aboutsummaryrefslogtreecommitdiff
path: root/net/bluetooth
diff options
context:
space:
mode:
authorLuiz Augusto von Dentz2018-09-04 13:39:21 +0300
committerMarcel Holtmann2018-09-27 12:52:08 +0200
commit96cd8eaa131f0ffd4cfae09e1b4bdfafb9570907 (patch)
tree6d5f16337fdb75ac7cc472ef78f35e82ba2b7cfc /net/bluetooth
parentfe1493101ac1313cbdbef1af65342fb17d944e71 (diff)
Bluetooth: L2CAP: Derive rx credits from MTU and MPS
Give enough rx credits for a full packet instead of using an arbitrary number which may not be enough depending on the MTU and MPS which can cause interruptions while waiting for more credits, also remove debugfs entry for l2cap_le_max_credits. With these changes the credits are restored after each SDU is received instead of using fixed threshold, this way it is garanteed that there will always be enough credits to send a packet without waiting more credits to arrive. Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'net/bluetooth')
-rw-r--r--net/bluetooth/l2cap_core.c42
1 files changed, 27 insertions, 15 deletions
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 8a60db6261f7..3fb2d757df88 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -51,8 +51,6 @@ static u32 l2cap_feat_mask = L2CAP_FEAT_FIXED_CHAN | L2CAP_FEAT_UCD;
static LIST_HEAD(chan_list);
static DEFINE_RWLOCK(chan_list_lock);
-static u16 le_max_credits = L2CAP_LE_MAX_CREDITS;
-
static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn,
u8 code, u8 ident, u16 dlen, void *data);
static void l2cap_send_cmd(struct l2cap_conn *conn, u8 ident, u8 code, u16 len,
@@ -518,9 +516,10 @@ static void l2cap_le_flowctl_init(struct l2cap_chan *chan)
chan->sdu_last_frag = NULL;
chan->sdu_len = 0;
chan->tx_credits = 0;
- chan->rx_credits = le_max_credits;
/* Derive MPS from connection MTU to stop HCI fragmentation */
chan->mps = min_t(u16, chan->imtu, chan->conn->mtu - L2CAP_HDR_SIZE);
+ /* Give enough credits for a full packet */
+ chan->rx_credits = (chan->imtu / chan->mps) + 1;
skb_queue_head_init(&chan->tx_q);
}
@@ -6702,13 +6701,10 @@ static void l2cap_chan_le_send_credits(struct l2cap_chan *chan)
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 >= (le_max_credits + 1) / 2)
- return;
+ return_credits = ((chan->imtu / chan->mps) + 1) - chan->rx_credits;
- return_credits = le_max_credits - chan->rx_credits;
+ if (!return_credits)
+ return;
BT_DBG("chan %p returning %u credits to sender", chan, return_credits);
@@ -6722,6 +6718,21 @@ static void l2cap_chan_le_send_credits(struct l2cap_chan *chan)
l2cap_send_cmd(conn, chan->ident, L2CAP_LE_CREDITS, sizeof(pkt), &pkt);
}
+static int l2cap_le_recv(struct l2cap_chan *chan, struct sk_buff *skb)
+{
+ int err;
+
+ BT_DBG("SDU reassemble complete: chan %p skb->len %u", chan, skb->len);
+
+ /* Wait recv to confirm reception before updating the credits */
+ err = chan->ops->recv(chan, skb);
+
+ /* Update credits whenever an SDU is received */
+ l2cap_chan_le_send_credits(chan);
+
+ return err;
+}
+
static int l2cap_le_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
{
int err;
@@ -6740,7 +6751,11 @@ static int l2cap_le_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
chan->rx_credits--;
BT_DBG("rx_credits %u -> %u", chan->rx_credits + 1, chan->rx_credits);
- l2cap_chan_le_send_credits(chan);
+ /* Update if remote had run out of credits, this should only happens
+ * if the remote is not using the entire MPS.
+ */
+ if (!chan->rx_credits)
+ l2cap_chan_le_send_credits(chan);
err = 0;
@@ -6766,7 +6781,7 @@ static int l2cap_le_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
}
if (skb->len == sdu_len)
- return chan->ops->recv(chan, skb);
+ return l2cap_le_recv(chan, skb);
chan->sdu = skb;
chan->sdu_len = sdu_len;
@@ -6788,7 +6803,7 @@ static int l2cap_le_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
skb = NULL;
if (chan->sdu->len == chan->sdu_len) {
- err = chan->ops->recv(chan, chan->sdu);
+ err = l2cap_le_recv(chan, chan->sdu);
if (!err) {
chan->sdu = NULL;
chan->sdu_last_frag = NULL;
@@ -7647,9 +7662,6 @@ int __init l2cap_init(void)
l2cap_debugfs = debugfs_create_file("l2cap", 0444, bt_debugfs,
NULL, &l2cap_debugfs_fops);
- debugfs_create_u16("l2cap_le_max_credits", 0644, bt_debugfs,
- &le_max_credits);
-
return 0;
}