+ mm-rmap-fix-cache-flush-on-thp-pages.patch added to -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: rmap: fix cache flush on THP pages
has been added to the -mm tree.  Its filename is
     mm-rmap-fix-cache-flush-on-thp-pages.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-rmap-fix-cache-flush-on-thp-pages.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-rmap-fix-cache-flush-on-thp-pages.patch

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------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: rmap: fix cache flush on THP pages

Patch series "Fix some bugs related to ramp and dax", v5.

Patch 1-2 fixes a cache flush bug, because subsequent patches depend on
those on those changes, there are placed in this series.  Patch 3-4 are
preparation for fixing a dax bug in patch 5.  Patch 6 is code cleanup
since the previous patch remove the usage of follow_invalidate_pte().


This patch (of 6):

flush_cache_page() only removes 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.

Link: https://lkml.kernel.org/r/20220318074529.5261-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20220318074529.5261-2-songmuchun@bytedance.com
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>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/rmap.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/rmap.c~mm-rmap-fix-cache-flush-on-thp-pages
+++ a/mm/rmap.c
@@ -970,7 +970,8 @@ static bool page_mkclean_one(struct foli
 			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);
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-kfence-fix-objcgs-vector-allocation.patch
mm-rmap-fix-cache-flush-on-thp-pages.patch
dax-fix-cache-flush-on-pmd-mapped-pages.patch
mm-rmap-introduce-pfn_mkclean_range-to-cleans-ptes.patch
mm-pvmw-add-support-for-walking-devmap-pages.patch
dax-fix-missing-writeprotect-the-pte-entry.patch
dax-fix-missing-writeprotect-the-pte-entry-v6.patch
mm-simplify-follow_invalidate_pte.patch