Re: [PATCH] pktcdvd: added sysfs interface + bio write queue handling fix

Kay Sievers
2006-09-10T22:27:16Z

On Sun, 2006-09-10 at 21:33 +0200, Thomas Maier wrote:
> Hello,
>
> > Is this always device specific, or also driver global information? Is
> > pktcdvd always on a block device? Maybe you just want them to be a group
> > of attributes in the block device directory where they belong to, like:
> > /sys/block/sr0/pktcdvd/info
> > /sys/block/sr0/pktcdvd/write_queue_size
> > /sys/block/sr0/pktcdvd/...
> >
> > Does that make sense? We should avoid messing around with symlinks
> > pointing to other devices, if not absolutely needed. We should also not
> > create a new device type, just for adding properties to an existing one,
> > especially if there is not some kind of "device stacking". The
> > "mapped_to" link to the parent device looks like a wild hack to me, we
> > should avoid.
>
> The pktcdvd driver creates new block devices using a "struct gendisk"
> that creates the /sys/block/pktcdvd[0-7]/ entries (alloc_disk() -> add_disk()).
>
> Since the files like write_queue_size are per pktcdvd device and belong to
> this device, they should be below the /sys/block/pktcdvd[0-7]/ directory,
> not below the e.g. /sys/block/sr0/ .

So the pktcdvd device have their own device nodes, userspace talks to?

Kay