2 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 6690e8bae7bb..413284a51ccc 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1287,6 +1287,8 @@ struct block_device_operations {
                                                 unsigned long long);
         int (*revalidate_disk) (struct gendisk *);
         int (*getgeo)(struct block_device *, struct hd_geometry *);
+        /* this callback is with swap_lock and sometimes page table lock held */
+        void (*swap_slot_free_notify) (struct block_device *, unsigned long);
         struct module *owner;
 };
 
diff --git a/mm/swapfile.c b/mm/swapfile.c
index ecb069e213d0..f5ccc476aa51 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -574,6 +574,7 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
 
         /* free if no reference */
         if (!usage) {
+                struct gendisk *disk = p->bdev->bd_disk;
                 if (offset < p->lowest_bit)
                         p->lowest_bit = offset;
                 if (offset > p->highest_bit)
@@ -583,6 +584,9 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
                         swap_list.next = p->type;
                 nr_swap_pages++;
                 p->inuse_pages--;
+                if ((p->flags & SWP_BLKDEV) &&
+                                disk->fops->swap_slot_free_notify)
+                        disk->fops->swap_slot_free_notify(p->bdev, offset);
         }
 
         return usage;