Messages in this thread Patch in this message | | | Date | Thu, 15 Oct 2009 01:46:18 +0100 (BST) | From | Hugh Dickins <> | Subject | [PATCH 1/9] swap_info: private to swapfile.c |
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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> ---
include/linux/swap.h | 3 +-- mm/page_io.c | 19 +++++++------------ mm/swapfile.c | 29 +++++++++++++++++------------ 3 files changed, 25 insertions(+), 26 deletions(-)
--- 2.6.32-rc4/include/linux/swap.h 2009-09-28 00:28:39.000000000 +0100 +++ si1/include/linux/swap.h 2009-10-14 21:25:58.000000000 +0100 @@ -317,9 +317,8 @@ extern void swapcache_free(swp_entry_t, 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(struct swap_info_struct *, pgoff_t); +extern sector_t map_swap_page(swp_entry_t, struct block_device **); extern sector_t swapdev_block(int, pgoff_t); -extern struct swap_info_struct *get_swap_info_struct(unsigned); extern int reuse_swap_page(struct page *); extern int try_to_free_swap(struct page *); struct backing_dev_info; --- 2.6.32-rc4/mm/page_io.c 2009-09-09 23:13:59.000000000 +0100 +++ si1/mm/page_io.c 2009-10-14 21:25:58.000000000 +0100 @@ -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, st 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; --- 2.6.32-rc4/mm/swapfile.c 2009-10-05 04:33:14.000000000 +0100 +++ si1/mm/swapfile.c 2009-10-14 21:25:58.000000000 +0100 @@ -1284,12 +1284,22 @@ static void drain_mmlist(void) /* * Use this swapdev's extent info to locate the (PAGE_SIZE) block which - * corresponds to page offset `offset'. + * 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. */ -sector_t map_swap_page(struct swap_info_struct *sis, pgoff_t offset) +sector_t map_swap_page(swp_entry_t entry, struct block_device **bdev) { - struct swap_extent *se = sis->curr_swap_extent; - struct swap_extent *start_se = se; + struct swap_info_struct *sis; + struct swap_extent *start_se; + struct swap_extent *se; + pgoff_t offset; + + sis = swap_info + swp_type(entry); + *bdev = sis->bdev; + + offset = swp_offset(entry); + start_se = sis->curr_swap_extent; + se = start_se; for ( ; ; ) { struct list_head *lh; @@ -1315,12 +1325,14 @@ sector_t map_swap_page(struct swap_info_ sector_t swapdev_block(int swap_type, pgoff_t offset) { struct swap_info_struct *sis; + struct block_device *bdev; if (swap_type >= nr_swapfiles) return 0; sis = swap_info + swap_type; - return (sis->flags & SWP_WRITEOK) ? map_swap_page(sis, offset) : 0; + return (sis->flags & SWP_WRITEOK) ? + map_swap_page(swp_entry(swap_type, offset), &bdev) : 0; } #endif /* CONFIG_HIBERNATION */ @@ -2160,13 +2172,6 @@ int swapcache_prepare(swp_entry_t entry) return __swap_duplicate(entry, SWAP_CACHE); } - -struct swap_info_struct * -get_swap_info_struct(unsigned type) -{ - return &swap_info[type]; -} - /* * swap_lock prevents swap_map being freed. Don't grab an extra * reference on the swaphandle, it doesn't matter if it becomes unused.
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