1 files changed, 102 insertions, 2 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b61d2db9f34e..cc5be788a39f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -18,6 +18,9 @@
 #include <linux/bootmem.h>
 #include <linux/sysfs.h>
 #include <linux/slab.h>
+#include <linux/rmap.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
 
 #include <asm/page.h>
 #include <asm/pgtable.h>
@@ -220,6 +223,12 @@ static pgoff_t vma_hugecache_offset(struct hstate *h,
                         (vma->vm_pgoff >> huge_page_order(h));
 }
 
+pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
+                                     unsigned long address)
+{
+        return vma_hugecache_offset(hstate_vma(vma), vma, address);
+}
+
 /*
  * Return the size of the pages allocated when backing a VMA. In the majority
  * cases this will be same size as used by the page table entries.
@@ -552,6 +561,7 @@ static void free_huge_page(struct page *page)
         set_page_private(page, 0);
         page->mapping = NULL;
         BUG_ON(page_count(page));
+        BUG_ON(page_mapcount(page));
         INIT_LIST_HEAD(&page->lru);
 
         spin_lock(&hugetlb_lock);
@@ -605,6 +615,8 @@ int PageHuge(struct page *page)
         return dtor == free_huge_page;
 }
 
+EXPORT_SYMBOL_GPL(PageHuge);
+
 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
 {
         struct page *page;
@@ -2129,6 +2141,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
                         entry = huge_ptep_get(src_pte);
                         ptepage = pte_page(entry);
                         get_page(ptepage);
+                        page_dup_rmap(ptepage);
                         set_huge_pte_at(dst, addr, dst_pte, entry);
                 }
                 spin_unlock(&src->page_table_lock);
@@ -2140,6 +2153,19 @@ nomem:
         return -ENOMEM;
 }
 
+static int is_hugetlb_entry_hwpoisoned(pte_t pte)
+{
+        swp_entry_t swp;
+
+        if (huge_pte_none(pte) || pte_present(pte))
+                return 0;
+        swp = pte_to_swp_entry(pte);
+        if (non_swap_entry(swp) && is_hwpoison_entry(swp)) {
+                return 1;
+        } else
+                return 0;
+}
+
 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
                             unsigned long end, struct page *ref_page)
 {
@@ -2198,6 +2224,12 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
                 if (huge_pte_none(pte))
                         continue;
 
+                /*
+                 * HWPoisoned hugepage is already unmapped and dropped reference
+                 */
+                if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
+                        continue;
+
                 page = pte_page(pte);
                 if (pte_dirty(pte))
                         set_page_dirty(page);
@@ -2207,6 +2239,7 @@ void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
         flush_tlb_range(vma, start, end);
         mmu_notifier_invalidate_range_end(mm, start, end);
         list_for_each_entry_safe(page, tmp, &page_list, lru) {
+                page_remove_rmap(page);
                 list_del(&page->lru);
                 put_page(page);
         }
@@ -2272,6 +2305,9 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
         return 1;
 }
 
+/*
+ * Hugetlb_cow() should be called with page lock of the original hugepage held.
+ */
 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
                         unsigned long address, pte_t *ptep, pte_t pte,
                         struct page *pagecache_page)
@@ -2286,8 +2322,13 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 retry_avoidcopy:
         /* If no-one else is actually using this page, avoid the copy
          * and just make the page writable */
-        avoidcopy = (page_count(old_page) == 1);
+        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);
                 set_huge_ptep_writable(vma, address, ptep);
                 return 0;
         }
@@ -2338,6 +2379,13 @@ retry_avoidcopy:
                 return -PTR_ERR(new_page);
         }
 
+        /*
+         * When the original hugepage is shared one, it does not have
+         * anon_vma prepared.
+         */
+        if (unlikely(anon_vma_prepare(vma)))
+                return VM_FAULT_OOM;
+
         copy_huge_page(new_page, old_page, address, vma);
         __SetPageUptodate(new_page);
 
@@ -2355,6 +2403,8 @@ retry_avoidcopy:
                 huge_ptep_clear_flush(vma, address, ptep);
                 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);
                 /* Make the old page be freed below */
                 new_page = old_page;
                 mmu_notifier_invalidate_range_end(mm,
@@ -2458,10 +2508,29 @@ retry:
                         spin_lock(&inode->i_lock);
                         inode->i_blocks += blocks_per_huge_page(h);
                         spin_unlock(&inode->i_lock);
+                        page_dup_rmap(page);
                 } else {
                         lock_page(page);
-                        page->mapping = HUGETLB_POISON;
+                        if (unlikely(anon_vma_prepare(vma))) {
+                                ret = VM_FAULT_OOM;
+                                goto backout_unlocked;
+                        }
+                        hugepage_add_new_anon_rmap(page, vma, address);
                 }
+        } else {
+                page_dup_rmap(page);
+        }
+
+        /*
+         * Since memory error handler replaces pte into hwpoison swap entry
+         * at the time of error handling, a process which reserved but not have
+         * the mapping to the error hugepage does not have hwpoison swap entry.
+         * So we need to block accesses from such a process by checking
+         * PG_hwpoison bit here.
+         */
+        if (unlikely(PageHWPoison(page))) {
+                ret = VM_FAULT_HWPOISON;
+                goto backout_unlocked;
         }
 
         /*
@@ -2513,10 +2582,18 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
         pte_t *ptep;
         pte_t entry;
         int ret;
+        struct page *page = NULL;
         struct page *pagecache_page = NULL;
         static DEFINE_MUTEX(hugetlb_instantiation_mutex);
         struct hstate *h = hstate_vma(vma);
 
+        ptep = huge_pte_offset(mm, address);
+        if (ptep) {
+                entry = huge_ptep_get(ptep);
+                if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
+                        return VM_FAULT_HWPOISON;
+        }
+
         ptep = huge_pte_alloc(mm, address, huge_page_size(h));
         if (!ptep)
                 return VM_FAULT_OOM;
@@ -2554,6 +2631,11 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                                                                 vma, address);
         }
 
+        if (!pagecache_page) {
+                page = pte_page(entry);
+                lock_page(page);
+        }
+
         spin_lock(&mm->page_table_lock);
         /* Check for a racing update before calling hugetlb_cow */
         if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
@@ -2579,6 +2661,8 @@ out_page_table_lock:
         if (pagecache_page) {
                 unlock_page(pagecache_page);
                 put_page(pagecache_page);
+        } else {
+                unlock_page(page);
         }
 
 out_mutex:
@@ -2791,3 +2875,19 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
         hugetlb_put_quota(inode->i_mapping, (chg - freed));
         hugetlb_acct_memory(h, -(chg - freed));
 }
+
+/*
+ * This function is called from memory failure code.
+ * Assume the caller holds page lock of the head page.
+ */
+void __isolate_hwpoisoned_huge_page(struct page *hpage)
+{
+        struct hstate *h = page_hstate(hpage);
+        int nid = page_to_nid(hpage);
+
+        spin_lock(&hugetlb_lock);
+        list_del(&hpage->lru);
+        h->free_huge_pages--;
+        h->free_huge_pages_node[nid]--;
+        spin_unlock(&hugetlb_lock);
+}