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>

2 files changed, 29 insertions, 3 deletions

diff --git a/include/linux/atm.h b/include/linux/atm.h
index c791ddd96939..d3b292174aeb 100644
--- a/include/linux/atm.h
+++ b/include/linux/atm.h
@@ -231,10 +231,21 @@ static __inline__ int atmpvc_addr_in_use(struct sockaddr_atmpvc addr)
  */
 
 struct atmif_sioc {
-    int number;
-    int length;
-    void __user *arg;
+	int number;
+	int length;
+	void __user *arg;
 };
 
+#ifdef __KERNEL__
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+struct compat_atmif_sioc {
+	int number;
+	int length;
+	compat_uptr_t arg;
+};
+#endif
+#endif
+
 typedef unsigned short atm_backend_t;
 #endif
diff --git a/include/linux/atmdev.h b/include/linux/atmdev.h
index a3d07c29d16c..086e5c362d3a 100644
--- a/include/linux/atmdev.h
+++ b/include/linux/atmdev.h
@@ -100,6 +100,10 @@ struct atm_dev_stats {
 					/* use backend to make new if */
 #define ATM_ADDPARTY  	_IOW('a', ATMIOC_SPECIAL+4,struct atm_iobuf)
  					/* add party to p2mp call */
+#ifdef CONFIG_COMPAT
+/* It actually takes struct sockaddr_atmsvc, not struct atm_iobuf */
+#define COMPAT_ATM_ADDPARTY  	_IOW('a', ATMIOC_SPECIAL+4,struct compat_atm_iobuf)
+#endif
 #define ATM_DROPPARTY 	_IOW('a', ATMIOC_SPECIAL+5,int)
 					/* drop party from p2mp call */
 
@@ -224,6 +228,13 @@ struct atm_cirange {
 extern struct proc_dir_entry *atm_proc_root;
 #endif
 
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+struct compat_atm_iobuf {
+	int length;
+	compat_uptr_t buffer;
+};
+#endif
 
 struct k_atm_aal_stats {
 #define __HANDLE_ITEM(i) atomic_t i
@@ -379,6 +390,10 @@ struct atmdev_ops { /* only send is required */
 	int (*open)(struct atm_vcc *vcc);
 	void (*close)(struct atm_vcc *vcc);
 	int (*ioctl)(struct atm_dev *dev,unsigned int cmd,void __user *arg);
+#ifdef CONFIG_COMPAT
+	int (*compat_ioctl)(struct atm_dev *dev,unsigned int cmd,
+			    void __user *arg);
+#endif
 	int (*getsockopt)(struct atm_vcc *vcc,int level,int optname,
 	    void __user *optval,int optlen);
 	int (*setsockopt)(struct atm_vcc *vcc,int level,int optname,