[PATCH net-next 4/6] l2tp: ppp: convert to getsockopt_iter

[Breno Leitao <leitao@debian.org>]

Convert PPPoL2TP socket's getsockopt implementation to use the new
getsockopt_iter callback with sockopt_t.

Key changes:
- Replace (char __user *optval, int __user *optlen) with sockopt_t *opt
- Use opt->optlen for buffer length (input) and returned size (output)
- Use copy_to_iter() instead of put_user()/copy_to_user()

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 net/l2tp/l2tp_ppp.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/net/l2tp/l2tp_ppp.c b/net/l2tp/l2tp_ppp.c
index 99d6582f41de2..4c7a1152b20ba 100644
--- a/net/l2tp/l2tp_ppp.c
+++ b/net/l2tp/l2tp_ppp.c
@@ -59,6 +59,7 @@
 #include <linux/string.h>
 #include <linux/list.h>
 #include <linux/uaccess.h>
+#include <linux/uio.h>
 
 #include <linux/kernel.h>
 #include <linux/spinlock.h>
@@ -1317,7 +1318,7 @@ static int pppol2tp_session_getsockopt(struct sock *sk,
  * or the special tunnel type.
  */
 static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
-			       char __user *optval, int __user *optlen)
+			       sockopt_t *opt)
 {
 	struct sock *sk = sock->sk;
 	struct l2tp_session *session;
@@ -1328,9 +1329,7 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
 	if (level != SOL_PPPOL2TP)
 		return -EINVAL;
 
-	if (get_user(len, optlen))
-		return -EFAULT;
-
+	len = opt->optlen;
 	if (len < 0)
 		return -EINVAL;
 
@@ -1358,12 +1357,11 @@ static int pppol2tp_getsockopt(struct socket *sock, int level, int optname,
 			goto end_put_sess;
 	}
 
-	err = -EFAULT;
-	if (put_user(len, optlen))
-		goto end_put_sess;
-
-	if (copy_to_user((void __user *)optval, &val, len))
+	opt->optlen = len;
+	if (copy_to_iter(&val, len, &opt->iter_out) != len) {
+		err = -EFAULT;
 		goto end_put_sess;
+	}
 
 	err = 0;
 
@@ -1634,7 +1632,7 @@ static const struct proto_ops pppol2tp_ops = {
 	.listen		= sock_no_listen,
 	.shutdown	= sock_no_shutdown,
 	.setsockopt	= pppol2tp_setsockopt,
-	.getsockopt	= pppol2tp_getsockopt,
+	.getsockopt_iter = pppol2tp_getsockopt,
 	.sendmsg	= pppol2tp_sendmsg,
 	.recvmsg	= pppol2tp_recvmsg,
 	.mmap		= sock_no_mmap,

-- 
2.53.0-Meta