mm: remove get_swap_bio

Just reuse the block_device and sector from the swap_info structure,
just as used by the SWP_SYNCHRONOUS path.  Also remove the checks for
NULL returns from bio_alloc as that can't happen for sleeping
allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 596bc2f..3f1f7ae 100644 (file)
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -468,7 +468,6 @@ extern int free_swap_and_cache(swp_entry_t);
 int swap_type_of(dev_t device, sector_t offset);
 int find_first_swap(dev_t *device);
 extern unsigned int count_swap_pages(int, int);
-extern sector_t map_swap_page(struct page *, struct block_device **);
 extern sector_t swapdev_block(int, pgoff_t);
 extern int page_swapcount(struct page *);
 extern int __swap_count(swp_entry_t entry);

diff --git a/mm/page_io.c b/mm/page_io.c
index a75f354..92f7941 100644 (file)
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -26,25 +26,6 @@
 #include <linux/uio.h>
 #include <linux/sched/task.h>
 
-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 block_device *bdev;
-
-               bio->bi_iter.bi_sector = map_swap_page(page, &bdev);
-               bio_set_dev(bio, bdev);
-               bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9;
-               bio->bi_end_io = end_io;
-
-               bio_add_page(bio, page, thp_size(page), 0);
-       }
-       return bio;
-}
-
 void end_swap_bio_write(struct bio *bio)
 {
        struct page *page = bio_first_page_all(bio);
@@ -361,13 +342,13 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
                return 0;
        }
 
-       bio = get_swap_bio(GFP_NOIO, page, end_write_func);
-       if (bio == NULL) {
-               set_page_dirty(page);
-               unlock_page(page);
-               return -ENOMEM;
-       }
+       bio = bio_alloc(GFP_NOIO, 1);
+       bio_set_dev(bio, sis->bdev);
+       bio->bi_iter.bi_sector = swap_page_sector(page);
        bio->bi_opf = REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc);
+       bio->bi_end_io = end_write_func;
+       bio_add_page(bio, page, thp_size(page), 0);
+
        bio_associate_blkg_from_page(bio, page);
        count_swpout_vm_event(page);
        set_page_writeback(page);
@@ -427,18 +408,18 @@ int swap_readpage(struct page *page, bool synchronous)
        }
 
        ret = 0;
-       bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
-       if (bio == NULL) {
-               unlock_page(page);
-               ret = -ENOMEM;
-               goto out;
-       }
+       bio = bio_alloc(GFP_KERNEL, 1);
+       bio_set_dev(bio, sis->bdev);
+       bio->bi_opf = REQ_OP_READ;
+       bio->bi_iter.bi_sector = swap_page_sector(page);
+       bio->bi_end_io = end_swap_bio_read;
+       bio_add_page(bio, page, thp_size(page), 0);
+
        disk = bio->bi_bdev->bd_disk;
        /*
         * Keep this task valid during swap readpage because the oom killer may
         * attempt to access it in the page fault retry time check.
         */
-       bio_set_op_attrs(bio, REQ_OP_READ, 0);
        if (synchronous) {
                bio->bi_opf |= REQ_HIPRI;
                get_task_struct(current);

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 9fffc5a..bfa9e8b 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2301,16 +2301,6 @@ static sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev)
        return se->start_block + (offset - se->start_page);
 }
 
-/*
- * 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
  */