[PATCH] swsusp: Do not fail if resume device is not set

In the kernels later than 2.6.19 there is a regression that makes swsusp
fail if the resume device is not explicitly specified.

It can be fixed by adding an additional parameter to
mm/swapfile.c:swap_type_of() allowing us to pass the (struct block_device
*) corresponding to the first available swap back to the caller.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index f133d4a..3581f8f 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -165,14 +165,15 @@
 {
 	int res;
 
-	res = swap_type_of(swsusp_resume_device, swsusp_resume_block);
+	res = swap_type_of(swsusp_resume_device, swsusp_resume_block,
+			&resume_bdev);
 	if (res < 0)
 		return res;
 
 	root_swap = res;
-	resume_bdev = open_by_devnum(swsusp_resume_device, FMODE_WRITE);
-	if (IS_ERR(resume_bdev))
-		return PTR_ERR(resume_bdev);
+	res = blkdev_get(resume_bdev, FMODE_WRITE, O_RDWR);
+	if (res)
+		return res;
 
 	res = set_blocksize(resume_bdev, PAGE_SIZE);
 	if (res < 0)