NFC: Stop sending LLCP frames when tx queues are getting too deep

When the tx pending queues and/or the socket tx queue is getting too deep,
we have to let userspace know. We won't be queueing any more frames until
the congestion is fixed.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/net/nfc/llcp/commands.c b/net/nfc/llcp/commands.c
index f0a3945..df24be4 100644 (file)
--- a/net/nfc/llcp/commands.c
+++ b/net/nfc/llcp/commands.c
@@ -528,6 +528,23 @@ int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
        if (local == NULL)
                return -ENODEV;
 
+       /* Remote is ready but has not acknowledged our frames */
+       if((sock->remote_ready &&
+           skb_queue_len(&sock->tx_pending_queue) >= sock->rw &&
+           skb_queue_len(&sock->tx_queue) >= 2 * sock->rw)) {
+               pr_err("Pending queue is full %d frames\n",
+                      skb_queue_len(&sock->tx_pending_queue));
+               return -ENOBUFS;
+       }
+
+       /* Remote is not ready and we've been queueing enough frames */
+       if ((!sock->remote_ready &&
+            skb_queue_len(&sock->tx_queue) >= 2 * sock->rw)) {
+               pr_err("Tx queue is full %d frames\n",
+                      skb_queue_len(&sock->tx_queue));
+               return -ENOBUFS;
+       }
+
        msg_data = kzalloc(len, GFP_KERNEL);
        if (msg_data == NULL)
                return -ENOMEM;