Am Mittwoch, 16. Januar 2008 16:58:51 schrieb Alan Stern:
> On Wed, 16 Jan 2008, Oliver Neukum wrote:
>
> > > This entire issue needs more thought. There must be plenty of ioctl
> > > calls which shouldn't force a device to remain resumed.
> >
> > Sure. The question is whether it is worth a lot of effort to filter them.
> > Are ioctl()s on block devices common?
>
> I have no idea. My guess is that they are not, other than for devices
> not holding filesystems (e.g., audio CDs).
Do any of them use sd? If not I am happy with a working patch and
refining it later.
> > > Also, your implementation in terms of a single bit will work only for
> > > single-open devices. If multiple-open is allowed then something would
> > > have to be stored in the file structure. More generic code...
> >
> > Why? I don't think you can assume that a user intends an ioctl() to be
> > "valid" only for the duration of that particular file. I intentionally put
> > the
> > put into release which is called for the last close().
>
> The only scenario where this would matter is when there are two
> overlapping open calls, of which one uses ioctls and the other does
> doesn't. I can't think of any examples, except perhaps where somebody
> does an ioctl on a mounted device (note that mounting a device does an
Exactly. In fact strictly speaking you must do it this way, or you have no
guarantee that you mount what you did an ioctl() on.
Regards
Oliver
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