swap_info: private to swapfile.c

The swap_info_struct is mostly private to mm/swapfile.c, with only
one other in-tree user: get_swap_bio().  Adjust its interface to
map_swap_page(), so that we can then remove get_swap_info_struct().

But there is a popular user out-of-tree, TuxOnIce: so leave the
declaration of swap_info_struct in linux/swap.h.

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Nigel Cunningham <ncunningham@crca.org.au>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 12 deletions

diff --git a/mm/page_io.c b/mm/page_io.c
index c6f3e50..afeed89 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -19,20 +19,17 @@
 #include <linux/writeback.h>
 #include <asm/pgtable.h>
 
-static struct bio *get_swap_bio(gfp_t gfp_flags, pgoff_t index,
+static struct bio *get_swap_bio(gfp_t gfp_flags,
 				struct page *page, bio_end_io_t end_io)
 {
 	struct bio *bio;
 
 	bio = bio_alloc(gfp_flags, 1);
 	if (bio) {
-		struct swap_info_struct *sis;
-		swp_entry_t entry = { .val = index, };
-
-		sis = get_swap_info_struct(swp_type(entry));
-		bio->bi_sector = map_swap_page(sis, swp_offset(entry)) *
-					(PAGE_SIZE >> 9);
-		bio->bi_bdev = sis->bdev;
+		swp_entry_t entry;
+		entry.val = page_private(page);
+		bio->bi_sector = map_swap_page(entry, &bio->bi_bdev);
+		bio->bi_sector <<= PAGE_SHIFT - 9;
 		bio->bi_io_vec[0].bv_page = page;
 		bio->bi_io_vec[0].bv_len = PAGE_SIZE;
 		bio->bi_io_vec[0].bv_offset = 0;
@@ -102,8 +99,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
 		unlock_page(page);
 		goto out;
 	}
-	bio = get_swap_bio(GFP_NOIO, page_private(page), page,
-				end_swap_bio_write);
+	bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
 	if (bio == NULL) {
 		set_page_dirty(page);
 		unlock_page(page);
@@ -127,8 +123,7 @@ int swap_readpage(struct page *page)
 
 	VM_BUG_ON(!PageLocked(page));
 	VM_BUG_ON(PageUptodate(page));
-	bio = get_swap_bio(GFP_KERNEL, page_private(page), page,
-				end_swap_bio_read);
+	bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
 	if (bio == NULL) {
 		unlock_page(page);
 		ret = -ENOMEM;