From: Johan Hedberg <johan.hedberg@xxxxxxxxx>
We should return credits to the remote side whenever they fall below a
certain level (in our case under half of the initially given amount).
Signed-off-by: Johan Hedberg <johan.hedberg@xxxxxxxxx>
---
net/bluetooth/l2cap_core.c | 33 ++++++++++++++++++++++++++++++++-
1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 8a1c528908fb..b99bdc53c57b 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -2542,8 +2542,10 @@ int l2cap_chan_send(struct l2cap_chan *chan, struct msghdr *msg, size_t len,
}
switch (chan->mode) {
- case L2CAP_MODE_BASIC:
case L2CAP_MODE_LE_FLOWCTL:
+ chan->tx_credits--;
+ /* fall through */
+ case L2CAP_MODE_BASIC:
/* Check outgoing MTU */
if (len > chan->omtu)
return -EMSGSIZE;
@@ -6608,6 +6610,32 @@ drop:
return 0;
}
+static void l2cap_chan_le_send_credits(struct l2cap_chan *chan)
+{
+ struct l2cap_conn *conn = chan->conn;
+ struct l2cap_le_credits pkt;
+ u16 return_credits;
+
+ /* We return more credits to the sender only after the amount of
+ * credits falls below half of the initial amount.
+ */
+ if (chan->rx_credits >= L2CAP_LE_MAX_CREDITS / 2)
+ return;
+
+ return_credits = L2CAP_LE_MAX_CREDITS - chan->rx_credits;
+
+ BT_DBG("chan %p returning %u credits to sender", chan, return_credits);
+
+ chan->rx_credits += return_credits;
+
+ pkt.cid = cpu_to_le16(chan->scid);
+ pkt.credits = cpu_to_le16(return_credits);
+
+ chan->ident = l2cap_get_ident(conn);
+
+ l2cap_send_cmd(conn, chan->ident, L2CAP_LE_CREDITS, sizeof(pkt), &pkt);
+}
+
static void l2cap_data_channel(struct l2cap_conn *conn, u16 cid,
struct sk_buff *skb)
{
@@ -6638,6 +6666,9 @@ static void l2cap_data_channel(struct l2cap_conn *conn, u16 cid,
switch (chan->mode) {
case L2CAP_MODE_LE_FLOWCTL:
+ chan->rx_credits--;
+ l2cap_chan_le_send_credits(chan);
+ /* fall through */
case L2CAP_MODE_BASIC:
/* If socket recv buffers overflows we drop data here
* which is *bad* because L2CAP has to be reliable.
--
1.8.4.2
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