[dpdk-stable] [dpdk-dev] [PATCH v4 3/5] net/tap: fix check for mbuf's nb_segs failure
Ferruh Yigit
ferruh.yigit at intel.com
Wed Apr 15 17:12:50 CEST 2020
On 4/11/2020 12:23 PM, wangyunjian wrote:
> From: Yunjian Wang <wangyunjian at huawei.com>
>
> Now the rxq->pool is mbuf concatenation, but its nb_segs is 1. When
> conducting some sanity checks on the mbuf with debug enabled, it fails.
>
> Fixes: 0781f5762cfe ("net/tap: support segmented mbufs")
> CC: stable at dpdk.org
>
> Signed-off-by: Yunjian Wang <wangyunjian at huawei.com>
> ---
> drivers/net/tap/rte_eth_tap.c | 21 +++++++++++++++++----
> 1 file changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
> index 0156d689d..6a77b2a7e 100644
> --- a/drivers/net/tap/rte_eth_tap.c
> +++ b/drivers/net/tap/rte_eth_tap.c
> @@ -339,6 +339,19 @@ tap_rx_offload_get_queue_capa(void)
> DEV_RX_OFFLOAD_TCP_CKSUM;
> }
>
> +static void
> +tap_rxq_pool_free(struct rte_mbuf *pool)
> +{
> + struct rte_mbuf *next;
> +
> + while (pool) {
> + next = pool->next;
> + pool->next = NULL;
> + rte_pktmbuf_free(pool);
> + pool = next;
> + }
> +}
I am aware I have suggested this but I have missed that 'rte_mbuf_check()' still
may fail.
The 'rxq->pool' is a set of linked mbufs, each mbuf->next points to next one.
But all mbufs in the pool has 'nb_segs' as '1'. As far as I can see from code
this will cause a warning in 'rte_mbuf_check()'. If you can reproduce it you can
double check.
Your initial implementation seems the correct one, to fix the nb_segs for first
mbuf in the pool, sorry for the noise.
> +
> /* Callback to handle the rx burst of packets to the correct interface and
> * file descriptor(s) in a multi-queue setup.
> */
> @@ -389,7 +402,7 @@ pmd_rx_burst(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
> goto end;
>
> seg->next = NULL;
> - rte_pktmbuf_free(mbuf);
> + tap_rxq_pool_free(mbuf);
>
> goto end;
> }
> @@ -1038,7 +1051,7 @@ tap_dev_close(struct rte_eth_dev *dev)
> rxq = &internals->rxq[i];
> close(process_private->rxq_fds[i]);
> process_private->rxq_fds[i] = -1;
> - rte_pktmbuf_free(rxq->pool);
> + tap_rxq_pool_free(rxq->pool);
> rte_free(rxq->iovecs);
> rxq->pool = NULL;
> rxq->iovecs = NULL;
> @@ -1077,7 +1090,7 @@ tap_rx_queue_release(void *queue)
> if (process_private->rxq_fds[rxq->queue_id] > 0) {
> close(process_private->rxq_fds[rxq->queue_id]);
> process_private->rxq_fds[rxq->queue_id] = -1;
> - rte_pktmbuf_free(rxq->pool);
> + tap_rxq_pool_free(rxq->pool);
> rte_free(rxq->iovecs);
> rxq->pool = NULL;
> rxq->iovecs = NULL;
> @@ -1485,7 +1498,7 @@ tap_rx_queue_setup(struct rte_eth_dev *dev,
> return 0;
>
> error:
> - rte_pktmbuf_free(rxq->pool);
> + tap_rxq_pool_free(rxq->pool);
> rxq->pool = NULL;
> rte_free(rxq->iovecs);
> rxq->iovecs = NULL;
>
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