Merge tag 'kbuild-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy...

[linux-2.6-microblaze.git] / mm / gup.c

diff --git a/mm/gup.c b/mm/gup.c
index 4bc5742..0697134 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1528,7 +1528,7 @@ static long __get_user_pages_locked(struct mm_struct *mm, unsigned long start,
 {
        struct vm_area_struct *vma;
        unsigned long vm_flags;
-       int i;
+       long i;
 
        /* calculate required read or write permissions.
         * If FOLL_FORCE is set, we only require the "MAY" flags.
@@ -1575,7 +1575,7 @@ finish_or_fault:
  * Returns NULL on any kind of failure - a hole must then be inserted into
  * the corefile, to preserve alignment with its headers; and also returns
  * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
- * allowing a hole to be left in the corefile to save diskspace.
+ * allowing a hole to be left in the corefile to save disk space.
  *
  * Called without mmap_lock (takes and releases the mmap_lock by itself).
  */
@@ -1602,27 +1602,28 @@ struct page *get_dump_page(unsigned long addr)
 #endif /* CONFIG_ELF_CORE */
 
 #ifdef CONFIG_MIGRATION
-static long check_and_migrate_movable_pages(struct mm_struct *mm,
-                                           unsigned long start,
-                                           unsigned long nr_pages,
+/*
+ * Check whether all pages are pinnable, if so return number of pages.  If some
+ * pages are not pinnable, migrate them, and unpin all pages. Return zero if
+ * pages were migrated, or if some pages were not successfully isolated.
+ * Return negative error if migration fails.
+ */
+static long check_and_migrate_movable_pages(unsigned long nr_pages,
                                            struct page **pages,
-                                           struct vm_area_struct **vmas,
                                            unsigned int gup_flags)
 {
-       unsigned long i, isolation_error_count;
-       bool drain_allow;
+       unsigned long i;
+       unsigned long isolation_error_count = 0;
+       bool drain_allow = true;
        LIST_HEAD(movable_page_list);
-       long ret = nr_pages;
-       struct page *prev_head, *head;
+       long ret = 0;
+       struct page *prev_head = NULL;
+       struct page *head;
        struct migration_target_control mtc = {
                .nid = NUMA_NO_NODE,
                .gfp_mask = GFP_USER | __GFP_NOWARN,
        };
 
-check_again:
-       prev_head = NULL;
-       isolation_error_count = 0;
-       drain_allow = true;
        for (i = 0; i < nr_pages; i++) {
                head = compound_head(pages[i]);
                if (head == prev_head)
@@ -1660,47 +1661,27 @@ check_again:
         * in the correct zone.
         */
        if (list_empty(&movable_page_list) && !isolation_error_count)
-               return ret;
+               return nr_pages;
 
+       if (gup_flags & FOLL_PIN) {
+               unpin_user_pages(pages, nr_pages);
+       } else {
+               for (i = 0; i < nr_pages; i++)
+                       put_page(pages[i]);
+       }
        if (!list_empty(&movable_page_list)) {
-               /*
-                * drop the above get_user_pages reference.
-                */
-               if (gup_flags & FOLL_PIN)
-                       unpin_user_pages(pages, nr_pages);
-               else
-                       for (i = 0; i < nr_pages; i++)
-                               put_page(pages[i]);
-
                ret = migrate_pages(&movable_page_list, alloc_migration_target,
                                    NULL, (unsigned long)&mtc, MIGRATE_SYNC,
                                    MR_LONGTERM_PIN);
-               if (ret) {
-                       if (!list_empty(&movable_page_list))
-                               putback_movable_pages(&movable_page_list);
-                       return ret > 0 ? -ENOMEM : ret;
-               }
-
-               /* We unpinned pages before migration, pin them again */
-               ret = __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
-                                             NULL, gup_flags);
-               if (ret <= 0)
-                       return ret;
-               nr_pages = ret;
+               if (ret && !list_empty(&movable_page_list))
+                       putback_movable_pages(&movable_page_list);
        }
 
-       /*
-        * check again because pages were unpinned, and we also might have
-        * had isolation errors and need more pages to migrate.
-        */
-       goto check_again;
+       return ret > 0 ? -ENOMEM : ret;
 }
 #else
-static long check_and_migrate_movable_pages(struct mm_struct *mm,
-                                           unsigned long start,
-                                           unsigned long nr_pages,
+static long check_and_migrate_movable_pages(unsigned long nr_pages,
                                            struct page **pages,
-                                           struct vm_area_struct **vmas,
                                            unsigned int gup_flags)
 {
        return nr_pages;
@@ -1718,22 +1699,22 @@ static long __gup_longterm_locked(struct mm_struct *mm,
                                  struct vm_area_struct **vmas,
                                  unsigned int gup_flags)
 {
-       unsigned long flags = 0;
+       unsigned int flags;
        long rc;
 
-       if (gup_flags & FOLL_LONGTERM)
-               flags = memalloc_pin_save();
-
-       rc = __get_user_pages_locked(mm, start, nr_pages, pages, vmas, NULL,
-                                    gup_flags);
+       if (!(gup_flags & FOLL_LONGTERM))
+               return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
+                                              NULL, gup_flags);
+       flags = memalloc_pin_save();
+       do {
+               rc = __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
+                                            NULL, gup_flags);
+               if (rc <= 0)
+                       break;
+               rc = check_and_migrate_movable_pages(rc, pages, gup_flags);
+       } while (!rc);
+       memalloc_pin_restore(flags);
 
-       if (gup_flags & FOLL_LONGTERM) {
-               if (rc > 0)
-                       rc = check_and_migrate_movable_pages(mm, start, rc,
-                                                            pages, vmas,
-                                                            gup_flags);
-               memalloc_pin_restore(flags);
-       }
        return rc;
 }