mirrors/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-08-21 16:29:59 +00:00
Code Issues Releases Wiki Activity

driver core: Do not call rpm_put_suppliers() in pm_runtime_drop_link()

Browse source 
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: a0504aecba ("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>
This commit is contained in:
Rafael J. Wysocki 2019-02-01 01:52:45 +01:00 committed by Greg Kroah-Hartman
parent 15cfb09416
commit a1fdbfbb1d
2 changed files with 3 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
drivers/base/core.c
View file

@ -374,6 +374,9 @@ 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);

2
drivers/base/power/runtime.c
View file

@ -1611,8 +1611,6 @@ 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--;