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Bluetooth: L2CAP: Prevent the channel to stall

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If the remote stack is not able to fully utilize each segment it is
possible it would run out of credits before completing the SDU, these
changes detects if that would happen and attempt to restore enough
credits for the SDU to be received.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Luiz Augusto von Dentz 2018-09-04 11:14:30 +03:00 • committed by Johan Hedberg
commit 62f41df283
1 changed files with 24 additions and 0 deletions
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24
subsys/bluetooth/host/l2cap.c
View file

@ -1355,6 +1355,22 @@ static void l2cap_chan_send_credits(struct bt_l2cap_le_chan *chan,
BT_DBG("chan %p credits %u", chan, k_sem_count_get(&chan->rx.credits));
}
static void l2cap_chan_update_credits(struct bt_l2cap_le_chan *chan,
struct net_buf *buf)
{
s16_t credits;
/* Restore enough credits to complete the sdu */
credits = ((chan->_sdu_len - net_buf_frags_len(buf)) +
(chan->rx.mps - 1)) / chan->rx.mps;
credits -= k_sem_count_get(&chan->rx.credits);
if (credits <= 0) {
return;
}
l2cap_chan_send_credits(chan, buf, credits);
}
int bt_l2cap_chan_recv_complete(struct bt_l2cap_chan *chan, struct net_buf *buf)
{
struct bt_l2cap_le_chan *ch = BT_L2CAP_LE_CHAN(chan);
@ -1468,6 +1484,14 @@ static void l2cap_chan_le_recv_seg(struct bt_l2cap_le_chan *chan,
}
if (net_buf_frags_len(chan->_sdu) < chan->_sdu_len) {
/* Give more credits if remote has run out of them, this
* should only happen if the remote cannot fully utilize the
* MPS for some reason.
*/
if (!k_sem_count_get(&chan->rx.credits) &&
seg == chan->rx.init_credits) {
l2cap_chan_update_credits(chan, buf);
}
return;
}