From: "Rafael J. Wysocki" <rjw@sisk.pl>

Restore the compatibility with the older code and make it possible to
suspend if the kernel command line doesn't contain the "resume=" argument.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 kernel/power/user.c |   13 +++++++++----
 mm/swapfile.c       |    6 ++++--
 2 files changed, 13 insertions(+), 6 deletions(-)

diff -puN kernel/power/user.c~swsusp-userland-interface-fix-breakage-with-swap-on-lvm kernel/power/user.c
--- devel/kernel/power/user.c~swsusp-userland-interface-fix-breakage-with-swap-on-lvm	2006-02-18 15:37:38.000000000 -0800
+++ devel-akpm/kernel/power/user.c	2006-02-18 15:37:38.000000000 -0800
@@ -51,7 +51,7 @@ static int snapshot_open(struct inode *i
 	filp->private_data = data;
 	memset(&data->handle, 0, sizeof(struct snapshot_handle));
 	if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
-		data->swap = swap_type_of(swsusp_resume_device);
+		data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : -1;
 		data->mode = O_RDONLY;
 	} else {
 		data->swap = -1;
@@ -256,9 +256,14 @@ static int snapshot_ioctl(struct inode *
 			 * User space encodes device types as two-byte values,
 			 * so we need to recode them
 			 */
-			data->swap = swap_type_of(old_decode_dev(arg));
-			if (data->swap < 0)
-				error = -ENODEV;
+			if (old_decode_dev(arg)) {
+				data->swap = swap_type_of(old_decode_dev(arg));
+				if (data->swap < 0)
+					error = -ENODEV;
+			} else {
+				data->swap = -1;
+				error = -EINVAL;
+			}
 		} else {
 			error = -EPERM;
 		}
diff -puN mm/swapfile.c~swsusp-userland-interface-fix-breakage-with-swap-on-lvm mm/swapfile.c
--- devel/mm/swapfile.c~swsusp-userland-interface-fix-breakage-with-swap-on-lvm	2006-02-18 15:37:38.000000000 -0800
+++ devel-akpm/mm/swapfile.c	2006-02-18 15:37:38.000000000 -0800
@@ -428,14 +428,16 @@ int swap_type_of(dev_t device)
 {
 	int i;
 
-	if (!device)
-		return -EINVAL;
 	spin_lock(&swap_lock);
 	for (i = 0; i < nr_swapfiles; i++) {
 		struct inode *inode;
 
 		if (!(swap_info[i].flags & SWP_WRITEOK))
 			continue;
+		if (!device) {
+			spin_unlock(&swap_lock);
+			return i;
+		}
 		inode = swap_info->swap_file->f_dentry->d_inode;
 		if (S_ISBLK(inode->i_mode) &&
 		    device == MKDEV(imajor(inode), iminor(inode))) {
_