kcm: Splice support

Implement kcm_splice_read. This is supported only for seqpacket.
Add kcm_seqpacket_ops and set splice read to kcm_splice_read.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index f938d7d..982ea5f 100644 (file)
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1256,6 +1256,76 @@ out:
        return copied ? : err;
 }
 
+static ssize_t kcm_sock_splice(struct sock *sk,
+                              struct pipe_inode_info *pipe,
+                              struct splice_pipe_desc *spd)
+{
+       int ret;
+
+       release_sock(sk);
+       ret = splice_to_pipe(pipe, spd);
+       lock_sock(sk);
+
+       return ret;
+}
+
+static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
+                              struct pipe_inode_info *pipe, size_t len,
+                              unsigned int flags)
+{
+       struct sock *sk = sock->sk;
+       struct kcm_sock *kcm = kcm_sk(sk);
+       long timeo;
+       struct kcm_rx_msg *rxm;
+       int err = 0;
+       size_t copied;
+       struct sk_buff *skb;
+
+       /* Only support splice for SOCKSEQPACKET */
+
+       timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+
+       lock_sock(sk);
+
+       skb = kcm_wait_data(sk, flags, timeo, &err);
+       if (!skb)
+               goto err_out;
+
+       /* Okay, have a message on the receive queue */
+
+       rxm = kcm_rx_msg(skb);
+
+       if (len > rxm->full_len)
+               len = rxm->full_len;
+
+       copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags,
+                                kcm_sock_splice);
+       if (copied < 0) {
+               err = copied;
+               goto err_out;
+       }
+
+       KCM_STATS_ADD(kcm->stats.rx_bytes, copied);
+
+       rxm->offset += copied;
+       rxm->full_len -= copied;
+
+       /* We have no way to return MSG_EOR. If all the bytes have been
+        * read we still leave the message in the receive socket buffer.
+        * A subsequent recvmsg needs to be done to return MSG_EOR and
+        * finish reading the message.
+        */
+
+       release_sock(sk);
+
+       return copied;
+
+err_out:
+       release_sock(sk);
+
+       return err;
+}
+
 /* kcm sock lock held */
 static void kcm_recv_disable(struct kcm_sock *kcm)
 {
@@ -1907,7 +1977,7 @@ static int kcm_release(struct socket *sock)
        return 0;
 }
 
-static const struct proto_ops kcm_ops = {
+static const struct proto_ops kcm_dgram_ops = {
        .family =       PF_KCM,
        .owner =        THIS_MODULE,
        .release =      kcm_release,
@@ -1928,6 +1998,28 @@ static const struct proto_ops kcm_ops = {
        .sendpage =     sock_no_sendpage,
 };
 
+static const struct proto_ops kcm_seqpacket_ops = {
+       .family =       PF_KCM,
+       .owner =        THIS_MODULE,
+       .release =      kcm_release,
+       .bind =         sock_no_bind,
+       .connect =      sock_no_connect,
+       .socketpair =   sock_no_socketpair,
+       .accept =       sock_no_accept,
+       .getname =      sock_no_getname,
+       .poll =         datagram_poll,
+       .ioctl =        kcm_ioctl,
+       .listen =       sock_no_listen,
+       .shutdown =     sock_no_shutdown,
+       .setsockopt =   kcm_setsockopt,
+       .getsockopt =   kcm_getsockopt,
+       .sendmsg =      kcm_sendmsg,
+       .recvmsg =      kcm_recvmsg,
+       .mmap =         sock_no_mmap,
+       .sendpage =     sock_no_sendpage,
+       .splice_read =  kcm_splice_read,
+};
+
 /* Create proto operation for kcm sockets */
 static int kcm_create(struct net *net, struct socket *sock,
                      int protocol, int kern)
@@ -1938,8 +2030,10 @@ static int kcm_create(struct net *net, struct socket *sock,
 
        switch (sock->type) {
        case SOCK_DGRAM:
+               sock->ops = &kcm_dgram_ops;
+               break;
        case SOCK_SEQPACKET:
-               sock->ops = &kcm_ops;
+               sock->ops = &kcm_seqpacket_ops;
                break;
        default:
                return -ESOCKTNOSUPPORT;