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dm ioctl: introduce ioctl_flags

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This patch introduces flags for each ioctl function.

So far, one flag is defined, IOCTL_FLAGS_NO_PARAMS.  It is set if the
function processing the ioctl doesn't take or produce any parameters in
the section of the data buffer that has a variable size.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Mikulas Patocka 2013-03-01 22:45:48 +00:00 committed by Alasdair G Kergon
parent 5f01520415
commit e2914cc26b
1 changed files with 37 additions and 19 deletions
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56
drivers/md/dm-ioctl.c
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@ -1478,39 +1478,52 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
return r;
}
/*
* The ioctl parameter block consists of two parts, a dm_ioctl struct
* followed by a data buffer. This flag is set if the second part,
* which has a variable size, is not used by the function processing
* the ioctl.
*/
#define IOCTL_FLAGS_NO_PARAMS 1
/*-----------------------------------------------------------------
* Implementation of open/close/ioctl on the special char
* device.
*---------------------------------------------------------------*/
static ioctl_fn lookup_ioctl(unsigned int cmd)
static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags)
{
static struct {
int cmd;
int flags;
ioctl_fn fn;
} _ioctls[] = {
{DM_VERSION_CMD, NULL}, /* version is dealt with elsewhere */
{DM_REMOVE_ALL_CMD, remove_all},
{DM_LIST_DEVICES_CMD, list_devices},
{DM_VERSION_CMD, 0, NULL}, /* version is dealt with elsewhere */
{DM_REMOVE_ALL_CMD, IOCTL_FLAGS_NO_PARAMS, remove_all},
{DM_LIST_DEVICES_CMD, 0, list_devices},
{DM_DEV_CREATE_CMD, dev_create},
{DM_DEV_REMOVE_CMD, dev_remove},
{DM_DEV_RENAME_CMD, dev_rename},
{DM_DEV_SUSPEND_CMD, dev_suspend},
{DM_DEV_STATUS_CMD, dev_status},
{DM_DEV_WAIT_CMD, dev_wait},
{DM_DEV_CREATE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_create},
{DM_DEV_REMOVE_CMD, IOCTL_FLAGS_NO_PARAMS, dev_remove},
{DM_DEV_RENAME_CMD, 0, dev_rename},
{DM_DEV_SUSPEND_CMD, IOCTL_FLAGS_NO_PARAMS, dev_suspend},
{DM_DEV_STATUS_CMD, IOCTL_FLAGS_NO_PARAMS, dev_status},
{DM_DEV_WAIT_CMD, 0, dev_wait},
{DM_TABLE_LOAD_CMD, table_load},
{DM_TABLE_CLEAR_CMD, table_clear},
{DM_TABLE_DEPS_CMD, table_deps},
{DM_TABLE_STATUS_CMD, table_status},
{DM_TABLE_LOAD_CMD, 0, table_load},
{DM_TABLE_CLEAR_CMD, IOCTL_FLAGS_NO_PARAMS, table_clear},
{DM_TABLE_DEPS_CMD, 0, table_deps},
{DM_TABLE_STATUS_CMD, 0, table_status},
{DM_LIST_VERSIONS_CMD, list_versions},
{DM_LIST_VERSIONS_CMD, 0, list_versions},
{DM_TARGET_MSG_CMD, target_message},
{DM_DEV_SET_GEOMETRY_CMD, dev_set_geometry}
{DM_TARGET_MSG_CMD, 0, target_message},
{DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry}
};
return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
if (unlikely(cmd >= ARRAY_SIZE(_ioctls)))
return NULL;
*ioctl_flags = _ioctls[cmd].flags;
return _ioctls[cmd].fn;
}
/*
@ -1652,6 +1665,7 @@ static int validate_params(uint cmd, struct dm_ioctl *param)
static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
{
int r = 0;
int ioctl_flags;
int param_flags;
unsigned int cmd;
struct dm_ioctl *uninitialized_var(param);
@ -1681,7 +1695,7 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
if (cmd == DM_VERSION_CMD)
return 0;
fn = lookup_ioctl(cmd);
fn = lookup_ioctl(cmd, &ioctl_flags);
if (!fn) {
DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
return -ENOTTY;
@ -1703,6 +1717,10 @@ static int ctl_ioctl(uint command, struct dm_ioctl __user *user)
param->data_size = sizeof(*param);
r = fn(param, input_param_size);
if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&
unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS))
DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd);
/*
* Copy the results back to userland.
*/