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driver core: Do not resume suppliers under device_links_write_lock() 

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: 21d5c57b37 ("PM / runtime: Use device links")
Fixes: baa8809f60 ("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>
This commit is contained in:
Rafael J. Wysocki 2019-02-01 01:47:53 +01:00 committed by Greg Kroah-Hartman
parent f265df550a
commit 5db25c9eb8
1 changed files with 14 additions and 6 deletions
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20
drivers/base/core.c
View File

@ -201,12 +201,21 @@ struct device_link *device_link_add(struct device *consumer,
struct device *supplier, u32 flags) struct device *supplier, u32 flags)
{ {
struct device_link *link; struct device_link *link;
bool rpm_put_supplier = false;
if (!consumer || !supplier || if (!consumer || !supplier ||
(flags & DL_FLAG_STATELESS && (flags & DL_FLAG_STATELESS &&
flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER))) flags & (DL_FLAG_AUTOREMOVE_CONSUMER | DL_FLAG_AUTOREMOVE_SUPPLIER)))
return NULL; 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_links_write_lock();
device_pm_lock(); device_pm_lock();
@ -250,13 +259,8 @@ struct device_link *device_link_add(struct device *consumer,
if (flags & DL_FLAG_PM_RUNTIME) { if (flags & DL_FLAG_PM_RUNTIME) {
if (flags & DL_FLAG_RPM_ACTIVE) { 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; link->rpm_active = true;
rpm_put_supplier = false;
} }
pm_runtime_new_link(consumer); pm_runtime_new_link(consumer);
/* /*
@ -328,6 +332,10 @@ struct device_link *device_link_add(struct device *consumer,
out: out:
device_pm_unlock(); device_pm_unlock();
device_links_write_unlock(); device_links_write_unlock();
if (rpm_put_supplier)
pm_runtime_put(supplier);
return link; return link;
} }
EXPORT_SYMBOL_GPL(device_link_add); EXPORT_SYMBOL_GPL(device_link_add);