Re: [PATCH v2] Bluetooth: BCSP fails to ACK re-transmitted frames from the peer
From: Jiada Wang
Date: Tue Jul 15 2014 - 08:57:48 EST
Hi Marcel
On 07/15/2014 04:42 AM, Marcel Holtmann wrote:
Hi Jiada,
Send an ACK frame with the current txack value in response to
every received reliable frame unless a TX reliable frame is being
sent. This modification allows re-transmitted frames from the remote
peer to be acknowledged rather than ignored. It means that the remote
peer knows which frame number to start re-transmitting from.
Without this modification, the recovery time to a missing frame
from the remote peer was unnecessarily being extended because the
headers of the out of order reliable frames were being discarded rather
than being processed. The frame headers of received frames will
indicate whether the local peer's transmissions have been
acknowledged by the remote peer. Therefore, the local peer may
unnecessarily re-transmit despite the remote peer already indicating
that the frame had been acknowledged in out of order reliable frame.
Signed-off-by: Dean Jenkins <djenkins@xxxxxxxxxx>
Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
---
drivers/bluetooth/hci_bcsp.c | 94 ++++++++++++++++++++++++++++----------------
1 file changed, 60 insertions(+), 34 deletions(-)
diff --git a/drivers/bluetooth/hci_bcsp.c b/drivers/bluetooth/hci_bcsp.c
index 21cc45b..0f4664d 100644
--- a/drivers/bluetooth/hci_bcsp.c
+++ b/drivers/bluetooth/hci_bcsp.c
@@ -478,13 +478,29 @@ static inline void bcsp_unslip_one_byte(struct bcsp_struct *bcsp, unsigned char
static void bcsp_complete_rx_pkt(struct hci_uart *hu)
{
struct bcsp_struct *bcsp = hu->priv;
- int pass_up;
+ int pass_up = 0;
if (bcsp->rx_skb->data[0] & 0x80) { /* reliable pkt */
BT_DBG("Received seqno %u from card", bcsp->rxseq_txack);
- bcsp->rxseq_txack++;
- bcsp->rxseq_txack %= 0x8;
- bcsp->txack_req = 1;
+
+ /* check the rx sequence number is as expected */
+ if ((bcsp->rx_skb->data[0] & 0x07) == bcsp->rxseq_txack) {
+ bcsp->rxseq_txack++;
+ bcsp->rxseq_txack %= 0x8;
+ } else {
+ /*
+ * handle re-transmitted packet or
+ * when packet was missed
+ */
Comment style is wrong.
/* aaa
* bbb
*/
+ BT_ERR ("Out-of-order packet arrived, got %u expected %u",
+ bcsp->rx_skb->data[0] & 0x07, bcsp->rxseq_txack);
It is BT_ERR(" and not BT_ERR (".
+
+ /* do not process out-of-order packet payload */
+ pass_up = 2;
+ }
+
+ /* send current txack value to all recieved reliable packets */
+ bcsp->txack_req = 1;
/* If needed, transmit an ack pkt */
hci_uart_tx_wakeup(hu);
@@ -493,26 +509,36 @@ static void bcsp_complete_rx_pkt(struct hci_uart *hu)
bcsp->rxack = (bcsp->rx_skb->data[0] >> 3) & 0x07;
BT_DBG("Request for pkt %u from card", bcsp->rxack);
+ /*
+ * handle recieved ACK indications,
+ * including those from out-of-order packets
+ */
Same here. Please fix comment style.
bcsp_pkt_cull(bcsp);
- if ((bcsp->rx_skb->data[1] & 0x0f) == 6 &&
- bcsp->rx_skb->data[0] & 0x80) {
- bt_cb(bcsp->rx_skb)->pkt_type = HCI_ACLDATA_PKT;
- pass_up = 1;
- } else if ((bcsp->rx_skb->data[1] & 0x0f) == 5 &&
- bcsp->rx_skb->data[0] & 0x80) {
- bt_cb(bcsp->rx_skb)->pkt_type = HCI_EVENT_PKT;
- pass_up = 1;
- } else if ((bcsp->rx_skb->data[1] & 0x0f) == 7) {
- bt_cb(bcsp->rx_skb)->pkt_type = HCI_SCODATA_PKT;
- pass_up = 1;
- } else if ((bcsp->rx_skb->data[1] & 0x0f) == 1 &&
- !(bcsp->rx_skb->data[0] & 0x80)) {
- bcsp_handle_le_pkt(hu);
- pass_up = 0;
- } else
- pass_up = 0;
-
- if (!pass_up) {
+
+ if (pass_up != 2) {
+ if ((bcsp->rx_skb->data[1] & 0x0f) == 6 &&
+ bcsp->rx_skb->data[0] & 0x80) {
Fix indentation here.
Can you tell me what should be the correct indentation.
+ bt_cb(bcsp->rx_skb)->pkt_type = HCI_ACLDATA_PKT;
+ pass_up = 1;
+ } else if ((bcsp->rx_skb->data[1] & 0x0f) == 5 &&
+ bcsp->rx_skb->data[0] & 0x80) {
And here.
+ bt_cb(bcsp->rx_skb)->pkt_type = HCI_EVENT_PKT;
+ pass_up = 1;
+ } else if ((bcsp->rx_skb->data[1] & 0x0f) == 7) {
+ bt_cb(bcsp->rx_skb)->pkt_type = HCI_SCODATA_PKT;
+ pass_up = 1;
+ } else if ((bcsp->rx_skb->data[1] & 0x0f) == 1 &&
+ !(bcsp->rx_skb->data[0] & 0x80)) {
Same here.
+ bcsp_handle_le_pkt(hu);
+ pass_up = 0;
+ } else {
+ pass_up = 0;
+ }
+ }
+
+ switch (pass_up) {
+ case 0:
+ {
struct hci_event_hdr hdr;
u8 desc = (bcsp->rx_skb->data[1] & 0x0f);
In general I do not prefer using { } in case statements. Please declare the variables where they are needed or use if else.
@@ -537,11 +563,21 @@ static void bcsp_complete_rx_pkt(struct hci_uart *hu)
}
} else
kfree_skb(bcsp->rx_skb);
- } else {
+ break;
+ }
+ case 1:
/* Pull out BCSP hdr */
skb_pull(bcsp->rx_skb, 4);
hci_recv_frame(hu->hdev, bcsp->rx_skb);
+ break;
+ default:
+ /*
+ * ignore packet payload of already ACKed re-transmitted
+ * packets or when a packet was missed in the BCSP window
+ */
Fix up comment style.
+ kfree_skb(bcsp->rx_skb);
+ break;
}
bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
@@ -587,16 +623,6 @@ static int bcsp_recv(struct hci_uart *hu, void *data, int count)
bcsp->rx_count = 0;
continue;
}
- if (bcsp->rx_skb->data[0] & 0x80 /* reliable pkt */
- && (bcsp->rx_skb->data[0] & 0x07) != bcsp->rxseq_txack) {
- BT_ERR ("Out-of-order packet arrived, got %u expected %u",
- bcsp->rx_skb->data[0] & 0x07, bcsp->rxseq_txack);
-
- kfree_skb(bcsp->rx_skb);
- bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
- bcsp->rx_count = 0;
- continue;
- }
bcsp->rx_state = BCSP_W4_DATA;
bcsp->rx_count = (bcsp->rx_skb->data[1] >> 4) +
(bcsp->rx_skb->data[2] << 4); /* May be 0 */
Regards
Marcel
Thanks,
Jiada
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