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Bluetooth: L2CAP: Offload processing of tx_queue to a work

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This offloads the processing of tx_queue to a work so the callbacks
calling resume don't start sending packets directly which can cause
stack overflow.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Luiz Augusto von Dentz 2019-11-18 18:29:45 +02:00 • committed by Johan Hedberg
commit cf84216b1a
2 changed files with 83 additions and 61 deletions
Download patch file Download diff file Expand all files Collapse all files

2
include/bluetooth/l2cap.h
View file

@ -126,6 +126,8 @@ struct bt_l2cap_le_chan {
struct k_fifo tx_queue; struct k_fifo tx_queue;
/** Channel Pending Transmission buffer */ /** Channel Pending Transmission buffer */
struct net_buf *tx_buf; struct net_buf *tx_buf;
/** Channel Transmission work */
struct k_work tx_work;
/** Segment SDU packet from upper layer */ /** Segment SDU packet from upper layer */
struct net_buf *_sdu; struct net_buf *_sdu;
u16_t _sdu_len; u16_t _sdu_len;

142
subsys/bluetooth/host/l2cap.c
View file

@ -724,6 +724,46 @@ static void l2cap_chan_rx_init(struct bt_l2cap_le_chan *chan)
} }
} }
static struct net_buf *l2cap_chan_le_get_tx_buf(struct bt_l2cap_le_chan *ch)
{
struct net_buf *buf;
/* Return current buffer */
if (ch->tx_buf) {
buf = ch->tx_buf;
ch->tx_buf = NULL;
return buf;
}
return net_buf_get(&ch->tx_queue, K_NO_WAIT);
}
static int l2cap_chan_le_send_sdu(struct bt_l2cap_le_chan *ch,
struct net_buf **buf, u16_t sent);
static void l2cap_chan_tx_process(struct k_work *work)
{
struct bt_l2cap_le_chan *ch;
struct net_buf *buf;
ch = CONTAINER_OF(work, struct bt_l2cap_le_chan, tx_work);
/* Resume tx in case there are buffers in the queue */
while ((buf = l2cap_chan_le_get_tx_buf(ch))) {
int sent = data_sent(buf)->len;
BT_DBG("buf %p sent %u", buf, sent);
sent = l2cap_chan_le_send_sdu(ch, &buf, sent);
if (sent < 0) {
if (sent == -EAGAIN) {
ch->tx_buf = buf;
}
break;
}
}
}
static void l2cap_chan_tx_init(struct bt_l2cap_le_chan *chan) static void l2cap_chan_tx_init(struct bt_l2cap_le_chan *chan)
{ {
BT_DBG("chan %p", chan); BT_DBG("chan %p", chan);
@ -731,6 +771,7 @@ static void l2cap_chan_tx_init(struct bt_l2cap_le_chan *chan)
(void)memset(&chan->tx, 0, sizeof(chan->tx)); (void)memset(&chan->tx, 0, sizeof(chan->tx));
k_sem_init(&chan->tx.credits, 0, UINT_MAX); k_sem_init(&chan->tx.credits, 0, UINT_MAX);
k_fifo_init(&chan->tx_queue); k_fifo_init(&chan->tx_queue);
k_work_init(&chan->tx_work, l2cap_chan_tx_process);
} }
static void l2cap_chan_tx_give_credits(struct bt_l2cap_le_chan *chan, static void l2cap_chan_tx_give_credits(struct bt_l2cap_le_chan *chan,
@ -1180,7 +1221,15 @@ segment:
return seg; return seg;
} }
static void l2cap_chan_le_send_resume(struct bt_l2cap_le_chan *ch); static void l2cap_chan_tx_resume(struct bt_l2cap_le_chan *ch)
{
if (!k_sem_count_get(&ch->tx.credits) ||
(k_fifo_is_empty(&ch->tx_queue) && !ch->tx_buf)) {
return;
}
k_work_submit(&ch->tx_work);
}
