Re: [dpdk-dev] [PATCH 1/2] librte_ethdev: Introduce a function to release HW rings

[Lukasz Wojciechowski <l.wojciechow@partner.samsung.com>]

Hi Renata,

few minor hints inline

W dniu 03.05.2020 o 18:26, Renata Saiakhova pisze:
> Free previously allocated memzone for HW rings
>
> Signed-off-by: Renata Saiakhova <Renata.Saiakhova@ekinops.com>
> ---
>   lib/librte_ethdev/rte_ethdev.c           | 23 +++++++++++++++++++++++
>   lib/librte_ethdev/rte_ethdev_driver.h    | 14 ++++++++++++++
>   lib/librte_ethdev/rte_ethdev_version.map |  1 +
>   3 files changed, 38 insertions(+)
>
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index 72aed59a5..c6d27e1aa 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -4206,6 +4206,29 @@ rte_eth_dma_zone_reserve(const struct rte_eth_dev *dev, const char *ring_name,
>   			RTE_MEMZONE_IOVA_CONTIG, align);
>   }
>   
> +int
> +rte_eth_dma_zone_free(const struct rte_eth_dev *dev, const char *ring_name,
> +		uint16_t queue_id)
> +{
> +	char z_name[RTE_MEMZONE_NAMESIZE];
> +	const struct rte_memzone *mz;
> +	int rc = 0;
> +
> +	snprintf(z_name, sizeof(z_name), "eth_p%d_q%d_%s",
> +			dev->data->port_id, queue_id, ring_name);

probably rc=snprintf(...)

but maybe create a macro for that fancy memzone name as the same code 
appears already in rte_eth_dma_zone_reserve and keeping it in one place 
seems to be better idea to me.

> +	if (rc >= RTE_MEMZONE_NAMESIZE) {
> +		RTE_ETHDEV_LOG(ERR, "ring name too long\n");
> +		rte_errno = ENAMETOOLONG;
> +		return NULL;
It's an int returning function so instead of setting rte_errno, just:
     return -ENAMETOOLONG;
> +	}
> +
> +	mz = rte_memzone_lookup(z_name);
> +	if (mz)
> +		rc = rte_memzone_free(mz);
> +
> +	return rc;
> +}
> +
>   int
>   rte_eth_dev_create(struct rte_device *device, const char *name,
>   	size_t priv_data_size,
> diff --git a/lib/librte_ethdev/rte_ethdev_driver.h b/lib/librte_ethdev/rte_ethdev_driver.h
> index 99d4cd6cd..2769a185b 100644
> --- a/lib/librte_ethdev/rte_ethdev_driver.h
> +++ b/lib/librte_ethdev/rte_ethdev_driver.h
> @@ -180,6 +180,20 @@ rte_eth_dma_zone_reserve(const struct rte_eth_dev *eth_dev, const char *name,
>   			 uint16_t queue_id, size_t size,
>   			 unsigned align, int socket_id);
>   
> +/**
> + * Free previously allocated memzone for HW rings.
> + *
> + * @param eth_dev
> + *   The *eth_dev* pointer is the address of the *rte_eth_dev* structure
param name is dev
> + * @param name
> + *   The name of the memory zone
param name is ring_name
> + * @param queue_id
> + *   The index of the queue to add to name
> + * @param size
There is no size param, but some info about return would be probably nice:
  * @return
*   Negative errno value on error, 0 on success.


And as it's a new API function maybe it should be experimental. Should it?

> + */
> +int rte_eth_dma_zone_free(const struct rte_eth_dev *dev, const char *ring_name,
> +		 uint16_t queue_id);
> +
>   /**
>    * @internal
>    * Atomically set the link status for the specific device.
> diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map
> index 715505604..5d3c209bc 100644
> --- a/lib/librte_ethdev/rte_ethdev_version.map
> +++ b/lib/librte_ethdev/rte_ethdev_version.map
> @@ -82,6 +82,7 @@ DPDK_20.0 {
>   	rte_eth_dev_vlan_filter;
>   	rte_eth_devices;
>   	rte_eth_dma_zone_reserve;
> +	rte_eth_dma_zone_free;
>   	rte_eth_find_next;
>   	rte_eth_find_next_owned_by;
>   	rte_eth_iterator_cleanup;

Best regards

Lukasz

-- 

Lukasz Wojciechowski
Principal Software Engineer

Samsung R&D Institute Poland
Samsung Electronics
Office +48 22 377 88 25
l.wojciechow@partner.samsung.com