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.
Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
Changes for v6:
- Rebased onto mm-unstable
Changes for v3:
- Move WARN_ON() out of loop
---
mm/gup.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 3b656b7..8d66ee2 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1934,8 +1934,7 @@ 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;
@@ -1968,10 +1967,8 @@ 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;
@@ -2024,10 +2021,7 @@ 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)) {
@@ -2050,8 +2044,7 @@ 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;
}
@@ -2074,6 +2067,9 @@ 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,
@@ -2081,8 +2077,7 @@ static long __gup_longterm_locked(struct mm_struct *mm,
gup_flags);
if (nr_pinned_pages <= 0)
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);
base-commit: d711de4adbec4cb0b8769bcae971b13293e6d311
--
git-series 0.9.1
