[PATCH v4 10/20] mm: Introduce __lru_cache_add_active_or_unevictable

[Laurent Dufour]

The speculative page fault handler which is run without holding the
mmap_sem is calling lru_cache_add_active_or_unevictable() but the vm_flags
is not guaranteed to remain constant.
Introducing __lru_cache_add_active_or_unevictable() which has the vma flags
value parameter instead of the vma pointer.

Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
---
 include/linux/swap.h | 11 +++++++++--
 mm/memory.c          |  8 ++++----
 mm/swap.c            | 12 ++++++------
 3 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index cd2f66fdfc2d..a50d64f06bcf 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -324,8 +324,15 @@ extern void swap_setup(void);
 
 extern void add_page_to_unevictable_list(struct page *page);
 
-extern void lru_cache_add_active_or_unevictable(struct page *page,
-						struct vm_area_struct *vma);
+extern void __lru_cache_add_active_or_unevictable(struct page *page,
+						unsigned long vma_flags);
+
+static inline void lru_cache_add_active_or_unevictable(struct page *page,
+						struct vm_area_struct *vma)
+{
+	return __lru_cache_add_active_or_unevictable(page, vma->vm_flags);
+}
+
 
 /* linux/mm/vmscan.c */
 extern unsigned long zone_reclaimable_pages(struct zone *zone);
diff --git a/mm/memory.c b/mm/memory.c
index 49b1dc9a2ed6..687d4395111f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2552,7 +2552,7 @@ static int wp_page_copy(struct vm_fault *vmf)
 		ptep_clear_flush_notify(vma, vmf->address, vmf->pte);
 		page_add_new_anon_rmap(new_page, vma, vmf->address, false);
 		mem_cgroup_commit_charge(new_page, memcg, false, false);
-		lru_cache_add_active_or_unevictable(new_page, vma);
+		__lru_cache_add_active_or_unevictable(new_page, vmf->vma_flags);
 		/*
 		 * We call the notify macro here because, when using secondary
 		 * mmu page tables (such as kvm shadow page tables), we want the
@@ -3065,7 +3065,7 @@ int do_swap_page(struct vm_fault *vmf)
 	if (unlikely(page != swapcache && swapcache)) {
 		page_add_new_anon_rmap(page, vma, vmf->address, false);
 		mem_cgroup_commit_charge(page, memcg, false, false);
-		lru_cache_add_active_or_unevictable(page, vma);
+		__lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
 	} else {
 		do_page_add_anon_rmap(page, vma, vmf->address, exclusive);
 		mem_cgroup_commit_charge(page, memcg, true, false);
@@ -3215,7 +3215,7 @@ static int do_anonymous_page(struct vm_fault *vmf)
 	inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
 	page_add_new_anon_rmap(page, vma, vmf->address, false);
 	mem_cgroup_commit_charge(page, memcg, false, false);
-	lru_cache_add_active_or_unevictable(page, vma);
+	__lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
 setpte:
 	set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry);
 
@@ -3467,7 +3467,7 @@ int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
 		inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
 		page_add_new_anon_rmap(page, vma, vmf->address, false);
 		mem_cgroup_commit_charge(page, memcg, false, false);
-		lru_cache_add_active_or_unevictable(page, vma);
+		__lru_cache_add_active_or_unevictable(page, vmf->vma_flags);
 	} else {
 		inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page));
 		page_add_file_rmap(page, false);
diff --git a/mm/swap.c b/mm/swap.c
index a77d68f2c1b6..30e1b038f9b0 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -470,21 +470,21 @@ void add_page_to_unevictable_list(struct page *page)
 }
 
 /**
- * lru_cache_add_active_or_unevictable
- * @page:  the page to be added to LRU
- * @vma:   vma in which page is mapped for determining reclaimability
+ * __lru_cache_add_active_or_unevictable
+ * @page:	the page to be added to LRU
+ * @vma_flags:  vma in which page is mapped for determining reclaimability
  *
  * Place @page on the active or unevictable LRU list, depending on its
  * evictability.  Note that if the page is not evictable, it goes
  * directly back onto it's zone's unevictable list, it does NOT use a
  * per cpu pagevec.
  */
-void lru_cache_add_active_or_unevictable(struct page *page,
-					 struct vm_area_struct *vma)
+void __lru_cache_add_active_or_unevictable(struct page *page,
+					   unsigned long vma_flags)
 {
 	VM_BUG_ON_PAGE(PageLRU(page), page);
 
-	if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) {
+	if (likely((vma_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) {
 		SetPageActive(page);
 		lru_cache_add(page);
 		return;
-- 
2.7.4