Hibernation: Introduce SNAPSHOT_GET_IMAGE_SIZE ioctl

[karo-tx-linux.git] / Documentation / power / userland-swsusp.txt

diff --git a/Documentation/power/userland-swsusp.txt b/Documentation/power/userland-swsusp.txt
index e00c6cf09e85aad17e587f0ac9d19d0a543a4cad..32f1874796979a70a9fa80f05d7dcb5b1c47b727 100644 (file)
--- a/Documentation/power/userland-swsusp.txt
+++ b/Documentation/power/userland-swsusp.txt
@@ -54,6 +54,8 @@ SNAPSHOT_SET_IMAGE_SIZE - set the preferred maximum size of the image
        this number, but if it turns out to be impossible, the kernel will
        create the smallest image possible)
 
+SNAPSHOT_GET_IMAGE_SIZE - return the actual size of the hibernation image
+
 SNAPSHOT_AVAIL_SWAP - return the amount of available swap in bytes (the last
        argument should be a pointer to an unsigned int variable that will
        contain the result if the call is successful).
@@ -136,13 +138,9 @@ required, as they can use, for example, a special (blank) suspend partition or
 a file on a partition that is unmounted before SNAPSHOT_ATOMIC_SNAPSHOT and
 mounted afterwards.
 
-These utilities SHOULD NOT make any assumptions regarding the ordering of
-data within the snapshot image, except for the image header that MAY be
-assumed to start with an swsusp_info structure, as specified in
-kernel/power/power.h.  This structure MAY be used by the userland utilities
-to obtain some information about the snapshot image, such as the size
-of the snapshot image, including the metadata and the header itself,
-contained in the .size member of swsusp_info.
+These utilities MUST NOT make any assumptions regarding the ordering of
+data within the snapshot image.  The contents of the image are entirely owned
+by the kernel and its structure may be changed in future kernel releases.
 
 The snapshot image MUST be written to the kernel unaltered (ie. all of the image
 data, metadata and header MUST be written in _exactly_ the same amount, form