[PATCH v4 2/6] dax: fix cache flush on PMD-mapped pages

From: Muchun Song <songmuchun@bytedance.com>
To: dan.j.williams@intel.com, willy@infradead.org, jack@suse.cz,
	viro@zeniv.linux.org.uk, akpm@linux-foundation.org,
	apopple@nvidia.com, shy828301@gmail.com, rcampbell@nvidia.com,
	hughd@google.com, xiyuyang19@fudan.edu.cn,
	kirill.shutemov@linux.intel.com, zwisler@kernel.org,
	hch@infradead.org
Cc: linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	duanxiongchun@bytedance.com, smuchun@gmail.com,
	Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH v4 2/6] dax: fix cache flush on PMD-mapped pages
Date: Wed,  2 Mar 2022 16:27:14 +0800	[thread overview]
Message-ID: <20220302082718.32268-3-songmuchun@bytedance.com> (raw)
In-Reply-To: <20220302082718.32268-1-songmuchun@bytedance.com>

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@bytedance.com>
---
 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);
-- 
2.11.0

