Re: Re: [PATCH] remove duplicated ioctl entries in compat_ioctl.c

["John W. Linville" <linville@tuxdriver.com>]

On Fri, Jul 27, 2007 at 10:13:01AM -0700, Jean Tourrilhes wrote:
> "John W. Linville" wrote :
> > On Mon, Jul 09, 2007 at 07:54:39PM +0900, Masakazu Mokuno wrote:
> > > This patch removes some duplicated wireless ioctl entries in the array
> > > 'struct ioctl_trans ioctl_start[]' of fs/compat_ioctl.c
> > > 
> > > These entries are registered twice like:
> > > 
> > > 	COMPATIBLE_IOCTL(SIOCGIWPRIV)
> > > 
> > > and
> > > 
> > > 	HANDLE_IOCTL(SIOCGIWPRIV, do_wireless_ioctl)
> > > 
> > > 
> > > Signed-off-by: Masakazu Mokuno <mokuno@sm.sony.co.jp>

> > As I read the code in compat_ioctl.c, it looks to me like the
> > COMPATIBLE_IOCTL definitions are the ones that are actually being
> > used today.  Do you agree?
> 
> 	Actually, you are wrong, and Masakazu is right. All those
> ioctls contains a pointer and should go through the pointer
> conversion.

Masakazu replied in agreement that the COMPATIBLE_IOCTL entries are
the effective ones i.e. the code currently uses those entries and
the others are currently just wasting space.

Perhaps the HANDLE_IOCTL entries are indeed the correct and intended ones.  You seem to be indicating so.

> 	The reason why Masakazu sent that patch is that he actually
> stumbled on the problem and tested it.

The only problem stated is the not-quite-duplicate entries.  If there
is an actual problem (and not just sloppy code) then that makes the
situation more clear.

What is the manifestation of the problem?

> > Given the...stability...of the wireless extensions API, if we are going
> > to remove one or the other of these not-quite-duplicate definitions,
> > shouldn't we remove the HANDLE_IOCTL defintions instead?
> 
> 	I don't understand, you are in favor of breaking the API ?

I'm not sure how an honest reading could imply that.

If this fixes a bug, then fine.  If we are trading the one "duplicate"
entry we have been using for one that hasn't been in use, it doesn't
make much sense.

John
-- 
John W. Linville
linville@tuxdriver.com