sys_swapoff: change order to match sys_swapon

The block in sys_swapon which does the final adjustments to the
swap_info_struct and to swap_list is the same as the block which
re-inserts it again at sys_swapoff on failure of try_to_unuse(), except
for the order of the operations within the lock. Since the order should
not matter, arbitrarily change sys_swapoff to match sys_swapon, in
preparation to making both share the same code.

Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Tested-by: Eric B Munson <emunson@mgebm.net>
Acked-by: Eric B Munson <emunson@mgebm.net>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/mm/swapfile.c b/mm/swapfile.c
index df3dc7a3c2e2..465d972f4c7c 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1625,6 +1625,10 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
                 spin_lock(&swap_lock);
                 if (p->prio < 0)
                         p->prio = --least_priority;
+                p->flags |= SWP_WRITEOK;
+                nr_swap_pages += p->pages;
+                total_swap_pages += p->pages;
+
                 prev = -1;
                 for (i = swap_list.head; i >= 0; i = swap_info[i]->next) {
                         if (p->prio >= swap_info[i]->prio)
@@ -1636,9 +1640,6 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
                         swap_list.head = swap_list.next = type;
                 else
                         swap_info[prev]->next = type;
-                nr_swap_pages += p->pages;
-                total_swap_pages += p->pages;
-                p->flags |= SWP_WRITEOK;
                 spin_unlock(&swap_lock);
                 goto out_dput;
         }