From: Samuel Ortiz <sameo@linux.intel.com>
Date: Thu, 1 Nov 2012 22:33:00 +0000 (+0100)
Subject: NFC: Stop sending LLCP frames when tx queues are getting too deep
X-Git-Tag: v3.8-rc1~139^2~17^2~164^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dd2bf43ffcf0d1bba94d20abc6cc44ed294db66b;p=platform%2Fkernel%2Flinux-exynos.git

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
--- 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;