From: Rafael J. Wysocki rafael.j.wysocki@intel.com
[ Upstream commit a1fdbfbb1da2063ba98a12eb6f1bdd07451c7145 ]
Calling rpm_put_suppliers() from pm_runtime_drop_link() is excessive as it affects all suppliers of the consumer device and not just the one pointed to by the device link being dropped. Worst case it may cause the consumer device to stop working unexpectedly. Moreover, in principle it is racy with respect to runtime PM of the consumer device.
To avoid these problems drop runtime PM references on the particular supplier pointed to by the link in question only and do that after the link has been dropped from the consumer device's list of links to suppliers, which is in device_link_free().
Fixes: a0504aecba76 ("PM / runtime: Drop usage count for suppliers at device link removal") 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 --- drivers/base/core.c | 3 +++ drivers/base/power/runtime.c | 2 -- 2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c index 20ae18f44dcdf..7599147d5f83c 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -357,6 +357,9 @@ EXPORT_SYMBOL_GPL(device_link_add);
static void device_link_free(struct device_link *link) { + while (refcount_dec_not_one(&link->rpm_active)) + pm_runtime_put(link->supplier); + put_device(link->consumer); put_device(link->supplier); kfree(link); diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index b914932d3ca1a..ab454c4533ba1 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -1603,8 +1603,6 @@ void pm_runtime_new_link(struct device *dev)
void pm_runtime_drop_link(struct device *dev) { - rpm_put_suppliers(dev); - spin_lock_irq(&dev->power.lock); WARN_ON(dev->power.links_count == 0); dev->power.links_count--;