1 files changed, 6 insertions, 40 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index aafcf3611b31..8c6b3ce38f09 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.
  */
@@ -880,7 +847,7 @@ unsigned int count_swap_pages(int type, int free)
 static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
                 unsigned long addr, swp_entry_t entry, struct page *page)
 {
-        struct mem_cgroup *ptr = NULL;
+        struct mem_cgroup *ptr;
         spinlock_t *ptl;
         pte_t *pte;
         int ret = 1;
@@ -1662,10 +1629,6 @@ 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);
@@ -2088,7 +2051,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 
         p->swap_file = swap_file;
         mapping = swap_file->f_mapping;
-        inode = mapping->host;
 
         for (i = 0; i < nr_swapfiles; i++) {
                 struct swap_info_struct *q = swap_info[i];
@@ -2101,6 +2063,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
                 }
         }
 
+        inode = mapping->host;
+        /* If S_ISREG(inode->i_mode) will do mutex_lock(&inode->i_mutex); */
         error = claim_swapfile(p, inode);
         if (unlikely(error))
                 goto bad_swap;
@@ -2187,8 +2151,10 @@ bad_swap:
         spin_unlock(&swap_lock);
         vfree(swap_map);
         if (swap_file) {
-                if (inode && S_ISREG(inode->i_mode))
+                if (inode && S_ISREG(inode->i_mode)) {
                         mutex_unlock(&inode->i_mutex);
+                        inode = NULL;
+                }
                 filp_close(swap_file, NULL);
         }
 out: