From afa179eb603847494aa5061d4f501224a30dd187 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Mon, 16 Sep 2019 05:55:42 -0400 Subject: [PATCH] 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 Signed-off-by: Mike Snitzer --- drivers/md/dm-ioctl.c | 32 +++++++++++++++++++++++++++++--- include/uapi/linux/dm-ioctl.h | 6 ++++-- 2 files changed, 33 insertions(+), 5 deletions(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index fb6f8fb1f13d..ac83f5002ce5 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -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))) diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h index f396a82dfd3e..2df8ceca1f9b 100644 --- a/include/uapi/linux/dm-ioctl.h +++ b/include/uapi/linux/dm-ioctl.h @@ -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 */