mm/page_isolation: fix clang deadcode warning

When !CONFIG_VM_BUG_ON, there is warning of
clang-analyzer-deadcode.DeadStores:
Value stored to 'mt' during its initialization is never read.

Link: https://lkml.kernel.org/r/20221021101555.7992-2-quic_aiquny@quicinc.com
Signed-off-by: Maria Yu <quic_aiquny@quicinc.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Doug Berger <opendmb@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 04141a9..47fbc16 100644 (file)
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -330,7 +330,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
                                      zone->zone_start_pfn);
 
        if (skip_isolation) {
-               int mt = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
+               int mt __maybe_unused = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
 
                VM_BUG_ON(!is_migrate_isolate(mt));
        } else {