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Bluetooth: Perform L2CAP SDU reassembly without copying data

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Use sk_buff fragment capabilities to link together incoming skbs
instead of allocating a new skb for reassembly and copying.

The new reassembly code works equally well for ERTM and streaming
mode, so there is now one reassembly function instead of two.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This commit is contained in:
Mat Martineau 2011-07-22 14:54:00 -07:00 committed by Gustavo F. Padovan
parent 5b668eb327
commit 84084a3197
2 changed files with 82 additions and 166 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/bluetooth/l2cap.h
View File

@ -354,8 +354,8 @@ struct l2cap_chan {
__u8 retry_count;
__u8 num_acked;
__u16 sdu_len;
__u16 partial_sdu_len;
struct sk_buff *sdu;
struct sk_buff *sdu_last_frag;
__u8 remote_tx_win;
__u8 remote_max_tx;
@ -448,7 +448,6 @@ enum {
#define L2CAP_CONF_MAX_CONF_RSP 2
enum {
CONN_SAR_SDU,
CONN_SREJ_SENT,
CONN_WAIT_F,
CONN_SREJ_ACT,

237
net/bluetooth/l2cap_core.c
View File

@ -3128,102 +3128,104 @@ static int l2cap_add_to_srej_queue(struct l2cap_chan *chan, struct sk_buff *skb,
return 0;
}
static int l2cap_ertm_reassembly_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
static void append_skb_frag(struct sk_buff *skb,
struct sk_buff *new_frag, struct sk_buff **last_frag)
{
struct sk_buff *_skb;
int err;
/* skb->len reflects data in skb as well as all fragments
* skb->data_len reflects only data in fragments
*/
if (!skb_has_frag_list(skb))
skb_shinfo(skb)->frag_list = new_frag;
new_frag->next = NULL;
(*last_frag)->next = new_frag;
*last_frag = new_frag;
skb->len += new_frag->len;
skb->data_len += new_frag->len;
skb->truesize += new_frag->truesize;
}
static int l2cap_reassemble_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
{
int err = -EINVAL;
switch (control & L2CAP_CTRL_SAR) {
case L2CAP_SDU_UNSEGMENTED:
if (test_bit(CONN_SAR_SDU, &chan->conn_state))
goto drop;
if (chan->sdu)
break;
return chan->ops->recv(chan->data, skb);
err = chan->ops->recv(chan->data, skb);
break;
case L2CAP_SDU_START:
if (test_bit(CONN_SAR_SDU, &chan->conn_state))
goto drop;
if (chan->sdu)
break;
chan->sdu_len = get_unaligned_le16(skb->data);
if (chan->sdu_len > chan->imtu)
goto disconnect;
chan->sdu = bt_skb_alloc(chan->sdu_len, GFP_ATOMIC);
if (!chan->sdu)
return -ENOMEM;
/* pull sdu_len bytes only after alloc, because of Local Busy
* condition we have to be sure that this will be executed
* only once, i.e., when alloc does not fail */
skb_pull(skb, 2);
memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
if (chan->sdu_len > chan->imtu) {
err = -EMSGSIZE;
break;
}
set_bit(CONN_SAR_SDU, &chan->conn_state);
chan->partial_sdu_len = skb->len;
if (skb->len >= chan->sdu_len)
break;
chan->sdu = skb;
chan->sdu_last_frag = skb;
skb = NULL;
err = 0;
break;
case L2CAP_SDU_CONTINUE:
if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
goto disconnect;
if (!chan->sdu)
goto disconnect;
break;
chan->partial_sdu_len += skb->len;
if (chan->partial_sdu_len > chan->sdu_len)
goto drop;
append_skb_frag(chan->sdu, skb,
&chan->sdu_last_frag);
skb = NULL;
memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
if (chan->sdu->len >= chan->sdu_len)
break;
err = 0;
break;
case L2CAP_SDU_END:
if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
goto disconnect;
if (!chan->sdu)
goto disconnect;
break;
chan->partial_sdu_len += skb->len;
append_skb_frag(chan->sdu, skb,
&chan->sdu_last_frag);
skb = NULL;
if (chan->partial_sdu_len > chan->imtu)
goto drop;
if (chan->sdu->len != chan->sdu_len)
break;
if (chan->partial_sdu_len != chan->sdu_len)
goto drop;
err = chan->ops->recv(chan->data, chan->sdu);
memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
