sys_swapon: remove bdev variable

The bdev variable is always equivalent to (S_ISBLK(inode->i_mode) ?
p->bdev : NULL), as long as it being set is moved to a bit earlier. Use
this fact to remove the bdev 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 e4dc949..a314d42 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1893,7 +1893,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 {
        struct swap_info_struct *p;
        char *name;
-       struct block_device *bdev = NULL;
        struct file *swap_file = NULL;
        struct address_space *mapping;
        int i, prev;
@@ -1944,19 +1943,19 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
        }
 
        if (S_ISBLK(inode->i_mode)) {
-               bdev = bdgrab(I_BDEV(inode));
-               error = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL,
+               p->bdev = bdgrab(I_BDEV(inode));
+               error = blkdev_get(p->bdev,
+                                  FMODE_READ | FMODE_WRITE | FMODE_EXCL,
                                   sys_swapon);
                if (error < 0) {
-                       bdev = NULL;
+                       p->bdev = NULL;
                        error = -EINVAL;
                        goto bad_swap;
                }
-               p->old_block_size = block_size(bdev);
-               error = set_blocksize(bdev, PAGE_SIZE);
+               p->old_block_size = block_size(p->bdev);
+               error = set_blocksize(p->bdev, PAGE_SIZE);
                if (error < 0)
                        goto bad_swap;
-               p->bdev = bdev;
                p->flags |= SWP_BLKDEV;
        } else if (S_ISREG(inode->i_mode)) {
                p->bdev = inode->i_sb->s_bdev;
@@ -2140,9 +2139,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
        error = 0;
        goto out;
 bad_swap:
-       if (bdev) {
-               set_blocksize(bdev, p->old_block_size);
-               blkdev_put(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
+       if (S_ISBLK(inode->i_mode) && p->bdev) {
+               set_blocksize(p->bdev, p->old_block_size);
+               blkdev_put(p->bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL);
        }
        destroy_swap_extents(p);
        swap_cgroup_swapoff(p->type);