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driver core: Do not resume suppliers under device_links_write_lock()

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[ Upstream commit 5db25c9eb893df8f6b93c1d97b8006d768e1b6f5 ]

It is incorrect to call pm_runtime_get_sync() under
device_links_write_lock(), because it may end up trying to take
device_links_read_lock() while resuming the target device and that
will deadlock in the non-SRCU case, so avoid that by resuming the
supplier device in device_link_add() before calling
device_links_write_lock().

Fixes: 21d5c57b3726 ("PM / runtime: Use device links")
Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Rafael J. Wysocki 2019-02-01 01:47:53 +01:00 committed by Greg Kroah-Hartman
parent d7a7f04e10
commit d7ee5bfb55
1 changed files with 14 additions and 6 deletions
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20
drivers/base/core.c
View File

@ -180,11 +180,20 @@ struct device_link *device_link_add(struct device *consumer,
struct device *supplier, u32 flags)
{
struct device_link *link;
bool rpm_put_supplier = false;
if (!consumer || !supplier ||
((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE)))
return NULL;
if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) {
if (pm_runtime_get_sync(supplier) < 0) {
pm_runtime_put_noidle(supplier);
return NULL;
}
rpm_put_supplier = true;
}
device_links_write_lock();
device_pm_lock();
@ -209,13 +218,8 @@ struct device_link *device_link_add(struct device *consumer,
if (flags & DL_FLAG_PM_RUNTIME) {
if (flags & DL_FLAG_RPM_ACTIVE) {
if (pm_runtime_get_sync(supplier) < 0) {
pm_runtime_put_noidle(supplier);
kfree(link);
link = NULL;
goto out;
}
link->rpm_active = true;
rpm_put_supplier = false;
}
pm_runtime_new_link(consumer);
/*
@ -286,6 +290,10 @@ struct device_link *device_link_add(struct device *consumer,
out:
device_pm_unlock();
device_links_write_unlock();
if (rpm_put_supplier)
pm_runtime_put(supplier);
return link;
}
EXPORT_SYMBOL_GPL(device_link_add);