From f6d299ec39d8ebb62fc047022d4904575c99a28c Mon Sep 17 00:00:00 2001 From: Alistair Popple Date: Wed, 24 Aug 2022 15:09:51 +1000 Subject: mm/gup.c: don't pass gup_flags to check_and_migrate_movable_pages() gup_flags is passed to check_and_migrate_movable_pages() so that it can call either put_page() or unpin_user_page() to drop the page reference. However check_and_migrate_movable_pages() is only called for FOLL_LONGTERM, which implies FOLL_PIN so there is no need to pass gup_flags. Link: https://lkml.kernel.org/r/d611c65a9008ff55887307df457c6c2220ad6163.1661317396.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple Reviewed-by: David Hildenbrand Reviewed-by: John Hubbard Cc: Alex Sierra Cc: Dan Williams Cc: Felix Kuehling Cc: Jason Gunthorpe Cc: Logan Gunthorpe Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Muchun Song Cc: Ralph Campbell Cc: Shigeru Yoshida Signed-off-by: Andrew Morton --- mm/gup.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) (limited to 'mm/gup.c') diff --git a/mm/gup.c b/mm/gup.c index b05810e7e9bb..1800af4806e3 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1933,8 +1933,7 @@ struct page *get_dump_page(unsigned long addr) * migration failure. */ static long check_and_migrate_movable_pages(unsigned long nr_pages, - struct page **pages, - unsigned int gup_flags) + struct page **pages) { unsigned long i; struct folio *prev_folio = NULL; @@ -1967,10 +1966,8 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages, * Migration will fail if the page is pinned, so convert * the pin on the source page to a normal reference. */ - if (gup_flags & FOLL_PIN) { - get_page(&folio->page); - unpin_user_page(&folio->page); - } + get_page(&folio->page); + unpin_user_page(&folio->page); if (migrate_device_coherent_page(&folio->page)) { ret = -EBUSY; @@ -2023,10 +2020,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages, if (!pages[i]) continue; - if (gup_flags & FOLL_PIN) - unpin_user_page(pages[i]); - else - put_page(pages[i]); + unpin_user_page(pages[i]); } if (!list_empty(&movable_page_list)) { @@ -2049,8 +2043,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages, } #else static long check_and_migrate_movable_pages(unsigned long nr_pages, - struct page **pages, - unsigned int gup_flags) + struct page **pages) { return 0; } @@ -2073,6 +2066,9 @@ static long __gup_longterm_locked(struct mm_struct *mm, if (!(gup_flags & FOLL_LONGTERM)) return __get_user_pages_locked(mm, start, nr_pages, pages, vmas, NULL, gup_flags); + /* check_and_migrate_movable_pages() assumes pages have been pinned. */ + if (WARN_ON(!(gup_flags & FOLL_PIN))) + return -EINVAL; flags = memalloc_pin_save(); do { nr_pinned_pages = __get_user_pages_locked(mm, start, nr_pages, @@ -2082,8 +2078,7 @@ static long __gup_longterm_locked(struct mm_struct *mm, rc = nr_pinned_pages; break; } - rc = check_and_migrate_movable_pages(nr_pinned_pages, pages, - gup_flags); + rc = check_and_migrate_movable_pages(nr_pinned_pages, pages); } while (rc == -EAGAIN); memalloc_pin_restore(flags); -- cgit v1.2.3