From ea4525b6008fb29553306ec6719f8e6930ac9499 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Tue, 26 Oct 2010 14:22:01 -0700 Subject: [PATCH] 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/rmap.h | 15 ++++++++++++++- mm/rmap.c | 4 +++- 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 5c98df6..07ea89c 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -230,7 +230,20 @@ int try_to_munlock(struct page *); /* * Called by memory-failure.c to kill processes. */ -struct anon_vma *page_lock_anon_vma(struct page *page); +struct anon_vma *__page_lock_anon_vma(struct page *page); + +static inline struct anon_vma *page_lock_anon_vma(struct page *page) +{ + struct anon_vma *anon_vma; + + __cond_lock(RCU, anon_vma = __page_lock_anon_vma(page)); + + /* (void) is needed to make gcc happy */ + (void) __cond_lock(&anon_vma->root->lock, anon_vma); + + return anon_vma; +} + void page_unlock_anon_vma(struct anon_vma *anon_vma); int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); 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 @@ 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. */ -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 @@ out: } 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(); -- 2.7.4