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>

3 files changed, 6 insertions, 2 deletions

diff --git a/include/net/phonet/pep.h b/include/net/phonet/pep.h
index 4c61cdce4e5f..c37162547a93 100644
--- 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 d183509d3fa6..d01208968c83 100644
--- 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 b6356f3832f6..e23e30907d34 100644
--- 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)) {