mm/huge_memory: remove unnecessary VM_BUG_ON_PAGE()

This has been around since the beginnings of the THP implementation.  I
think we can safely assume that, if we have a THP folio, it will have a
head page.

Link: https://lkml.kernel.org/r/f3fa8eb4634ccb2e78209f570cc1a769a02ce93e.1774029655.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 283685dd6d9fe335b7a5e96dda344f90a49d5b44..f072acd5b2799728f1f3ab51120970a321b91148 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2452,7 +2452,6 @@ bool zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
                folio = page_folio(page);
                folio_remove_rmap_pmd(folio, page, vma);
                WARN_ON_ONCE(folio_mapcount(folio) < 0);
-               VM_BUG_ON_PAGE(!PageHead(page), page);
        } else if (pmd_is_valid_softleaf(orig_pmd)) {
                const softleaf_t entry = softleaf_from_pmd(orig_pmd);