Re: [PATCH v8 06/14] eal, ethdev: Add a function and function pointers to close ether device

[Tetsuya Mukawa <mukawa-AlSX/UN32fvPDbFq/vQRIQ@public.gmane.org>]

On 2015/02/17 9:56, Thomas Monjalon wrote:
> 2015-02-16 13:14, Tetsuya Mukawa:
>> The patch adds function pointer to rte_pci_driver and eth_driver
>> structure. These function pointers are used when ports are detached.
>> Also, the patch adds rte_eth_dev_uninit(). So far, it's not called
>> by anywhere, but it will be called when port hotplug function is
>> implemented.
>>
>> v6:
>> - Fix rte_eth_dev_uninit() to handle a return value of uninit
>>   function of PMD.
>> v4:
>> - Add parameter checking.
>> - Change function names.
>>
>> Signed-off-by: Tetsuya Mukawa <mukawa-AlSX/UN32fvPDbFq/vQRIQ@public.gmane.org>
>> ---
>>  lib/librte_eal/common/include/rte_pci.h |  7 +++++
>>  lib/librte_ether/rte_ethdev.c           | 47 +++++++++++++++++++++++++++++++++
>>  lib/librte_ether/rte_ethdev.h           | 24 +++++++++++++++++
>>  3 files changed, 78 insertions(+)
>>
>> diff --git a/lib/librte_eal/common/include/rte_pci.h b/lib/librte_eal/common/include/rte_pci.h
>> index 4814cd7..87ca4cf 100644
>> --- a/lib/librte_eal/common/include/rte_pci.h
>> +++ b/lib/librte_eal/common/include/rte_pci.h
>> @@ -189,12 +189,19 @@ struct rte_pci_driver;
>>  typedef int (pci_devinit_t)(struct rte_pci_driver *, struct rte_pci_device *);
>>  
>>  /**
>> + * Uninitialisation function for the driver called during hotplugging.
>> + */
>> +typedef int (pci_devuninit_t)(
>> +		struct rte_pci_driver *, struct rte_pci_device *);
>> +
>> +/**
>>   * A structure describing a PCI driver.
>>   */
>>  struct rte_pci_driver {
>>  	TAILQ_ENTRY(rte_pci_driver) next;       /**< Next in list. */
>>  	const char *name;                       /**< Driver name. */
>>  	pci_devinit_t *devinit;                 /**< Device init. function. */
>> +	pci_devuninit_t *devuninit;             /**< Device uninit function. */
>>  	struct rte_pci_id *id_table;            /**< ID table, NULL terminated. */
>>  	uint32_t drv_flags;                     /**< Flags contolling handling of device. */
>>  };
>> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
>> index 2463d18..58d8072 100644
>> --- a/lib/librte_ether/rte_ethdev.c
>> +++ b/lib/librte_ether/rte_ethdev.c
>> @@ -326,6 +326,52 @@ rte_eth_dev_init(struct rte_pci_driver *pci_drv,
>>  	return diag;
>>  }
>>  
>> +static int
>> +rte_eth_dev_uninit(struct rte_pci_driver *pci_drv,
>> +		 struct rte_pci_device *pci_dev)
> There's something strange here: this is an uninit of an ethdev but the parameter
> is a pci_dev.

rte_eth_dev_init and rte_eth_dev_uninit are called by PCI layer.
I guess PCI layer cannot handle eth device or eth driver directly.

I guess receiving pci dev in eth layer may be fair.
But as you said, pci_drv can be removed.
 
> The driver parameter shouldn't be needed.

