kcm: Sendpage support
Implement kcm_sendpage. Set in sendpage to kcm_sendpage in both
dgram and seqpacket ops.
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 982ea5f..9ac2499 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -990,6 +990,149 @@
kcm_write_msgs(kcm);
}
+static ssize_t kcm_sendpage(struct socket *sock, struct page *page,
+ int offset, size_t size, int flags)
+
+{
+ struct sock *sk = sock->sk;
+ struct kcm_sock *kcm = kcm_sk(sk);
+ struct sk_buff *skb = NULL, *head = NULL;
+ long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+ bool eor;
+ int err = 0;
+ int i;
+
+ if (flags & MSG_SENDPAGE_NOTLAST)
+ flags |= MSG_MORE;
+
+ /* No MSG_EOR from splice, only look at MSG_MORE */
+ eor = !(flags & MSG_MORE);
+
+ lock_sock(sk);
+
+ sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);
+
+ err = -EPIPE;
+ if (sk->sk_err)
+ goto out_error;
+
+ if (kcm->seq_skb) {
+ /* Previously opened message */
+ head = kcm->seq_skb;
+ skb = kcm_tx_msg(head)->last_skb;
+ i = skb_shinfo(skb)->nr_frags;
+
+ if (skb_can_coalesce(skb, i, page, offset)) {
+ skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], size);
+ skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
+ goto coalesced;
+ }
+
+ if (i >= MAX_SKB_FRAGS) {
+ struct sk_buff *tskb;
+
+ tskb = alloc_skb(0, sk->sk_allocation);
+ while (!tskb) {
+ kcm_push(kcm);
+ err = sk_stream_wait_memory(sk, &timeo);
+ if (err)
+ goto out_error;
+ }
+
+ if (head == skb)
+ skb_shinfo(head)->frag_list = tskb;
+ else
+ skb->next = tskb;
+
+ skb = tskb;
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ i = 0;
+ }
+ } else {
+ /* Call the sk_stream functions to manage the sndbuf mem. */
+ if (!sk_stream_memory_free(sk)) {
+ kcm_push(kcm);
+ set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+ err = sk_stream_wait_memory(sk, &timeo);
+ if (err)
+ goto out_error;
+ }
+
+ head = alloc_skb(0, sk->sk_allocation);
+ while (!head) {
+ kcm_push(kcm);
+ err = sk_stream_wait_memory(sk, &timeo);
+ if (err)
+ goto out_error;
+ }
+
+ skb = head;
+ i = 0;
+ }
+
+ get_page(page);
+ skb_fill_page_desc(skb, i, page, offset, size);
+ skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
+
+coalesced:
+ skb->len += size;
+ skb->data_len += size;
+ skb->truesize += size;
+ sk->sk_wmem_queued += size;
+ sk_mem_charge(sk, size);
+
+ if (head != skb) {
+ head->len += size;
+ head->data_len += size;
+ head->truesize += size;
+ }
+
+ if (eor) {
+ bool not_busy = skb_queue_empty(&sk->sk_write_queue);
+
+ /* Message complete, queue it on send buffer */
+ __skb_queue_tail(&sk->sk_write_queue, head);
+ kcm->seq_skb = NULL;
+ KCM_STATS_INCR(kcm->stats.tx_msgs);
+
+ if (flags & MSG_BATCH) {
+ kcm->tx_wait_more = true;
+ } else if (kcm->tx_wait_more || not_busy) {
+ err = kcm_write_msgs(kcm);
+ if (err < 0) {
+ /* We got a hard error in write_msgs but have
+ * already queued this message. Report an error
+ * in the socket, but don't affect return value
+ * from sendmsg
+ */
+ pr_warn("KCM: Hard failure on kcm_write_msgs\n");
+ report_csk_error(&kcm->sk, -err);
+ }
+ }
+ } else {
+ /* Message not complete, save state */
+ kcm->seq_skb = head;
+ kcm_tx_msg(head)->last_skb = skb;
+ }
+
+ KCM_STATS_ADD(kcm->stats.tx_bytes, size);
+
+ release_sock(sk);
+ return size;
+
+out_error:
+ kcm_push(kcm);
+
+ err = sk_stream_error(sk, flags, err);
+
+ /* make sure we wake any epoll edge trigger waiter */
+ if (unlikely(skb_queue_len(&sk->sk_write_queue) == 0 && err == -EAGAIN))
+ sk->sk_write_space(sk);
+
+ release_sock(sk);
+ return err;
+}
+
static int kcm_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
{
struct sock *sk = sock->sk;
@@ -1995,7 +2138,7 @@
.sendmsg = kcm_sendmsg,
.recvmsg = kcm_recvmsg,
.mmap = sock_no_mmap,
- .sendpage = sock_no_sendpage,
+ .sendpage = kcm_sendpage,
};
static const struct proto_ops kcm_seqpacket_ops = {
@@ -2016,7 +2159,7 @@
.sendmsg = kcm_sendmsg,
.recvmsg = kcm_recvmsg,
.mmap = sock_no_mmap,
- .sendpage = sock_no_sendpage,
+ .sendpage = kcm_sendpage,
.splice_read = kcm_splice_read,
};
