net/tap: fix missing _SC_IOV_MAX
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Commit Message
If the value _SC_IOV_MAX is missing, sysconf returns -1.
In this case, iov_max is set to a default value of 1024.
Cc: stable@dpdk.org
Signed-off-by: olegpoly123 <olegp123@walla.co.il>
---
drivers/net/tap/rte_eth_tap.c | 8 ++++++++
1 file changed, 8 insertions(+)
Comments
> On Mar 8, 2019, at 12:00 PM, olegpoly123 <olegp123@walla.co.il> wrote:
>
> If the value _SC_IOV_MAX is missing, sysconf returns -1.
> In this case, iov_max is set to a default value of 1024.
>
> Cc: stable@dpdk.org
>
> Signed-off-by: olegpoly123 <olegp123@walla.co.il>
> ---
> drivers/net/tap/rte_eth_tap.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
> index 6f5109fca..2a7e6aa00 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 +1328,12 @@ 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\n", 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
>
Sorry the email subject does not list [PATCH v3], but maybe someone can fix it when it is applied or should another patch be submitted with [PATCH v3]?
In any case I approve the patch.
Acked-by: Keith Wiles <keith.wiles@intel.com>
Regards,
Keith
Thanks for contributing.
Please find two comments below.
> > On Mar 8, 2019, at 12:00 PM, olegpoly123 <olegp123@walla.co.il> wrote:
> >
> > If the value _SC_IOV_MAX is missing, sysconf returns -1.
> > In this case, iov_max is set to a default value of 1024.
> >
> > Cc: stable@dpdk.org
Is there any specific commit we can reference for backport?
Maybe this one?
Fixes: ec12df9504fe ("net/tap: fix support for large Rx queues")
> > Signed-off-by: olegpoly123 <olegp123@walla.co.il>
Please provide your real name.
On Fri, 8 Mar 2019 13:00:16 -0500
olegpoly123 <olegp123@walla.co.il> wrote:
> long iov_max = sysconf(_SC_IOV_MAX);
> +
> + if (iov_max <= 0) {
> + TAP_LOG(WARNING,
> + "_SC_IOV_MAX is not defined. Using %d as default\n", TAP_IOV_DEFAULT_MAX);
> + iov_max = TAP_IOV_DEFAULT_MAX;
> + }
You haven't listened to my comment about mixing declaration and
code. Why?
@@ -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 +1328,12 @@ 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\n", 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;