[PATCH v4 10/15] mm,hwpoison: Unify THP handling for hard and soft offline

[Oscar Salvador]

Place the THP's page handling in a helper and use it
from both hard and soft-offline machinery, so we get rid
of some duplicated code.

Signed-off-by: Oscar Salvador <osalva...@suse.com>
Acked-by: Naoya Horiguchi <n-horigu...@ah.jp.nec.com>
---
 mm/memory-failure.c | 48 +++++++++++++++++++++------------------------
 1 file changed, 22 insertions(+), 26 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 03d3aae77f89..2e244d5b83e0 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1103,6 +1103,25 @@ static int identify_page_state(unsigned long pfn, struct 
page *p,
        return page_action(ps, p, pfn);
 }
 
+static int try_to_split_thp_page(struct page *page, const char *msg)
+{
+       lock_page(page);
+       if (!PageAnon(page) || unlikely(split_huge_page(page))) {
+               unsigned long pfn = page_to_pfn(page);
+
+               unlock_page(page);
+               if (!PageAnon(page))
+                       pr_info("%s: %#lx: non anonymous thp\n", msg, pfn);
+               else
+                       pr_info("%s: %#lx: thp split failed\n", msg, pfn);
+               put_page(page);
+               return -EBUSY;
+       }
+       unlock_page(page);
+
+       return 0;
+}
+
 static int memory_failure_hugetlb(unsigned long pfn, int flags)
 {
        struct page *p = pfn_to_page(pfn);
@@ -1325,21 +1344,8 @@ int memory_failure(unsigned long pfn, int flags)
        }
 
        if (PageTransHuge(hpage)) {
-               lock_page(p);
-               if (!PageAnon(p) || unlikely(split_huge_page(p))) {
-                       unlock_page(p);
-                       if (!PageAnon(p))
-                               pr_err("Memory failure: %#lx: non anonymous 
thp\n",
-                                       pfn);
-                       else
-                               pr_err("Memory failure: %#lx: thp split 
failed\n",
-                                       pfn);
-                       if (TestClearPageHWPoison(p))
-                               num_poisoned_pages_dec();
-                       put_page(p);
+               if (try_to_split_thp_page(p, "Memory Failure") < 0)
                        return -EBUSY;
-               }
-               unlock_page(p);
                VM_BUG_ON_PAGE(!page_count(p), p);
        }
 
@@ -1847,19 +1853,9 @@ static int soft_offline_in_use_page(struct page *page)
        int mt;
        struct page *hpage = compound_head(page);
 
-       if (!PageHuge(page) && PageTransHuge(hpage)) {
-               lock_page(page);
-               if (!PageAnon(page) || unlikely(split_huge_page(page))) {
-                       unlock_page(page);
-                       if (!PageAnon(page))
-                               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_page(page);
+       if (!PageHuge(page) && PageTransHuge(hpage))
+               if (try_to_split_thp_page(page, "soft offline") < 0)
                        return -EBUSY;
-               }
-               unlock_page(page);
-       }
 
        /*
         * Setting MIGRATE_ISOLATE here ensures that the page will be linked
-- 
2.26.2