dm: introduce DM_GET_TARGET_VERSION

This commit introduces a new ioctl DM_GET_TARGET_VERSION. It will load a
target that is specified in the "name" entry in the parameter structure
and return its version.

This functionality is intended to be used by cryptsetup, so that it can
query kernel capabilities before activating the device.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka
2019-09-16 05:55:42 -04:00
committed by Mike Snitzer
parent 6e913b28cd
commit afa179eb60
2 changed files with 33 additions and 5 deletions

View File

@@ -601,17 +601,27 @@ static void list_version_get_info(struct target_type *tt, void *param)
info->vers = align_ptr(((void *) ++info->vers) + strlen(tt->name) + 1);
}
static int list_versions(struct file *filp, struct dm_ioctl *param, size_t param_size)
static int __list_versions(struct dm_ioctl *param, size_t param_size, const char *name)
{
size_t len, needed = 0;
struct dm_target_versions *vers;
struct vers_iter iter_info;
struct target_type *tt = NULL;
if (name) {
tt = dm_get_target_type(name);
if (!tt)
return -EINVAL;
}
/*
* Loop through all the devices working out how much
* space we need.
*/
dm_target_iterate(list_version_get_needed, &needed);
if (!tt)
dm_target_iterate(list_version_get_needed, &needed);
else
list_version_get_needed(tt, &needed);
/*
* Grab our output buffer.
@@ -632,13 +642,28 @@ static int list_versions(struct file *filp, struct dm_ioctl *param, size_t param
/*
* Now loop through filling out the names & versions.
*/
dm_target_iterate(list_version_get_info, &iter_info);
if (!tt)
dm_target_iterate(list_version_get_info, &iter_info);
else
list_version_get_info(tt, &iter_info);
param->flags |= iter_info.flags;
out:
if (tt)
dm_put_target_type(tt);
return 0;
}
static int list_versions(struct file *filp, struct dm_ioctl *param, size_t param_size)
{
return __list_versions(param, param_size, NULL);
}
static int get_target_version(struct file *filp, struct dm_ioctl *param, size_t param_size)
{
return __list_versions(param, param_size, param->name);
}
static int check_name(const char *name)
{
if (strchr(name, '/')) {
@@ -1664,6 +1689,7 @@ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags)
{DM_TARGET_MSG_CMD, 0, target_message},
{DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry},
{DM_DEV_ARM_POLL, IOCTL_FLAGS_NO_PARAMS, dev_arm_poll},
{DM_GET_TARGET_VERSION, 0, get_target_version},
};
if (unlikely(cmd >= ARRAY_SIZE(_ioctls)))