dm ioctl: optimize functions without variable params
Device-mapper ioctls receive and send data in a buffer supplied
by userspace. The buffer has two parts. The first part contains
a 'struct dm_ioctl' and has a fixed size. The second part depends
on the ioctl and has a variable size.
This patch recognises the specific ioctls that do not use the variable
part of the buffer and skips allocating memory for it.
In particular, when a device is suspended and a resume ioctl is sent,
this now avoid memory allocation completely.
The variable "struct dm_ioctl tmp" is moved from the function
copy_params to its caller ctl_ioctl and renamed to param_kernel.
It is used directly when the ioctl function doesn't need any arguments.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h
index 539b179..b8a6bdd 100644
--- a/include/uapi/linux/dm-ioctl.h
+++ b/include/uapi/linux/dm-ioctl.h
@@ -267,9 +267,9 @@
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
#define DM_VERSION_MAJOR 4
-#define DM_VERSION_MINOR 23
-#define DM_VERSION_PATCHLEVEL 1
-#define DM_VERSION_EXTRA "-ioctl (2012-12-18)"
+#define DM_VERSION_MINOR 24
+#define DM_VERSION_PATCHLEVEL 0
+#define DM_VERSION_EXTRA "-ioctl (2013-01-15)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */