From fe1493101ac1313cbdbef1af65342fb17d944e71 Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Tue, 4 Sep 2018 13:39:20 +0300 Subject: [PATCH] Bluetooth: L2CAP: Derive MPS from connection MTU This ensures the MPS can fit in a single HCI fragment so each segment don't have to be reassembled at HCI level, in addition to that also remove the debugfs entry to configure the MPS. Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann --- include/net/bluetooth/l2cap.h | 1 - net/bluetooth/l2cap_core.c | 14 +++++++------- 2 files changed, 7 insertions(+), 8 deletions(-) diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 0697fd4..1729667 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -456,7 +456,6 @@ struct l2cap_conn_param_update_rsp { #define L2CAP_CONN_PARAM_REJECTED 0x0001 #define L2CAP_LE_MAX_CREDITS 10 -#define L2CAP_LE_DEFAULT_MPS 230 struct l2cap_le_conn_req { __le16 psm; diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index d17a473..8a60db6 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -52,7 +52,6 @@ static LIST_HEAD(chan_list); static DEFINE_RWLOCK(chan_list_lock); static u16 le_max_credits = L2CAP_LE_MAX_CREDITS; -static u16 le_default_mps = L2CAP_LE_DEFAULT_MPS; static struct sk_buff *l2cap_build_cmd(struct l2cap_conn *conn, u8 code, u8 ident, u16 dlen, void *data); @@ -520,7 +519,8 @@ static void l2cap_le_flowctl_init(struct l2cap_chan *chan) chan->sdu_len = 0; chan->tx_credits = 0; chan->rx_credits = le_max_credits; - chan->mps = min_t(u16, chan->imtu, le_default_mps); + /* Derive MPS from connection MTU to stop HCI fragmentation */ + chan->mps = min_t(u16, chan->imtu, chan->conn->mtu - L2CAP_HDR_SIZE); skb_queue_head_init(&chan->tx_q); } @@ -1282,6 +1282,8 @@ static void l2cap_le_connect(struct l2cap_chan *chan) if (test_and_set_bit(FLAG_LE_CONN_REQ_SENT, &chan->flags)) return; + l2cap_le_flowctl_init(chan); + req.psm = chan->psm; req.scid = cpu_to_le16(chan->scid); req.mtu = cpu_to_le16(chan->imtu); @@ -5493,8 +5495,6 @@ static int l2cap_le_connect_req(struct l2cap_conn *conn, goto response_unlock; } - l2cap_le_flowctl_init(chan); - bacpy(&chan->src, &conn->hcon->src); bacpy(&chan->dst, &conn->hcon->dst); chan->src_type = bdaddr_src_type(conn->hcon); @@ -5506,6 +5506,9 @@ static int l2cap_le_connect_req(struct l2cap_conn *conn, chan->tx_credits = __le16_to_cpu(req->credits); __l2cap_chan_add(conn, chan); + + l2cap_le_flowctl_init(chan); + dcid = chan->scid; credits = chan->rx_credits; @@ -7102,7 +7105,6 @@ int l2cap_chan_connect(struct l2cap_chan *chan, __le16 psm, u16 cid, case L2CAP_MODE_BASIC: break; case L2CAP_MODE_LE_FLOWCTL: - l2cap_le_flowctl_init(chan); break; case L2CAP_MODE_ERTM: case L2CAP_MODE_STREAMING: @@ -7647,8 +7649,6 @@ int __init l2cap_init(void) debugfs_create_u16("l2cap_le_max_credits", 0644, bt_debugfs, &le_max_credits); - debugfs_create_u16("l2cap_le_default_mps", 0644, bt_debugfs, - &le_default_mps); return 0; } -- 2.7.4