mm/memory-failure.c: move set_migratetype_isolate() outside get_any_page()

Chen Gong pointed out that set/unset_migratetype_isolate() was done in
different functions in mm/memory-failure.c, which makes the code less
readable/maintainable.  So this patch does it in soft_offline_page().

With this patch, we get to hold lock_memory_hotplug() longer but it's
not a problem because races between memory hotplug and soft offline are
very rare.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Chen, Gong <gong.chen@linux.intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 17 insertions, 19 deletions

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index bf3351b5115e..f9d78ec7831f 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1423,19 +1423,6 @@ static int __get_any_page(struct page *p, unsigned long pfn, int flags)
                 return 1;
 
         /*
-         * The lock_memory_hotplug prevents a race with memory hotplug.
-         * This is a big hammer, a better would be nicer.
-         */
-        lock_memory_hotplug();
-
-        /*
-         * Isolate the page, so that it doesn't get reallocated if it
-         * was free. This flag should be kept set until the source page
-         * is freed and PG_hwpoison on it is set.
-         */
-        if (get_pageblock_migratetype(p) != MIGRATE_ISOLATE)
-                set_migratetype_isolate(p, true);
-        /*
          * When the target page is a free hugepage, just remove it
          * from free hugepage list.
          */
@@ -1455,7 +1442,6 @@ static int __get_any_page(struct page *p, unsigned long pfn, int flags)
                 /* Not a free page */
                 ret = 1;
         }
-        unlock_memory_hotplug();
         return ret;
 }
 
@@ -1654,15 +1640,28 @@ int soft_offline_page(struct page *page, int flags)
                 }
         }
 
+        /*
+         * The lock_memory_hotplug prevents a race with memory hotplug.
+         * This is a big hammer, a better would be nicer.
+         */
+        lock_memory_hotplug();
+
+        /*
+         * Isolate the page, so that it doesn't get reallocated if it
+         * was free. This flag should be kept set until the source page
+         * is freed and PG_hwpoison on it is set.
+         */
+        if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
+                set_migratetype_isolate(page, true);
+
         ret = get_any_page(page, pfn, flags);
-        if (ret < 0)
-                goto unset;
-        if (ret) { /* for in-use pages */
+        unlock_memory_hotplug();
+        if (ret > 0) { /* for in-use pages */
                 if (PageHuge(page))
                         ret = soft_offline_huge_page(page, flags);
                 else
                         ret = __soft_offline_page(page, flags);
-        } else { /* for free pages */
+        } else if (ret == 0) { /* for free pages */
                 if (PageHuge(page)) {
                         set_page_hwpoison_huge_page(hpage);
                         dequeue_hwpoisoned_huge_page(hpage);
@@ -1673,7 +1672,6 @@ int soft_offline_page(struct page *page, int flags)
                         atomic_long_inc(&num_poisoned_pages);
                 }
         }
-unset:
         unset_migratetype_isolate(page, MIGRATE_MOVABLE);
         return ret;
 }