diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c index 2198548663..7eaeccc19d 100644 --- a/lib/librte_ethdev/rte_ethdev.c +++ b/lib/librte_ethdev/rte_ethdev.c @@ -4610,12 +4610,20 @@ rte_eth_add_rx_callback(uint16_t port_id, uint16_t queue_id, rte_eth_devices[port_id].post_rx_burst_cbs[queue_id]; if (!tail) { - rte_eth_devices[port_id].post_rx_burst_cbs[queue_id] = cb; + /* Stores to cb->fn and cb->param should complete before + * cb is visible to data plane. + */ + __atomic_store_n( + &rte_eth_devices[port_id].post_rx_burst_cbs[queue_id], + cb, __ATOMIC_RELEASE); } else { while (tail->next) tail = tail->next; - tail->next = cb; + /* Stores to cb->fn and cb->param should complete before + * cb is visible to data plane. + */ + __atomic_store_n(&tail->next, cb, __ATOMIC_RELEASE); } rte_spinlock_unlock(&rte_eth_rx_cb_lock); @@ -4700,12 +4708,20 @@ rte_eth_add_tx_callback(uint16_t port_id, uint16_t queue_id, rte_eth_devices[port_id].pre_tx_burst_cbs[queue_id]; if (!tail) { - rte_eth_devices[port_id].pre_tx_burst_cbs[queue_id] = cb; + /* Stores to cb->fn and cb->param should complete before + * cb is visible to data plane. + */ + __atomic_store_n( + &rte_eth_devices[port_id].pre_tx_burst_cbs[queue_id], + cb, __ATOMIC_RELEASE); } else { while (tail->next) tail = tail->next; - tail->next = cb; + /* Stores to cb->fn and cb->param should complete before + * cb is visible to data plane. + */ + __atomic_store_n(&tail->next, cb, __ATOMIC_RELEASE); } rte_spinlock_unlock(&rte_eth_tx_cb_lock); @@ -4736,7 +4752,7 @@ rte_eth_remove_rx_callback(uint16_t port_id, uint16_t queue_id, cb = *prev_cb; if (cb == user_cb) { /* Remove the user cb from the callback list. */ - *prev_cb = cb->next; + __atomic_store_n(prev_cb, cb->next, __ATOMIC_RELAXED); ret = 0; break; } @@ -4770,7 +4786,7 @@ rte_eth_remove_tx_callback(uint16_t port_id, uint16_t queue_id, cb = *prev_cb; if (cb == user_cb) { /* Remove the user cb from the callback list. */ - *prev_cb = cb->next; + __atomic_store_n(prev_cb, cb->next, __ATOMIC_RELAXED); ret = 0; break; } diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h index f07dbc4d26..c37b3a1a81 100644 --- a/lib/librte_ethdev/rte_ethdev.h +++ b/lib/librte_ethdev/rte_ethdev.h @@ -3911,7 +3911,8 @@ struct rte_eth_rxtx_callback; * The callback function * @param user_param * A generic pointer parameter which will be passed to each invocation of the - * callback function on this port and queue. + * callback function on this port and queue. Inter-thread synchronization + * of any user data changes is the responsibility of the user. * * @return * NULL on error. @@ -3940,7 +3941,8 @@ rte_eth_add_rx_callback(uint16_t port_id, uint16_t queue_id, * The callback function * @param user_param * A generic pointer parameter which will be passed to each invocation of the - * callback function on this port and queue. + * callback function on this port and queue. Inter-thread synchronization + * of any user data changes is the responsibility of the user. * * @return * NULL on error. @@ -3968,7 +3970,8 @@ rte_eth_add_first_rx_callback(uint16_t port_id, uint16_t queue_id, * The callback function * @param user_param * A generic pointer parameter which will be passed to each invocation of the - * callback function on this port and queue. + * callback function on this port and queue. Inter-thread synchronization + * of any user data changes is the responsibility of the user. * * @return * NULL on error. @@ -3993,7 +3996,9 @@ rte_eth_add_tx_callback(uint16_t port_id, uint16_t queue_id, * on that queue. * * - After a short delay - where the delay is sufficient to allow any - * in-flight callbacks to complete. + * in-flight callbacks to complete. Alternately, the RCU mechanism can be + * used to detect when data plane threads have ceased referencing the + * callback memory. * * @param port_id * The port identifier of the Ethernet device. @@ -4026,7 +4031,9 @@ int rte_eth_remove_rx_callback(uint16_t port_id, uint16_t queue_id, * on that queue. * * - After a short delay - where the delay is sufficient to allow any - * in-flight callbacks to complete. + * in-flight callbacks to complete. Alternately, the RCU mechanism can be + * used to detect when data plane threads have ceased referencing the + * callback memory. * * @param port_id * The port identifier of the Ethernet device. @@ -4687,10 +4694,18 @@ rte_eth_rx_burst(uint16_t port_id, uint16_t queue_id, rx_pkts, nb_pkts); #ifdef RTE_ETHDEV_RXTX_CALLBACKS - if (unlikely(dev->post_rx_burst_cbs[queue_id] != NULL)) { - struct rte_eth_rxtx_callback *cb = - dev->post_rx_burst_cbs[queue_id]; + struct rte_eth_rxtx_callback *cb; + /* __ATOMIC_RELEASE memory order was used when the + * call back was inserted into the list. + * Since there is a clear dependency between loading + * cb and cb->fn/cb->next, __ATOMIC_ACQUIRE memory order is + * not required. + */ + cb = __atomic_load_n(&dev->post_rx_burst_cbs[queue_id], + __ATOMIC_RELAXED); + + if (unlikely(cb != NULL)) { do { nb_rx = cb->fn.rx(port_id, queue_id, rx_pkts, nb_rx, nb_pkts, cb->param); @@ -4953,7 +4968,16 @@ rte_eth_tx_burst(uint16_t port_id, uint16_t queue_id, #endif #ifdef RTE_ETHDEV_RXTX_CALLBACKS - struct rte_eth_rxtx_callback *cb = dev->pre_tx_burst_cbs[queue_id]; + struct rte_eth_rxtx_callback *cb; + + /* __ATOMIC_RELEASE memory order was used when the + * call back was inserted into the list. + * Since there is a clear dependency between loading + * cb and cb->fn/cb->next, __ATOMIC_ACQUIRE memory order is + * not required. + */ + cb = __atomic_load_n(&dev->pre_tx_burst_cbs[queue_id], + __ATOMIC_RELAXED); if (unlikely(cb != NULL)) { do {