From 3f105b0e1e4f53c28659cc0bcb6f3e67f214d113 Mon Sep 17 00:00:00 2001
From: Wu Fengguang <fengguang.wu@intel.com>
Date: Wed, 16 Dec 2009 12:19:58 +0100
Subject: [PATCH] --- yaml --- r: 177617 b: refs/heads/master c:
 1668bfd5be9d8a52536c4865000fbbe065a3613b h: refs/heads/master i:   177615:
 abed3733868ce4ab19c29ed36ac321129766229c v: v3

---
 [refs]                    |  2 +-
 trunk/mm/memory-failure.c | 20 +++++++++++++++-----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/[refs] b/[refs]
index 0d690d1abe79..c76e3a40c444 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 82ba011b9041dd31c15e4f63797b08aa0a288e61
+refs/heads/master: 1668bfd5be9d8a52536c4865000fbbe065a3613b
diff --git a/trunk/mm/memory-failure.c b/trunk/mm/memory-failure.c
index 3338c443272c..b62287db87af 100644
--- a/trunk/mm/memory-failure.c
+++ b/trunk/mm/memory-failure.c
@@ -655,7 +655,7 @@ static int page_action(struct page_state *ps, struct page *p,
  * Do all that is necessary to remove user space mappings. Unmap
  * the pages and send SIGBUS to the processes if the data was dirty.
  */
-static void hwpoison_user_mappings(struct page *p, unsigned long pfn,
+static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
 				  int trapno)
 {
 	enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
@@ -665,15 +665,18 @@ static void hwpoison_user_mappings(struct page *p, unsigned long pfn,
 	int i;
 	int kill = 1;
 
-	if (PageReserved(p) || PageCompound(p) || PageSlab(p) || PageKsm(p))
-		return;
+	if (PageReserved(p) || PageSlab(p))
+		return SWAP_SUCCESS;
 
 	/*
 	 * This check implies we don't kill processes if their pages
 	 * are in the swap cache early. Those are always late kills.
 	 */
 	if (!page_mapped(p))
-		return;
+		return SWAP_SUCCESS;
+
+	if (PageCompound(p) || PageKsm(p))
+		return SWAP_FAIL;
 
 	if (PageSwapCache(p)) {
 		printk(KERN_ERR
@@ -735,6 +738,8 @@ static void hwpoison_user_mappings(struct page *p, unsigned long pfn,
 	 */
 	kill_procs_ao(&tokill, !!PageDirty(p), trapno,
 		      ret != SWAP_SUCCESS, pfn);
+
+	return ret;
 }
 
 int __memory_failure(unsigned long pfn, int trapno, int flags)
@@ -807,8 +812,13 @@ int __memory_failure(unsigned long pfn, int trapno, int flags)
 
 	/*
 	 * Now take care of user space mappings.
+	 * Abort on fail: __remove_from_page_cache() assumes unmapped page.
 	 */
-	hwpoison_user_mappings(p, pfn, trapno);
+	if (hwpoison_user_mappings(p, pfn, trapno) != SWAP_SUCCESS) {
+		printk(KERN_ERR "MCE %#lx: cannot unmap page, give up\n", pfn);
+		res = -EBUSY;
+		goto out;
+	}
 
 	/*
 	 * Torn down by someone else?