PM: sleep: core: Use built-in RCU list checking

This patch passes the cond argument to list_for_each_entry_rcu()
to fix the following false-positive lockdep warnings:
(with CONFIG_PROVE_RCU_LIST = y)

[  330.302784] =============================
[  330.302789] WARNING: suspicious RCU usage
[  330.302796] 5.6.0-rc1+ #5 Not tainted
[  330.302801] -----------------------------
[  330.302808] drivers/base/power/main.c:326 RCU-list traversed in non-reader section!!

[  330.303303] =============================
[  330.303307] WARNING: suspicious RCU usage
[  330.303311] 5.6.0-rc1+ #5 Not tainted
[  330.303315] -----------------------------
[  330.303319] drivers/base/power/main.c:1698 RCU-list traversed in non-reader section!!

[  331.934969] =============================
[  331.934971] WARNING: suspicious RCU usage
[  331.934973] 5.6.0-rc1+ #5 Not tainted
[  331.934975] -----------------------------
[  331.934977] drivers/base/power/main.c:1238 RCU-list traversed in non-reader section!!

[  332.467772] WARNING: suspicious RCU usage
[  332.467775] 5.6.0-rc1+ #5 Not tainted
[  332.467775] -----------------------------
[  332.467778] drivers/base/power/main.c:269 RCU-list traversed in non-reader section!!

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 0e99a760aebd07998c91f1dc836a05de43ec6a7a..6d1dee7051eb12eb5e1226c16e2658eceb008e99 100644 (file)
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -40,6 +40,10 @@
 
 typedef int (*pm_callback_t)(struct device *);
 
+#define list_for_each_entry_rcu_locked(pos, head, member) \
+       list_for_each_entry_rcu(pos, head, member, \
+                       device_links_read_lock_held())
+
 /*
  * The entries in the dpm_list list are in a depth first order, simply
  * because children are guaranteed to be discovered after parents, and
@@ -266,7 +270,7 @@ static void dpm_wait_for_suppliers(struct device *dev, bool async)
         * callbacks freeing the link objects for the links in the list we're
         * walking.
         */
-       list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+       list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
                if (READ_ONCE(link->status) != DL_STATE_DORMANT)
                        dpm_wait(link->supplier, async);
 
@@ -323,7 +327,7 @@ static void dpm_wait_for_consumers(struct device *dev, bool async)
         * continue instead of trying to continue in parallel with its
         * unregistration).
         */
-       list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
+       list_for_each_entry_rcu_locked(link, &dev->links.consumers, s_node)
                if (READ_ONCE(link->status) != DL_STATE_DORMANT)
                        dpm_wait(link->consumer, async);
 
@@ -1235,7 +1239,7 @@ static void dpm_superior_set_must_resume(struct device *dev)
 
        idx = device_links_read_lock();
 
-       list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+       list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
                link->supplier->power.must_resume = true;
 
        device_links_read_unlock(idx);
@@ -1695,7 +1699,7 @@ static void dpm_clear_superiors_direct_complete(struct device *dev)
 
        idx = device_links_read_lock();
 
-       list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
+       list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) {
                spin_lock_irq(&link->supplier->power.lock);
                link->supplier->power.direct_complete = false;
                spin_unlock_irq(&link->supplier->power.lock);