Re: [PATCH] MMC block removable flag

[Russell King <rmk+lkml@arm.linux.org.uk>]

On Thu, Dec 30, 2004 at 04:56:45PM +0100, Pierre Ossman wrote:
> Russell King wrote:
> >On Thu, Dec 30, 2004 at 03:14:07AM +0100, Pierre Ossman wrote:
> >>A MMC card is a highly removable device. This patch makes the block 
> >>layer part of the MMC layer set the removable flag.
> >
> >I have this patch also floating around, but I've decided it isn't needed.
> >I believe this flag is to indicate that we have removable media for a
> >block device rather than to indicate that the block device can be removed.
> >
> >However, when we insert and remove a MMC card, we create and destroy the
> >block device itself.  Therefore, as far as the block layer is concerned,
> >the device itself is being inserted and removed, so telling the block
> >layer that the media is removable is just silly - you can't separate the
> >flash media from the on-board MMC controller.
> >
> >(Note: any block device can be removed - you just rmmod the module
> >supplying the block device driver, but this doesn't mean we mark all
> >block devices with GENHD_FL_REMOVABLE.)
>
> I suspect that the removable flag might be used in different GUI:s to 
> figure out with block devices should be presented to the user in a nice 
> way. It's usually just the removable devices that need some form of 
> special handling. So even though, as you point out, the entire device 
> disappears it might be useful from a user interface perspective to have 
> this hint set. From what I've found this flag doesn't seem to change any 
> handling inside the kernel, just how the device should be perceived.

Can anyone comment on the purpose of this (GENHD_FL_REMOVABLE) flag?
Al?  Jens?

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                 2.6 Serial core