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

Thomas Maier
2006-09-10T19:25:28Z

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/ .

The pktcdvd driver can only be mapped to block devices, as i know.

-Thomas Maier