[PATCH -mm 4/5] Hibernation: Correct definitions of some ioctls (rev. 2)

Rafael J. Wysocki
2007-09-09T21:12:52Z

Three ioctl numbers belonging to the hibernation userland interface,
SNAPSHOT_ATOMIC_SNAPSHOT, SNAPSHOT_SET_IMAGE_SIZE, 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>
---
Documentation/power/userland-swsusp.txt | 26 +++++++++++++-------------
kernel/power/power.h | 10 +++++-----
kernel/power/user.c | 18 ++++++++++++++++--
3 files changed, 34 insertions(+), 20 deletions(-)

Index: linux-2.6.23-rc5/kernel/power/power.h
===================================================================
--- linux-2.6.23-rc5.orig/kernel/power/power.h 2007-09-09 22:30:36.000000000 +0200
+++ linux-2.6.23-rc5/kernel/power/power.h 2007-09-09 22:36:10.000000000 +0200
@@ -149,12 +149,8 @@ struct resume_swap_area {
#define SNAPSHOT_IOC_MAGIC '3'
#define SNAPSHOT_FREEZE _IO(SNAPSHOT_IOC_MAGIC, 1)
#define SNAPSHOT_UNFREEZE _IO(SNAPSHOT_IOC_MAGIC, 2)
-#define SNAPSHOT_ATOMIC_SNAPSHOT _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
#define SNAPSHOT_ATOMIC_RESTORE _IO(SNAPSHOT_IOC_MAGIC, 4)
#define SNAPSHOT_FREE _IO(SNAPSHOT_IOC_MAGIC, 5)
-#define SNAPSHOT_SET_IMAGE_SIZE _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
-#define SNAPSHOT_AVAIL_SWAP _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
-#define SNAPSHOT_GET_SWAP_PAGE _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
#define SNAPSHOT_FREE_SWAP_PAGES _IO(SNAPSHOT_IOC_MAGIC, 9)
#define SNAPSHOT_S2RAM _IO(SNAPSHOT_IOC_MAGIC, 11)
#define SNAPSHOT_SET_SWAP_AREA _IOW(SNAPSHOT_IOC_MAGIC, 13, \
@@ -162,7 +158,11 @@ struct resume_swap_area {
#define SNAPSHOT_GET_IMAGE_SIZE _IOR(SNAPSHOT_IOC_MAGIC, 14, loff_t)
#define SNAPSHOT_PLATFORM_SUPPORT _IO(SNAPSHOT_IOC_MAGIC, 15)
#define SNAPSHOT_POWER_OFF _IO(SNAPSHOT_IOC_MAGIC, 16)
-#define SNAPSHOT_IOC_MAXNR 16
+#define SNAPSHOT_CREATE_IMAGE _IOW(SNAPSHOT_IOC_MAGIC, 17, int)
+#define SNAPSHOT_PREF_IMAGE_SIZE _IO(SNAPSHOT_IOC_MAGIC, 18)
+#define SNAPSHOT_AVAIL_SWAP_SIZE _IOR(SNAPSHOT_IOC_MAGIC, 19, loff_t)
+#define SNAPSHOT_ALLOC_SWAP_PAGE _IOR(SNAPSHOT_IOC_MAGIC, 20, loff_t)
+#define SNAPSHOT_IOC_MAXNR 20

/* If unset, the snapshot device cannot be open. */
extern atomic_t snapshot_device_available;
Index: linux-2.6.23-rc5/kernel/power/user.c
===================================================================
--- linux-2.6.23-rc5.orig/kernel/power/user.c 2007-09-09 22:30:36.000000000 +0200
+++ linux-2.6.23-rc5/kernel/power/user.c 2007-09-09 22:37:11.000000000 +0200
@@ -40,6 +40,16 @@
#define PMOPS_ENTER 2
#define PMOPS_FINISH 3

+/*
+ * NOTE: The following ioctl definitions are wrong and have been replaced with
+ * correct ones. They are only preserved here for compatibility with existing
+ * userland utilities and will be removed in the future.
+ */
+#define SNAPSHOT_ATOMIC_SNAPSHOT _IOW(SNAPSHOT_IOC_MAGIC, 3, void *)
+#define SNAPSHOT_SET_IMAGE_SIZE _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long)
+#define SNAPSHOT_AVAIL_SWAP _IOR(SNAPSHOT_IOC_MAGIC, 7, void *)
+#define SNAPSHOT_GET_SWAP_PAGE _IOR(SNAPSHOT_IOC_MAGIC, 8, void *)
+

#define SNAPSHOT_MINOR 231

@@ -191,6 +201,7 @@ static int snapshot_ioctl(struct inode *
data->frozen = 0;
break;

+ case SNAPSHOT_CREATE_IMAGE:
case SNAPSHOT_ATOMIC_SNAPSHOT:
if (data->mode != O_RDONLY || !data->frozen || data->ready) {
error = -EPERM;
@@ -198,7 +209,7 @@ static int snapshot_ioctl(struct inode *
}
error = hibernation_snapshot(data->platform_support);
if (!error)
- error = put_user(in_suspend, (unsigned int __user *)arg);
+ error = put_user(in_suspend, (int __user *)arg);
if (!error)
data->ready = 1;
break;
@@ -219,6 +230,7 @@ static int snapshot_ioctl(struct inode *
data->ready = 0;
break;

+ case SNAPSHOT_PREF_IMAGE_SIZE:
case SNAPSHOT_SET_IMAGE_SIZE:
image_size = arg;
break;
@@ -233,12 +245,14 @@ static int snapshot_ioctl(struct inode *
error = put_user(size, (loff_t __user *)arg);
break;

+ case SNAPSHOT_AVAIL_SWAP_SIZE:
case SNAPSHOT_AVAIL_SWAP:
size = count_swap_pages(data->swap, 1);
size <<= PAGE_SHIFT;
error = put_user(size, (loff_t __user *)arg);
break;

+ case SNAPSHOT_ALLOC_SWAP_PAGE:
case SNAPSHOT_GET_SWAP_PAGE:
if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
error = -ENODEV;
@@ -247,7 +261,7 @@ static int snapshot_ioctl(struct inode *
offset = alloc_swapdev_block(data->swap);
if (offset) {
offset <<= PAGE_SHIFT;
- error = put_user(offset, (sector_t __user *)arg);
+ error = put_user(offset, (loff_t __user *)arg);
} else {
error = -ENOSPC;
}
Index: linux-2.6.23-rc5/Documentation/power/userland-swsusp.txt
===================================================================
--- linux-2.6.23-rc5.orig/Documentation/power/userland-swsusp.txt 2007-09-09 22:32:45.000000000 +0200
+++ linux-2.6.23-rc5/Documentation/power/userland-swsusp.txt 2007-09-09 22:38:02.000000000 +0200
@@ -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 sy

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 f
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 u
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
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).