[PATCH] mm/hugetlb: Ensure adequate CMA areas available for hugetlb_cma[]

[Anshuman Khandual <anshuman.khandual@arm.com>]

HugeTLB CMA area array is being created for possible MAX_NUMNODES without
ensuring corresponding MAX_CMA_AREAS support in CMA. Let's just warn for
such scenarios indicating need for CONFIG_CMA_AREAS adjustment.

Cc: Muchun Song <muchun.song@linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
This applies on v6.8-rc3

 mm/hugetlb.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a188b7c60f4f..fda8ced69832 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7750,6 +7750,13 @@ void __init hugetlb_cma_reserve(int order)
 	}
 
 	reserved = 0;
+
+	/*
+	 * There needs to be enough MAX_CMA_AREAS to accommodate
+	 * MAX_NUMNODES heap areas being created here. Otherwise
+	 * adjust CONFIG_CMA_AREAS as required.
+	 */
+	VM_WARN_ON(MAX_CMA_AREAS < MAX_NUMNODES);
 	for_each_online_node(nid) {
 		int res;
 		char name[CMA_MAX_NAME];
-- 
2.25.1