[PATCH net-next 2/2] can: isotp: convert to getsockopt_iter

[Breno Leitao <leitao@debian.org>]

Convert CAN ISO-TP 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/can/isotp.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/net/can/isotp.c b/net/can/isotp.c
index c48b4a818297e..1c33f09fbd338 100644
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1500,7 +1500,7 @@ static int isotp_setsockopt(struct socket *sock, int level, int optname,
 }
 
 static int isotp_getsockopt(struct socket *sock, int level, int optname,
-			    char __user *optval, int __user *optlen)
+			    sockopt_t *opt)
 {
 	struct sock *sk = sock->sk;
 	struct isotp_sock *so = isotp_sk(sk);
@@ -1509,8 +1509,7 @@ static int isotp_getsockopt(struct socket *sock, int level, int optname,
 
 	if (level != SOL_CAN_ISOTP)
 		return -EINVAL;
-	if (get_user(len, optlen))
-		return -EFAULT;
+	len = opt->optlen;
 	if (len < 0)
 		return -EINVAL;
 
@@ -1544,9 +1543,8 @@ static int isotp_getsockopt(struct socket *sock, int level, int optname,
 		return -ENOPROTOOPT;
 	}
 
-	if (put_user(len, optlen))
-		return -EFAULT;
-	if (copy_to_user(optval, val, len))
+	opt->optlen = len;
+	if (copy_to_iter(val, len, &opt->iter_out) != len)
 		return -EFAULT;
 	return 0;
 }
@@ -1718,7 +1716,7 @@ static const struct proto_ops isotp_ops = {
 	.listen = sock_no_listen,
 	.shutdown = sock_no_shutdown,
 	.setsockopt = isotp_setsockopt,
-	.getsockopt = isotp_getsockopt,
+	.getsockopt_iter = isotp_getsockopt,
 	.sendmsg = isotp_sendmsg,
 	.recvmsg = isotp_recvmsg,
 	.mmap = sock_no_mmap,

-- 
2.52.0