[PATCH 5.15 219/230] Revert "mm/memory-failure.c: fix race with changing page compound again"

Greg Kroah-Hartman
2022-07-11T10:06:17Z

From: Naoya Horiguchi <naoya.horiguchi@nec.com>

commit 2ba2b008a8bf5fd268a43d03ba79e0ad464d6836 upstream.

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>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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
+++ b/include/linux/mm.h
@@ -3175,7 +3175,6 @@ enum mf_action_page_type {
MF_MSG_BUDDY_2ND,
MF_MSG_DAX,
MF_MSG_UNSPLIT_THP,
- MF_MSG_DIFFERENT_PAGE_SIZE,
MF_MSG_UNKNOWN,
};

--- a/include/ras/ras_event.h
+++ b/include/ras/ras_event.h
@@ -376,7 +376,6 @@ TRACE_EVENT(aer_event,
EM ( MF_MSG_BUDDY_2ND, "free buddy page (2nd try)" ) \
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
+++ b/mm/memory-failure.c
@@ -741,7 +741,6 @@ static const char * const action_page_ty
[MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)",
[MF_MSG_DAX] = "dax page",
[MF_MSG_UNSPLIT_THP] = "unsplit thp",
- [MF_MSG_DIFFERENT_PAGE_SIZE] = "different page size",
[MF_MSG_UNKNOWN] = "unknown page",
};

@@ -1526,16 +1525,6 @@ 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;

/*