dax: fix cache flush on PMD-mapped pages

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 caches")

Link: https://lkml.kernel.org/r/[email protected]
Fixes: f729c8c9b24f ("dax: wrprotect pmd_t in dax_mapping_entry_mkclean")
Signed-off-by: Muchun Song <[email protected]>
Reviewed-by: Dan Williams <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Ralph Campbell <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Xiongchun Duan <[email protected]>
Cc: Xiyu Yang <[email protected]>
Cc: Yang Shi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions