On Tue, Apr 28, 2009 at 23:16, Milan Broz <mbroz@xxxxxxxxxx> wrote: > Kay Sievers wrote: >> On Tue, Apr 28, 2009 at 20:45, Alasdair G Kergon <agk@xxxxxxxxxx> wrote: >>> The /dev/dm-* devices have been a support headache for us. I don't know >>> how they first sneaked into some distros but I maintain that dm-* are >>> internal kernel names only of use for debugging purposes and the average >>> sysadmin should never have to encounter them. If I had my way they >>> would never have become visible to userspace. (Unfortunately the size >>> restriction on the field prevents us from replacing them with our >>> preferred names within the kernel, unless that's changed since >>> I last looked.) >> >> There is no size limit anymore. > > I think that limit comes from 16 chars for block device name > in register_blkdev() in kernel. > And also DISK_NAME_LEN is 32 (for genhd->disk_name, used by bdevname())... Ah, I see. The driver core used to have a limit of 20 chars, this has gone recently. Removing the entire copy of the device name in genhd should be easy, if that helps here. The name is in the kobject, and does not need to be copied to a static array in the same structure. Kobjects do not have any limit anymore. > (The dm device name has limit 128. How to set internal kernel name > to properly to match dm name?) Don't know, the name is probably not the right thing, because it can be changed, The uuid might fit better. > (And DM device name is already in /sys/block/<dm-X>/dm/name, > udev rules can use that value for symlink, no timing problem here.) Right, udev calls dmsetup since long to get this name and to create these links. Kay -- To unsubscribe from this list: send the line "unsubscribe linux-hotplug" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
