sys_swapon: remove did_down variable

Since mutex_lock(&inode->i_mutex) is called just after setting inode,
did_down is always equivalent to (inode && S_ISREG(inode->i_mode)).

Use this fact to remove the did_down variable.

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: 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>

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 6f25ece88c4ac0e7191d159200ac6fdb876921f8..b261e55e0b82cfbb5bdacc3f2e08e64e9d1193f3 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1907,7 +1907,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
        unsigned char *swap_map = NULL;
        struct page *page = NULL;
        struct inode *inode = NULL;
-       int did_down = 0;
 
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
@@ -1962,7 +1961,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
        } else if (S_ISREG(inode->i_mode)) {
                p->bdev = inode->i_sb->s_bdev;
                mutex_lock(&inode->i_mutex);
-               did_down = 1;
                if (IS_SWAPFILE(inode)) {
                        error = -EBUSY;
                        goto bad_swap;
@@ -2154,10 +2152,8 @@ bad_swap_2:
        spin_unlock(&swap_lock);
        vfree(swap_map);
        if (swap_file) {
-               if (did_down) {
+               if (inode && S_ISREG(inode->i_mode))
                        mutex_unlock(&inode->i_mutex);
-                       did_down = 0;
-               }
                filp_close(swap_file, NULL);
        }
 out:
@@ -2167,7 +2163,7 @@ out:
        }
        if (name)
                putname(name);
-       if (did_down) {
+       if (inode && S_ISREG(inode->i_mode)) {
                if (!error)
                        inode->i_flags |= S_SWAPFILE;
                mutex_unlock(&inode->i_mutex);