[PATCH v1 23/40] j1939: socket: add j1939_sk_alloc_skb()

[Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>]

..and move part of j1939_sk_sendmsg to it. This function is needed for multi
skb support within single session.

Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
 net/can/j1939/socket.c | 99 +++++++++++++++++++++++++-----------------
 1 file changed, 58 insertions(+), 41 deletions(-)

diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index e003d3cae24c..b1ab7df7eef6 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c
@@ -620,47 +620,14 @@ static int j1939_sk_recvmsg(struct socket *sock, struct msghdr *msg,
 	return size;
 }
 
-static int j1939_sk_sendmsg(struct socket *sock, struct msghdr *msg,
-			    size_t size)
+static struct sk_buff *j1939_sk_alloc_skb(struct net_device *ndev, struct sock *sk,
+			      struct msghdr *msg, size_t size, int *errcode)
 {
-	struct sock *sk = sock->sk;
 	struct j1939_sock *jsk = j1939_sk(sk);
-	struct sockaddr_can *addr = msg->msg_name;
 	struct j1939_sk_buff_cb *skcb;
-	struct j1939_priv *priv;
 	struct sk_buff *skb;
-	struct net_device *ndev;
-	int ifindex;
 	int ret;
 
-	/* various socket state tests */
-	if (!(jsk->state & J1939_SOCK_BOUND))
-		return -EBADFD;
-
-	ifindex = jsk->ifindex;
-
-	if (jsk->addr.sa == J1939_NO_ADDR && !jsk->addr.src_name)
-		/* no address assigned yet */
-		return -EBADFD;
-
-	/* deal with provided address info */
-	if (msg->msg_name) {
-		if (msg->msg_namelen < J1939_MIN_NAMELEN)
-			return -EINVAL;
-		if (addr->can_family != AF_CAN)
-			return -EINVAL;
-		if (j1939_pgn_is_valid(addr->can_addr.j1939.pgn) &&
-		    !j1939_pgn_is_clean_pdu(addr->can_addr.j1939.pgn))
-			return -EINVAL;
-		/* TODO: always check if ifindex is correct? */
-		if (addr->can_ifindex && ifindex != addr->can_ifindex)
-			return -EBADFD;
-	}
-
-	ndev = dev_get_by_index(sock_net(sk), ifindex);
-	if (!ndev)
-		return -ENXIO;
-
 	skb = sock_alloc_send_skb(sk,
 				  size +
 				  sizeof(struct can_frame) -
@@ -668,7 +635,7 @@ static int j1939_sk_sendmsg(struct socket *sock, struct msghdr *msg,
 				  sizeof(struct can_skb_priv),
 				  msg->msg_flags & MSG_DONTWAIT, &ret);
 	if (!skb)
-		goto put_dev;
+		goto failure;
 
 	can_skb_reserve(skb);
 	can_skb_prv(skb)->ifindex = ndev->ifindex;
@@ -699,13 +666,63 @@ static int j1939_sk_sendmsg(struct socket *sock, struct msghdr *msg,
 		if (j1939_pgn_is_valid(addr->can_addr.j1939.pgn))
 			skcb->addr.pgn = addr->can_addr.j1939.pgn;
 	}
-	if (!j1939_pgn_is_valid(skcb->addr.pgn)) {
-		ret = -EINVAL;
-		goto free_skb;
+
+	*errcode = ret;
+	return skb;
+
+free_skb:
+	kfree_skb(skb);
+failure:
+	*errcode = ret;
+	return NULL;
+}
+
+static int j1939_sk_sendmsg(struct socket *sock, struct msghdr *msg,
+			    size_t size)
+{
+	struct sock *sk = sock->sk;
+	struct j1939_sock *jsk = j1939_sk(sk);
+	struct sockaddr_can *addr = msg->msg_name;
+	struct j1939_priv *priv;
+	struct sk_buff *skb;
+	struct net_device *ndev;
+	int ifindex;
+	int ret;
+
+	/* various socket state tests */
+	if (!(jsk->state & J1939_SOCK_BOUND))
+		return -EBADFD;
+
+	ifindex = jsk->ifindex;
+
+	if (jsk->addr.sa == J1939_NO_ADDR && !jsk->addr.src_name)
+		/* no address assigned yet */
+		return -EBADFD;
+
+	/* deal with provided address info */
+	if (msg->msg_name) {
+		if (msg->msg_namelen < J1939_MIN_NAMELEN)
+			return -EINVAL;
+		if (addr->can_family != AF_CAN)
+			return -EINVAL;
+		if (j1939_pgn_is_valid(addr->can_addr.j1939.pgn) &&
+		    !j1939_pgn_is_clean_pdu(addr->can_addr.j1939.pgn))
+			return -EINVAL;
+		/* TODO: always check if ifindex is correct? */
+		if (addr->can_ifindex && ifindex != addr->can_ifindex)
+			return -EBADFD;
 	}
 
-	if (skcb->msg_flags & MSG_SYN) {
-		if (skcb->msg_flags & MSG_DONTWAIT) {
+	ndev = dev_get_by_index(sock_net(sk), ifindex);
+	if (!ndev)
+		return -ENXIO;
+
+	skb = j1939_sk_alloc_skb(ndev, sk, msg, size, &ret);
+	if (!skb)
+		goto put_dev;
+
+	if (msg->msg_flags & MSG_SYN) {
+		if (msg->msg_flags & MSG_DONTWAIT) {
 			ret = j1939_sock_pending_add_first(&jsk->sk);
 			if (ret > 0)
 				ret = -EAGAIN;
-- 
2.19.1