From efa28ae847546a1376b2112544490251dd0ea5cd Mon Sep 17 00:00:00 2001 From: Oleg Polyakov Date: Mon, 18 Mar 2019 14:20:47 -0400 Subject: [PATCH] net/tap: fix getting max iovec If the value _SC_IOV_MAX is missing, sysconf returns -1. In this case, iov_max is set to a default value of 1024. This should never happen except for redhat bug: https://bugzilla.redhat.com/show_bug.cgi?id=1504165 Fixes: ec12df9504fe ("net/tap: fix support for large Rx queues") Cc: stable@dpdk.org Signed-off-by: Oleg Polyakov Acked-by: Keith Wiles --- drivers/net/tap/rte_eth_tap.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c index 6f5109fca5..9aae4c77fb 100644 --- a/drivers/net/tap/rte_eth_tap.c +++ b/drivers/net/tap/rte_eth_tap.c @@ -68,6 +68,8 @@ /* IPC key for queue fds sync */ #define TAP_MP_KEY "tap_mp_sync_queues" +#define TAP_IOV_DEFAULT_MAX 1024 + static int tap_devices_count; static struct rte_vdev_driver pmd_tap_drv; static struct rte_vdev_driver pmd_tun_drv; @@ -1326,6 +1328,13 @@ tap_rx_queue_setup(struct rte_eth_dev *dev, struct rx_queue *rxq = &internals->rxq[rx_queue_id]; struct rte_mbuf **tmp = &rxq->pool; long iov_max = sysconf(_SC_IOV_MAX); + + if (iov_max <= 0) { + TAP_LOG(WARNING, + "_SC_IOV_MAX is not defined. Using %d as default", + TAP_IOV_DEFAULT_MAX); + iov_max = TAP_IOV_DEFAULT_MAX; + } uint16_t nb_desc = RTE_MIN(nb_rx_desc, iov_max - 1); struct iovec (*iovecs)[nb_desc + 1]; int data_off = RTE_PKTMBUF_HEADROOM; -- 2.20.1