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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 v3 1/6] mm: rmap: fix cache flush on THP pages
Date:   Mon, 28 Feb 2022 14:35:31 +0800
Message-Id: <20220228063536.24911-2-songmuchun@bytedance.com>
In-Reply-To: <20220228063536.24911-1-songmuchun@bytedance.com>
References: <20220228063536.24911-1-songmuchun@bytedance.com>
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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. At least, no
problems were found due to this. Maybe because the architectures that
have virtual indexed caches is less.

Fixes: f27176cfc363 ("mm: convert page_mkclean_one() to use page_vma_mapped_walk()")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
---
 mm/rmap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/rmap.c b/mm/rmap.c
index fc46a3d7b704..723682ddb9e8 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -970,7 +970,8 @@ static bool page_mkclean_one(struct folio *folio, struct vm_area_struct *vma,
 			if (!pmd_dirty(*pmd) && !pmd_write(*pmd))
 				continue;
 
-			flush_cache_page(vma, address, folio_pfn(folio));
+			flush_cache_range(vma, address,
+					  address + HPAGE_PMD_SIZE);
 			entry = pmdp_invalidate(vma, address, pmd);
 			entry = pmd_wrprotect(entry);
 			entry = pmd_mkclean(entry);
-- 
2.11.0