drivers/acpi/scan.c: document why we don't need the device_hotplug_lock

Let's document why the lock is not needed in acpi_scan_init(), right now
this is not really obvious.

[akpm@linux-foundation.org: fix tpyo]
Link: http://lkml.kernel.org/r/20190731135306.31524-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Hildenbrand 2019-08-02 21:49:29 -07:00 committed by Linus Torvalds
parent 14c5cebad5
commit 7291edca20

View File

@ -2204,6 +2204,12 @@ int __init acpi_scan_init(void)
acpi_gpe_apply_masked_gpes();
acpi_update_all_gpes();
/*
* Although we call __add_memory() that is documented to require the
* device_hotplug_lock, it is not necessary here because this is an
* early code when userspace or any other code path cannot trigger
* hotplug/hotunplug operations.
*/
mutex_lock(&acpi_scan_lock);
/*
* Enumerate devices in the ACPI namespace.