Re: kern/38889

[Masao Uebayashi <uebayasi%tombi.co.jp@localhost>]

On Thu, May 24, 2012 at 03:00:02AM +0000, YAMAMOTO Takashi wrote:
> hi,
> 
> > I wonder if we can completely disallow mmap'ing block devices?  I suspect
> > it has never worked nor needed by anyone - otherwise why such a serious
> > problem has been open for a long time!
> 
> i don't know.  but it might be useful for applications which want to
> do mmap+send for zero copy.  eg. an iscsi target

Understood, but that could be properly designed/implamented later.  I
think it's better to just disallow mmap(bdev) on netbsd-6.

(I also think that genfs is a wrong place to handle mmap(bdev).  IIUC, bdev's
data has nothing to do with its hosting mount/filesystem.  Handling VREG and
VBLK in one place sounds very odd to me.)

> 
> please keep gnats-bugs%NetBSD.org@localhost in Cc: so that it's filed in 
> gnats.
> 
> YAMAMOTO Takashi