Hibernation: Introduce SNAPSHOT_GET_IMAGE_SIZE ioctl

Add a new ioctl, SNAPSHOT_GET_IMAGE_SIZE, returning the size of the (just
created) hibernation image, to the hibernation userland interface.

This ioctl is necessary so that the userland utilities using the interface need
not access the hibernation image header, owned by the kernel, in order to obtain
the size of the image.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 78039b477d2b..c5ce0f34a5d4 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1264,12 +1264,17 @@ static char *check_image_kernel(struct swsusp_info *info)
 }
 #endif /* CONFIG_ARCH_HIBERNATION_HEADER */
 
+unsigned long snapshot_get_image_size(void)
+{
+        return nr_copy_pages + nr_meta_pages + 1;
+}
+
 static int init_header(struct swsusp_info *info)
 {
         memset(info, 0, sizeof(struct swsusp_info));
         info->num_physpages = num_physpages;
         info->image_pages = nr_copy_pages;
-        info->pages = nr_copy_pages + nr_meta_pages + 1;
+        info->pages = snapshot_get_image_size();
         info->size = info->pages;
         info->size <<= PAGE_SHIFT;
         return init_header_complete(info);