static void l2cap_chan_sdu_sent(struct bt_conn *conn, void *user_data) static void l2cap_chan_sdu_sent(struct bt_conn *conn, void *user_data)
{ {
@ -1192,7 +1241,7 @@ static void l2cap_chan_sdu_sent(struct bt_conn *conn, void *user_data)
chan->ops->sent(chan); chan->ops->sent(chan);
} }
l2cap_chan_le_send_resume(BT_L2CAP_LE_CHAN(chan)); l2cap_chan_tx_resume(BT_L2CAP_LE_CHAN(chan));
} }
static void l2cap_chan_seg_sent(struct bt_conn *conn, void *user_data) static void l2cap_chan_seg_sent(struct bt_conn *conn, void *user_data)
@ -1201,14 +1250,14 @@ static void l2cap_chan_seg_sent(struct bt_conn *conn, void *user_data)
BT_DBG("conn %p chan %p", conn, chan); BT_DBG("conn %p chan %p", conn, chan);
l2cap_chan_le_send_resume(BT_L2CAP_LE_CHAN(chan)); l2cap_chan_tx_resume(BT_L2CAP_LE_CHAN(chan));
} }
static int l2cap_chan_le_send(struct bt_l2cap_le_chan *ch, struct net_buf *buf, static int l2cap_chan_le_send(struct bt_l2cap_le_chan *ch, struct net_buf *buf,
u16_t sdu_hdr_len) u16_t sdu_hdr_len)
{ {
struct net_buf *seg; struct net_buf *seg;
int len; int len, err;
/* Wait for credits */ /* Wait for credits */
if (k_sem_take(&ch->tx.credits, K_NO_WAIT)) { if (k_sem_take(&ch->tx.credits, K_NO_WAIT)) {
@ -1224,7 +1273,7 @@ static int l2cap_chan_le_send(struct bt_l2cap_le_chan *ch, struct net_buf *buf,
/* Channel may have been disconnected while waiting for a buffer */ /* Channel may have been disconnected while waiting for a buffer */
if (!ch->chan.conn) { if (!ch->chan.conn) {
net_buf_unref(buf); net_buf_unref(seg);
return -ECONNRESET; return -ECONNRESET;
} }
@ -1237,11 +1286,22 @@ static int l2cap_chan_le_send(struct bt_l2cap_le_chan *ch, struct net_buf *buf,
* callback has been set. * callback has been set.
*/ */
if ((buf == seg || !buf->len) && ch->chan.ops->sent) { if ((buf == seg || !buf->len) && ch->chan.ops->sent) {
bt_l2cap_send_cb(ch->chan.conn, ch->tx.cid, seg, err = bt_l2cap_send_cb(ch->chan.conn, ch->tx.cid, seg,
l2cap_chan_sdu_sent, &ch->chan); l2cap_chan_sdu_sent, &ch->chan);
} else { } else {
bt_l2cap_send_cb(ch->chan.conn, ch->tx.cid, seg, err = bt_l2cap_send_cb(ch->chan.conn, ch->tx.cid, seg,
l2cap_chan_seg_sent, &ch->chan); l2cap_chan_seg_sent, &ch->chan);
}
if (err) {
BT_WARN("Unable to send seg %d", err);
k_sem_give(&ch->tx.credits);
if (err == -ENOBUFS) {
return -EAGAIN;
}
return err;
} }
/* Check if there is no credits left clear output status and notify its /* Check if there is no credits left clear output status and notify its
@ -1314,44 +1374,6 @@ static int l2cap_chan_le_send_sdu(struct bt_l2cap_le_chan *ch,
return ret; return ret;
} }
static struct net_buf *l2cap_chan_le_get_tx_buf(struct bt_l2cap_le_chan *ch)
{
struct net_buf *buf;
/* Return current buffer */
if (ch->tx_buf) {
buf = ch->tx_buf;
ch->tx_buf = NULL;
return buf;
}
return net_buf_get(&ch->tx_queue, K_NO_WAIT);
}
static void l2cap_chan_le_send_resume(struct bt_l2cap_le_chan *ch)
{
struct net_buf *buf;
if (!k_sem_count_get(&ch->tx.credits)) {
return;
}
/* Resume tx in case there are buffers in the queue */
while ((buf = l2cap_chan_le_get_tx_buf(ch))) {
u16_t sent = data_sent(buf)->len;
BT_DBG("buf %p sent %u", buf, sent);
