[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>

2 files changed, 9 insertions, 7 deletions

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index f133d4a6d817..3581f8f86acd 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -165,14 +165,15 @@ static int swsusp_swap_check(void) /* This is called before saving image */
 {
         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)
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 89443b85163b..f7b7a785a5c6 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -57,7 +57,7 @@ static int snapshot_open(struct inode *inode, struct file *filp)
         memset(&data->handle, 0, sizeof(struct snapshot_handle));
         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
                 data->swap = swsusp_resume_device ?
-                                swap_type_of(swsusp_resume_device, 0) : -1;
+                        swap_type_of(swsusp_resume_device, 0, NULL) : -1;
                 data->mode = O_RDONLY;
         } else {
                 data->swap = -1;
@@ -268,7 +268,8 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                          * so we need to recode them
                          */
                         if (old_decode_dev(arg)) {
-                                data->swap = swap_type_of(old_decode_dev(arg), 0);
+                                data->swap = swap_type_of(old_decode_dev(arg),
+                                                        0, NULL);
                                 if (data->swap < 0)
                                         error = -ENODEV;
                         } else {
@@ -365,7 +366,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp,
                         swdev = old_decode_dev(swap_area.dev);
                         if (swdev) {
                                 offset = swap_area.offset;
-                                data->swap = swap_type_of(swdev, offset);
+                                data->swap = swap_type_of(swdev, offset, NULL);
                                 if (data->swap < 0)
                                         error = -ENODEV;
                         } else {