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 --- mm/swapfile.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'mm/swapfile.c') diff --git a/mm/swapfile.c b/mm/swapfile.c index 58bec660016..d5eb2e85600 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