2 files changed, 44 insertions, 1 deletions

diff --git a/kernel/power/power.h b/kernel/power/power.h
index adaf7d4fbdaf..7dbfd9f67e1c 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -106,6 +106,16 @@ extern int snapshot_write_next(struct snapshot_handle *handle, size_t count);
 extern int snapshot_image_loaded(struct snapshot_handle *handle);
 extern void snapshot_free_unused_memory(struct snapshot_handle *handle);
 
+/*
+ * This structure is used to pass the values needed for the identification
+ * of the resume swap area from a user space to the kernel via the
+ * SNAPSHOT_SET_SWAP_AREA ioctl
+ */
+struct resume_swap_area {
+        loff_t offset;
+        u_int32_t dev;
+} __attribute__((packed));
+
 #define SNAPSHOT_IOC_MAGIC      '3'
 #define SNAPSHOT_FREEZE                 _IO(SNAPSHOT_IOC_MAGIC, 1)
 #define SNAPSHOT_UNFREEZE               _IO(SNAPSHOT_IOC_MAGIC, 2)
@@ -119,7 +129,9 @@ extern void snapshot_free_unused_memory(struct snapshot_handle *handle);
 #define SNAPSHOT_SET_SWAP_FILE          _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)
 #define SNAPSHOT_S2RAM                  _IO(SNAPSHOT_IOC_MAGIC, 11)
 #define SNAPSHOT_PMOPS                  _IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)
-#define SNAPSHOT_IOC_MAXNR      12
+#define SNAPSHOT_SET_SWAP_AREA          _IOW(SNAPSHOT_IOC_MAGIC, 13, \
+                                                        struct resume_swap_area)
+#define SNAPSHOT_IOC_MAXNR      13
 
 #define PMOPS_PREPARE   1
 #define PMOPS_ENTER     2
diff --git a/kernel/power/user.c b/kernel/power/user.c
index f0b7ef8bdd74..05c58a2c0dd4 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -343,6 +343,37 @@ OutS3:
                 }
                 break;
 
+        case SNAPSHOT_SET_SWAP_AREA:
+                if (data->bitmap) {
+                        error = -EPERM;
+                } else {
+                        struct resume_swap_area swap_area;
+                        dev_t swdev;
+
+                        error = copy_from_user(&swap_area, (void __user *)arg,
+                                        sizeof(struct resume_swap_area));
+                        if (error) {
+                                error = -EFAULT;
+                                break;
+                        }
+
+                        /*
+                         * User space encodes device types as two-byte values,
+                         * so we need to recode them
+                         */
+                        swdev = old_decode_dev(swap_area.dev);
+                        if (swdev) {
+                                offset = swap_area.offset;
+                                data->swap = swap_type_of(swdev, offset);
+                                if (data->swap < 0)
+                                        error = -ENODEV;
+                        } else {
+                                data->swap = -1;
+                                error = -EINVAL;
+                        }
+                }
+                break;
+
         default:
                 error = -ENOTTY;