[PATCH net-next 2/3] vsock: convert to getsockopt_iter

[Breno Leitao <leitao@debian.org>]

Convert AF_VSOCK's getsockopt implementation to use the new
getsockopt_iter callback with sockopt_t. The single
vsock_connectible_getsockopt() callback is shared by both
vsock_stream_ops and vsock_seqpacket_ops, so both proto_ops are
updated to use .getsockopt_iter.

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/vmw_vsock/af_vsock.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 44037b066a5ff..d4a97eeb596e6 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -155,6 +155,7 @@
 #include <linux/random.h>
 #include <linux/skbuff.h>
 #include <linux/smp.h>
+#include <linux/uio.h>
 #include <linux/socket.h>
 #include <linux/stddef.h>
 #include <linux/sysctl.h>
@@ -2091,8 +2092,7 @@ static int vsock_connectible_setsockopt(struct socket *sock,
 
 static int vsock_connectible_getsockopt(struct socket *sock,
 					int level, int optname,
-					char __user *optval,
-					int __user *optlen)
+					sockopt_t *opt)
 {
 	struct sock *sk = sock->sk;
 	struct vsock_sock *vsk = vsock_sk(sk);
@@ -2110,8 +2110,7 @@ static int vsock_connectible_getsockopt(struct socket *sock,
 	if (level != AF_VSOCK)
 		return -ENOPROTOOPT;
 
-	if (get_user(len, optlen))
-		return -EFAULT;
+	len = opt->optlen;
 
 	memset(&v, 0, sizeof(v));
 
@@ -2142,11 +2141,10 @@ static int vsock_connectible_getsockopt(struct socket *sock,
 		return -EINVAL;
 	if (len > lv)
 		len = lv;
-	if (copy_to_user(optval, &v, len))
+	if (copy_to_iter(&v, len, &opt->iter_out) != len)
 		return -EFAULT;
 
-	if (put_user(len, optlen))
-		return -EFAULT;
+	opt->optlen = len;
 
 	return 0;
 }
@@ -2631,7 +2629,7 @@ static const struct proto_ops vsock_stream_ops = {
 	.listen = vsock_listen,
 	.shutdown = vsock_shutdown,
 	.setsockopt = vsock_connectible_setsockopt,
-	.getsockopt = vsock_connectible_getsockopt,
+	.getsockopt_iter = vsock_connectible_getsockopt,
 	.sendmsg = vsock_connectible_sendmsg,
 	.recvmsg = vsock_connectible_recvmsg,
 	.mmap = sock_no_mmap,
@@ -2653,7 +2651,7 @@ static const struct proto_ops vsock_seqpacket_ops = {
 	.listen = vsock_listen,
 	.shutdown = vsock_shutdown,
 	.setsockopt = vsock_connectible_setsockopt,
-	.getsockopt = vsock_connectible_getsockopt,
+	.getsockopt_iter = vsock_connectible_getsockopt,
 	.sendmsg = vsock_connectible_sendmsg,
 	.recvmsg = vsock_connectible_recvmsg,
 	.mmap = sock_no_mmap,

-- 
2.52.0