Re: [Xen-devel] [PATCH 3 of 5] blkif.h: Add definitions for virtual block device major numbers

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2012-02-09 at 16:52 +0000, Ian Jackson wrote:
> Justin T. Gibbs writes ("Re: [Xen-devel] [PATCH 3 of 5] blkif.h: Add 
> definitions for virtual block device major numbers"):
> > The upstreamed Linux driver supports 15 SCSI major numbers.
> > Are 13 of these the "deprecated high-numbered" ones, or were
> > there more than 15 at some point?
> 
> My understanding was that current upstream Linux does not ever "steal"
> scsi major numbers for xen vbds.  If this is wrong then so is my
> document :-).

Looks like it understands the SCSI/IDE major numbers but translates them
to the xvd major since:
        commit c80a420995e721099906607b07c09a24543b31d9
        Author: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
        Date:   Thu Dec 2 17:55:00 2010 +0000
        
            xen-blkfront: handle Xen major numbers other than XENVBD
            
            This patch makes sure blkfront handles correctly virtual device 
numbers
            corresponding to Xen emulated IDE and SCSI disks: in those cases
            blkfront translates the major number to XENVBD and the minor number 
to a
            low xvd minor.
            
            Note: this behaviour is different from what old xenlinux PV guests 
used
            to do: they used to steal an IDE or SCSI major number and use it
            instead.
            
            Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
            Acked-by: Jeremy Fitzhardinge <jeremy@xxxxxxxx>

Ian.



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel