Re: [PATCH] scsi sysfs update (scsi_debug 3/3)

Christoph Hellwig
2002-11-08T02:30:56Z

On Fri, Nov 08, 2002 at 10:35:06AM +1100, Douglas Gilbert wrote:
> BTW Is the 256 minors limit history yet in 2.5?

No. but for blockdevices minors are basically meaningless now.

> Whither sg?? Well it has been my intention to put
> a functionally stripped down version of the sg_io_hdr
> interface in a mid level ioctl. It could overlay the
> current SCSI_IOCTL_SEND_COMMAND or be a new ioctl
> number.

Please use a new one one, overloading only creates confusion.

> that it is dreadful (making sg_header look good :-) ).
> However from an application point of view you are
> still going to have sd, sr or st in the way of what
> you are really trying to do. Then there are the odd
> ball devices: this week I came across a SCSI printer
> type device for the first time. It's a modern device
> build to hide its true purpose from OSes!
>
> Rather than a free standing upper level device, sg
> could be seen as an adjunct to the mid level. There is
> no need to probe sg to find out whether it is interested
> in a newly attach scsi device - by definition it is
> (unless it has run out of resources).

Yupp. What I was thinking about was not to remove the sg device
nodes and leaving only the ioctl functionality as part of other
device nodes but rather creating a sg node for every scsi device,
without it beeing a "real" upper layer driver.