Phonet: zero-copy GPRS TX

Send aligned pipe payload if requested to do so. Then, the socket buffer
needs not be fragmented anymore.

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 2 deletions

diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index e23e30907d34..72db27e3fc06 100644
--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -444,6 +444,7 @@ static int pep_connreq_rcv(struct sock *sk, struct sk_buff *skb)
         struct sockaddr_pn dst;
         u16 peer_type;
         u8 pipe_handle, enabled, n_sb;
+        u8 aligned = 0;
 
         if (!pskb_pull(skb, sizeof(*hdr) + 4))
                 return -EINVAL;
@@ -482,6 +483,9 @@ static int pep_connreq_rcv(struct sock *sk, struct sk_buff *skb)
                                 return -EINVAL;
                         peer_type = (peer_type & 0xff00) | data[0];
                         break;
+                case PN_PIPE_SB_ALIGNED_DATA:
+                        aligned = data[0] != 0;
+                        break;
                 }
                 n_sb--;
         }
@@ -513,6 +517,7 @@ static int pep_connreq_rcv(struct sock *sk, struct sk_buff *skb)
         newpn->rx_credits = 0;
         newpn->rx_fc = newpn->tx_fc = PN_LEGACY_FLOW_CONTROL;
         newpn->init_enable = enabled;
+        newpn->aligned = aligned;
 
         BUG_ON(!skb_queue_empty(&newsk->sk_receive_queue));
         skb_queue_head(&newsk->sk_receive_queue, skb);
@@ -832,11 +837,15 @@ static int pipe_skb_send(struct sock *sk, struct sk_buff *skb)
                 return -ENOBUFS;
         }
 
-        skb_push(skb, 3);
+        skb_push(skb, 3 + pn->aligned);
         skb_reset_transport_header(skb);
         ph = pnp_hdr(skb);
         ph->utid = 0;
-        ph->message_id = PNS_PIPE_DATA;
+        if (pn->aligned) {
+                ph->message_id = PNS_PIPE_ALIGNED_DATA;
+                ph->data[0] = 0; /* padding */
+        } else
+                ph->message_id = PNS_PIPE_DATA;
         ph->pipe_handle = pn->pipe_handle;
 
         return pn_skb_send(sk, skb, &pipe_srv);
@@ -930,6 +939,9 @@ int pep_write(struct sock *sk, struct sk_buff *skb)
         struct sk_buff *rskb, *fs;
         int flen = 0;
 
+        if (pep_sk(sk)->aligned)
+                return pipe_skb_send(sk, skb);
+
         rskb = alloc_skb(MAX_PNPIPE_HEADER, GFP_ATOMIC);
         if (!rskb) {
                 kfree_skb(skb);