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| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-12-10 19:10:13 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-01-27 12:54:17 +0300 |
| commit | 37b25de3af10a3082f9ef5888de0f8602c5dcadf (patch) | |
| tree | 184f27e48ad239837a413251b6c95876686ef6c0 /include/linux | |
| parent | 5dfc6fa0b8c2f8a336a2e559a79d5a98ac28a81d (diff) | |
| download | linux-37b25de3af10a3082f9ef5888de0f8602c5dcadf.tar.xz | |
PM: runtime: Add safety net to supplier device release
[ Upstream commit d1579e61192e0e686faa4208500ef4c3b529b16c ]
Because refcount_dec_not_one() returns true if the target refcount
becomes saturated, it is generally unsafe to use its return value as
a loop termination condition, but that is what happens when a device
link's supplier device is released during runtime PM suspend
operations and on device link removal.
To address this, introduce pm_runtime_release_supplier() to be used
in the above cases which will check the supplier device's runtime
PM usage counter in addition to the refcount_dec_not_one() return
value, so the loop can be terminated in case the rpm_active refcount
value becomes invalid, and update the code in question to use it as
appropriate.
This change is not expected to have any visible functional impact.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/pm_runtime.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 161acd4ede44..30091ab5de28 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -58,6 +58,7 @@ extern void pm_runtime_get_suppliers(struct device *dev); extern void pm_runtime_put_suppliers(struct device *dev); extern void pm_runtime_new_link(struct device *dev); extern void pm_runtime_drop_link(struct device_link *link); +extern void pm_runtime_release_supplier(struct device_link *link, bool check_idle); /** * pm_runtime_get_if_in_use - Conditionally bump up runtime PM usage counter. @@ -279,6 +280,8 @@ static inline void pm_runtime_get_suppliers(struct device *dev) {} static inline void pm_runtime_put_suppliers(struct device *dev) {} static inline void pm_runtime_new_link(struct device *dev) {} static inline void pm_runtime_drop_link(struct device_link *link) {} +static inline void pm_runtime_release_supplier(struct device_link *link, + bool check_idle) {} #endif /* !CONFIG_PM */ |