HWPOISON: return 0 to indicate success reliably

Return 0 to indicate success, when
- action result is RECOVERED or DELAYED
- no extra page reference

Note that dirty swapcache pages are kept in swapcache, so can have one
more reference count.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index fd1ac1537f06..edeaf2319e74 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -654,17 +654,21 @@ static int page_action(struct page_state *ps, struct page *p,
         action_result(pfn, ps->msg, result);
 
         count = page_count(p) - 1;
-        if (count != 0)
+        if (ps->action == me_swapcache_dirty && result == DELAYED)
+                count--;
+        if (count != 0) {
                 printk(KERN_ERR
                        "MCE %#lx: %s page still referenced by %d users\n",
                        pfn, ps->msg, count);
+                result = FAILED;
+        }
 
         /* Could do more checks here if page looks ok */
         /*
          * Could adjust zone counters here to correct for the missing page.
          */
 
-        return result == RECOVERED ? 0 : -EBUSY;
+        return (result == RECOVERED || result == DELAYED) ? 0 : -EBUSY;
 }
 
 #define N_UNMAP_TRIES 5