The flush_cache_page() only remove a PAGE_SIZE sized range from the cache.
However, it does not cover the full pages in a THP except a head page.
Replace it with flush_cache_range() to fix this issue.  This is just a
documentation issue with the respect to properly documenting the expected
usage of cache flushing before modifying the pmd.  However, in practice
this is not a problem due to the fact that DAX is not available on
architectures with virtually indexed caches per:

  commit d92576f1167c ("dax: does not work correctly with virtual aliasing 

Fixes: f729c8c9b24f ("dax: wrprotect pmd_t in dax_mapping_entry_mkclean")
Signed-off-by: Muchun Song <>
Reviewed-by: Dan Williams <>
 fs/dax.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/dax.c b/fs/dax.c
index 67a08a32fccb..a372304c9695 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -845,7 +845,8 @@ static void dax_entry_mkclean(struct address_space 
*mapping, pgoff_t index,
                        if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp))
                                goto unlock_pmd;
-                       flush_cache_page(vma, address, pfn);
+                       flush_cache_range(vma, address,
+                                         address + HPAGE_PMD_SIZE);
                        pmd = pmdp_invalidate(vma, address, pmdp);
                        pmd = pmd_wrprotect(pmd);
                        pmd = pmd_mkclean(pmd);

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