/**
* blk_alloc_devt - allocate a dev_t for a partition
* @part: partition to allocate dev_t for
* @devt: out parameter for resulting dev_t
*
* Allocate a dev_t for block device.
*
* RETURNS:
* 0 on success, allocated dev_t is returned in *@devt. -errno on
* failure.
*
* CONTEXT:
* Might sleep.
*/
int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
{
struct gendisk *disk = part_to_disk(part);
int idx, rc;
/* in consecutive minor range? */
if (part->partno < disk->minors) {
*devt = MKDEV(disk->major, disk->first_minor + part->partno);
return 0;
}
/* allocate ext devt */
do {
if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL))
return -ENOMEM;
rc = idr_get_new(&ext_devt_idr, part, &idx);
} while (rc == -EAGAIN);
if (rc)
return rc;
if (idx > MAX_EXT_DEVT) {
idr_remove(&ext_devt_idr, idx);
return -EBUSY;
}
*devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
return 0;
}
/**
* devt_from_partuuid - looks up the dev_t of a partition by its UUID
* @uuid: min 36 byte char array containing a hex ascii UUID
*
* The function will return the first partition which contains a matching
* UUID value in its partition_meta_info struct. This does not search
* by filesystem UUIDs.
*
* If @uuid is followed by a "/PARTNROFF=%d", then the number will be
* extracted and used as an offset from the partition identified by the UUID.
*
* Returns the matching dev_t on success or 0 on failure.
*/
static dev_t devt_from_partuuid(char *uuid_str)
{
dev_t res = 0;
struct device *dev = NULL;
u8 uuid[16];
struct gendisk *disk;
struct hd_struct *part;
int offset = 0;
if (strlen(uuid_str) < 36)
goto done;
/* Check for optional partition number offset attributes. */
if (uuid_str[36]) {
char c = 0;
/* Explicitly fail on poor PARTUUID syntax. */
if (sscanf(&uuid_str[36],
"/PARTNROFF=%d%c", &offset, &c) != 1) {
printk(KERN_ERR "VFS: PARTUUID= is invalid.\n"
"Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
if (root_wait)
printk(KERN_ERR
"Disabling rootwait; root= is invalid.\n");
root_wait = 0;
goto done;
}
}
/* Pack the requested UUID in the expected format. */
part_pack_uuid(uuid_str, uuid);
dev = class_find_device(&block_class, NULL, uuid, &match_dev_by_uuid);
if (!dev)
goto done;
res = dev->devt;
/* Attempt to find the partition by offset. */
if (!offset)
goto no_offset;
res = 0;
disk = part_to_disk(dev_to_part(dev));
part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
if (part) {
res = part_devt(part);
put_device(part_to_dev(part));
}
no_offset:
put_device(dev);
done:
return res;
}
/**
* devt_from_partuuid - looks up the dev_t of a partition by its UUID
* @uuid: char array containing ascii UUID
*
* The function will return the first partition which contains a matching
* UUID value in its partition_meta_info struct. This does not search
* by filesystem UUIDs.
*
* If @uuid is followed by a "/PARTNROFF=%d", then the number will be
* extracted and used as an offset from the partition identified by the UUID.
*
* Returns the matching dev_t on success or 0 on failure.
*/
static dev_t devt_from_partuuid(const char *uuid_str)
{
dev_t res = 0;
struct uuidcmp cmp;
struct device *dev = NULL;
struct gendisk *disk;
struct hd_struct *part;
int offset = 0;
bool clear_root_wait = false;
char *slash;
cmp.uuid = uuid_str;
slash = strchr(uuid_str, '/');
/* Check for optional partition number offset attributes. */
if (slash) {
char c = 0;
/* Explicitly fail on poor PARTUUID syntax. */
if (sscanf(slash + 1,
"PARTNROFF=%d%c", &offset, &c) != 1) {
clear_root_wait = true;
goto done;
}
cmp.len = slash - uuid_str;
} else {
cmp.len = strlen(uuid_str);
}
if (!cmp.len) {
clear_root_wait = true;
goto done;
}
dev = class_find_device(&block_class, NULL, &cmp,
&match_dev_by_uuid);
if (!dev)
goto done;
res = dev->devt;
/* Attempt to find the partition by offset. */
if (!offset)
goto no_offset;
res = 0;
disk = part_to_disk(dev_to_part(dev));
part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
if (part) {
res = part_devt(part);
put_device(part_to_dev(part));
}
no_offset:
put_device(dev);
done:
if (clear_root_wait) {
pr_err("VFS: PARTUUID= is invalid.\n"
"Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
if (root_wait)
pr_err("Disabling rootwait; root= is invalid.\n");
root_wait = 0;
}
return res;
}
