Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

[firefly-linux-kernel-4.4.55.git] / mm / mlock.c

diff --git a/mm/mlock.c b/mm/mlock.c
index 4e1a68162285688ad1f1158681a6908e7e237924..ce84cb0b83ef56179facdacc286bce88abd05fae 100644 (file)
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -79,6 +79,7 @@ void clear_page_mlock(struct page *page)
  */
 void mlock_vma_page(struct page *page)
 {
+       /* Serialize with page migration */
        BUG_ON(!PageLocked(page));
 
        if (!TestSetPageMlocked(page)) {
@@ -174,6 +175,7 @@ unsigned int munlock_vma_page(struct page *page)
        unsigned int nr_pages;
        struct zone *zone = page_zone(page);
 
+       /* For try_to_munlock() and to serialize with page migration */
        BUG_ON(!PageLocked(page));
 
        /*
@@ -208,12 +210,19 @@ out:
  * @vma:   target vma
  * @start: start address
  * @end:   end address
+ * @nonblocking:
  *
  * This takes care of making the pages present too.
  *
  * return 0 on success, negative error code on error.
  *
- * vma->vm_mm->mmap_sem must be held for at least read.
+ * vma->vm_mm->mmap_sem must be held.
+ *
+ * If @nonblocking is NULL, it may be held for read or write and will
+ * be unperturbed.
+ *
+ * If @nonblocking is non-NULL, it must held for read only and may be
+ * released.  If it's released, *@nonblocking will be set to 0.
  */
 long __mlock_vma_pages_range(struct vm_area_struct *vma,
                unsigned long start, unsigned long end, int *nonblocking)