[PATCH -V3 3/5] swap: remove __swp_swapcount()

[Huang Ying]

__swp_swapcount() just encloses the calling to swap_swapcount() with
get/put_swap_device().  It is called in __read_swap_cache_async()
only, which encloses the calling with get/put_swap_device() already.
So, __read_swap_cache_async() can call swap_swapcount() directly.

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>
Cc: Chris Li <chrisl@xxxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
---
 include/linux/swap.h |  4 ++--
 mm/swap_state.c      |  2 +-
 mm/swapfile.c        | 20 +-------------------
 3 files changed, 4 insertions(+), 22 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 3c69cb653cb9..f6bd51aa05ea 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -512,7 +512,7 @@ int find_first_swap(dev_t *device);
 extern unsigned int count_swap_pages(int, int);
 extern sector_t swapdev_block(int, pgoff_t);
 extern int __swap_count(swp_entry_t entry);
-extern int __swp_swapcount(swp_entry_t entry);
+extern int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry);
 extern int swp_swapcount(swp_entry_t entry);
 extern struct swap_info_struct *page_swap_info(struct page *);
 extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
@@ -590,7 +590,7 @@ static inline int __swap_count(swp_entry_t entry)
 	return 0;
 }
 
-static inline int __swp_swapcount(swp_entry_t entry)
+static inline int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
 {
 	return 0;
 }
diff --git a/mm/swap_state.c b/mm/swap_state.c
index a8450b4a110c..ef32353c18a6 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -447,7 +447,7 @@ 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)
+		if (!swap_swapcount(si, entry) && swap_slot_cache_enabled)
 			goto fail_put_swap;
 
 		/*
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 8419cba9c192..e9cce775fb25 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1443,7 +1443,7 @@ int __swap_count(swp_entry_t entry)
  * This does not give an exact answer when swap count is continued,
  * but does include the high COUNT_CONTINUED flag to allow for that.
  */
-static int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
+int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
 {
 	pgoff_t offset = swp_offset(entry);
 	struct swap_cluster_info *ci;
@@ -1455,24 +1455,6 @@ static int swap_swapcount(struct swap_info_struct *si, swp_entry_t entry)
 	return count;
 }
 
-/*
- * How many references to @entry are currently swapped out?
- * This does not give an exact answer when swap count is continued,
- * but does include the high COUNT_CONTINUED flag to allow for that.
- */
-int __swp_swapcount(swp_entry_t entry)
-{
-	int count = 0;
-	struct swap_info_struct *si;
-
-	si = get_swap_device(entry);
-	if (si) {
-		count = swap_swapcount(si, entry);
-		put_swap_device(si);
-	}
-	return count;
-}
-
 /*
  * How many references to @entry are currently swapped out?
  * This considers COUNT_CONTINUED so it returns exact answer.
-- 
2.39.2