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

[Mika Penttilä]

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


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