linux-kernel - [PATCH 2/5] dax: fix cache flush on PMD-mapped pages

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Message-Id: <20220121075515.79311-2-songmuchun@bytedance.com>
Date:   Fri, 21 Jan 2022 15:55:12 +0800
From:   Muchun Song <songmuchun@...edance.com>
To:     dan.j.williams@...el.com, willy@...radead.org, jack@...e.cz,
        viro@...iv.linux.org.uk, akpm@...ux-foundation.org,
        apopple@...dia.com, shy828301@...il.com, rcampbell@...dia.com,
        hughd@...gle.com, xiyuyang19@...an.edu.cn,
        kirill.shutemov@...ux.intel.com, zwisler@...nel.org
Cc:     linux-fsdevel@...r.kernel.org, nvdimm@...ts.linux.dev,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Muchun Song <songmuchun@...edance.com>
Subject: [PATCH 2/5] 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.

Fixes: f729c8c9b24f ("dax: wrprotect pmd_t in dax_mapping_entry_mkclean")
Signed-off-by: Muchun Song <songmuchun@...edance.com>
---
 fs/dax.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/dax.c b/fs/dax.c
index 88be1c02a151..2955ec65eb65 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -857,7 +857,7 @@ 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);
-- 
2.11.0