* [PATCH v1 1/2] PM: core: Annotate loops walking device links as _srcu
2025-09-02 13:40 [PATCH v1 0/2] PM: core: Updates related to device link lists Rafael J. Wysocki
@ 2025-09-02 13:43 ` Rafael J. Wysocki
2025-09-04 9:23 ` Ulf Hansson
2025-09-02 13:45 ` [PATCH v1 2/2] PM: core: Add two macros for walking device links Rafael J. Wysocki
2025-09-06 12:01 ` [PATCH v1 0/2] PM: core: Updates related to device link lists Greg Kroah-Hartman
2 siblings, 1 reply; 6+ messages in thread
From: Rafael J. Wysocki @ 2025-09-02 13:43 UTC (permalink / raw)
To: Linux PM
Cc: Greg Kroah-Hartman, LKML, Danilo Krummrich, Ulf Hansson,
Saravana Kannan, Johannes Berg
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);
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v1 1/2] PM: core: Annotate loops walking device links as _srcu
2025-09-02 13:43 ` [PATCH v1 1/2] PM: core: Annotate loops walking device links as _srcu Rafael J. Wysocki
@ 2025-09-04 9:23 ` Ulf Hansson
0 siblings, 0 replies; 6+ messages in thread
From: Ulf Hansson @ 2025-09-04 9:23 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Linux PM, Greg Kroah-Hartman, LKML, Danilo Krummrich,
Saravana Kannan, Johannes Berg
On Tue, 2 Sept 2025 at 15:45, Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> 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>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Kind regards
Uffe
> ---
> 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);
>
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v1 2/2] PM: core: Add two macros for walking device links
2025-09-02 13:40 [PATCH v1 0/2] PM: core: Updates related to device link lists Rafael J. Wysocki
2025-09-02 13:43 ` [PATCH v1 1/2] PM: core: Annotate loops walking device links as _srcu Rafael J. Wysocki
@ 2025-09-02 13:45 ` Rafael J. Wysocki
2025-09-04 9:23 ` Ulf Hansson
2025-09-06 12:01 ` [PATCH v1 0/2] PM: core: Updates related to device link lists Greg Kroah-Hartman
2 siblings, 1 reply; 6+ messages in thread
From: Rafael J. Wysocki @ 2025-09-02 13:45 UTC (permalink / raw)
To: Linux PM
Cc: Greg Kroah-Hartman, LKML, Danilo Krummrich, Ulf Hansson,
Saravana Kannan, Johannes Berg
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);
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH v1 2/2] PM: core: Add two macros for walking device links
2025-09-02 13:45 ` [PATCH v1 2/2] PM: core: Add two macros for walking device links Rafael J. Wysocki
@ 2025-09-04 9:23 ` Ulf Hansson
0 siblings, 0 replies; 6+ messages in thread
From: Ulf Hansson @ 2025-09-04 9:23 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Linux PM, Greg Kroah-Hartman, LKML, Danilo Krummrich,
Saravana Kannan, Johannes Berg
On Tue, 2 Sept 2025 at 15:45, Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> 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>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Kind regards
Uffe
> ---
> 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);
>
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v1 0/2] PM: core: Updates related to device link lists
2025-09-02 13:40 [PATCH v1 0/2] PM: core: Updates related to device link lists Rafael J. Wysocki
2025-09-02 13:43 ` [PATCH v1 1/2] PM: core: Annotate loops walking device links as _srcu Rafael J. Wysocki
2025-09-02 13:45 ` [PATCH v1 2/2] PM: core: Add two macros for walking device links Rafael J. Wysocki
@ 2025-09-06 12:01 ` Greg Kroah-Hartman
2 siblings, 0 replies; 6+ messages in thread
From: Greg Kroah-Hartman @ 2025-09-06 12:01 UTC (permalink / raw)
To: Rafael J. Wysocki
Cc: Linux PM, LKML, Danilo Krummrich, Ulf Hansson, Saravana Kannan,
Johannes Berg
On Tue, Sep 02, 2025 at 03:40:54PM +0200, Rafael J. Wysocki wrote:
> Hi All,
>
> The changes in this series clean up the usage of _rcu list walks for
> walking lists of a device's links to suppliers and consumers.
>
> The first patch changes the _rcu annotation of those list walks to
> the _srcu one which is more appropriate because SRCU is used for
> device link lists protection.
>
> The second patch (which is not expected to make any functional difference)
> adds two macros for walking lists of a device's links to suppliers and
> consumers and updates power management code walking those lists to use
> the new macros for more clarity and protection against possible coding
> mistakes.
>
> Thanks!
>
>
>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
^ permalink raw reply [flat|nested] 6+ messages in thread