From f29ad6a99b596b8169744d107bf088e8be9e8d0d Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Mon, 14 Dec 2009 17:58:40 -0800 Subject: 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 Cc: Nigel Cunningham Cc: KAMEZAWA Hiroyuki Reviewed-by: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_io.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) (limited to 'mm/page_io.c') diff --git a/mm/page_io.c b/mm/page_io.c index c6f3e5071de3..afeed89a0a5d 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -19,20 +19,17 @@ #include #include -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; -- cgit v1.2.3 From d4906e1aa516cc965292b43b5a26122dd4344e7e Mon Sep 17 00:00:00 2001 From: Lee Schermerhorn Date: Mon, 14 Dec 2009 17:58:49 -0800 Subject: swap: rework map_swap_page() again Seems that page_io.c doesn't really need to know that page_private(page) is the swp_entry 'val'. Rework map_swap_page() to do what its name says and map a page to a page offset in the swap space. The only other caller of map_swap_page() is internal to mm/swapfile.c and it does want to map a swap entry to the 'sector'. So rename map_swap_page() to map_swap_entry(), make it 'static' and and implement map_swap_page() as a wrapper around that. Signed-off-by: Lee Schermerhorn Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swap.h | 2 +- mm/page_io.c | 4 +--- mm/swapfile.c | 20 ++++++++++++++++---- 3 files changed, 18 insertions(+), 8 deletions(-) (limited to 'mm/page_io.c') diff --git a/include/linux/swap.h b/include/linux/swap.h index 9f0ca325e30d..a2602a8207a6 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -325,7 +325,7 @@ extern void swapcache_free(swp_entry_t, struct page *page); extern int free_swap_and_cache(swp_entry_t); extern int swap_type_of(dev_t, sector_t, struct block_device **); extern unsigned int count_swap_pages(int, int); -extern sector_t map_swap_page(swp_entry_t, struct block_device **); +extern sector_t map_swap_page(struct page *, struct block_device **); extern sector_t swapdev_block(int, pgoff_t); extern int reuse_swap_page(struct page *); extern int try_to_free_swap(struct page *); diff --git a/mm/page_io.c b/mm/page_io.c index afeed89a0a5d..a19af956ee1b 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -26,9 +26,7 @@ static struct bio *get_swap_bio(gfp_t gfp_flags, bio = bio_alloc(gfp_flags, 1); if (bio) { - swp_entry_t entry; - entry.val = page_private(page); - bio->bi_sector = map_swap_page(entry, &bio->bi_bdev); + bio->bi_sector = map_swap_page(page, &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; diff --git a/mm/swapfile.c b/mm/swapfile.c index 58bec6600167..d5eb2e85600b 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -38,6 +38,7 @@ static bool swap_count_continued(struct swap_info_struct *, pgoff_t, unsigned char); static void free_swap_count_continuations(struct swap_info_struct *); +static sector_t map_swap_entry(swp_entry_t, struct block_device**); static DEFINE_SPINLOCK(swap_lock); static unsigned int nr_swapfiles; @@ -782,7 +783,7 @@ sector_t swapdev_block(int type, pgoff_t offset) return 0; if (!(swap_info[type]->flags & SWP_WRITEOK)) return 0; - return map_swap_page(swp_entry(type, offset), &bdev); + return map_swap_entry(swp_entry(type, offset), &bdev); } /* @@ -1249,10 +1250,11 @@ static void drain_mmlist(void) /* * Use this swapdev's extent info to locate the (PAGE_SIZE) block which - * corresponds to page offset `offset'. Note that the type of this function - * is sector_t, but it returns page offset into the bdev, not sector offset. + * corresponds to page offset for the specified swap entry. + * Note that the type of this function is sector_t, but it returns page offset + * into the bdev, not sector offset. */ -sector_t map_swap_page(swp_entry_t entry, struct block_device **bdev) +static sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev) { struct swap_info_struct *sis; struct swap_extent *start_se; @@ -1280,6 +1282,16 @@ sector_t map_swap_page(swp_entry_t entry, struct block_device **bdev) } } +/* + * Returns the page offset into bdev for the specified page's swap entry. + */ +sector_t map_swap_page(struct page *page, struct block_device **bdev) +{ + swp_entry_t entry; + entry.val = page_private(page); + return map_swap_entry(entry, bdev); +} + /* * Free all of a swapdev's extent information */ -- cgit v1.2.3