Pages that are written to swap are owned by the MM subsystem - not any
filesystem.
When such a page is passed to a filesystem to be written out to a
swap-file, the filesystem handles the data, but the page itself does not
belong to the filesystem. So calling the filesystem's set_page_dirty
address_space operation makes no sense. This is for pages in the given
address space, and a page to be written to swap does not exist in the
given address space.
So drop swap_set_page_dirty() which calls the address-space's
set_page_dirty, and alway use __set_page_dirty_no_writeback, which is
appropriate for pages being swapped out.
Fixes-no-auto-backport: 62c230bc1790 ("mm: add support for a filesystem to activate swap files and use direct_IO for writing swap pages")
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
include/linux/swap.h | 1 -
mm/page_io.c | 14 --------------
mm/swap_state.c | 2 +-
3 files changed, 1 insertion(+), 16 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 3f54a8941c9d..a43929f7033e 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -419,7 +419,6 @@ extern void kswapd_stop(int nid);
#ifdef CONFIG_SWAP
-extern int swap_set_page_dirty(struct page *page);
int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page,
unsigned long nr_pages, sector_t start_block);
int generic_swapfile_activate(struct swap_info_struct *, struct file *,
diff --git a/mm/page_io.c b/mm/page_io.c
index f8c26092e869..34b12d6f94d7 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -438,17 +438,3 @@ int swap_readpage(struct page *page, bool synchronous)
delayacct_swapin_end();
return ret;
}
-
-int swap_set_page_dirty(struct page *page)
-{
- struct swap_info_struct *sis = page_swap_info(page);
-
- if (data_race(sis->flags & SWP_FS_OPS)) {
- struct address_space *mapping = sis->swap_file->f_mapping;
-
- VM_BUG_ON_PAGE(!PageSwapCache(page), page);
- return mapping->a_ops->set_page_dirty(page);
- } else {
- return __set_page_dirty_no_writeback(page);
- }
-}
diff --git a/mm/swap_state.c b/mm/swap_state.c
index bb38453425c7..514b86b05488 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -31,7 +31,7 @@
*/
static const struct address_space_operations swap_aops = {
.writepage = swap_writepage,
- .set_page_dirty = swap_set_page_dirty,
+ .set_page_dirty = __set_page_dirty_no_writeback,
#ifdef CONFIG_MIGRATION
.migratepage = migrate_page,
#endif
