mm: soft-offline: exit with failure for non anonymous thp

Currently memory_failure() doesn't handle non anonymous thp case,
because we can hardly expect the error handling to be successful, and it
can just hit some corner case which results in BUG_ON or something
severe like that.  This is also the case for soft offline code, so let's
make it in the same way.

Orignal code has a MF_COUNT_INCREASED check before put_hwpoison_page(),
but it's unnecessary because get_any_page() is already called when
running on this code, which takes a refcount of the target page
regardress of the flag.  So this patch also removes it.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 2015c9a..ac595e7 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1691,16 +1691,16 @@ static int soft_offline_in_use_page(struct page *page, int flags)
 
        if (!PageHuge(page) && PageTransHuge(hpage)) {
                lock_page(hpage);
-               ret = split_huge_page(hpage);
-               unlock_page(hpage);
-               if (unlikely(ret || PageTransCompound(page) ||
-                            !PageAnon(page))) {
-                       pr_info("soft offline: %#lx: failed to split THP\n",
-                               page_to_pfn(page));
-                       if (flags & MF_COUNT_INCREASED)
-                               put_hwpoison_page(hpage);
+               if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {
+                       unlock_page(hpage);
+                       if (!PageAnon(hpage))
+                               pr_info("soft offline: %#lx: non anonymous thp\n", page_to_pfn(page));
+                       else
+                               pr_info("soft offline: %#lx: thp split failed\n", page_to_pfn(page));
+                       put_hwpoison_page(hpage);
                        return -EBUSY;
                }
+               unlock_page(hpage);
                get_hwpoison_page(page);
                put_hwpoison_page(hpage);
        }