This patch introduces MIGRATEPAGE_SUCCESS as the default return code for address_space_operations.migratepage() method and documents the expected return code for the same method in failure cases.
Signed-off-by: Rafael Aquini <aqu...@redhat.com> --- fs/hugetlbfs/inode.c | 4 ++-- include/linux/migrate.h | 7 +++++++ mm/migrate.c | 22 +++++++++++----------- 3 files changed, 20 insertions(+), 13 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index c5bc355..bdeda2c 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -608,11 +608,11 @@ static int hugetlbfs_migrate_page(struct address_space *mapping, int rc; rc = migrate_huge_page_move_mapping(mapping, newpage, page); - if (rc) + if (rc != MIGRATEPAGE_SUCCESS) return rc; migrate_page_copy(newpage, page); - return 0; + return MIGRATEPAGE_SUCCESS; } static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index ce7e667..a4e886d 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -7,6 +7,13 @@ typedef struct page *new_page_t(struct page *, unsigned long private, int **); +/* + * Return values from addresss_space_operations.migratepage(): + * - negative errno on page migration failure; + * - zero on page migration success; + */ +#define MIGRATEPAGE_SUCCESS 0 + #ifdef CONFIG_MIGRATION extern void putback_lru_pages(struct list_head *l); diff --git a/mm/migrate.c b/mm/migrate.c index 77ed2d7..98c7a89 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -286,7 +286,7 @@ static int migrate_page_move_mapping(struct address_space *mapping, /* Anonymous page without mapping */ if (page_count(page) != 1) return -EAGAIN; - return 0; + return MIGRATEPAGE_SUCCESS; } spin_lock_irq(&mapping->tree_lock); @@ -356,7 +356,7 @@ static int migrate_page_move_mapping(struct address_space *mapping, } spin_unlock_irq(&mapping->tree_lock); - return 0; + return MIGRATEPAGE_SUCCESS; } /* @@ -372,7 +372,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, if (!mapping) { if (page_count(page) != 1) return -EAGAIN; - return 0; + return MIGRATEPAGE_SUCCESS; } spin_lock_irq(&mapping->tree_lock); @@ -399,7 +399,7 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, page_unfreeze_refs(page, expected_count - 1); spin_unlock_irq(&mapping->tree_lock); - return 0; + return MIGRATEPAGE_SUCCESS; } /* @@ -486,11 +486,11 @@ int migrate_page(struct address_space *mapping, rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode); - if (rc) + if (rc != MIGRATEPAGE_SUCCESS) return rc; migrate_page_copy(newpage, page); - return 0; + return MIGRATEPAGE_SUCCESS; } EXPORT_SYMBOL(migrate_page); @@ -513,7 +513,7 @@ int buffer_migrate_page(struct address_space *mapping, rc = migrate_page_move_mapping(mapping, newpage, page, head, mode); - if (rc) + if (rc != MIGRATEPAGE_SUCCESS) return rc; /* @@ -549,7 +549,7 @@ int buffer_migrate_page(struct address_space *mapping, } while (bh != head); - return 0; + return MIGRATEPAGE_SUCCESS; } EXPORT_SYMBOL(buffer_migrate_page); #endif @@ -814,7 +814,7 @@ skip_unmap: put_anon_vma(anon_vma); uncharge: - mem_cgroup_end_migration(mem, page, newpage, rc == 0); + mem_cgroup_end_migration(mem, page, newpage, rc == MIGRATEPAGE_SUCCESS); unlock: unlock_page(page); out: @@ -987,7 +987,7 @@ int migrate_pages(struct list_head *from, case -EAGAIN: retry++; break; - case 0: + case MIGRATEPAGE_SUCCESS: break; default: /* Permanent failure */ @@ -1024,7 +1024,7 @@ int migrate_huge_page(struct page *hpage, new_page_t get_new_page, /* try again */ cond_resched(); break; - case 0: + case MIGRATEPAGE_SUCCESS: goto out; default: rc = -EIO; -- 1.7.11.7 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization