Re: removable media revalidation - udev vs. devfs or static /dev

Mika Penttilä
2004-01-07T19:19:19Z

Greg KH wrote:

>On Wed, Jan 07, 2004 at 10:38:31AM -0800, Linus Torvalds wrote:
>
>
>>On Fri, 2 Jan 2004, Greg KH wrote:
>>
>>
>>>Doesn't the kernel always create the main block device for this device?
>>>If so, udev will catch that.
>>>
>>>
>>But udev should probably also create all the sub-nodes if it doesn't
>>already.
>>
>>
>
>It doesn't, as I thought we could rely on the kernel partition support.
>
>
>
>>And it really has to create _all_ of them, exactly because there's no way
>>to know ahead-of-time which of them will be available.
>>
>>Then, user space can just access "/dev/sda1" or whatever, and the act of
>>accessing it will force the re-scan.
>>
>>
>
>Hm, that would work, but what about a user program that just polls on
>the device, as the rest of this thread discusses? As removable devices
>are not the "norm" it would seem a bit of overkill to create 16
>partitions for every block device, if they need them or not.
>
>thanks,
>
>greg k-h
>
>
>
Accessing the partition would not cause the rescan (accessing the whole
disk causes.) I think devfs does/did this rescan on access.

--Mika