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authorMuchun Song <songmuchun@bytedance.com>2022-04-28 23:16:09 -0700
committerakpm <akpm@linux-foundation.org>2022-04-28 23:16:09 -0700
commite583b5c472bd23d450e06f148dc1f37be74f7666 (patch)
tree055e2f40774113d9fb46b0eef7fdc9bda29702fe
parent7f9c9b607dc2641c77266efe788fab853d27dbd1 (diff)
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/20220403053957.10770-3-songmuchun@bytedance.com Fixes: f729c8c9b24f ("dax: wrprotect pmd_t in dax_mapping_entry_mkclean") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ross Zwisler <zwisler@kernel.org> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--fs/dax.c3
1 files changed, 2 insertions, 1 deletions
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);