HWPOISON: Export some rmap vma locking to outside world

Needed for later patch that walks rmap entries on its own.

This used to be very frowned upon, but memory-failure.c does
some rather specialized rmap walking and rmap has been stable
for quite some time, so I think it's ok now to export it.

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

2 files changed, 8 insertions, 2 deletions

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index bf116d0dbf23..8dff2ffab82c 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -112,6 +112,12 @@ int page_mkclean(struct page *);
  */
 int try_to_munlock(struct page *);
 
+/*
+ * Called by memory-failure.c to kill processes.
+ */
+struct anon_vma *page_lock_anon_vma(struct page *page);
+void page_unlock_anon_vma(struct anon_vma *anon_vma);
+
 #else   /* !CONFIG_MMU */
 
 #define anon_vma_init()         do {} while (0)
diff --git a/mm/rmap.c b/mm/rmap.c
index 0895b5c7cbff..5a35c030e779 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -191,7 +191,7 @@ void __init anon_vma_init(void)
  * Getting a lock on a stable anon_vma from a page off the LRU is
  * tricky: page_lock_anon_vma rely on RCU to guard against the races.
  */
-static struct anon_vma *page_lock_anon_vma(struct page *page)
+struct anon_vma *page_lock_anon_vma(struct page *page)
 {
         struct anon_vma *anon_vma;
         unsigned long anon_mapping;
@@ -211,7 +211,7 @@ out:
         return NULL;
 }
 
-static void page_unlock_anon_vma(struct anon_vma *anon_vma)
+void page_unlock_anon_vma(struct anon_vma *anon_vma)
 {
         spin_unlock(&anon_vma->lock);
         rcu_read_unlock();