[PATCH net-next 4/5] llc: convert to getsockopt_iter

[Breno Leitao <leitao@debian.org>]

Convert LLC 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()
- Add linux/uio.h for copy_to_iter()

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 net/llc/af_llc.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index 1b210db3119e8..7d723f0bd26c2 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -27,6 +27,7 @@
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/sched/signal.h>
+#include <linux/uio.h>
 
 #include <net/llc.h>
 #include <net/llc_sap.h>
@@ -1172,19 +1173,16 @@ static int llc_ui_setsockopt(struct socket *sock, int level, int optname,
  *	Get connection specific socket information.
  */
 static int llc_ui_getsockopt(struct socket *sock, int level, int optname,
-			     char __user *optval, int __user *optlen)
+			     sockopt_t *opt)
 {
 	struct sock *sk = sock->sk;
 	struct llc_sock *llc = llc_sk(sk);
-	int val = 0, len = 0, rc = -EINVAL;
+	int val = 0, len, rc = -EINVAL;
 
 	lock_sock(sk);
 	if (unlikely(level != SOL_LLC))
 		goto out;
-	rc = get_user(len, optlen);
-	if (rc)
-		goto out;
-	rc = -EINVAL;
+	len = opt->optlen;
 	if (len != sizeof(int))
 		goto out;
 	switch (optname) {
@@ -1212,7 +1210,8 @@ static int llc_ui_getsockopt(struct socket *sock, int level, int optname,
 		goto out;
 	}
 	rc = 0;
-	if (put_user(len, optlen) || copy_to_user(optval, &val, len))
+	opt->optlen = len;
+	if (copy_to_iter(&val, len, &opt->iter_out) != len)
 		rc = -EFAULT;
 out:
 	release_sock(sk);
@@ -1239,7 +1238,7 @@ static const struct proto_ops llc_ui_ops = {
 	.listen      = llc_ui_listen,
 	.shutdown    = llc_ui_shutdown,
 	.setsockopt  = llc_ui_setsockopt,
-	.getsockopt  = llc_ui_getsockopt,
+	.getsockopt_iter = llc_ui_getsockopt,
 	.sendmsg     = llc_ui_sendmsg,
 	.recvmsg     = llc_ui_recvmsg,
 	.mmap	     = sock_no_mmap,

-- 
2.52.0