[PATCH v1 1/2] PM: core: Annotate loops walking device links as _srcu

Rafael J. Wysocki
2025-09-02T13:45:39Z

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Since SRCU is used for the protection of device link lists, the loops
over device link lists in multiple places in drivers/base/power/main.c
and in pm_runtime_get_suppliers() should be annotated as _srcu rather
than as _rcu which is the case currently.

Change the annotations accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/base/power/main.c | 18 +++++++++---------
drivers/base/power/runtime.c | 4 ++--
2 files changed, 11 insertions(+), 11 deletions(-)

--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -40,8 +40,8 @@

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, \
+#define list_for_each_entry_srcu_locked(pos, head, member) \
+ list_for_each_entry_srcu(pos, head, member, \
device_links_read_lock_held())

/*
@@ -281,7 +281,7 @@
* callbacks freeing the link objects for the links in the list we're
* walking.
*/
- list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
+ list_for_each_entry_srcu_locked(link, &dev->links.suppliers, c_node)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->supplier, async);

@@ -338,7 +338,7 @@
* continue instead of trying to continue in parallel with its
* unregistration).
*/
- list_for_each_entry_rcu_locked(link, &dev->links.consumers, s_node)
+ list_for_each_entry_srcu_locked(link, &dev->links.consumers, s_node)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->consumer, async);

@@ -675,7 +675,7 @@
idx = device_links_read_lock();

/* Start processing the device's "async" consumers. */
- list_for_each_entry_rcu_locked(link, &dev->links.consumers, s_node)
+ list_for_each_entry_srcu_locked(link, &dev->links.consumers, s_node)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_async_with_cleanup(link->consumer, func);

@@ -1330,7 +1330,7 @@
idx = device_links_read_lock();

/* Start processing the device's "async" suppliers. */
- list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
+ list_for_each_entry_srcu_locked(link, &dev->links.suppliers, c_node)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_async_with_cleanup(link->supplier, func);

@@ -1384,7 +1384,7 @@

idx = device_links_read_lock();

- list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
+ list_for_each_entry_srcu_locked(link, &dev->links.suppliers, c_node)
link->supplier->power.must_resume = true;

device_links_read_unlock(idx);
@@ -1813,7 +1813,7 @@

idx = device_links_read_lock();

- list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) {
+ list_for_each_entry_srcu_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);
@@ -2065,7 +2065,7 @@

idx = device_links_read_lock();

- list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) {
+ list_for_each_entry_srcu_locked(link, &dev->links.suppliers, c_node) {
if (!device_link_test(link, DL_FLAG_PM_RUNTIME))
continue;

--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1903,8 +1903,8 @@

idx = device_links_read_lock();

- list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
- device_links_read_lock_held())
+ list_for_each_entry_srcu(link, &dev->links.suppliers, c_node,
+ device_links_read_lock_held())
if (device_link_test(link, DL_FLAG_PM_RUNTIME)) {
link->supplier_preactivated = true;
pm_runtime_get_sync(link->supplier);