Re: [dpdk-dev] [PATCH v4 1/4] librte_ethdev: Introduce a function to release HW rings

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 6/22/2020 10:54 AM, Renata Saiakhova wrote:
> Free previously allocated memzone for HW rings
> 
> Signed-off-by: Renata Saiakhova <Renata.Saiakhova@ekinops.com>
> ---
>  lib/librte_ethdev/rte_ethdev.c           | 30 ++++++++++++++++++++++--
>  lib/librte_ethdev/rte_ethdev_driver.h    | 20 ++++++++++++++++
>  lib/librte_ethdev/rte_ethdev_version.map |  1 +
>  3 files changed, 49 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
> index 72aed59a5..ec1da2006 100644
> --- a/lib/librte_ethdev/rte_ethdev.c
> +++ b/lib/librte_ethdev/rte_ethdev.c
> @@ -4181,6 +4181,10 @@ rte_eth_dev_rx_intr_ctl_q_get_fd(uint16_t port_id, uint16_t queue_id)
>  	return fd;
>  }
>  
> +#define ETH_DMA_MZONE_NAME(_name, _port_id, _queue_id, _ring_name) \
> +	snprintf(_name, sizeof(_name), "eth_p%d_q%d_%s", \
> +			_port_id, _queue_id, _ring_name)
> +
>  const struct rte_memzone *
>  rte_eth_dma_zone_reserve(const struct rte_eth_dev *dev, const char *ring_name,
>  			 uint16_t queue_id, size_t size, unsigned align,
> @@ -4190,8 +4194,7 @@ rte_eth_dma_zone_reserve(const struct rte_eth_dev *dev, const char *ring_name,
>  	const struct rte_memzone *mz;
>  	int rc;
>  
> -	rc = snprintf(z_name, sizeof(z_name), "eth_p%d_q%d_%s",
> -		      dev->data->port_id, queue_id, ring_name);
> +	rc = ETH_DMA_MZONE_NAME(z_name, dev->data->port_id, queue_id, ring_name);
>  	if (rc >= RTE_MEMZONE_NAMESIZE) {
>  		RTE_ETHDEV_LOG(ERR, "ring name too long\n");
>  		rte_errno = ENAMETOOLONG;
> @@ -4206,6 +4209,29 @@ 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;
> +
> +	rc = ETH_DMA_MZONE_NAME(z_name, dev->data->port_id, queue_id, ring_name);
> +	if (rc >= RTE_MEMZONE_NAMESIZE) {
> +		RTE_ETHDEV_LOG(ERR, "ring name too long\n");
> +		return -ENAMETOOLONG;
> +	}
> +
> +	mz = rte_memzone_lookup(z_name);
> +	if (mz)
> +		rc = rte_memzone_free(mz);
> +	else
> +		rc = -EINVAL;
> +
> +	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..462e765d1 100644
> --- a/lib/librte_ethdev/rte_ethdev_driver.h
> +++ b/lib/librte_ethdev/rte_ethdev_driver.h
> @@ -180,6 +180,26 @@ 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);
>  
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice.
> + *
> + * 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
> + *   The name of the memory zone
> + * @param queue_id
> + *   The index of the queue to add to name
> + * @return
> + *   Negative errno value on error, 0 on success.
> + */
> +__rte_experimental
> +int
> +rte_eth_dma_zone_free(const struct rte_eth_dev *dev, const char *ring_name,
> +		 uint16_t queue_id);
> +

Hi Renata,

This API is not for applications, only for drivers, right?
We recently (last release ?) introduced 'internal' (__rte_internal) attribute,
we can use '__rte_internal' instead of '__rte_experimental' if the API is not
for applications. This requires adding 'INTERNAL' block in .map file (sample
'lib/librte_eal/rte_eal_version.map')


Also there are a few contribution conventions related issues which can be fixed
while merging but please check them if you will be doing new version:
 subsystem is only libname without prefix: 'ethdev'
 Commit title description starts with lowercase: 'introduce'.
sample => "ethdev: add function to release HW rings"


Thanks,
ferruh