isdn/gigaset: correct bas_gigaset rx buffer handling

In transparent data reception, avoid a NULL pointer dereference
in case an skbuff cannot be allocated, remove an inappropriate
call to the HDLC flush routine, and correct the accounting of
received bytes for continued buffers.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
CC: stable <stable@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/isdn/gigaset/isocdata.c b/drivers/isdn/gigaset/isocdata.c
index 2dfd346fc889..f39ccdf87a17 100644
--- a/drivers/isdn/gigaset/isocdata.c
+++ b/drivers/isdn/gigaset/isocdata.c
@@ -842,13 +842,14 @@ static inline void trans_receive(unsigned char *src, unsigned count,
 
         if (unlikely(bcs->ignore)) {
                 bcs->ignore--;
-                hdlc_flush(bcs);
                 return;
         }
         skb = bcs->rx_skb;
-        if (skb == NULL)
+        if (skb == NULL) {
                 skb = gigaset_new_rx_skb(bcs);
-        bcs->hw.bas->goodbytes += skb->len;
+                if (skb == NULL)
+                        return;
+        }
         dobytes = bcs->rx_bufsize - skb->len;
         while (count > 0) {
                 dst = skb_put(skb, count < dobytes ? count : dobytes);
@@ -860,6 +861,7 @@ static inline void trans_receive(unsigned char *src, unsigned count,
                 if (dobytes == 0) {
                         dump_bytes(DEBUG_STREAM_DUMP,
                                    "rcv data", skb->data, skb->len);
+                        bcs->hw.bas->goodbytes += skb->len;
                         gigaset_skb_rcvd(bcs, skb);
                         skb = gigaset_new_rx_skb(bcs);
                         if (skb == NULL)