From 21658b863d246055c225286d9bce8a0a884fc9d9 Mon Sep 17 00:00:00 2001 From: Chengwen Feng Date: Fri, 13 May 2022 10:53:49 +0800 Subject: [PATCH 087/122] ethdev: clarify null location case in xstats get MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When xstats location is null in rte_eth_xstats_get() the return value is not clearly specified. Some PMDs (eg. hns3/ipn3ke/mvpp2/axgbe) return zero while others return the required number of elements. In this patch, special parameter combinations are restricted: 1. highlight that xstats location may be null if and only if n is 0. 2. amend n parameter description to specify that if n is lower than the required number of elements, the function returns the required number of elements. 3. specify that if n is zero, the xstats must be NULL, the function returns the required number of elements (a duplicate which should help to not very attentive readers). Add sanity check for null xstats and non-zero n case on API level to make it unnecessary to care about it in drivers. Fixes: ce757f5c9a4d ("ethdev: new method to retrieve extended statistics") Cc: stable@dpdk.org Signed-off-by: Chengwen Feng Acked-by: Morten Brørup Reviewed-by: Andrew Rybchenko --- lib/ethdev/rte_ethdev.c | 4 +++- lib/ethdev/rte_ethdev.h | 6 +++++- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c index cea2f0b498..b4a331b671 100644 --- a/lib/ethdev/rte_ethdev.c +++ b/lib/ethdev/rte_ethdev.c @@ -3319,6 +3319,8 @@ rte_eth_xstats_get(uint16_t port_id, struct rte_eth_xstat *xstats, int ret; RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV); + if (xstats == NULL && n > 0) + return -EINVAL; dev = &rte_eth_devices[port_id]; nb_rxqs = RTE_MIN(dev->data->nb_rx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS); @@ -3335,7 +3337,7 @@ rte_eth_xstats_get(uint16_t port_id, struct rte_eth_xstat *xstats, * xstats struct. */ xcount = (*dev->dev_ops->xstats_get)(dev, - xstats ? xstats + count : NULL, + (n > count) ? xstats + count : NULL, (n > count) ? n - count : 0); if (xcount < 0) diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h index b8f135ba3f..082166ed42 100644 --- a/lib/ethdev/rte_ethdev.h +++ b/lib/ethdev/rte_ethdev.h @@ -3105,9 +3105,13 @@ int rte_eth_xstats_get_names(uint16_t port_id, * @param xstats * A pointer to a table of structure of type *rte_eth_xstat* * to be filled with device statistics ids and values. - * This parameter can be set to NULL if n is 0. + * This parameter can be set to NULL if and only if n is 0. * @param n * The size of the xstats array (number of elements). + * If lower than the required number of elements, the function returns + * the required number of elements. + * If equal to zero, the xstats must be NULL, the function returns the + * required number of elements. * @return * - A positive value lower or equal to n: success. The return value * is the number of entries filled in the stats table. -- 2.22.0