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-rw-r--r--mm/swapfile.c37
1 files changed, 0 insertions, 37 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 07a458d72fa..7ceea78ceb2 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)
95} 95}
96 96
97/* 97/*
98 * We need this because the bdev->unplug_fn can sleep and we cannot
99 * hold swap_lock while calling the unplug_fn. And swap_lock
100 * cannot be turned into a mutex.
101 */
102static DECLARE_RWSEM(swap_unplug_sem);
103
104void swap_unplug_io_fn(struct backing_dev_info *unused_bdi, struct page *page)
105{
106 swp_entry_t entry;
107
108 down_read(&swap_unplug_sem);
109 entry.val = page_private(page);
110 if (PageSwapCache(page)) {
111 struct block_device *bdev = swap_info[swp_type(entry)]->bdev;
112 struct backing_dev_info *bdi;
113
114 /*
115 * If the page is removed from swapcache from under us (with a
116 * racy try_to_unuse/swapoff) we need an additional reference
117 * count to avoid reading garbage from page_private(page) above.
118 * If the WARN_ON triggers during a swapoff it maybe the race
119 * condition and it's harmless. However if it triggers without
120 * swapoff it signals a problem.
121 */
122 WARN_ON(page_count(page) <= 1);
123
124 bdi = bdev->bd_inode->i_mapping->backing_dev_info;
125 blk_run_backing_dev(bdi, page);
126 }
127 up_read(&swap_unplug_sem);
128}
129
130/*
131 * swapon tell device that all the old swap contents can be discarded, 98 * swapon tell device that all the old swap contents can be discarded,
132 * to allow the swap device to optimize its wear-levelling. 99 * to allow the swap device to optimize its wear-levelling.
133 */ 100 */
@@ -1643,10 +1610,6 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
1643 goto out_dput; 1610 goto out_dput;
1644 } 1611 }
1645 1612
1646 /* wait for any unplug function to finish */
1647 down_write(&swap_unplug_sem);
1648 up_write(&swap_unplug_sem);
1649
1650 destroy_swap_extents(p); 1613 destroy_swap_extents(p);
1651 if (p->flags & SWP_CONTINUED) 1614 if (p->flags & SWP_CONTINUED)
1652 free_swap_count_continuations(p); 1615 free_swap_count_continuations(p);