1 files changed, 50 insertions, 12 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 757ca983fd99..67a71191136e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -565,7 +565,7 @@ static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
                 huge_page_order(h));
         if (page) {
                 if (arch_prepare_hugepage(page)) {
-                        __free_pages(page, HUGETLB_PAGE_ORDER);
+                        __free_pages(page, huge_page_order(h));
                         return NULL;
                 }
                 prep_new_huge_page(h, page, nid);
@@ -665,6 +665,11 @@ static struct page *alloc_buddy_huge_page(struct hstate *h,
                                         __GFP_REPEAT|__GFP_NOWARN,
                                         huge_page_order(h));
 
+        if (page && arch_prepare_hugepage(page)) {
+                __free_pages(page, huge_page_order(h));
+                return NULL;
+        }
+
         spin_lock(&hugetlb_lock);
         if (page) {
                 /*
@@ -1937,6 +1942,18 @@ retry:
                         lock_page(page);
         }
 
+        /*
+         * If we are going to COW a private mapping later, we examine the
+         * pending reservations for this page now. This will ensure that
+         * any allocations necessary to record that reservation occur outside
+         * the spinlock.
+         */
+        if (write_access && !(vma->vm_flags & VM_SHARED))
+                if (vma_needs_reservation(h, vma, address) < 0) {
+                        ret = VM_FAULT_OOM;
+                        goto backout_unlocked;
+                }
+
         spin_lock(&mm->page_table_lock);
         size = i_size_read(mapping->host) >> huge_page_shift(h);
         if (idx >= size)
@@ -1962,6 +1979,7 @@ out:
 
 backout:
         spin_unlock(&mm->page_table_lock);
+backout_unlocked:
         unlock_page(page);
         put_page(page);
         goto out;
@@ -1973,6 +1991,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
         pte_t *ptep;
         pte_t entry;
         int ret;
+        struct page *pagecache_page = NULL;
         static DEFINE_MUTEX(hugetlb_instantiation_mutex);
         struct hstate *h = hstate_vma(vma);
 
@@ -1989,25 +2008,44 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
         entry = huge_ptep_get(ptep);
         if (huge_pte_none(entry)) {
                 ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
-                mutex_unlock(&hugetlb_instantiation_mutex);
-                return ret;
+                goto out_unlock;
         }
 
         ret = 0;
 
+        /*
+         * If we are going to COW the mapping later, we examine the pending
+         * reservations for this page now. This will ensure that any
+         * allocations necessary to record that reservation occur outside the
+         * spinlock. For private mappings, we also lookup the pagecache
+         * page now as it is used to determine if a reservation has been
+         * consumed.
+         */
+        if (write_access && !pte_write(entry)) {
+                if (vma_needs_reservation(h, vma, address) < 0) {
+                        ret = VM_FAULT_OOM;
+                        goto out_unlock;
+                }
+
+                if (!(vma->vm_flags & VM_SHARED))
+                        pagecache_page = hugetlbfs_pagecache_page(h,
+                                                                vma, address);
+        }
+
         spin_lock(&mm->page_table_lock);
         /* Check for a racing update before calling hugetlb_cow */
         if (likely(pte_same(entry, huge_ptep_get(ptep))))
-                if (write_access && !pte_write(entry)) {
-                        struct page *page;
-                        page = hugetlbfs_pagecache_page(h, vma, address);
-                        ret = hugetlb_cow(mm, vma, address, ptep, entry, page);
-                        if (page) {
-                                unlock_page(page);
-                                put_page(page);
-                        }
-                }
+                if (write_access && !pte_write(entry))
+                        ret = hugetlb_cow(mm, vma, address, ptep, entry,
+                                                        pagecache_page);
         spin_unlock(&mm->page_table_lock);
+
+        if (pagecache_page) {
+                unlock_page(pagecache_page);
+                put_page(pagecache_page);
+        }
+
+out_unlock:
         mutex_unlock(&hugetlb_instantiation_mutex);
 
         return ret;