summaryrefslogtreecommitdiffstats
path: root/drivers/base/power/runtime.c
diff options
context:
space:
mode:
authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-06-30 21:16:41 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2022-07-01 21:04:15 +0200
commit887371066039011144b4a94af97d9328df6869a2 (patch)
treed5e2d98d1beb583bc4276618c5af4e493a759c10 /drivers/base/power/runtime.c
parentPM: runtime: Redefine pm_runtime_release_supplier() (diff)
downloadlinux-887371066039011144b4a94af97d9328df6869a2.tar.xz
linux-887371066039011144b4a94af97d9328df6869a2.zip
PM: runtime: Fix supplier device management during consumer probe
Because pm_runtime_get_suppliers() bumps up the rpm_active counter of each device link to a supplier of the given device in addition to bumping up the supplier's PM-runtime usage counter, a runtime suspend of the consumer device may case the latter to go down to 0 when pm_runtime_put_suppliers() is running on a remote CPU. If that happens after pm_runtime_put_suppliers() has released power.lock for the consumer device, and a runtime resume of that device takes place immediately after it, before pm_runtime_put() is called for the supplier, that pm_runtime_put() call may cause the supplier to be suspended even though the consumer is active. To prevent that from happening, modify pm_runtime_get_suppliers() to call pm_runtime_get_sync() for the given device's suppliers without touching the rpm_active counters of the involved device links Accordingly, modify pm_runtime_put_suppliers() to call pm_runtime_put() for the given device's suppliers without looking at the rpm_active counters of the device links at hand. [This is analogous to what happened before commit 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance").] Since pm_runtime_get_suppliers() sets supplier_preactivated for each device link where the supplier's PM-runtime usage counter has been incremented and pm_runtime_put_suppliers() calls pm_runtime_put() for the suppliers whose device links have supplier_preactivated set, the PM-runtime usage counter is balanced for each supplier and this is independent of the runtime suspend and resume of the consumer device. However, in case a device link with DL_FLAG_PM_RUNTIME set is dropped during the consumer device probe, so pm_runtime_get_suppliers() bumps up the supplier's PM-runtime usage counter, but it cannot be dropped by pm_runtime_put_suppliers(), make device_link_release_fn() take care of that. Fixes: 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance") Reported-by: Peter Wang <peter.wang@mediatek.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Peter Wang <peter.wang@mediatek.com> Cc: 5.1+ <stable@vger.kernel.org> # 5.1+
Diffstat (limited to 'drivers/base/power/runtime.c')
-rw-r--r--drivers/base/power/runtime.c14
1 files changed, 1 insertions, 13 deletions
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 23cc4c377d77..949907e2e242 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1768,7 +1768,6 @@ void pm_runtime_get_suppliers(struct device *dev)
if (link->flags & DL_FLAG_PM_RUNTIME) {
link->supplier_preactivated = true;
pm_runtime_get_sync(link->supplier);
- refcount_inc(&link->rpm_active);
}
device_links_read_unlock(idx);
@@ -1788,19 +1787,8 @@ void pm_runtime_put_suppliers(struct device *dev)
list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
device_links_read_lock_held())
if (link->supplier_preactivated) {
- bool put;
-
link->supplier_preactivated = false;
-
- spin_lock_irq(&dev->power.lock);
-
- put = pm_runtime_status_suspended(dev) &&
- refcount_dec_not_one(&link->rpm_active);
-
- spin_unlock_irq(&dev->power.lock);
-
- if (put)
- pm_runtime_put(link->supplier);
+ pm_runtime_put(link->supplier);
}
device_links_read_unlock(idx);