lift compat definitions of mcast [sg]etsockopt requests into net/compat.h

We want to get rid of compat_mc_[sg]etsockopt() and to have that stuff
handled without compat_alloc_user_space(), extra copying through
userland, etc.  To do that we'll need ipv4 and ipv6 instances of
->compat_[sg]etsockopt() to manipulate the 32bit variants of mcast
requests, so we need to move the definitions of those out of net/compat.c
and into a public header.

This patch just does a mechanical move to include/net/compat.h
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/net/compat.h

@@ -74,4 +74,28 @@ int compat_mc_getsockopt(struct sock *, int, int, char __user *, int __user *,
 			 int (*)(struct sock *, int, int, char __user *,
 				 int __user *));
 
+struct compat_group_req {
+	__u32				 gr_interface;
+	struct __kernel_sockaddr_storage gr_group
+		__aligned(4);
+} __packed;
+
+struct compat_group_source_req {
+	__u32				 gsr_interface;
+	struct __kernel_sockaddr_storage gsr_group
+		__aligned(4);
+	struct __kernel_sockaddr_storage gsr_source
+		__aligned(4);
+} __packed;
+
+struct compat_group_filter {
+	__u32				 gf_interface;
+	struct __kernel_sockaddr_storage gf_group
+		__aligned(4);
+	__u32				 gf_fmode;
+	__u32				 gf_numsrc;
+	struct __kernel_sockaddr_storage gf_slist[1]
+		__aligned(4);
+} __packed;
+
 #endif /* NET_COMPAT_H */

net/compat.c

@@ -448,34 +448,9 @@ COMPAT_SYSCALL_DEFINE5(getsockopt, int, fd, int, level, int, optname,
 	return __compat_sys_getsockopt(fd, level, optname, optval, optlen);
 }
 
-struct compat_group_req {
-	__u32				 gr_interface;
-	struct __kernel_sockaddr_storage gr_group
-		__aligned(4);
-} __packed;
-
-struct compat_group_source_req {
-	__u32				 gsr_interface;
-	struct __kernel_sockaddr_storage gsr_group
-		__aligned(4);
-	struct __kernel_sockaddr_storage gsr_source
-		__aligned(4);
-} __packed;
-
-struct compat_group_filter {
-	__u32				 gf_interface;
-	struct __kernel_sockaddr_storage gf_group
-		__aligned(4);
-	__u32				 gf_fmode;
-	__u32				 gf_numsrc;
-	struct __kernel_sockaddr_storage gf_slist[1]
-		__aligned(4);
-} __packed;
-
 #define __COMPAT_GF0_SIZE (sizeof(struct compat_group_filter) - \
 			sizeof(struct __kernel_sockaddr_storage))
 
-
 int compat_mc_setsockopt(struct sock *sock, int level, int optname,
 	char __user *optval, unsigned int optlen,
 	int (*setsockopt)(struct sock *, int, int, char __user *, unsigned int))