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| author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2011-07-26 02:12:10 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-07-26 05:57:08 +0200 |
| commit | c27fe4c8942d3ca715986f79cc26f44608d7d9fb (patch) | |
| tree | d954d0417c941f5e51cf029608311ef04acd9575 /mm | |
| parent | pagewalk: don't look up vma if walk->hugetlb_entry is unused (diff) | |
| download | linux-c27fe4c8942d3ca715986f79cc26f44608d7d9fb.tar.xz linux-c27fe4c8942d3ca715986f79cc26f44608d7d9fb.zip | |
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.
[akpm@linux-foundation.org: clarify comment]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/pagewalk.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/pagewalk.c b/mm/pagewalk.c index ee4ff87c58c1..f7929406e776 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -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) |