[dpdk-dev] [PATCH v2] net/af_packet: fix ignoring full ring on tx
flat view
From: Tudor Cornea <hidden>
Date: 2021-09-13 13:46:04
Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted> Signed-off-by: Tudor Cornea <redacted> --- 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