sent = l2cap_chan_le_send_sdu(ch, &buf, sent);
if (sent < 0) {
if (sent == -EAGAIN) {
ch->tx_buf = buf;
}
break;
}
}
}
static void le_credits(struct bt_l2cap *l2cap, u8_t ident, static void le_credits(struct bt_l2cap *l2cap, u8_t ident,
struct net_buf *buf) struct net_buf *buf)
{ {
@ -1390,7 +1412,7 @@ static void le_credits(struct bt_l2cap *l2cap, u8_t ident,
BT_DBG("chan %p total credits %u", ch, BT_DBG("chan %p total credits %u", ch,
k_sem_count_get(&ch->tx.credits)); k_sem_count_get(&ch->tx.credits));
l2cap_chan_le_send_resume(ch); l2cap_chan_tx_resume(ch);
} }
static void reject_cmd(struct bt_l2cap *l2cap, u8_t ident, static void reject_cmd(struct bt_l2cap *l2cap, u8_t ident,
@ -1491,14 +1513,16 @@ static void l2cap_chan_send_credits(struct bt_l2cap_le_chan *chan,
credits = chan->rx.init_credits; credits = chan->rx.init_credits;
} }
l2cap_chan_rx_give_credits(chan, credits);
buf = l2cap_create_le_sig_pdu(buf, BT_L2CAP_LE_CREDITS, get_ident(), buf = l2cap_create_le_sig_pdu(buf, BT_L2CAP_LE_CREDITS, get_ident(),
sizeof(*ev)); sizeof(*ev));
if (!buf) { if (!buf) {
BT_ERR("Unable to send credits update");
bt_l2cap_chan_disconnect(&chan->chan);
return; return;
} }
l2cap_chan_rx_give_credits(chan, credits);
ev = net_buf_add(buf, sizeof(*ev)); ev = net_buf_add(buf, sizeof(*ev));
ev->cid = sys_cpu_to_le16(chan->rx.cid); ev->cid = sys_cpu_to_le16(chan->rx.cid);
ev->credits = sys_cpu_to_le16(credits); ev->credits = sys_cpu_to_le16(credits);
@ -1919,6 +1943,7 @@ int bt_l2cap_chan_disconnect(struct bt_l2cap_chan *chan)
int bt_l2cap_chan_send(struct bt_l2cap_chan *chan, struct net_buf *buf) int bt_l2cap_chan_send(struct bt_l2cap_chan *chan, struct net_buf *buf)
{ {
struct bt_l2cap_le_chan *ch = BT_L2CAP_LE_CHAN(chan);
int err; int err;
if (!buf) { if (!buf) {
@ -1936,24 +1961,19 @@ int bt_l2cap_chan_send(struct bt_l2cap_chan *chan, struct net_buf *buf)
return bt_l2cap_br_chan_send(chan, buf); return bt_l2cap_br_chan_send(chan, buf);
} }
/* Attempt to resume first since there could be data from previous /* Queue if there pending segments left from previous packets */
* packets pending. if (ch->tx_buf || !k_fifo_is_empty(&ch->tx_queue)) {
*/
l2cap_chan_le_send_resume(BT_L2CAP_LE_CHAN(chan));
/* Check if there are still pending segments */
if (BT_L2CAP_LE_CHAN(chan)->tx_buf) {
/* Queue buffer to be sent later */
data_sent(buf)->len = 0; data_sent(buf)->len = 0;
net_buf_put(&(BT_L2CAP_LE_CHAN(chan))->tx_queue, buf); net_buf_put(&ch->tx_queue, buf);
k_work_submit(&ch->tx_work);
return 0; return 0;
} }
err = l2cap_chan_le_send_sdu(BT_L2CAP_LE_CHAN(chan), &buf, 0); err = l2cap_chan_le_send_sdu(ch, &buf, 0);
if (err < 0) { if (err < 0) {
if (err == -EAGAIN && data_sent(buf)->len) { if (err == -EAGAIN && data_sent(buf)->len) {
/* Queue buffer if at least one segment could be sent */ /* Queue buffer if at least one segment could be sent */
net_buf_put(&(BT_L2CAP_LE_CHAN(chan))->tx_queue, buf); net_buf_put(&ch->tx_queue, buf);
return data_sent(buf)->len; return data_sent(buf)->len;
} }
BT_ERR("failed to send message %d", err); BT_ERR("failed to send message %d", err);