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rfcomm: fix deadlock in l2cap can send now handling

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This commit is contained in:
Matthias Ringwald 2016-09-29 12:08:00 +02:00
parent ec3f4248d9
commit e9a7c22d24
1 changed files with 23 additions and 24 deletions
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45
src/classic/rfcomm.c
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@ -844,42 +844,40 @@ static void rfcomm_multiplexer_opened(rfcomm_multiplexer_t *multiplexer){
static void rfcomm_handle_can_send_now(uint16_t l2cap_cid){ static void rfcomm_handle_can_send_now(uint16_t l2cap_cid){
btstack_linked_list_iterator_t it; log_debug("rfcomm_handle_can_send_now enter: %u", l2cap_cid);
// find multiplexer ready for this cid btstack_linked_list_iterator_t it;
int token_consumed = 0;
// forward token to multiplexer
btstack_linked_list_iterator_init(&it, &rfcomm_multiplexers); btstack_linked_list_iterator_init(&it, &rfcomm_multiplexers);
while (btstack_linked_list_iterator_has_next(&it)){ while (!token_consumed && btstack_linked_list_iterator_has_next(&it)){
rfcomm_multiplexer_t * multiplexer = (rfcomm_multiplexer_t *) btstack_linked_list_iterator_next(&it); rfcomm_multiplexer_t * multiplexer = (rfcomm_multiplexer_t *) btstack_linked_list_iterator_next(&it);
if (multiplexer->l2cap_cid != l2cap_cid) continue; if (multiplexer->l2cap_cid != l2cap_cid) continue;
if (rfcomm_multiplexer_ready_to_send(multiplexer)){ if (rfcomm_multiplexer_ready_to_send(multiplexer)){
log_debug("rfcomm_handle_can_send_now enter: multiplexer token");
token_consumed = 1;
rfcomm_multiplexer_state_machine(multiplexer, MULT_EV_READY_TO_SEND); rfcomm_multiplexer_state_machine(multiplexer, MULT_EV_READY_TO_SEND);
// more to send?
if (rfcomm_multiplexer_ready_to_send(multiplexer)){
l2cap_request_can_send_now_event(l2cap_cid);
}
return;
} }
} }
// find channels ready for this cid // forward token to channel state machine
btstack_linked_list_iterator_init(&it, &rfcomm_channels); btstack_linked_list_iterator_init(&it, &rfcomm_channels);
while (btstack_linked_list_iterator_has_next(&it)){ while (!token_consumed && btstack_linked_list_iterator_has_next(&it)){
rfcomm_channel_t * channel = (rfcomm_channel_t *) btstack_linked_list_iterator_next(&it); rfcomm_channel_t * channel = (rfcomm_channel_t *) btstack_linked_list_iterator_next(&it);
if (channel->multiplexer->l2cap_cid != l2cap_cid) continue; if (channel->multiplexer->l2cap_cid != l2cap_cid) continue;
// channel state machine // channel state machine
if (rfcomm_channel_ready_to_send(channel)){ if (rfcomm_channel_ready_to_send(channel)){
log_debug("rfcomm_handle_can_send_now enter: channel token");
token_consumed = 1;
const rfcomm_channel_event_t event = { CH_EVT_READY_TO_SEND }; const rfcomm_channel_event_t event = { CH_EVT_READY_TO_SEND };
rfcomm_channel_state_machine_with_channel(channel, &event); rfcomm_channel_state_machine_with_channel(channel, &event);
if (rfcomm_channel_ready_to_send(channel)){
l2cap_request_can_send_now_event(l2cap_cid);
}
return;
} }
} }
// inform clients if waiting // forward token to client
btstack_linked_list_iterator_init(&it, &rfcomm_channels); btstack_linked_list_iterator_init(&it, &rfcomm_channels);
while (btstack_linked_list_iterator_has_next(&it)){ while (!token_consumed && btstack_linked_list_iterator_has_next(&it)){
rfcomm_channel_t * channel = (rfcomm_channel_t *) btstack_linked_list_iterator_next(&it); rfcomm_channel_t * channel = (rfcomm_channel_t *) btstack_linked_list_iterator_next(&it);
if (channel->multiplexer->l2cap_cid != l2cap_cid) continue; if (channel->multiplexer->l2cap_cid != l2cap_cid) continue;
// client waiting for can send now // client waiting for can send now
@ -887,17 +885,18 @@ static void rfcomm_handle_can_send_now(uint16_t l2cap_cid){
if (!channel->credits_outgoing) continue; if (!channel->credits_outgoing) continue;
if ((channel->multiplexer->fcon & 1) == 0) continue; if ((channel->multiplexer->fcon & 1) == 0) continue;
log_debug("rfcomm_handle_can_send_now enter: client token");
token_consumed = 1;
channel->waiting_for_can_send_now = 0; channel->waiting_for_can_send_now = 0;
rfcomm_emit_can_send_now(channel); rfcomm_emit_can_send_now(channel);
// note: if client wants to send more, it will call rfcomm_request_can_send_now which in turn will
// call l2cap_request_can_send_now -> nothing to do for us here.
// check if we can still send
if (!l2cap_can_send_packet_now(l2cap_cid)) {
return;
} }
// if token was consumed, request another one
if (token_consumed) {
l2cap_request_can_send_now_event(l2cap_cid);
} }
log_debug("rfcomm_handle_can_send_now exit");
} }
static void rfcomm_multiplexer_set_state_and_request_can_send_now_event(rfcomm_multiplexer_t * multiplexer, RFCOMM_MULTIPLEXER_STATE state){ static void rfcomm_multiplexer_set_state_and_request_can_send_now_event(rfcomm_multiplexer_t * multiplexer, RFCOMM_MULTIPLEXER_STATE state){