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[5.4,091/111] PM: EM: postpone creating the debugfs dir till fs_initcall

Message ID 20210329075618.252474746@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman March 29, 2021, 7:58 a.m. UTC 
From: Lukasz Luba <lukasz.luba@arm.com>

[ Upstream commit fb9d62b27ab1e07d625591549c314b7d406d21df ]

The debugfs directory '/sys/kernel/debug/energy_model' is needed before
the Energy Model registration can happen. With the recent change in
debugfs subsystem it's not allowed to create this directory at early
stage (core_initcall). Thus creating this directory would fail.

Postpone the creation of the EM debug dir to later stage: fs_initcall.

It should be safe since all clients: CPUFreq drivers, Devfreq drivers
will be initialized in later stages.

The custom debug log below prints the time of creation the EM debug dir
at fs_initcall and successful registration of EMs at later stages.

[    1.505717] energy_model: creating rootdir
[    3.698307] cpu cpu0: EM: created perf domain
[    3.709022] cpu cpu1: EM: created perf domain

Fixes: 56348560d495 ("debugfs: do not attempt to create a new file before the filesystem is initalized")
Reported-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/power/energy_model.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index 0a9326f5f421..8dac32bd9089 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -74,7 +74,7 @@  static int __init em_debug_init(void)
 
 	return 0;
 }
-core_initcall(em_debug_init);
+fs_initcall(em_debug_init);
 #else /* CONFIG_DEBUG_FS */
 static void em_debug_create_pd(struct em_perf_domain *pd, int cpu) {}
 #endif