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Hibernation: Correct definitions of some ioctls (rev. 2)

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Three ioctl numbers belonging to the hibernation userland interface,
SNAPSHOT_ATOMIC_SNAPSHOT, SNAPSHOT_AVAIL_SWAP, SNAPSHOT_GET_SWAP_PAGE,
are defined in a wrong way (eg. not portable).  Provide new ioctl numbers for
these ioctls and mark the existing ones as deprecated.

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>
This commit is contained in:
Rafael J. Wysocki
2007-10-26 01:03:33 +02:00
committed by Len Brown
parent 96f737490c
commit cc5d207c85
3 changed files with 34 additions and 20 deletions
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26
Documentation/power/userland-swsusp.txt
View File

@@ -27,17 +27,17 @@ once at a time.
The ioctl() commands recognized by the device are:
SNAPSHOT_FREEZE - freeze user space processes (the current process is
not frozen); this is required for SNAPSHOT_ATOMIC_SNAPSHOT
not frozen); this is required for SNAPSHOT_CREATE_IMAGE
and SNAPSHOT_ATOMIC_RESTORE to succeed
SNAPSHOT_UNFREEZE - thaw user space processes frozen by SNAPSHOT_FREEZE
SNAPSHOT_ATOMIC_SNAPSHOT - create a snapshot of the system memory; the
SNAPSHOT_CREATE_IMAGE - create a snapshot of the system memory; the
last argument of ioctl() should be a pointer to an int variable,
the value of which will indicate whether the call returned after
creating the snapshot (1) or after restoring the system memory state
from it (0) (after resume the system finds itself finishing the
SNAPSHOT_ATOMIC_SNAPSHOT ioctl() again); after the snapshot
SNAPSHOT_CREATE_IMAGE ioctl() again); after the snapshot
has been created the read() operation can be used to transfer
it out of the kernel
@@ -49,23 +49,23 @@ SNAPSHOT_ATOMIC_RESTORE - restore the system memory state from the
SNAPSHOT_FREE - free memory allocated for the snapshot image
SNAPSHOT_SET_IMAGE_SIZE - set the preferred maximum size of the image
SNAPSHOT_PREF_IMAGE_SIZE - set the preferred maximum size of the image
(the kernel will do its best to ensure the image size will not exceed
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
SNAPSHOT_AVAIL_SWAP_SIZE - 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).
SNAPSHOT_GET_SWAP_PAGE - allocate a swap page from the resume partition
SNAPSHOT_ALLOC_SWAP_PAGE - allocate a swap page from the resume partition
(the last argument should be a pointer to a loff_t variable that
will contain the swap page offset if the call is successful)
SNAPSHOT_FREE_SWAP_PAGES - free all swap pages allocated with
SNAPSHOT_GET_SWAP_PAGE
SNAPSHOT_FREE_SWAP_PAGES - free all swap pages allocated by
SNAPSHOT_ALLOC_SWAP_PAGE
SNAPSHOT_SET_SWAP_AREA - set the resume partition and the offset (in <PAGE_SIZE>
units) from the beginning of the partition at which the swap header is
@@ -102,7 +102,7 @@ The device's write() operation is used for uploading the system memory snapshot
into the kernel. It has the same limitations as the read() operation.
The release() operation frees all memory allocated for the snapshot image
and all swap pages allocated with SNAPSHOT_GET_SWAP_PAGE (if any).
and all swap pages allocated with SNAPSHOT_ALLOC_SWAP_PAGE (if any).
Thus it is not necessary to use either SNAPSHOT_FREE or
SNAPSHOT_FREE_SWAP_PAGES before closing the device (in fact it will also
unfreeze user space processes frozen by SNAPSHOT_UNFREEZE if they are
@@ -113,7 +113,7 @@ snapshot image from/to the kernel will use a swap parition, called the resume
partition, or a swap file as storage space (if a swap file is used, the resume
partition is the partition that holds this file). However, this is not really
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
a file on a partition that is unmounted before SNAPSHOT_CREATE_IMAGE and
mounted afterwards.
These utilities MUST NOT make any assumptions regarding the ordering of
@@ -135,7 +135,7 @@ means, such as checksums, to ensure the integrity of the snapshot image.
The suspending and resuming utilities MUST lock themselves in memory,
preferrably using mlockall(), before calling SNAPSHOT_FREEZE.
The suspending utility MUST check the value stored by SNAPSHOT_ATOMIC_SNAPSHOT
The suspending utility MUST check the value stored by SNAPSHOT_CREATE_IMAGE
in the memory location pointed to by the last argument of ioctl() and proceed
in accordance with it:
1. If the value is 1 (ie. the system memory snapshot has just been
@@ -149,7 +149,7 @@ in accordance with it:
image has been saved.
(b) The suspending utility SHOULD NOT attempt to perform any
file system operations (including reads) on the file systems
that were mounted before SNAPSHOT_ATOMIC_SNAPSHOT has been
that were mounted before SNAPSHOT_CREATE_IMAGE has been
called. However, it MAY mount a file system that was not
mounted at that time and perform some operations on it (eg.
use it for saving the image).