Phonet: zero-copy aligned GPRS RX

Newer Nokia cellular modems can use aligned payload for their GPRS pipe.

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

diff --git a/include/net/phonet/pep.h b/include/net/phonet/pep.h
index 4c61cdc..c371625 100644 (file)
--- a/include/net/phonet/pep.h
+++ b/include/net/phonet/pep.h
@@ -77,6 +77,7 @@ static inline struct pnpipehdr *pnp_hdr(struct sk_buff *skb)
 
 enum {
        PNS_PIPE_DATA = 0x20,
+       PNS_PIPE_ALIGNED_DATA,
 
        PNS_PEP_CONNECT_REQ = 0x40,
        PNS_PEP_CONNECT_RESP,

diff --git a/net/phonet/pep-gprs.c b/net/phonet/pep-gprs.c
index d183509..d012089 100644 (file)
--- a/net/phonet/pep-gprs.c
+++ b/net/phonet/pep-gprs.c
@@ -96,11 +96,11 @@ static int gprs_recv(struct gprs_dev *gp, struct sk_buff *skb)
                goto drop;
        }
 
-       if (likely(skb_headroom(skb) & 3)) {
+       if (skb_headroom(skb) & 3) {
                struct sk_buff *rskb, *fs;
                int flen = 0;
 
-               /* Phonet Pipe data header is misaligned (3 bytes),
+               /* Phonet Pipe data header may be misaligned (3 bytes),
                 * so wrap the IP packet as a single fragment of an head-less
                 * socket buffer. The network stack will pull what it needs,
                 * but at least, the whole IP payload is not memcpy'd. */

diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index b6356f3..e23e309 100644 (file)
--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -354,6 +354,9 @@ static int pipe_do_rcv(struct sock *sk, struct sk_buff *skb)
                queue = &pn->ctrlreq_queue;
                goto queue;
 
+       case PNS_PIPE_ALIGNED_DATA:
+               __skb_pull(skb, 1);
+               /* fall through */
        case PNS_PIPE_DATA:
                __skb_pull(skb, 3); /* Pipe data header */
                if (!pn_flow_safe(pn->rx_fc)) {