rmap: annotate lock context change on page_[un]lock_anon_vma()
The page_lock_anon_vma() conditionally grabs RCU and anon_vma lock but
page_unlock_anon_vma() releases them unconditionally. This leads sparse
to complain about context imbalance. Annotate them.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/rmap.c b/mm/rmap.c
index f5ad996..0995a8f 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -314,7 +314,7 @@
* 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.
*/
-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, *root_anon_vma;
unsigned long anon_mapping;
@@ -348,6 +348,8 @@
}
void page_unlock_anon_vma(struct anon_vma *anon_vma)
+ __releases(&anon_vma->root->lock)
+ __releases(RCU)
{
anon_vma_unlock(anon_vma);
rcu_read_unlock();