PM / sleep: handle the compat case in snapshot_set_swap_area()

Use in_compat_syscall to copy directly from the 32-bit ABI structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/kernel/power/user.c b/kernel/power/user.c
index 0cb555f526e4096724bfbee92784c508b9dc5546..7959449765d9a557822d6932e8471c02daf5653c 100644 (file)
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -196,28 +196,44 @@ unlock:
        return res;
 }
 
+struct compat_resume_swap_area {
+       compat_loff_t offset;
+       u32 dev;
+} __packed;
+
 static int snapshot_set_swap_area(struct snapshot_data *data,
                void __user *argp)
 {
-       struct resume_swap_area swap_area;
        sector_t offset;
        dev_t swdev;
 
        if (swsusp_swap_in_use())
                return -EPERM;
-       if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
-               return -EFAULT;
+
+       if (in_compat_syscall()) {
+               struct compat_resume_swap_area swap_area;
+
+               if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
+                       return -EFAULT;
+               swdev = new_decode_dev(swap_area.dev);
+               offset = swap_area.offset;
+       } else {
+               struct resume_swap_area swap_area;
+
+               if (copy_from_user(&swap_area, argp, sizeof(swap_area)))
+                       return -EFAULT;
+               swdev = new_decode_dev(swap_area.dev);
+               offset = swap_area.offset;
+       }
 
        /*
         * User space encodes device types as two-byte values,
         * so we need to recode them
         */
-       swdev = new_decode_dev(swap_area.dev);
        if (!swdev) {
                data->swap = -1;
                return -EINVAL;
        }
-       offset = swap_area.offset;
        data->swap = swap_type_of(swdev, offset, NULL);
        if (data->swap < 0)
                return -ENODEV;
@@ -394,12 +410,6 @@ static long snapshot_ioctl(struct file *filp, unsigned int cmd,
 }
 
 #ifdef CONFIG_COMPAT
-
-struct compat_resume_swap_area {
-       compat_loff_t offset;
-       u32 dev;
-} __packed;
-
 static long
 snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
@@ -410,33 +420,13 @@ snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
        case SNAPSHOT_AVAIL_SWAP_SIZE:
        case SNAPSHOT_ALLOC_SWAP_PAGE:
        case SNAPSHOT_CREATE_IMAGE:
+       case SNAPSHOT_SET_SWAP_AREA:
                return snapshot_ioctl(file, cmd,
                                      (unsigned long) compat_ptr(arg));
-
-       case SNAPSHOT_SET_SWAP_AREA: {
-               struct compat_resume_swap_area __user *u_swap_area =
-                       compat_ptr(arg);
-               struct resume_swap_area swap_area;
-               mm_segment_t old_fs;
-               int err;
-
-               err = get_user(swap_area.offset, &u_swap_area->offset);
-               err |= get_user(swap_area.dev, &u_swap_area->dev);
-               if (err)
-                       return -EFAULT;
-               old_fs = get_fs();
-               set_fs(KERNEL_DS);
-               err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
-                                    (unsigned long) &swap_area);
-               set_fs(old_fs);
-               return err;
-       }
-
        default:
                return snapshot_ioctl(file, cmd, arg);
        }
 }
-
 #endif /* CONFIG_COMPAT */
 
 static const struct file_operations snapshot_fops = {