Datagram queue race fixed: insert datagrams into master-fsm_queue with fsm_queue list_head
--- a/master/datagram.c Wed Jan 12 14:56:53 2011 +0100
+++ b/master/datagram.c Fri Jan 14 11:36:53 2011 +0100
@@ -87,7 +87,10 @@
*/
void ec_datagram_init(ec_datagram_t *datagram /**< EtherCAT datagram. */)
{
+ INIT_LIST_HEAD(&datagram->list); // mark as unqueued
INIT_LIST_HEAD(&datagram->queue); // mark as unqueued
+ INIT_LIST_HEAD(&datagram->fsm_queue); // mark as unqueued
+ INIT_LIST_HEAD(&datagram->sent); // mark as unqueued
datagram->type = EC_DATAGRAM_NONE;
memset(datagram->address, 0x00, EC_ADDR_LEN);
datagram->data = NULL;
@@ -131,8 +134,8 @@
*/
void ec_datagram_unqueue(ec_datagram_t *datagram /**< EtherCAT datagram. */)
{
- if (!list_empty(&datagram->queue)) {
- list_del_init(&datagram->queue);
+ if (!list_empty(&datagram->fsm_queue)) {
+ list_del_init(&datagram->fsm_queue);
}
}
--- a/master/datagram.h Wed Jan 12 14:56:53 2011 +0100
+++ b/master/datagram.h Fri Jan 14 11:36:53 2011 +0100
@@ -86,7 +86,8 @@
*/
typedef struct {
struct list_head list; /**< Needed by domain datagram lists. */
- struct list_head queue; /**< Master datagram queue item. */
+ struct list_head queue; /**< Master datagram send-receive queue item. */
+ struct list_head fsm_queue; /**< Master datagram fsm queue item. */
struct list_head sent; /**< Master list item for sent datagrams. */
ec_datagram_type_t type; /**< Datagram type (APRD, BWR, etc.). */
uint8_t address[EC_ADDR_LEN]; /**< Recipient address. */
--- a/master/master.c Wed Jan 12 14:56:53 2011 +0100
+++ b/master/master.c Fri Jan 14 11:36:53 2011 +0100
@@ -416,11 +416,18 @@
wake_up(&master->reg_queue);
}
+ // we must lock the fsm_queue here because the slave's fsm_datagram will be unqueued
+ if (master->fsm_queue_lock_cb)
+ master->fsm_queue_lock_cb(master->fsm_queue_locking_data);
+ ec_mutex_lock(&master->fsm_queue_mutex);
for (slave = master->slaves;
slave < master->slaves + master->slave_count;
slave++) {
ec_slave_clear(slave);
}
+ ec_mutex_unlock(&master->fsm_queue_mutex);
+ if (master->fsm_queue_unlock_cb)
+ master->fsm_queue_unlock_cb(master->fsm_queue_locking_data);
if (master->slaves) {
kfree(master->slaves);
@@ -668,8 +675,11 @@
if (master->fsm_queue_lock_cb)
master->fsm_queue_lock_cb(master->fsm_queue_locking_data);
- if (ec_mutex_trylock(&master->fsm_queue_mutex) == 0)
- return;
+ if (ec_mutex_trylock(&master->fsm_queue_mutex) == 0) {
+ if (master->fsm_queue_unlock_cb)
+ master->fsm_queue_unlock_cb(master->fsm_queue_locking_data);
+ return;
+ }
if (list_empty(&master->fsm_datagram_queue)) {
ec_mutex_unlock(&master->fsm_queue_mutex);
if (master->fsm_queue_unlock_cb)
@@ -681,10 +691,10 @@
}
list_for_each_entry_safe(datagram, n, &master->fsm_datagram_queue,
- queue) {
+ fsm_queue) {
queue_size += datagram->data_size;
if (queue_size <= master->max_queue_size) {
- list_del_init(&datagram->queue);
+ list_del_init(&datagram->fsm_queue);
#if DEBUG_INJECT
EC_MASTER_DBG(master, 2, "Injecting fsm datagram %p"
" size=%zu, queue_size=%zu\n", datagram,
@@ -698,7 +708,7 @@
}
else {
if (datagram->data_size > master->max_queue_size) {
- list_del_init(&datagram->queue);
+ list_del_init(&datagram->fsm_queue);
datagram->state = EC_DATAGRAM_ERROR;
EC_MASTER_ERR(master, "Fsm datagram %p is too large,"
" size=%zu, max_queue_size=%zu\n",
@@ -717,7 +727,7 @@
{
unsigned int time_us;
- list_del_init(&datagram->queue);
+ list_del_init(&datagram->fsm_queue);
datagram->state = EC_DATAGRAM_ERROR;
#ifdef EC_HAVE_CYCLES
time_us = (unsigned int)
@@ -794,7 +804,7 @@
// check, if the datagram is already queued
list_for_each_entry(queued_datagram, &master->fsm_datagram_queue,
- queue) {
+ fsm_queue) {
if (queued_datagram == datagram) {
datagram->state = EC_DATAGRAM_QUEUED;
ec_mutex_unlock(&master->fsm_queue_mutex);
@@ -809,7 +819,7 @@
datagram, datagram->data_size);
#endif
- list_add_tail(&datagram->queue, &master->fsm_datagram_queue);
+ list_add_tail(&datagram->fsm_queue, &master->fsm_datagram_queue);
datagram->state = EC_DATAGRAM_QUEUED;
#ifdef EC_HAVE_CYCLES
datagram->cycles_sent = get_cycles();