Commit f6d299ec authored by Alistair Popple's avatar Alistair Popple Committed by Andrew Morton
Browse files

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: default avatarAlistair Popple <apopple@nvidia.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shigeru Yoshida <syoshida@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 32d77270

mm/gup.c

+9 −14
Original line number Diff line number Diff line
@@ -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);

			}



			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]);

	}



	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);