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Subject[PATCH] driver core: Drop devices_kset_move_last() call from really_probe()
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The devices_kset_move_last() call in really_probe() is a mistake
as it may cause parents to follow children in the devices_kset list
which then causes system shutdown to fail. Namely, if a device has
children before really_probe() is called for it (which is not
uncommon), that call will cause it to be reordered after the children
in the devices_kset list and the ordering of that list will not
reflect the correct device shutdown order.

Also it causes the devices_kset list to be constantly reordered
until all drivers have been probed which is totally pointless
overhead in the majority of cases.

For that reason, revert the really_probe() modifications made by
commit 52cdbdd49853.

Fixes: 52cdbdd49853 (driver core: correct device's shutdown order)
Link: https://lore.kernel.org/lkml/CAFgQCTt7VfqM=UyCnvNFxrSw8Z6cUtAi3HUwR4_xPAc03SgHjQ@mail.gmail.com/
Reported-by: Pingfan Liu <kernelfans@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/base/dd.c | 8 --------
1 file changed, 8 deletions(-)

Index: linux-pm/drivers/base/dd.c
===================================================================
--- linux-pm.orig/drivers/base/dd.c
+++ linux-pm/drivers/base/dd.c
@@ -434,14 +434,6 @@ re_probe:
goto probe_failed;
}

- /*
- * Ensure devices are listed in devices_kset in correct order
- * It's important to move Dev to the end of devices_kset before
- * calling .probe, because it could be recursive and parent Dev
- * should always go first
- */
- devices_kset_move_last(dev);
-
if (dev->bus->probe) {
ret = dev->bus->probe(dev);
if (ret)
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