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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
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32
drivers/md/dm-ioctl.c
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)))

6
include/uapi/linux/dm-ioctl.h
View File

@ -243,6 +243,7 @@ enum {
DM_TARGET_MSG_CMD,
DM_DEV_SET_GEOMETRY_CMD,
DM_DEV_ARM_POLL_CMD,
DM_GET_TARGET_VERSION_CMD,
};
#define DM_IOCTL 0xfd
@ -265,14 +266,15 @@ enum {
#define DM_TABLE_STATUS _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, struct dm_ioctl)
#define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)
#define DM_GET_TARGET_VERSION _IOWR(DM_IOCTL, DM_GET_TARGET_VERSION_CMD, struct dm_ioctl)
#define DM_TARGET_MSG _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, struct dm_ioctl)
#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 40
#define DM_VERSION_MINOR 41
#define DM_VERSION_PATCHLEVEL 0
#define DM_VERSION_EXTRA "-ioctl (2019-01-18)"
#define DM_VERSION_EXTRA "-ioctl (2019-09-16)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */