pagewalk: add locking-rule comments

Originally, walk_hugetlb_range() didn't require a caller take any lock.
But commit d33b9f45bd ("mm: hugetlb: fix hugepage memory leak in
walk_page_range") changed its rule.  Because it added find_vma() call in
walk_hugetlb_range().

Any locking-rule change commit should write a doc too.

[[email protected]: clarify comment]
Signed-off-by: KOSAKI Motohiro <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Hiroyuki Kamezawa <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Matt Mackall <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
KOSAKI Motohiro 2011-07-25 17:12:10 -07:00 • committed by Linus Torvalds
commit c27fe4c894
2 changed files with 5 additions and 0 deletions

View file

@ -181,6 +181,9 @@ static int walk_hugetlb_range(struct vm_area_struct *vma,
*
* If any callback returns a non-zero value, the walk is aborted and
* the return value is propagated back to the caller. Otherwise 0 is returned.
*
* walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry
* is !NULL.
*/
int walk_page_range(unsigned long addr, unsigned long end,
struct mm_walk *walk)