This makes the function a little easier to be understood because we
don't need to consider swapoff. And this makes it possible to remove
get/put_swap_device() calling in some functions called by
__read_swap_cache_async().
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
---
mm/swap_state.c | 33 ++++++++++++++++++++++-----------
1 file changed, 22 insertions(+), 11 deletions(-)
diff --git a/mm/swap_state.c b/mm/swap_state.c
index b76a65ac28b3..a1028fe7214e 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -417,9 +417,13 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
{
struct swap_info_struct *si;
struct folio *folio;
+ struct page *page;
void *shadow = NULL;
*new_page_allocated = false;
+ si = get_swap_device(entry);
+ if (!si)
+ return NULL;
for (;;) {
int err;
@@ -428,14 +432,12 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
* called after swap_cache_get_folio() failed, re-calling
* that would confuse statistics.
*/
- si = get_swap_device(entry);
- if (!si)
- return NULL;
folio = filemap_get_folio(swap_address_space(entry),
swp_offset(entry));
- put_swap_device(si);
- if (!IS_ERR(folio))
- return folio_file_page(folio, swp_offset(entry));
+ if (!IS_ERR(folio)) {
+ page = folio_file_page(folio, swp_offset(entry));
+ goto got_page;
+ }
/*
* Just skip read ahead for unused swap slot.
@@ -445,8 +447,8 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
* as SWAP_HAS_CACHE. That's done in later part of code or
* else swap_off will be aborted if we return NULL.
*/
- if (!__swp_swapcount(entry) && swap_slot_cache_enabled)
- return NULL;
+ if (!swap_swapcount(si, entry) && swap_slot_cache_enabled)
+ goto fail;
/*
* Get a new page to read into from swap. Allocate it now,
@@ -455,7 +457,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
*/
folio = vma_alloc_folio(gfp_mask, 0, vma, addr, false);
if (!folio)
- return NULL;
+ goto fail;
/*
* Swap entry may have been freed since our caller observed it.
@@ -466,7 +468,7 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
folio_put(folio);
if (err != -EEXIST)
- return NULL;
+ goto fail;
/*
* We might race against __delete_from_swap_cache(), and
@@ -500,12 +502,17 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
/* Caller will initiate read into locked folio */
folio_add_lru(folio);
*new_page_allocated = true;
- return &folio->page;
+ page = &folio->page;
+got_page:
+ put_swap_device(si);
+ return page;
fail_unlock:
put_swap_folio(folio, entry);
folio_unlock(folio);
folio_put(folio);
+fail:
