[net-next,v3,0/4] remove compat_alloc_user_space()

From: Arnd Bergmann <arnd@arndb.de>

This is the third version of my seires, now spanning four patches
instead of two, with a new approach for handling struct ifreq
compatibility after I realized that my earlier approach introduces
additional problems.

The idea here is to always push down the compat conversion
deeper into the call stack: rather than pretending to be
native mode with a modified copy of the original data on
the user space stack, have the code that actually works on
the data understand the difference between native and compat
versions.

I have spent a long time looking at all drivers that implement
an ndo_do_ioctl callback to verify that my assumptions are
correct. This has led to a series of 29 additional patches
that I am not including here but will post separately, fixing
a number of bugs in SIOCDEVPRIVATE ioctls, removing dead
code, and splitting ndo_do_ioctl into two new ndo callbacks
for private and ethernet specific commands.

    Arnd

Arnd Bergmann (4):
  ethtool: improve compat ioctl handling
  net: socket: rework SIOC?IFMAP ioctls
  net: socket: simplify dev_ifconf handling
  net: socket: rework compat_ifreq_ioctl()

 include/linux/compat.h     |  18 +--
 include/linux/ethtool.h    |   4 -
 include/linux/inetdevice.h |   8 +
 include/linux/netdevice.h  |  12 +-
 net/appletalk/ddp.c        |   4 +-
 net/core/dev_ioctl.c       | 156 +++++++++++---------
 net/ethtool/ioctl.c        | 143 ++++++++++++++++--
 net/ieee802154/socket.c    |   4 +-
 net/ipv4/af_inet.c         |   6 +-
 net/ipv4/devinet.c         |   4 +-
 net/qrtr/qrtr.c            |   4 +-
 net/socket.c               | 291 +++++++++----------------------------
 12 files changed, 311 insertions(+), 343 deletions(-)

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

On Fri, Nov 6, 2020 at 6:32 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> This is the third version of my seires, now spanning four patches
> instead of two, with a new approach for handling struct ifreq
> compatibility after I realized that my earlier approach introduces
> additional problems.
>
> The idea here is to always push down the compat conversion
> deeper into the call stack: rather than pretending to be
> native mode with a modified copy of the original data on
> the user space stack, have the code that actually works on
> the data understand the difference between native and compat
> versions.
>
> I have spent a long time looking at all drivers that implement
> an ndo_do_ioctl callback to verify that my assumptions are
> correct. This has led to a series of 29 additional patches
> that I am not including here but will post separately, fixing
> a number of bugs in SIOCDEVPRIVATE ioctls, removing dead
> code, and splitting ndo_do_ioctl into two new ndo callbacks
> for private and ethernet specific commands.

I got a reply from the build bots that the version I sent was broken
on 32-bit machines, so don't merge it just yet. Let me know if
there are any other comments I should address before resending
though.

       Arnd

On Fri, 6 Nov 2020 22:48:18 +0100 Arnd Bergmann wrote:
> On Fri, Nov 6, 2020 at 6:32 PM Arnd Bergmann <arnd@kernel.org> wrote:
> >
> > From: Arnd Bergmann <arnd@arndb.de>
> >
> > This is the third version of my seires, now spanning four patches
> > instead of two, with a new approach for handling struct ifreq
> > compatibility after I realized that my earlier approach introduces
> > additional problems.
> >
> > The idea here is to always push down the compat conversion
> > deeper into the call stack: rather than pretending to be
> > native mode with a modified copy of the original data on
> > the user space stack, have the code that actually works on
> > the data understand the difference between native and compat
> > versions.
> >
> > I have spent a long time looking at all drivers that implement
> > an ndo_do_ioctl callback to verify that my assumptions are
> > correct. This has led to a series of 29 additional patches
> > that I am not including here but will post separately, fixing
> > a number of bugs in SIOCDEVPRIVATE ioctls, removing dead
> > code, and splitting ndo_do_ioctl into two new ndo callbacks
> > for private and ethernet specific commands.  
> 
> I got a reply from the build bots that the version I sent was broken
> on 32-bit machines, so don't merge it just yet. Let me know if
> there are any other comments I should address before resending
> though.

Looks like patch 4 also breaks 64 bit allmodconfig build.

Beyond that - patches 1 and 4 warrant need a second look at:

	checkpatch.pl --strict --min-conf-desc-length=80