mm: hwpoison: remove incorrect comments

dequeue_hwpoisoned_huge_page() can be called without page lock hold, so
let's remove incorrect comment.

The reason why the page lock is not really needed is that
dequeue_hwpoisoned_huge_page() checks page_huge_active() inside
hugetlb_lock, which allows us to avoid trying to dequeue a hugepage that
are just allocated but not linked to active list yet, even without
taking page lock.

Link: http://lkml.kernel.org/r/20160720092901.GA15995@www9186uo.sakura.ne.jp
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Zhan Chen <zhanc1@andrew.cmu.edu>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index abc1c5fb722243769ee345ccee68ab9ea4ad9445..213ff90903a66602bd2486e62e84d960ad78011f 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -4391,7 +4391,6 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address,
 
 /*
  * This function is called from memory failure code.
- * Assume the caller holds page lock of the head page.
  */
 int dequeue_hwpoisoned_huge_page(struct page *hpage)
 {

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 11de752ccaf50ab39911c2e894ced4d7ae0c33bd..de88f33519c0d6398de8fcc06bfa82f2a477dd95 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -741,8 +741,6 @@ static int me_huge_page(struct page *p, unsigned long pfn)
         * page->lru because it can be used in other hugepage operations,
         * such as __unmap_hugepage_range() and gather_surplus_pages().
         * So instead we use page_mapping() and PageAnon().
-        * We assume that this function is called with page lock held,
-        * so there is no race between isolation and mapping/unmapping.
         */
        if (!(page_mapping(hpage) || PageAnon(hpage))) {
                res = dequeue_hwpoisoned_huge_page(hpage);