mm/hugetlb: deal with multiple calls to hugetlb_bootmem_alloc

Architectures that want pre-HVO of hugetlb vmemmap pages will need to call
hugetlb_bootmem_alloc from an earlier spot in boot (before sparse_init). 
To facilitate some architectures doing this, protect hugetlb_bootmem_alloc
against multiple calls.

Also provide a helper function to check if it's been called, so that the
early HVO code, to be added later, can see if there is anything to do.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Frank van der Linden <[email protected]>
Cc: Alexander Gordeev <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Dan Carpenter <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Joao Martins <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Roman Gushchin (Cruise) <[email protected]>
Cc: Usama Arif <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Yu Zhao <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 12 insertions, 0 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e4bf06f13178..826af96455aa 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4918,16 +4918,28 @@ static int __init default_hugepagesz_setup(char *s)
 }
 hugetlb_early_param("default_hugepagesz", default_hugepagesz_setup);
 
+static bool __hugetlb_bootmem_allocated __initdata;
+
+bool __init hugetlb_bootmem_allocated(void)
+{
+	return __hugetlb_bootmem_allocated;
+}
+
 void __init hugetlb_bootmem_alloc(void)
 {
 	struct hstate *h;
 
+	if (__hugetlb_bootmem_allocated)
+		return;
+
 	hugetlb_parse_params();
 
 	for_each_hstate(h) {
 		if (hstate_is_gigantic(h))
 			hugetlb_hstate_alloc_pages(h);
 	}
+
+	__hugetlb_bootmem_allocated = true;
 }
 
 static unsigned int allowed_mems_nr(struct hstate *h)