[patch] mm: fix potential infinite loop in dissolve_free_huge_pages() fix

[David Rientjes <rientjes@google.com>]

No legitimate reason to call dissolve_free_huge_pages() when 
!hugepages_supported().

Signed-off-by: David Rientjes <rientjes@google.com>
---
 To be folded into 
 mm-fix-potential-infinite-loop-in-dissolve_free_huge_pages.patch.

 mm/hugetlb.c        | 3 +++
 mm/memory_hotplug.c | 3 +--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1088,6 +1088,9 @@ void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
 	unsigned long pfn;
 	struct hstate *h;
 
+	if (!hugepages_supported())
+		return;
+
 	/* Set scan step to minimum hugepage size */
 	for_each_hstate(h)
 		if (order > huge_page_order(h))
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1726,8 +1726,7 @@ repeat:
 	 * dissolve free hugepages in the memory block before doing offlining
 	 * actually in order to make hugetlbfs's object counting consistent.
 	 */
-	if (hugepages_supported())
-		dissolve_free_huge_pages(start_pfn, end_pfn);
+	dissolve_free_huge_pages(start_pfn, end_pfn);
 	/* check again */
 	offlined_pages = check_pages_isolated(start_pfn, end_pfn);
 	if (offlined_pages < 0) {

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