Re: [dpdk-dev] [PATCH v3 1/4] librte_ethdev: Introduce a function to release HW rings

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

On 5/15/2020 9:04 AM, Jeff Guo wrote:
> hi, renata
> 
> On 5/13/2020 9:14 PM, 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           | 28 ++++++++++++++++++++++--
>>   lib/librte_ethdev/rte_ethdev_driver.h    | 20 +++++++++++++++++
>>   lib/librte_ethdev/rte_ethdev_version.map |  1 +
>>   3 files changed, 47 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
>> index 72aed59a5..55f047e22 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 +4209,27 @@ 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);
>> +
>> +	return rc;
> 
> 
> If rc <  RTE_MEMZONE_NAMESIZE && !mz, what value should be return base 
> on the parameter description in .h?

+1,

When 'mz' not found return value will be wrong according API documentation.

> 
> Although it would not affect the other patch set, but could you please 
> clarify it?
> 
> 
>> +}
>> +
>>   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);
>> +
>>   /**
>>    * @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..139a81302 100644
>> --- a/lib/librte_ethdev/rte_ethdev_version.map
>> +++ b/lib/librte_ethdev/rte_ethdev_version.map
>> @@ -241,4 +241,5 @@ EXPERIMENTAL {
>>   	__rte_ethdev_trace_rx_burst;
>>   	__rte_ethdev_trace_tx_burst;
>>   	rte_flow_get_aged_flows;
>> +	rte_eth_dma_zone_free;
>>   };