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-rw-r--r--mm/hugetlb.c22
1 files changed, 12 insertions, 10 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9519f3f6c1da..c03273807182 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2324,11 +2324,8 @@ retry_avoidcopy:
2324 * and just make the page writable */ 2324 * and just make the page writable */
2325 avoidcopy = (page_mapcount(old_page) == 1); 2325 avoidcopy = (page_mapcount(old_page) == 1);
2326 if (avoidcopy) { 2326 if (avoidcopy) {
2327 if (!trylock_page(old_page)) { 2327 if (PageAnon(old_page))
2328 if (PageAnon(old_page)) 2328 page_move_anon_rmap(old_page, vma, address);
2329 page_move_anon_rmap(old_page, vma, address);
2330 } else
2331 unlock_page(old_page);
2332 set_huge_ptep_writable(vma, address, ptep); 2329 set_huge_ptep_writable(vma, address, ptep);
2333 return 0; 2330 return 0;
2334 } 2331 }
@@ -2631,10 +2628,16 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2631 vma, address); 2628 vma, address);
2632 } 2629 }
2633 2630
2634 if (!pagecache_page) { 2631 /*
2635 page = pte_page(entry); 2632 * hugetlb_cow() requires page locks of pte_page(entry) and
2633 * pagecache_page, so here we need take the former one
2634 * when page != pagecache_page or !pagecache_page.
2635 * Note that locking order is always pagecache_page -> page,
2636 * so no worry about deadlock.
2637 */
2638 page = pte_page(entry);
2639 if (page != pagecache_page)
2636 lock_page(page); 2640 lock_page(page);
2637 }
2638 2641
2639 spin_lock(&mm->page_table_lock); 2642 spin_lock(&mm->page_table_lock);
2640 /* Check for a racing update before calling hugetlb_cow */ 2643 /* Check for a racing update before calling hugetlb_cow */
@@ -2661,9 +2664,8 @@ out_page_table_lock:
2661 if (pagecache_page) { 2664 if (pagecache_page) {
2662 unlock_page(pagecache_page); 2665 unlock_page(pagecache_page);
2663 put_page(pagecache_page); 2666 put_page(pagecache_page);
2664 } else {
2665 unlock_page(page);
2666 } 2667 }
2668 unlock_page(page);
2667 2669
2668out_mutex: 2670out_mutex:
2669 mutex_unlock(&hugetlb_instantiation_mutex); 2671 mutex_unlock(&hugetlb_instantiation_mutex);