From 02f4ee5a144cef6b26421cb42cca64bb4138d459 Mon Sep 17 00:00:00 2001
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Date: Wed, 26 Jun 2024 16:53:24 +0800
Subject: [PATCH] mm: add folio_mc_copy()
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Add a #MC variant of folio_copy() which uses copy_mc_highpage() to support
#MC handled during folio copy, it will be used in folio migration soon.

Link: https://lkml.kernel.org/r/20240626085328.608006-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 include/linux/mm.h |  1 +
 mm/util.c          | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index e2140ea6ae98..a2e3ebead410 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1291,6 +1291,7 @@ void put_pages_list(struct list_head *pages);
 
 void split_page(struct page *page, unsigned int order);
 void folio_copy(struct folio *dst, struct folio *src);
+int folio_mc_copy(struct folio *dst, struct folio *src);
 
 unsigned long nr_free_buffer_pages(void);
 
diff --git a/mm/util.c b/mm/util.c
index fe723241b66f..172213f27c31 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -828,6 +828,23 @@ void folio_copy(struct folio *dst, struct folio *src)
 }
 EXPORT_SYMBOL(folio_copy);
 
+int folio_mc_copy(struct folio *dst, struct folio *src)
+{
+	long nr = folio_nr_pages(src);
+	long i = 0;
+
+	for (;;) {
+		if (copy_mc_highpage(folio_page(dst, i), folio_page(src, i)))
+			return -EHWPOISON;
+		if (++i == nr)
+			break;
+		cond_resched();
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(folio_mc_copy);
+
 int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS;
 int sysctl_overcommit_ratio __read_mostly = 50;
 unsigned long sysctl_overcommit_kbytes __read_mostly;