cls_can: Fixed protocol restriction + minor changes.

[lisovros/linux_canprio.git] / mm / hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index cc5be788a39fe132c72cbc1d2fb1c03f71708575..2697806746d0530b32eadc900014bef205c4790a 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2324,11 +2324,8 @@ retry_avoidcopy:
         * and just make the page writable */
        avoidcopy = (page_mapcount(old_page) == 1);
        if (avoidcopy) {
-               if (!trylock_page(old_page)) {
-                       if (PageAnon(old_page))
-                               page_move_anon_rmap(old_page, vma, address);
-               } else
-                       unlock_page(old_page);
+               if (PageAnon(old_page))
+                       page_move_anon_rmap(old_page, vma, address);
                set_huge_ptep_writable(vma, address, ptep);
                return 0;
        }
@@ -2383,8 +2380,11 @@ retry_avoidcopy:
         * When the original hugepage is shared one, it does not have
         * anon_vma prepared.
         */
-       if (unlikely(anon_vma_prepare(vma)))
+       if (unlikely(anon_vma_prepare(vma))) {
+               /* Caller expects lock to be held */
+               spin_lock(&mm->page_table_lock);
                return VM_FAULT_OOM;
+       }
 
        copy_huge_page(new_page, old_page, address, vma);
        __SetPageUptodate(new_page);
@@ -2404,7 +2404,7 @@ retry_avoidcopy:
                set_huge_pte_at(mm, address, ptep,
                                make_huge_pte(vma, new_page, 1));
                page_remove_rmap(old_page);
-               hugepage_add_anon_rmap(new_page, vma, address);
+               hugepage_add_new_anon_rmap(new_page, vma, address);
                /* Make the old page be freed below */
                new_page = old_page;
                mmu_notifier_invalidate_range_end(mm,
@@ -2631,10 +2631,16 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                                                                vma, address);
        }
 
-       if (!pagecache_page) {
-               page = pte_page(entry);
+       /*
+        * hugetlb_cow() requires page locks of pte_page(entry) and
+        * pagecache_page, so here we need take the former one
+        * when page != pagecache_page or !pagecache_page.
+        * Note that locking order is always pagecache_page -> page,
+        * so no worry about deadlock.
+        */
+       page = pte_page(entry);
+       if (page != pagecache_page)
                lock_page(page);
-       }
 
        spin_lock(&mm->page_table_lock);
        /* Check for a racing update before calling hugetlb_cow */
@@ -2661,9 +2667,9 @@ out_page_table_lock:
        if (pagecache_page) {
                unlock_page(pagecache_page);
                put_page(pagecache_page);
-       } else {
-               unlock_page(page);
        }
+       if (page != pagecache_page)
+               unlock_page(page);
 
 out_mutex:
        mutex_unlock(&hugetlb_instantiation_mutex);