333.025156] =============================
[ 333.025161] WARNING: suspicious RCU usage
[ 333.025168] 5.6.0-rc1+ #5 Not tainted
[ 333.025173] -----------------------------
[ 333.025180] drivers/base/power/wakeup.c:424 RCU-list traversed in non-reader section!!

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@xxxxxxxxx>
---
drivers/base/power/wakeup.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 27f3e60608e5..7e33a8d829dc 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -24,6 +24,9 @@ suspend_state_t pm_suspend_target_state;
#define pm_suspend_target_state (PM_SUSPEND_ON)
#endif

+#define list_for_each_entry_rcu_locked(pos, head, member) \
+ list_for_each_entry_rcu(pos, head, member, \
+ srcu_read_lock_held(&wakeup_srcu))
/*
* If set, the suspend/hibernate code will abort transitions to a sleep state
* if wakeup events are registered during or immediately before the transition.
@@ -405,7 +408,7 @@ void device_wakeup_arm_wake_irqs(void)
int srcuidx;

srcuidx = srcu_read_lock(&wakeup_srcu);
- list_for_each_entry_rcu(ws, &wakeup_sources, entry)
+ list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry)
dev_pm_arm_wake_irq(ws->wakeirq);
srcu_read_unlock(&wakeup_srcu, srcuidx);
}
@@ -421,7 +424,7 @@ void device_wakeup_disarm_wake_irqs(void)
int srcuidx;

srcuidx = srcu_read_lock(&wakeup_srcu);
- list_for_each_entry_rcu(ws, &wakeup_sources, entry)
+ list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry)
dev_pm_disarm_wake_irq(ws->wakeirq);
srcu_read_unlock(&wakeup_srcu, srcuidx);
}
@@ -874,7 +877,7 @@ void pm_print_active_wakeup_sources(void)
struct wakeup_source *last_activity_ws = NULL;

srcuidx = srcu_read_lock(&wakeup_srcu);
- list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
+ list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
if (ws->active) {
pm_pr_dbg("active wakeup source: %s\n", ws->name);
active = 1;
@@ -1025,7 +1028,7 @@ void pm_wakep_autosleep_enabled(bool set)
int srcuidx;

srcuidx = srcu_read_lock(&wakeup_srcu);
- list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
+ list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
spin_lock_irq(&ws->lock);
if (ws->autosleep_enabled != set) {
ws->autosleep_enabled = set;
@@ -1104,7 +1107,7 @@ static void *wakeup_sources_stats_seq_start(struct seq_file *m,
}

*srcuidx = srcu_read_lock(&wakeup_srcu);
- list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
+ list_for_each_entry_rcu_locked(ws, &wakeup_sources, entry) {
if (n-- <= 0)
return ws;
}
--
2.17.1