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PM: runtime: Take active children into account in pm_runtime_get_if_in_use()

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[ Upstream commit 51888393cc ]

For all practical purposes, there is no difference between the situation
in which a given device is not ignoring children and its active child
count is nonzero and the situation in which its runtime PM usage counter
is nonzero.  However, pm_runtime_get_if_in_use() will only increment the
device's usage counter and return 1 in the latter case.

For consistency, make it do so in the former case either by adjusting
pm_runtime_get_conditional() and update the related kerneldoc comments
accordingly.

Fixes: c111566bea ("PM: runtime: Add pm_runtime_get_if_active()")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: 5.10+ <stable@vger.kernel.org> # 5.10+: c0ef3df8db: PM: runtime: Simplify pm_runtime_get_if_active() usage
Cc: 5.10+ <stable@vger.kernel.org> # 5.10+
Link: https://patch.msgid.link/12700973.O9o76ZdvQC@rjwysocki.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Rafael J. Wysocki 2025-08-21 12:28:33 -04:00 committed by Greg Kroah-Hartman
parent ac2e62cab0
commit 9e9b1fa7ec
1 changed files with 18 additions and 9 deletions
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27
drivers/base/power/runtime.c
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@ -1181,10 +1181,12 @@ EXPORT_SYMBOL_GPL(__pm_runtime_resume);
*
* Return -EINVAL if runtime PM is disabled for @dev.
*
* Otherwise, if the runtime PM status of @dev is %RPM_ACTIVE and either
* @ign_usage_count is %true or the runtime PM usage counter of @dev is not
* zero, increment the usage counter of @dev and return 1. Otherwise, return 0
* without changing the usage counter.
* Otherwise, if its runtime PM status is %RPM_ACTIVE and (1) @ign_usage_count
* is set, or (2) @dev is not ignoring children and its active child count is
* nonero, or (3) the runtime PM usage counter of @dev is not zero, increment
* the usage counter of @dev and return 1.
*
* Otherwise, return 0 without changing the usage counter.
*
* If @ign_usage_count is %true, this function can be used to prevent suspending
* the device when its runtime PM status is %RPM_ACTIVE.
@ -1206,7 +1208,8 @@ static int pm_runtime_get_conditional(struct device *dev, bool ign_usage_count)
retval = -EINVAL;
} else if (dev->power.runtime_status != RPM_ACTIVE) {
retval = 0;
} else if (ign_usage_count) {
} else if (ign_usage_count || (!dev->power.ignore_children &&
atomic_read(&dev->power.child_count) > 0)) {
retval = 1;
atomic_inc(&dev->power.usage_count);
} else {
@ -1239,10 +1242,16 @@ EXPORT_SYMBOL_GPL(pm_runtime_get_if_active);
* @dev: Target device.
*
* Increment the runtime PM usage counter of @dev if its runtime PM status is
* %RPM_ACTIVE and its runtime PM usage counter is greater than 0, in which case
* it returns 1. If the device is in a different state or its usage_count is 0,
* 0 is returned. -EINVAL is returned if runtime PM is disabled for the device,
* in which case also the usage_count will remain unmodified.
* %RPM_ACTIVE and its runtime PM usage counter is greater than 0 or it is not
* ignoring children and its active child count is nonzero. 1 is returned in
* this case.
*
* If @dev is in a different state or it is not in use (that is, its usage
* counter is 0, or it is ignoring children, or its active child count is 0),
* 0 is returned.
*
* -EINVAL is returned if runtime PM is disabled for the device, in which case
* also the usage counter of @dev is not updated.
*/
int pm_runtime_get_if_in_use(struct device *dev)
{