4 files changed, 31 insertions, 16 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 89f8a39773bf..d51e35e4e168 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -247,7 +247,7 @@ extern int swap_duplicate(swp_entry_t);
 extern int valid_swaphandles(swp_entry_t, unsigned long *);
 extern void swap_free(swp_entry_t);
 extern void free_swap_and_cache(swp_entry_t);
-extern int swap_type_of(dev_t);
+extern int swap_type_of(dev_t, sector_t);
 extern unsigned int count_swap_pages(int, int);
 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
 extern struct swap_info_struct *get_swap_info_struct(unsigned);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 1a3b0dd2c3fc..7b10da16389e 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -74,7 +74,7 @@ static int mark_swapfiles(swp_entry_t start)
 
 static int swsusp_swap_check(void) /* This is called before saving image */
 {
-        int res = swap_type_of(swsusp_resume_device);
+        int res = swap_type_of(swsusp_resume_device, 0);
 
         if (res >= 0) {
                 root_swap = res;
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 4c24ca5d62e3..a327b18a5ffd 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -55,7 +55,8 @@ static int snapshot_open(struct inode *inode, struct file *filp)
         filp->private_data = data;
         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) : -1;
+                data->swap = swsusp_resume_device ?
+                                swap_type_of(swsusp_resume_device, 0) : -1;
                 data->mode = O_RDONLY;
         } else {
                 data->swap = -1;
@@ -265,7 +266,7 @@ 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));
+                                data->swap = swap_type_of(old_decode_dev(arg), 0);
                                 if (data->swap < 0)
                                         error = -ENODEV;
                         } else {
diff --git a/mm/swapfile.c b/mm/swapfile.c
index f315131db006..2bfacbac0f4c 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -427,34 +427,48 @@ void free_swap_and_cache(swp_entry_t entry)
 
 #ifdef CONFIG_SOFTWARE_SUSPEND
 /*
- * Find the swap type that corresponds to given device (if any)
+ * Find the swap type that corresponds to given device (if any).
  *
- * This is needed for software suspend and is done in such a way that inode
- * aliasing is allowed.
+ * @offset - number of the PAGE_SIZE-sized block of the device, starting
+ * from 0, in which the swap header is expected to be located.
+ *
+ * This is needed for the suspend to disk (aka swsusp).
  */
-int swap_type_of(dev_t device)
+int swap_type_of(dev_t device, sector_t offset)
 {
+        struct block_device *bdev = NULL;
         int i;
 
+        if (device)
+                bdev = bdget(device);
+
         spin_lock(&swap_lock);
         for (i = 0; i < nr_swapfiles; i++) {
-                struct inode *inode;
+                struct swap_info_struct *sis = swap_info + i;
 
-                if (!(swap_info[i].flags & SWP_WRITEOK))
+                if (!(sis->flags & SWP_WRITEOK))
                         continue;
 
-                if (!device) {
+                if (!bdev) {
                         spin_unlock(&swap_lock);
                         return i;
                 }
-                inode = swap_info[i].swap_file->f_dentry->d_inode;
-                if (S_ISBLK(inode->i_mode) &&
-                    device == MKDEV(imajor(inode), iminor(inode))) {
-                        spin_unlock(&swap_lock);
-                        return i;
+                if (bdev == sis->bdev) {
+                        struct swap_extent *se;
+
+                        se = list_entry(sis->extent_list.next,
+                                        struct swap_extent, list);
+                        if (se->start_block == offset) {
+                                spin_unlock(&swap_lock);
+                                bdput(bdev);
+                                return i;
+                        }
                 }
         }
         spin_unlock(&swap_lock);
+        if (bdev)
+                bdput(bdev);
+
         return -ENODEV;
 }