Merge tag 'block-5.6-2020-02-28' of git://git.kernel.dk/linux-block

[tomoyo/tomoyo-test1.git] / mm / migrate.c

diff --git a/mm/migrate.c b/mm/migrate.c
index 86873b6..b109287 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -48,6 +48,7 @@
 #include <linux/page_owner.h>
 #include <linux/sched/mm.h>
 #include <linux/ptrace.h>
+#include <linux/oom.h>
 
 #include <asm/tlbflush.h>
 
@@ -986,7 +987,7 @@ static int move_to_new_page(struct page *newpage, struct page *page,
                }
 
                /*
-                * Anonymous and movable page->mapping will be cleard by
+                * Anonymous and movable page->mapping will be cleared by
                 * free_pages_prepare so don't reset it here for keeping
                 * the type to work PageAnon, for example.
                 */
@@ -1199,8 +1200,7 @@ out:
                /*
                 * A page that has been migrated has all references
                 * removed and will be freed. A page that has not been
-                * migrated will have kepts its references and be
-                * restored.
+                * migrated will have kept its references and be restored.
                 */
                list_del(&page->lru);
 
@@ -1627,8 +1627,19 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
                        start = i;
                } else if (node != current_node) {
                        err = do_move_pages_to_node(mm, &pagelist, current_node);
-                       if (err)
+                       if (err) {
+                               /*
+                                * Positive err means the number of failed
+                                * pages to migrate.  Since we are going to
+                                * abort and return the number of non-migrated
+                                * pages, so need to incude the rest of the
+                                * nr_pages that have not been attempted as
+                                * well.
+                                */
+                               if (err > 0)
+                                       err += nr_pages - i - 1;
                                goto out;
+                       }
                        err = store_status(status, start, current_node, i - start);
                        if (err)
                                goto out;
@@ -1659,8 +1670,11 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
                        goto out_flush;
 
                err = do_move_pages_to_node(mm, &pagelist, current_node);
-               if (err)
+               if (err) {
+                       if (err > 0)
+                               err += nr_pages - i - 1;
                        goto out;
+               }
                if (i > start) {
                        err = store_status(status, start, current_node, i - start);
                        if (err)
@@ -1674,9 +1688,16 @@ out_flush:
 
        /* Make sure we do not overwrite the existing error */
        err1 = do_move_pages_to_node(mm, &pagelist, current_node);
+       /*
+        * Don't have to report non-attempted pages here since:
+        *     - If the above loop is done gracefully all pages have been
+        *       attempted.
+        *     - If the above loop is aborted it means a fatal error
+        *       happened, should return ret.
+        */
        if (!err1)
                err1 = store_status(status, start, current_node, i - start);
-       if (!err)
+       if (err >= 0)
                err = err1;
 out:
        return err;
@@ -2130,12 +2151,13 @@ out_unlock:
 #ifdef CONFIG_DEVICE_PRIVATE
 static int migrate_vma_collect_hole(unsigned long start,
                                    unsigned long end,
+                                   __always_unused int depth,
                                    struct mm_walk *walk)
 {
        struct migrate_vma *migrate = walk->private;
        unsigned long addr;
 
-       for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) {
+       for (addr = start; addr < end; addr += PAGE_SIZE) {
                migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE;
                migrate->dst[migrate->npages] = 0;
                migrate->npages++;
@@ -2152,7 +2174,7 @@ static int migrate_vma_collect_skip(unsigned long start,
        struct migrate_vma *migrate = walk->private;
        unsigned long addr;
 
-       for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) {
+       for (addr = start; addr < end; addr += PAGE_SIZE) {
                migrate->dst[migrate->npages] = 0;
                migrate->src[migrate->npages++] = 0;
        }
@@ -2174,7 +2196,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
 
 again:
        if (pmd_none(*pmdp))
-               return migrate_vma_collect_hole(start, end, walk);
+               return migrate_vma_collect_hole(start, end, -1, walk);
 
        if (pmd_trans_huge(*pmdp)) {
                struct page *page;
@@ -2207,7 +2229,7 @@ again:
                                return migrate_vma_collect_skip(start, end,
                                                                walk);
                        if (pmd_none(*pmdp))
-                               return migrate_vma_collect_hole(start, end,
+                               return migrate_vma_collect_hole(start, end, -1,
                                                                walk);
                }
        }
@@ -2675,6 +2697,14 @@ int migrate_vma_setup(struct migrate_vma *args)
 }
 EXPORT_SYMBOL(migrate_vma_setup);
 
+/*
+ * This code closely matches the code in:
+ *   __handle_mm_fault()
+ *     handle_pte_fault()
+ *       do_anonymous_page()
+ * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
+ * private page.
+ */
 static void migrate_vma_insert_page(struct migrate_vma *migrate,
                                    unsigned long addr,
                                    struct page *page,
@@ -2755,30 +2785,24 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
 
        ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
 
+       if (check_stable_address_space(mm))
+               goto unlock_abort;
+
        if (pte_present(*ptep)) {
                unsigned long pfn = pte_pfn(*ptep);
 
-               if (!is_zero_pfn(pfn)) {
-                       pte_unmap_unlock(ptep, ptl);
-                       mem_cgroup_cancel_charge(page, memcg, false);
-                       goto abort;
-               }
+               if (!is_zero_pfn(pfn))
+                       goto unlock_abort;
                flush = true;
-       } else if (!pte_none(*ptep)) {
-               pte_unmap_unlock(ptep, ptl);
-               mem_cgroup_cancel_charge(page, memcg, false);
-               goto abort;
-       }
+       } else if (!pte_none(*ptep))
+               goto unlock_abort;
 
        /*
-        * Check for usefaultfd but do not deliver the fault. Instead,
+        * Check for userfaultfd but do not deliver the fault. Instead,
         * just back off.
         */
-       if (userfaultfd_missing(vma)) {
-               pte_unmap_unlock(ptep, ptl);
-               mem_cgroup_cancel_charge(page, memcg, false);
-               goto abort;
-       }
+       if (userfaultfd_missing(vma))
+               goto unlock_abort;
 
        inc_mm_counter(mm, MM_ANONPAGES);
        page_add_new_anon_rmap(page, vma, addr, false);
@@ -2802,6 +2826,9 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
        *src = MIGRATE_PFN_MIGRATE;
        return;
 
+unlock_abort:
+       pte_unmap_unlock(ptep, ptl);
+       mem_cgroup_cancel_charge(page, memcg, false);
 abort:
        *src &= ~MIGRATE_PFN_MIGRATE;
 }
@@ -2834,9 +2861,8 @@ void migrate_vma_pages(struct migrate_vma *migrate)
                }
 
                if (!page) {
-                       if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE)) {
+                       if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE))
                                continue;
-                       }
                        if (!notified) {
                                notified = true;