The poll call can return POLLERR which is ignored, or it can return
POLLOUT, even if there are no free frames in the mmap-ed area.
We can account for both of these cases by re-checking if the next
frame is empty before writing into it.
Signed-off-by: Mihai Pogonaru <pogonarumi...@gmail.com>
Signed-off-by: Tudor Cornea <tudor.cor...@gmail.com>
---
drivers/net/af_packet/rte_eth_af_packet.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/net/af_packet/rte_eth_af_packet.c
b/drivers/net/af_packet/rte_eth_af_packet.c
index b73b211..087c196 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -216,6 +216,25 @@ eth_af_packet_tx(void *queue, struct rte_mbuf **bufs,
uint16_t nb_pkts)
(poll(&pfd, 1, -1) < 0))
break;
+ /*
+ * Poll can return POLLERR if the interface is down
+ *
+ * It will almost always return POLLOUT, even if there
+ * are no extra buffers available
+ *
+ * This happens, because packet_poll() calls datagram_poll()
+ * which checks the space left in the socket buffer and,
+ * in the case of packet_mmap, the default socket buffer length
+ * doesn't match the requested size for the tx_ring.
+ * As such, there is almost always space left in socket buffer,
+ * which doesn't seem to be correlated to the requested size
+ * for the tx_ring in packet_mmap.
+ *
+ * This results in poll() returning POLLOUT.
+ */
+ if (ppd->tp_status != TP_STATUS_AVAILABLE)
+ break;
+
/* copy the tx frame data */
pbuf = (uint8_t *) ppd + TPACKET2_HDRLEN -
sizeof(struct sockaddr_ll);
--
2.7.4
