[PATCH v1 2/2] PM: core: Add two macros for walking device links

Rafael J. Wysocki
2025-09-02T13:45:34Z

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

Add separate macros for walking links to suppliers and consumers of a
device to help device links users to avoid exposing the internals of
struct dev_links_info in their code and possible coding mistakes related
to that.

Accordingly, use the new macros to replace open-coded device links list
walks in the core power management code.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/base/base.h | 8 ++++++++
drivers/base/power/main.c | 18 +++++++-----------
drivers/base/power/runtime.c | 3 +--
3 files changed, 16 insertions(+), 13 deletions(-)

--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -251,6 +251,14 @@
void fw_devlink_drivers_done(void);
void fw_devlink_probing_done(void);

+#define dev_for_each_link_to_supplier(__link, __dev) \
+ list_for_each_entry_srcu(__link, &(__dev)->links.suppliers, c_node, \
+ device_links_read_lock_held())
+
+#define dev_for_each_link_to_consumer(__link, __dev) \
+ list_for_each_entry_srcu(__link, &(__dev)->links.consumers, s_node, \
+ device_links_read_lock_held())
+
/* device pm support */
void device_pm_move_to_tail(struct device *dev);

--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -40,10 +40,6 @@

typedef int (*pm_callback_t)(struct device *);

-#define list_for_each_entry_srcu_locked(pos, head, member) \
- list_for_each_entry_srcu(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
@@ -281,7 +277,7 @@
* callbacks freeing the link objects for the links in the list we're
* walking.
*/
- list_for_each_entry_srcu_locked(link, &dev->links.suppliers, c_node)
+ dev_for_each_link_to_supplier(link, dev)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->supplier, async);

@@ -338,7 +334,7 @@
* continue instead of trying to continue in parallel with its
* unregistration).
*/
- list_for_each_entry_srcu_locked(link, &dev->links.consumers, s_node)
+ dev_for_each_link_to_consumer(link, dev)
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->consumer, async);

@@ -675,7 +671,7 @@
idx = device_links_read_lock();

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

@@ -1330,7 +1326,7 @@
idx = device_links_read_lock();

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

@@ -1384,7 +1380,7 @@

idx = device_links_read_lock();

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

device_links_read_unlock(idx);
@@ -1813,7 +1809,7 @@

idx = device_links_read_lock();

- list_for_each_entry_srcu_locked(link, &dev->links.suppliers, c_node) {
+ dev_for_each_link_to_supplier(link, dev) {
spin_lock_irq(&link->supplier->power.lock);
link->supplier->power.direct_complete = false;
spin_unlock_irq(&link->supplier->power.lock);
@@ -2065,7 +2061,7 @@

idx = device_links_read_lock();

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

--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1903,8 +1903,7 @@

idx = device_links_read_lock();

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