folios that are written to swap are owned by the MM subsystem - not any
filesystem.
When such a folio is passed to a filesystem to be written out to a
swap-file, the filesystem handles the data, but the folio itself does not
belong to the filesystem. So calling the filesystem's ->dirty_folio()
address_space operation makes no sense. This is for folios in the given
address space, and a folio to be written to swap does not exist in the
given address space.
So drop swap_dirty_folio() which calls the address-space's
->dirty_folio(), and always use noop_dirty_folio(), which is
appropriate for folios being swapped out.
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
include/linux/swap.h | 1 -
mm/page_io.c | 17 -----------------
mm/swap_state.c | 2 +-
3 files changed, 1 insertion(+), 19 deletions(-)
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 11390dde5a6c..6bc9e21262de 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -420,7 +420,6 @@ extern void kswapd_stop(int nid);
#ifdef CONFIG_SWAP
-bool swap_dirty_folio(struct address_space *mapping, struct folio *folio);
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 d01ab9d5410a..5ffdbda31a16 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -439,20 +439,3 @@ int swap_readpage(struct page *page, bool synchronous)
delayacct_swapin_end();
return ret;
}
-
-bool swap_dirty_folio(struct address_space *mapping, struct folio *folio)
-{
- struct swap_info_struct *sis = swp_swap_info(folio_swap_entry(folio));
-
- if (data_race(sis->flags & SWP_FS_OPS)) {
- const struct address_space_operations *aops;
-
- mapping = sis->swap_file->f_mapping;
- aops = mapping->a_ops;
-
- VM_BUG_ON_FOLIO(!folio_test_swapcache(folio), folio);
- return aops->dirty_folio(mapping, folio);
- } else {
- return noop_dirty_folio(mapping, folio);
- }
-}
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 5437dd317cf3..f3ab01801629 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,
- .dirty_folio = swap_dirty_folio,
+ .dirty_folio = noop_dirty_folio,
#ifdef CONFIG_MIGRATION
.migratepage = migrate_page,
#endif
