From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Date: Wed, 4 Mar 2020 01:11:30 +0530
Subject: PM: sleep: core: Use built-in RCU list checking
Patch-mainline: v5.7-rc1
Git-commit: 42beb82ec4dc99a425e0fded34f7aa5276a709ab
References: jsc#SLE-16407
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>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
drivers/base/power/main.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--- 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(struc
* 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(struc
* 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
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_c
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);