caif: Use link layer MTU instead of fixed MTU
Previously CAIF supported maximum transfer size of ~4050.
The transfer size is now calculated dynamically based on the
link layers mtu size.
Signed-off-by: Sjur Braendeland@stericsson.com
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/caif/chnl_net.c b/net/caif/chnl_net.c
index 610966a..4293e19 100644
--- a/net/caif/chnl_net.c
+++ b/net/caif/chnl_net.c
@@ -23,7 +23,7 @@
#include <net/caif/caif_dev.h>
/* GPRS PDP connection has MTU to 1500 */
-#define SIZE_MTU 1500
+#define GPRS_PDP_MTU 1500
/* 5 sec. connect timeout */
#define CONNECT_TIMEOUT (5 * HZ)
#define CAIF_NET_DEFAULT_QUEUE_LEN 500
@@ -232,6 +232,8 @@
{
struct chnl_net *priv = NULL;
int result = -1;
+ int llifindex, headroom, tailroom, mtu;
+ struct net_device *lldev;
ASSERT_RTNL();
priv = netdev_priv(dev);
if (!priv) {
@@ -241,41 +243,88 @@
if (priv->state != CAIF_CONNECTING) {
priv->state = CAIF_CONNECTING;
- result = caif_connect_client(&priv->conn_req, &priv->chnl);
+ result = caif_connect_client(&priv->conn_req, &priv->chnl,
+ &llifindex, &headroom, &tailroom);
if (result != 0) {
- priv->state = CAIF_DISCONNECTED;
pr_debug("CAIF: %s(): err: "
"Unable to register and open device,"
" Err:%d\n",
__func__,
result);
- return result;
+ goto error;
+ }
+
+ lldev = dev_get_by_index(dev_net(dev), llifindex);
+
+ if (lldev == NULL) {
+ pr_debug("CAIF: %s(): no interface?\n", __func__);
+ result = -ENODEV;
+ goto error;
+ }
+
+ dev->needed_tailroom = tailroom + lldev->needed_tailroom;
+ dev->hard_header_len = headroom + lldev->hard_header_len +
+ lldev->needed_tailroom;
+
+ /*
+ * MTU, head-room etc is not know before we have a
+ * CAIF link layer device available. MTU calculation may
+ * override initial RTNL configuration.
+ * MTU is minimum of current mtu, link layer mtu pluss
+ * CAIF head and tail, and PDP GPRS contexts max MTU.
+ */
+ mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
+ mtu = min_t(int, GPRS_PDP_MTU, mtu);
+ dev_set_mtu(dev, mtu);
+ dev_put(lldev);
+
+ if (mtu < 100) {
+ pr_warning("CAIF: %s(): "
+ "CAIF Interface MTU too small (%d)\n",
+ __func__, mtu);
+ result = -ENODEV;
+ goto error;
}
}
+ rtnl_unlock(); /* Release RTNL lock during connect wait */
+
result = wait_event_interruptible_timeout(priv->netmgmt_wq,
priv->state != CAIF_CONNECTING,
CONNECT_TIMEOUT);
+ rtnl_lock();
+
if (result == -ERESTARTSYS) {
pr_debug("CAIF: %s(): wait_event_interruptible"
" woken by a signal\n", __func__);
- return -ERESTARTSYS;
+ result = -ERESTARTSYS;
+ goto error;
}
+
if (result == 0) {
pr_debug("CAIF: %s(): connect timeout\n", __func__);
caif_disconnect_client(&priv->chnl);
priv->state = CAIF_DISCONNECTED;
pr_debug("CAIF: %s(): state disconnected\n", __func__);
- return -ETIMEDOUT;
+ result = -ETIMEDOUT;
+ goto error;
}
if (priv->state != CAIF_CONNECTED) {
pr_debug("CAIF: %s(): connect failed\n", __func__);
- return -ECONNREFUSED;
+ result = -ECONNREFUSED;
+ goto error;
}
pr_debug("CAIF: %s(): CAIF Netdevice connected\n", __func__);
return 0;
+
+error:
+ caif_disconnect_client(&priv->chnl);
+ priv->state = CAIF_DISCONNECTED;
+ pr_debug("CAIF: %s(): state disconnected\n", __func__);
+ return result;
+
}
static int chnl_net_stop(struct net_device *dev)
@@ -321,9 +370,7 @@
dev->destructor = free_netdev;
dev->flags |= IFF_NOARP;
dev->flags |= IFF_POINTOPOINT;
- dev->needed_headroom = CAIF_NEEDED_HEADROOM;
- dev->needed_tailroom = CAIF_NEEDED_TAILROOM;
- dev->mtu = SIZE_MTU;
+ dev->mtu = GPRS_PDP_MTU;
dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
priv = netdev_priv(dev);