From 42beb82ec4dc99a425e0fded34f7aa5276a709ab Mon Sep 17 00:00:00 2001 From: Madhuparna Bhowmik Date: Wed, 4 Mar 2020 01:11:30 +0530 Subject: [PATCH] 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 Signed-off-by: Rafael J. Wysocki --- drivers/base/power/main.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 0e99a760aebd..6d1dee7051eb 100644 --- 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);