+ revert-mm-memory-failurec-fix-race-with-changing-page-compound-again.patch added to -mm tree

+ revert-mm-memory-failurec-fix-race-with-changing-page-compound-again.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: Revert "mm/memory-failure.c: fix race with changing page compound again"
has been added to the -mm tree.  Its filename is
     revert-mm-memory-failurec-fix-race-with-changing-page-compound-again.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/revert-mm-memory-failurec-fix-race-with-changing-page-compound-again.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/revert-mm-memory-failurec-fix-race-with-changing-page-compound-again.patch

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------------------------------------------------------
From: Naoya Horiguchi <naoya.horiguchi@nec.com>
Subject: Revert "mm/memory-failure.c: fix race with changing page compound again"

Reverts commit 888af2701db7 ("mm/memory-failure.c: fix race with changing
page compound again") because now we fetch the page refcount under
hugetlb_lock in try_memory_failure_hugetlb() so that the race check is no
longer necessary.

Link: https://lkml.kernel.org/r/20220408135323.1559401-4-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Suggested-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mm.h      |    1 -
 include/ras/ras_event.h |    1 -
 mm/memory-failure.c     |   11 -----------
 3 files changed, 13 deletions(-)

--- a/include/linux/mm.h~revert-mm-memory-failurec-fix-race-with-changing-page-compound-again
+++ a/include/linux/mm.h
@@ -3292,7 +3292,6 @@ enum mf_action_page_type {
 	MF_MSG_BUDDY,
 	MF_MSG_DAX,
 	MF_MSG_UNSPLIT_THP,
-	MF_MSG_DIFFERENT_PAGE_SIZE,
 	MF_MSG_UNKNOWN,
 };
 
--- a/include/ras/ras_event.h~revert-mm-memory-failurec-fix-race-with-changing-page-compound-again
+++ a/include/ras/ras_event.h
@@ -374,7 +374,6 @@ TRACE_EVENT(aer_event,
 	EM ( MF_MSG_BUDDY, "free buddy page" )				\
 	EM ( MF_MSG_DAX, "dax page" )					\
 	EM ( MF_MSG_UNSPLIT_THP, "unsplit thp" )			\
-	EM ( MF_MSG_DIFFERENT_PAGE_SIZE, "different page size" )	\
 	EMe ( MF_MSG_UNKNOWN, "unknown page" )
 
 /*
--- a/mm/memory-failure.c~revert-mm-memory-failurec-fix-race-with-changing-page-compound-again
+++ a/mm/memory-failure.c
@@ -734,7 +734,6 @@ static const char * const action_page_ty
 	[MF_MSG_BUDDY]			= "free buddy page",
 	[MF_MSG_DAX]			= "dax page",
 	[MF_MSG_UNSPLIT_THP]		= "unsplit thp",
-	[MF_MSG_DIFFERENT_PAGE_SIZE]	= "different page size",
 	[MF_MSG_UNKNOWN]		= "unknown page",
 };
 
@@ -1603,16 +1602,6 @@ retry:
 		return res == MF_RECOVERED ? 0 : -EBUSY;
 	}
 
-	/*
-	 * The page could have changed compound pages due to race window.
-	 * If this happens just bail out.
-	 */
-	if (!PageHuge(p) || compound_head(p) != head) {
-		action_result(pfn, MF_MSG_DIFFERENT_PAGE_SIZE, MF_IGNORED);
-		res = -EBUSY;
-		goto out;
-	}
-
 	page_flags = head->flags;
 
 	/*
_

Patches currently in -mm which might be from naoya.horiguchi@nec.com are

mm-hwpoison-fix-race-between-hugetlb-free-demotion-and-memory_failure_hugetlb.patch
mm-hwpoison-put-page-in-already-hwpoisoned-case-with-mf_count_increased.patch
revert-mm-memory-failurec-fix-race-with-changing-page-compound-again.patch