[HDLC] Fix dev->header_cache_update having a random value.

Switching HDLC devices from Ethernet-framing mode caused stale ethernet
function assignments within net_device.

Signed-off-by: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 10 deletions

diff --git a/drivers/net/wan/hdlc.c b/drivers/net/wan/hdlc.c
index 9040d7cf651e..65ad2e24caf0 100644
--- a/drivers/net/wan/hdlc.c
+++ b/drivers/net/wan/hdlc.c
@@ -38,7 +38,7 @@
 #include <linux/hdlc.h>
 
 
-static const char* version = "HDLC support module revision 1.20";
+static const char* version = "HDLC support module revision 1.21";
 
 #undef DEBUG_LINK
 
@@ -222,19 +222,31 @@ int hdlc_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
         return -EINVAL;
 }
 
+static void hdlc_setup_dev(struct net_device *dev)
+{
+        /* Re-init all variables changed by HDLC protocol drivers,
+         * including ether_setup() called from hdlc_raw_eth.c.
+         */
+        dev->get_stats           = hdlc_get_stats;
+        dev->flags               = IFF_POINTOPOINT | IFF_NOARP;
+        dev->mtu                 = HDLC_MAX_MTU;
+        dev->type                = ARPHRD_RAWHDLC;
+        dev->hard_header_len     = 16;
+        dev->addr_len            = 0;
+        dev->hard_header         = NULL;
+        dev->rebuild_header      = NULL;
+        dev->set_mac_address     = NULL;
+        dev->hard_header_cache   = NULL;
+        dev->header_cache_update = NULL;
+        dev->change_mtu          = hdlc_change_mtu;
+        dev->hard_header_parse   = NULL;
+}
+
 static void hdlc_setup(struct net_device *dev)
 {
         hdlc_device *hdlc = dev_to_hdlc(dev);
 
-        dev->get_stats = hdlc_get_stats;
-        dev->change_mtu = hdlc_change_mtu;
-        dev->mtu = HDLC_MAX_MTU;
-
-        dev->type = ARPHRD_RAWHDLC;
-        dev->hard_header_len = 16;
-
-        dev->flags = IFF_POINTOPOINT | IFF_NOARP;
-
+        hdlc_setup_dev(dev);
         hdlc->carrier = 1;
         hdlc->open = 0;
         spin_lock_init(&hdlc->state_lock);
@@ -294,6 +306,7 @@ void detach_hdlc_protocol(struct net_device *dev)
         }
         kfree(hdlc->state);
         hdlc->state = NULL;
+        hdlc_setup_dev(dev);
 }