[PATCH V4 1/3] arm64/mm/hotplug: Register boot memory hot remove notifier earlier

Anshuman Khandual
2020-09-29T13:57:33Z

This moves memory notifier registration earlier in the boot process from
device_initcall() to early_initcall() which will help in guarding against
potential early boot memory offline requests. Even though there should not
be any actual offlinig requests till memory block devices are initialized
with memory_dev_init() but then generic init sequence might just change in
future. Hence an early registration for the memory event notifier would be
helpful. While here, just skip the registration if CONFIG_MEMORY_HOTREMOVE
is not enabled and also call out when memory notifier registration fails.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
arch/arm64/mm/mmu.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 75df62fea1b6..4e70f4fea06c 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1499,7 +1499,16 @@ static struct notifier_block prevent_bootmem_remove_nb = {

static int __init prevent_bootmem_remove_init(void)
{
- return register_memory_notifier(&prevent_bootmem_remove_nb);
+ int ret = 0;
+
+ if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE))
+ return ret;
+
+ ret = register_memory_notifier(&prevent_bootmem_remove_nb);
+ if (ret)
+ pr_err("%s: Notifier registration failed %d\n", __func__, ret);
+
+ return ret;
}
-device_initcall(prevent_bootmem_remove_init);
+early_initcall(prevent_bootmem_remove_init);
#endif
--
2.20.1