[dpdk-dev] [dpdk-stable] [PATCH v3 3/5] net/tap: fix check for mbuf's nb_segs failure
Ferruh Yigit
ferruh.yigit at intel.com
Tue Apr 7 17:58:02 CEST 2020
On 4/7/2020 4:15 PM, Ferruh Yigit wrote:
> On 4/7/2020 5:23 AM, wangyunjian wrote:
>> From: Yunjian Wang <wangyunjian at huawei.com>
>>
>> Now the rxq->pool is mbuf concatenation, But its nb_segs is 1.
>> When do some sanity checks on the mbuf, it fails.
>
> +1, 'rxq->pool' seems Rx ring representation as linked mbufs and empty ones has
> 'nb_segs' values as 1.
>
>>
>> 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 | 27 ++++++++++++++++++++++-----
>> 1 file changed, 22 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
>> index a9ba0ca68..703fcceb9 100644
>> --- a/drivers/net/tap/rte_eth_tap.c
>> +++ b/drivers/net/tap/rte_eth_tap.c
>> @@ -339,6 +339,23 @@ 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 *mbuf = pool;
>> + uint16_t nb_segs = 1;
>> +
>> + if (mbuf == NULL)
>> + return;
>> +
>> + while (mbuf->next) {
>> + mbuf = mbuf->next;
>> + nb_segs++;
>> + }
>> + pool->nb_segs = nb_segs;
>> + rte_pktmbuf_free(pool);
>> +}
>
> Since you are already iterating the chain, why not free immediately instead of
> calculating the nb_segs and making API go through the chain again, what about
> following:
>
> tap_rxq_pool_free(struct rte_mbuf *pool)
> {
> struct rte_mbuf *next;
> while (pool) {
> next = pool->next;
> rte_pktmbuf_free(pool);
> pool = next;
> }
> }
Ignore this please, this may be still complaining in mbuf sanity check, so OK to
your usage.
>
>> +
>> /* Callback to handle the rx burst of packets to the correct interface and
>> * file descriptor(s) in a multi-queue setup.
>> */
>> @@ -389,7 +406,7 @@ 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);
>
> As far as I can see 'mbuf' should have correct 'nb_segs' value, and it can
> continue to use 'rte_pktmbuf_free()'. If you can observe the problem can you
> please try this?
>
>>
>> goto end;
>> }
>> @@ -1033,7 +1050,7 @@ 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;
>> @@ -1072,7 +1089,7 @@ 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;
>> @@ -1480,7 +1497,7 @@ 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;
>> @@ -2435,7 +2452,7 @@ rte_pmd_tap_remove(struct rte_vdev_device *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;
>>
>
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