[PATCH 2/3] mem-hwpoison: fix page refcount around isolate_lru_page()

Konstantin Khlebnikov
2011-04-21T13:12:44Z

Drop first page reference only after calling isolate_lru_page()
to keep page stable reference while isolating.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
---
mm/memory-failure.c | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 2b9a5ee..a17d31e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1440,16 +1440,12 @@ int soft_offline_page(struct page *page, int flags)
*/
ret = invalidate_inode_page(page);
unlock_page(page);
-
/*
- * Drop count because page migration doesn't like raised
- * counts. The page could get re-allocated, but if it becomes
- * LRU the isolation will just fail.
* RED-PEN would be better to keep it isolated here, but we
* would need to fix isolation locking first.
*/
- put_page(page);
if (ret == 1) {
+ put_page(page);
ret = 0;
pr_info("soft_offline: %#lx: invalidated\n", pfn);
goto done;
@@ -1461,6 +1457,11 @@ int soft_offline_page(struct page *page, int flags)
* handles a large number of cases for us.
*/
ret = isolate_lru_page(page);
+ /*
+ * Drop page reference which is came from get_any_page()
+ * successful isolate_lru_page() already took another one.
+ */
+ put_page(page);
if (!ret) {
LIST_HEAD(pagelist);