HWPOISON: Remove retry loop for try_to_unmap

We don't reply in other temporary failure cases and there were no
reports of replies happening. I think the original reason it was
added was also just an early bug, not an observation of the race.

So remove the loop for now, but keep a warning message.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 88653c9..2044fe8 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -840,8 +840,6 @@ static int page_action(struct page_state *ps, struct page *p,
        return (result == RECOVERED || result == DELAYED) ? 0 : -EBUSY;
 }
 
-#define N_UNMAP_TRIES 5
-
 /*
  * Do all that is necessary to remove user space mappings. Unmap
  * the pages and send SIGBUS to the processes if the data was dirty.
@@ -853,7 +851,6 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
        struct address_space *mapping;
        LIST_HEAD(tokill);
        int ret;
-       int i;
        int kill = 1;
        struct page *hpage = compound_head(p);
 
@@ -907,17 +904,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
        if (kill)
                collect_procs(hpage, &tokill);
 
-       /*
-        * try_to_unmap can fail temporarily due to races.
-        * Try a few times (RED-PEN better strategy?)
-        */
-       for (i = 0; i < N_UNMAP_TRIES; i++) {
-               ret = try_to_unmap(hpage, ttu);
-               if (ret == SWAP_SUCCESS)
-                       break;
-               pr_debug("MCE %#lx: try_to_unmap retry needed %d\n", pfn,  ret);
-       }
-
+       ret = try_to_unmap(hpage, ttu);
        if (ret != SWAP_SUCCESS)
                printk(KERN_ERR "MCE %#lx: failed to unmap page (mapcount=%d)\n",
                                pfn, page_mapcount(hpage));