[dpdk-dev] [PATCH v2] eventdev: fix Rx adapter stalls on event device backpressure
From: Mattias Rönnblom <hidden>
Date: 2021-11-10 11:14:06
Subsystem:
library code, the rest · Maintainers:
Andrew Morton, Linus Torvalds
In the Eventdev Ethernet RX Adapter, correctly handle the case where
the circular enqueue buffer head and last index point to the same
element.
This bug may be triggered in case there is backpressure from the event
device to the RX adapter.
v2:
* Corrected bug description
Fixes: 8113fd15e229 ("eventdev/eth_rx: make enqueue buffer circular")
Cc: ganapati.kundapura@intel.com
Signed-off-by: Mattias Rönnblom <redacted>
---
lib/eventdev/rte_event_eth_rx_adapter.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/lib/eventdev/rte_event_eth_rx_adapter.c b/lib/eventdev/rte_event_eth_rx_adapter.c
index 56318b5a6f..809416d9b7 100644
--- a/lib/eventdev/rte_event_eth_rx_adapter.c
+++ b/lib/eventdev/rte_event_eth_rx_adapter.c@@ -777,19 +777,25 @@ rxa_flush_event_buffer(struct event_eth_rx_adapter *rx_adapter, struct eth_event_enqueue_buffer *buf, struct rte_event_eth_rx_adapter_stats *stats) { - uint16_t count = buf->last ? buf->last - buf->head : buf->count; + uint16_t count = buf->count; + uint16_t n = 0; if (!count) return 0; - uint16_t n = rte_event_enqueue_new_burst(rx_adapter->eventdev_id, - rx_adapter->event_port_id, - &buf->events[buf->head], - count); - if (n != count) - stats->rx_enq_retry++; + if (buf->last) + count = buf->last - buf->head; + + if (count) { + n = rte_event_enqueue_new_burst(rx_adapter->eventdev_id, + rx_adapter->event_port_id, + &buf->events[buf->head], + count); + if (n != count) + stats->rx_enq_retry++; - buf->head += n; + buf->head += n; + } if (buf->last && n == count) { uint16_t n1;
--
2.25.1