Re: [PATCH] DAC960 open with O_NONBLOCK

[Christoph Hellwig]

On Mon, Apr 21, 2003 at 12:01:11PM -0700, Dave Olien wrote:
> > What applications?
> 
> John Kamp has run across a libhd applcation from Suse that hit this bug.
> It's some kind of hardware detection application.  It opens devices with
> O_NONBLOCK.  But, it doesn't in fact use the DAC960 pass-through commands.

Do you have source to it?

> The Mylex web page has a RAID management application for DAC960 on Linux that
> is available only in BINARY form.  Unfortunately, it requires
> a Windows front-end to provide a GUI.  So, I haven't actually experimented
> with it. If any application uses the pass-through commands, this would likely
> be it.  But since no one has complained about this being broken, it may
> indicate no one is using this application.

Hmm, breaking it wouldn't be nice, but if they're not willing to
release an updated version we'll just need a LD_PRELOAD wrapper
that maps the open to a new mangment device.

> The pass-through behavior could be made available either through
> a /proc or a sysfs file.

My preference would be a char device (miscdev)

> A related question, why does linux 2.5 continue to have a "struct file *"
> argument to driver release methods? As far as I can tell, that argument
> is always NULL?

->release will change to struct gendisk * at some point.  Touching
it before to just remove the struct file * sounds like a bad idea.