_skb = skb_clone(chan->sdu, GFP_ATOMIC);
if (!_skb) {
return -ENOMEM;
if (!err) {
/* Reassembly complete */
chan->sdu = NULL;
chan->sdu_last_frag = NULL;
chan->sdu_len = 0;
}
err = chan->ops->recv(chan->data, _skb);
if (err < 0) {
kfree_skb(_skb);
return err;
}
clear_bit(CONN_SAR_SDU, &chan->conn_state);
kfree_skb(chan->sdu);
break;
}
if (err) {
kfree_skb(skb);
return 0;
drop:
kfree_skb(chan->sdu);
chan->sdu = NULL;
chan->sdu_last_frag = NULL;
chan->sdu_len = 0;
}
disconnect:
l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
kfree_skb(skb);
return 0;
return err;
}
static void l2cap_ertm_enter_local_busy(struct l2cap_chan *chan)
@ -3277,99 +3279,6 @@ void l2cap_chan_busy(struct l2cap_chan *chan, int busy)
}
}
static int l2cap_streaming_reassembly_sdu(struct l2cap_chan *chan, struct sk_buff *skb, u16 control)
{
struct sk_buff *_skb;
int err = -EINVAL;
/*
* TODO: We have to notify the userland if some data is lost with the
* Streaming Mode.
*/
switch (control & L2CAP_CTRL_SAR) {
case L2CAP_SDU_UNSEGMENTED:
if (test_bit(CONN_SAR_SDU, &chan->conn_state)) {
kfree_skb(chan->sdu);
break;
}
err = chan->ops->recv(chan->data, skb);
if (!err)
return 0;
break;
case L2CAP_SDU_START:
if (test_bit(CONN_SAR_SDU, &chan->conn_state)) {
kfree_skb(chan->sdu);
break;
}
chan->sdu_len = get_unaligned_le16(skb->data);
skb_pull(skb, 2);
if (chan->sdu_len > chan->imtu) {
err = -EMSGSIZE;
break;
}
chan->sdu = bt_skb_alloc(chan->sdu_len, GFP_ATOMIC);
if (!chan->sdu) {
err = -ENOMEM;
break;
}
memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
set_bit(CONN_SAR_SDU, &chan->conn_state);
chan->partial_sdu_len = skb->len;
err = 0;
break;
case L2CAP_SDU_CONTINUE:
if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
break;
memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
chan->partial_sdu_len += skb->len;
if (chan->partial_sdu_len > chan->sdu_len)
kfree_skb(chan->sdu);
else
err = 0;
break;
case L2CAP_SDU_END:
if (!test_bit(CONN_SAR_SDU, &chan->conn_state))
break;
memcpy(skb_put(chan->sdu, skb->len), skb->data, skb->len);
clear_bit(CONN_SAR_SDU, &chan->conn_state);
chan->partial_sdu_len += skb->len;
if (chan->partial_sdu_len > chan->imtu)
goto drop;
if (chan->partial_sdu_len == chan->sdu_len) {
_skb = skb_clone(chan->sdu, GFP_ATOMIC);
err = chan->ops->recv(chan->data, _skb);
if (err < 0)
kfree_skb(_skb);
}
err = 0;
drop:
kfree_skb(chan->sdu);
break;
}
kfree_skb(skb);
return err;
}
static void l2cap_check_srej_gap(struct l2cap_chan *chan, u8 tx_seq)
{
struct sk_buff *skb;
@ -3384,7 +3293,7 @@ static void l2cap_check_srej_gap(struct l2cap_chan *chan, u8 tx_seq)
skb = skb_dequeue(&chan->srej_q);
control = bt_cb(skb)->sar << L2CAP_CTRL_SAR_SHIFT;
err = l2cap_ertm_reassembly_sdu(chan, skb, control);
err = l2cap_reassemble_sdu(chan, skb, control);
if (err < 0) {
l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
@ -3544,7 +3453,7 @@ expected:
return 0;
}
err = l2cap_ertm_reassembly_sdu(chan, skb, rx_control);
err = l2cap_reassemble_sdu(chan, skb, rx_control);
chan->buffer_seq = (chan->buffer_seq + 1) % 64;
if (err < 0) {
l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
@ -3860,12 +3769,20 @@ static inline int l2cap_data_channel(struct l2cap_conn *conn, u16 cid, struct sk
tx_seq = __get_txseq(control);
if (chan->expected_tx_seq == tx_seq)
chan->expected_tx_seq = (chan->expected_tx_seq + 1) % 64;
else
if (chan->expected_tx_seq != tx_seq) {
/* Frame(s) missing - must discard partial SDU */
kfree_skb(chan->sdu);
chan->sdu = NULL;
chan->sdu_last_frag = NULL;
chan->sdu_len = 0;
/* TODO: Notify userland of missing data */
}
chan->expected_tx_seq = (tx_seq + 1) % 64;
l2cap_streaming_reassembly_sdu(chan, skb, control);
if (l2cap_reassemble_sdu(chan, skb, control) == -EMSGSIZE)
l2cap_send_disconn_req(chan->conn, chan, ECONNRESET);
goto done;