Re: [PATCH 2/2] uio: do not expose inode to uio open/release hooks

From: Greg KH
Date: Wed Dec 12 2012 - 01:36:27 EST


On Wed, Dec 12, 2012 at 02:42:22AM +0100, Hans J. Koch wrote:
> On Tue, Dec 11, 2012 at 03:20:32PM -0800, Greg KH wrote:
> > On Wed, Dec 12, 2012 at 12:12:02AM +0100, Benedikt Spranger wrote:
> > > The inode parameter is unused by in kernel users of UIO.
> >
> > Ok.
> >
> > > Also the inode parameter makes it hard to resolve the existing open(),
> > > mmap() and close() difficulty.
> >
> > I don't understand, what do you mean by this? What is this parameter
> > causing problems with?
>
> The problem is that according to POSIX, it is guaranteed that in userspace
> you can do
>
> fd = open("/dev/uio0", ...)
> ptr = mmap(...fd...)
> close(fd)
>
> with ptr still being valid and useable after that.

Yes, but what does that have to do with this in-kernel, internal api?

confused,

greg k-h
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