atm: move copyin from atm_getnames() into the caller

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

net/atm/ioctl.c

@@ -56,6 +56,8 @@ static int do_vcc_ioctl(struct socket *sock, unsigned int cmd,
 	int error;
 	struct list_head *pos;
 	void __user *argp = (void __user *)arg;
+	void __user *buf;
+	int __user *len;
 
 	vcc = ATM_SD(sock);
 	switch (cmd) {
@@ -163,7 +165,22 @@ static int do_vcc_ioctl(struct socket *sock, unsigned int cmd,
 		goto done;
 
 	if (cmd == ATM_GETNAMES) {
-		error = atm_getnames(argp, compat);
+		if (IS_ENABLED(CONFIG_COMPAT) && compat) {
+#ifdef CONFIG_COMPAT
+			struct compat_atm_iobuf __user *ciobuf = argp;
+			compat_uptr_t cbuf;
+			len = &ciobuf->length;
+			if (get_user(cbuf, &ciobuf->buffer))
+				return -EFAULT;
+			buf = compat_ptr(cbuf);
+#endif
+		} else {
+			struct atm_iobuf __user *iobuf = argp;
+			len = &iobuf->length;
+			if (get_user(buf, &iobuf->buffer))
+				return -EFAULT;
+		}
+		error = atm_getnames(buf, len);
 	} else {
 		error = atm_dev_ioctl(cmd, argp, compat);
 	}

net/atm/resources.c

@@ -193,30 +193,13 @@ static int fetch_stats(struct atm_dev *dev, struct atm_dev_stats __user *arg,
 	return error ? -EFAULT : 0;
 }
 
-int atm_getnames(void __user *arg, int compat)
+int atm_getnames(void __user *buf, int __user *iobuf_len)
 {
-	void __user *buf;
 	int error, len, size = 0;
 	struct atm_dev *dev;
 	struct list_head *p;
 	int *tmp_buf, *tmp_p;
-	int __user *iobuf_len;
 
-	if (IS_ENABLED(CONFIG_COMPAT) && compat) {
-#ifdef CONFIG_COMPAT
-		struct compat_atm_iobuf __user *ciobuf = arg;
-		compat_uptr_t cbuf;
-		iobuf_len = &ciobuf->length;
-		if (get_user(cbuf, &ciobuf->buffer))
-			return -EFAULT;
-		buf = compat_ptr(cbuf);
-#endif
-	} else {
-		struct atm_iobuf __user *iobuf = arg;
-		iobuf_len = &iobuf->length;
-		if (get_user(buf, &iobuf->buffer))
-			return -EFAULT;
-	}
 	if (get_user(len, iobuf_len))
 		return -EFAULT;
 	mutex_lock(&atm_dev_mutex);

net/atm/resources.h

@@ -14,7 +14,7 @@
 extern struct list_head atm_devs;
 extern struct mutex atm_dev_mutex;
 
-int atm_getnames(void __user *arg, int compat);
+int atm_getnames(void __user *buf, int __user *iobuf_len);
 int atm_dev_ioctl(unsigned int cmd, void __user *arg, int compat);