From: Andrew Rybchenko <arybchenko@solarflare.com>
To: Stephen Hemminger <stephen@networkplumber.org>, <dev@dpdk.org>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Subject: Re: [dpdk-dev] [RFC 01/14] ethdev: add link status read/write functions
Date: Sun, 16 Jul 2017 16:26:06 +0300 [thread overview]
Message-ID: <0ce78069-6517-aaf1-cfe9-165192a4cc5f@solarflare.com> (raw)
In-Reply-To: <20170714183027.16021-2-stephen@networkplumber.org>
On 07/14/2017 09:30 PM, Stephen Hemminger wrote:
> Many drivers are all doing copy/paste of the same code to atomicly
> update the link status. Reduce duplication, and allow for future
> changes by having common function for this.
>
> Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
> ---
> lib/librte_ether/rte_ethdev.c | 36 ++++++++++++++++++++++++++++++++++++
> lib/librte_ether/rte_ethdev.h | 28 ++++++++++++++++++++++++++++
> 2 files changed, 64 insertions(+)
>
> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
> index a1b744704f3a..7532fc6b65f0 100644
> --- a/lib/librte_ether/rte_ethdev.c
> +++ b/lib/librte_ether/rte_ethdev.c
> @@ -1332,6 +1332,42 @@ rte_eth_link_get_nowait(uint8_t port_id, struct rte_eth_link *eth_link)
> }
>
> int
> +_rte_eth_link_update(struct rte_eth_dev *dev,
> + const struct rte_eth_link *link)
> +{
> + volatile struct rte_eth_link *dev_link = &(dev->data->dev_link);
> + struct rte_eth_link old;
> +
> + RTE_BUILD_BUG_ON(sizeof(*link) != sizeof(uint64_t));
> +
> + old = *dev_link;
> +
> + /* Only reason we use cmpset rather than set is
> + * that on some architecture may use sign bit as a flag value.
May I ask to provide more details here.
> + */
> + while (rte_atomic64_cmpset((volatile uint64_t *)dev_link,
> + *(volatile uint64_t *)dev_link,
> + *(const uint64_t *)link) == 0)
Shouldn't it be:
do {
old = *dev_link;
} while (rte_atomic64_cmpset((volatile uint64_t *)dev_link,
*(uint64_t *)&old, *(const uint64_t *)link) == 0);
At least it has some sense to guarantee transition from old to new
talking below comparison into account.
> + continue;
> +
> + return (old.link_status == link->link_status) ? -1 : 0;
> +}
> +
> +void _rte_eth_link_read(struct rte_eth_dev *dev,
> + struct rte_eth_link *link)
> +{
> + const uint64_t *src = (const uint64_t *)&(dev->data->dev_link);
> + volatile uint64_t *dst = (uint64_t *)link;
> +
> + RTE_BUILD_BUG_ON(sizeof(*link) != sizeof(uint64_t));
> +
> + /* Note: this should never fail since both destination and expected
> + * values are the same and are a pointer from caller.
> + */
> + rte_atomic64_cmpset(dst, *dst, *src);
> +}
> +
> +int
> rte_eth_stats_get(uint8_t port_id, struct rte_eth_stats *stats)
> {
> struct rte_eth_dev *dev;
> diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
> index f6837278521c..974657933f23 100644
> --- a/lib/librte_ether/rte_ethdev.h
> +++ b/lib/librte_ether/rte_ethdev.h
> @@ -2219,6 +2219,34 @@ void rte_eth_link_get(uint8_t port_id, struct rte_eth_link *link);
> */
> void rte_eth_link_get_nowait(uint8_t port_id, struct rte_eth_link *link);
>
> +
> +/**
> + * @internal
> + * Atomically write the link status for the specific device.
> + * It is for use by DPDK device driver use only.
> + * User applications should not call it
> + *
> + * @param dev
> + * Pointer to struct rte_eth_dev.
> + * @param link
> + * New link status value.
> + * @return
> + * -1 if link state has changed, 0 if the same.
> + */
> +int _rte_eth_link_update(struct rte_eth_dev *dev,
> + const struct rte_eth_link *link);
> +
> +/**
> + * @internal
> + * Atomically read the link speed and status.
> + * @param dev
> + * Pointer to struct rte_eth_dev.
> + * @param link
> + * link status value.
> + */
> +void _rte_eth_link_read(struct rte_eth_dev *dev,
> + struct rte_eth_link *link);
> +
> /**
> * Retrieve the general I/O statistics of an Ethernet device.
> *
next prev parent reply other threads:[~2017-07-16 13:26 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-14 18:30 [dpdk-dev] [RFC 00/14] link status API improvement and bugfixes Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 01/14] ethdev: add link status read/write functions Stephen Hemminger
2017-07-16 13:26 ` Andrew Rybchenko [this message]
2017-07-17 15:58 ` Stephen Hemminger
2017-07-17 16:12 ` Andrew Rybchenko
2017-07-17 16:21 ` Stephen Hemminger
2017-07-17 16:31 ` Andrew Rybchenko
2017-10-11 8:32 ` Yang, Qiming
2017-10-13 15:12 ` Stephen Hemminger
2018-01-05 14:24 ` Thomas Monjalon
2018-01-05 20:15 ` Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 02/14] virtio: use eth_link_read/write (and bug fix) Stephen Hemminger
2017-07-16 12:33 ` Andrew Rybchenko
2017-07-17 16:01 ` Stephen Hemminger
2017-07-17 16:14 ` [dpdk-dev] ***Spam*** " Andrew Rybchenko
2017-07-17 16:28 ` [dpdk-dev] " Stephen Hemminger
2018-01-05 15:04 ` Thomas Monjalon
2017-07-14 18:30 ` [dpdk-dev] [RFC 03/14] bnxt: use rte_link_update Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 04/14] vmxnet3: use rte_eth_link_update Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 05/14] dpaa2: " Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 06/14] nfp: " Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 07/14] e1000: " Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 08/14] ixgbe: " Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 09/14] sfc: use new rte_eth_link helpers Stephen Hemminger
2017-07-16 13:48 ` Andrew Rybchenko
2017-07-17 16:02 ` Stephen Hemminger
2017-07-17 16:19 ` Andrew Rybchenko
2017-07-14 18:30 ` [dpdk-dev] [RFC 10/14] i40e: use rte_eth_link_update (and bug fix) Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 11/14] liquidio: use _rte_eth_link_update Stephen Hemminger
2017-07-18 10:17 ` Shijith Thotton
2017-07-14 18:30 ` [dpdk-dev] [RFC 12/14] thunderx: " Stephen Hemminger
2017-07-14 18:30 ` [dpdk-dev] [RFC 13/14] szedata: " Stephen Hemminger
2017-07-16 12:46 ` Andrew Rybchenko
2017-07-14 18:30 ` [dpdk-dev] [RFC 14/14] enic: " Stephen Hemminger
2017-07-16 13:55 ` [dpdk-dev] [RFC 00/14] link status API improvement and bugfixes Andrew Rybchenko
2018-01-05 14:29 ` Thomas Monjalon
2018-01-05 20:18 ` Stephen Hemminger
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