mm/swap: remove the end_write_func argument to __swap_writepage

The argument is always set to end_swap_bio_write, so remove the argument
and mark end_swap_bio_write static.

Link: https://lkml.kernel.org/r/20220811141741.660214-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/page_io.c

@@ -28,7 +28,7 @@
 #include <linux/delayacct.h>
 #include "swap.h"
 
-void end_swap_bio_write(struct bio *bio)
+static void end_swap_bio_write(struct bio *bio)
 {
 	struct page *page = bio_first_page_all(bio);
 
@@ -202,7 +202,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
 		end_page_writeback(page);
 		goto out;
 	}
-	ret = __swap_writepage(page, wbc, end_swap_bio_write);
+	ret = __swap_writepage(page, wbc);
 out:
 	return ret;
 }
@@ -332,8 +332,7 @@ static int swap_writepage_fs(struct page *page, struct writeback_control *wbc)
 	return 0;
 }
 
-int __swap_writepage(struct page *page, struct writeback_control *wbc,
-		     bio_end_io_t end_write_func)
+int __swap_writepage(struct page *page, struct writeback_control *wbc)
 {
 	struct bio *bio;
 	int ret;
@@ -358,7 +357,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
 			REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc),
 			GFP_NOIO);
 	bio->bi_iter.bi_sector = swap_page_sector(page);
-	bio->bi_end_io = end_write_func;
+	bio->bi_end_io = end_swap_bio_write;
 	bio_add_page(bio, page, thp_size(page), 0);
 
 	bio_associate_blkg_from_page(bio, page);

mm/swap.h

@@ -18,9 +18,7 @@ static inline void swap_read_unplug(struct swap_iocb *plug)
 }
 void swap_write_unplug(struct swap_iocb *sio);
 int swap_writepage(struct page *page, struct writeback_control *wbc);
-void end_swap_bio_write(struct bio *bio);
-int __swap_writepage(struct page *page, struct writeback_control *wbc,
-		     bio_end_io_t end_write_func);
+int __swap_writepage(struct page *page, struct writeback_control *wbc);
 
 /* linux/mm/swap_state.c */
 /* One swap address space for each 64M swap space */

mm/zswap.c

@@ -1026,7 +1026,7 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle)
 	SetPageReclaim(page);
 
 	/* start writeback */
-	__swap_writepage(page, &wbc, end_swap_bio_write);
+	__swap_writepage(page, &wbc);
 	put_page(page);
 	zswap_written_back_pages++;