atm: 32-bit ioctl compatibility

We lack compat ioctl support through most of the ATM code. This patch
deals with most of it, and I can now at least use BR2684 and PPPoATM
with 32-bit userspace.

I haven't added a .compat_ioctl method to struct atm_ioctl, because
AFAICT none of the current users need any conversion -- so we can just
call the ->ioctl() method in every case. I looked at br2684, clip, lec,
mpc, pppoatm and atmtcp.

In svc_compat_ioctl() the only mangling which is needed is to change
COMPAT_ATM_ADDPARTY to ATM_ADDPARTY. Although it's defined as
	_IOW('a', ATMIOC_SPECIAL+4,struct atm_iobuf)
it doesn't actually _take_ a struct atm_iobuf as an argument -- it takes
a struct sockaddr_atmsvc, which _is_ the same between 32-bit and 64-bit
code, so doesn't need conversion.

Almost all of vcc_ioctl() would have been identical, so I converted that
into a core do_vcc_ioctl() function with an 'int compat' argument.

I've done the same with atm_dev_ioctl(), where there _are_ a few
differences, but still it's relatively contained and there would
otherwise have been a lot of duplication.

I haven't done any of the actual device-specific ioctls, although I've
added a compat_ioctl method to struct atmdev_ops.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 0 deletions

diff --git a/net/atm/svc.c b/net/atm/svc.c
index de1e4f2f3a43..e9c65500f84e 100644
--- a/net/atm/svc.c
+++ b/net/atm/svc.c
@@ -604,6 +604,22 @@ static int svc_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 	return error;
 }
 
+#ifdef CONFIG_COMPAT
+static int svc_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
+{
+	/* The definition of ATM_ADDPARTY uses the size of struct atm_iobuf.
+	   But actually it takes a struct sockaddr_atmsvc, which doesn't need
+	   compat handling. So all we have to do is fix up cmd... */
+	if (cmd == COMPAT_ATM_ADDPARTY)
+		cmd = ATM_ADDPARTY;
+
+	if (cmd == ATM_ADDPARTY || cmd == ATM_DROPPARTY)
+		return svc_ioctl(sock, cmd, arg);
+	else
+		return vcc_compat_ioctl(sock, cmd, arg);
+}
+#endif /* CONFIG_COMPAT */
+
 static const struct proto_ops svc_proto_ops = {
 	.family =	PF_ATMSVC,
 	.owner =	THIS_MODULE,
@@ -616,6 +632,9 @@ static const struct proto_ops svc_proto_ops = {
 	.getname =	svc_getname,
 	.poll =		vcc_poll,
 	.ioctl =	svc_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl =	svc_compat_ioctl,
+#endif
 	.listen =	svc_listen,
 	.shutdown =	svc_shutdown,
 	.setsockopt =	svc_setsockopt,