block: remove per-queue plugging

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 0 insertions, 37 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 07a458d72fa8..7ceea78ceb20 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -95,39 +95,6 @@ __try_to_reclaim_swap(struct swap_info_struct *si, unsigned long offset)
 }
 
 /*
- * We need this because the bdev->unplug_fn can sleep and we cannot
- * hold swap_lock while calling the unplug_fn. And swap_lock
- * cannot be turned into a mutex.
- */
-static DECLARE_RWSEM(swap_unplug_sem);
-
-void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page)
-{
-        swp_entry_t entry;
-
-        down_read(&swap_unplug_sem);
-        entry.val = page_private(page);
-        if (PageSwapCache(page)) {
-                struct block_device *bdev = swap_info[swp_type(entry)]->bdev;
-                struct backing_dev_info *bdi;
-
-                /*
-                 * If the page is removed from swapcache from under us (with a
-                 * racy try_to_unuse/swapoff) we need an additional reference
-                 * count to avoid reading garbage from page_private(page) above.
-                 * If the WARN_ON triggers during a swapoff it maybe the race
-                 * condition and it's harmless. However if it triggers without
-                 * swapoff it signals a problem.
-                 */
-                WARN_ON(page_count(page) <= 1);
-
-                bdi = bdev->bd_inode->i_mapping->backing_dev_info;
-                blk_run_backing_dev(bdi, page);
-        }
-        up_read(&swap_unplug_sem);
-}
-
-/*
  * swapon tell device that all the old swap contents can be discarded,
  * to allow the swap device to optimize its wear-levelling.
  */
@@ -1643,10 +1610,6 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
                 goto out_dput;
         }
 
-        /* wait for any unplug function to finish */
-        down_write(&swap_unplug_sem);
-        up_write(&swap_unplug_sem);
-
         destroy_swap_extents(p);
         if (p->flags & SWP_CONTINUED)
                 free_swap_count_continuations(p);