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: sta...@dpdk.org
Signed-off-by: Oleg Polyakov <olegp...@walla.co.il>
Acked-by: Keith Wiles <keith.wi...@intel.com>
---
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 6f5109fca..9aae4c77f 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;
--
2.14.1