I will change the function like below.

static int
rte_eth_dev_uninit(struct rte_pci_device *pci_dev)


>> +{
>> +	struct eth_driver *eth_drv;
>> +	struct rte_eth_dev *eth_dev;
>> +	char ethdev_name[RTE_ETH_NAME_MAX_LEN];
>> +	int ret;
>> +
>> +	if ((pci_drv == NULL) || (pci_dev == NULL))
>> +		return -EINVAL;
>> +
>> +	/* Create unique Ethernet device name using PCI address */
>> +	snprintf(ethdev_name, RTE_ETH_NAME_MAX_LEN, "%d:%d.%d",
>> +			pci_dev->addr.bus, pci_dev->addr.devid,
>> +			pci_dev->addr.function);
> You should call a function common to init and uninit to generate
> the same unique name.

Sure, I will.

>> +
>> +	eth_dev = rte_eth_dev_allocated(ethdev_name);
>> +	if (eth_dev == NULL)
>> +		return -ENODEV;
>> +
>> +	eth_drv = (struct eth_driver *)pci_drv;
>> +
>> +	/* Invoke PMD device uninit function */
>> +	if (*eth_drv->eth_dev_uninit) {
>> +		ret = (*eth_drv->eth_dev_uninit)(eth_drv, eth_dev);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>> +	/* free ether device */
>> +	rte_eth_dev_free(eth_dev);
>> +
>> +	/* init user callbacks */
>> +	TAILQ_INIT(&(eth_dev->callbacks));
> Please comment more why you are resetting callbacks.
> An init in an uninit function seems weird ;)

I agree. This code can be removed.
(Actually callbacks will be initialized when device is initialized.)

>> +
>> +	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
>> +		rte_free(eth_dev->data->dev_private);
>> +
>> +	eth_dev->pci_dev = NULL;
>> +	eth_dev->driver = NULL;
>> +	eth_dev->data = NULL;
>> +
>> +	return 0;
>> +}
>> +
>>  /**
>>   * Register an Ethernet [Poll Mode] driver.
>>   *
>> @@ -344,6 +390,7 @@ void
>>  rte_eth_driver_register(struct eth_driver *eth_drv)
>>  {
>>  	eth_drv->pci_drv.devinit = rte_eth_dev_init;
>> +	eth_drv->pci_drv.devuninit = rte_eth_dev_uninit;
>>  	rte_eal_pci_register(&eth_drv->pci_drv);
>>  }
>>  
>> diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
>> index fbe7ac1..91d9e86 100644
>> --- a/lib/librte_ether/rte_ethdev.h
>> +++ b/lib/librte_ether/rte_ethdev.h
>> @@ -1678,6 +1678,27 @@ typedef int (*eth_dev_init_t)(struct eth_driver  *eth_drv,
>>  
>>  /**
>>   * @internal
>> + * Finalization function of an Ethernet driver invoked for each matching
>> + * Ethernet PCI device detected during the PCI closing phase.
>> + *
>> + * @param eth_drv
>> + *   The pointer to the [matching] Ethernet driver structure supplied by
>> + *   the PMD when it registered itself.
>> + * @param eth_dev
>> + *   The *eth_dev* pointer is the address of the *rte_eth_dev* structure
>> + *   associated with the matching device and which have been [automatically]
>> + *   allocated in the *rte_eth_devices* array.
>> + * @return
>> + *   - 0: Success, the device is properly finalized by the driver.
>> + *        In particular, the driver MUST free the *dev_ops* pointer
>> + *        of the *eth_dev* structure.
>> + *   - <0: Error code of the device initialization failure.
>> + */
>> +typedef int (*eth_dev_uninit_t)(struct eth_driver  *eth_drv,
>> +				  struct rte_eth_dev *eth_dev);
>> +
>> +/**
>> + * @internal
>>   * The structure associated with a PMD Ethernet driver.
>>   *
>>   * Each Ethernet driver acts as a PCI driver and is represented by a generic
>> @@ -1687,11 +1708,14 @@ typedef int (*eth_dev_init_t)(struct eth_driver  *eth_drv,
>>   *
>>   * - The *eth_dev_init* function invoked for each matching PCI device.
>>   *
>> + * - The *eth_dev_uninit* function invoked for each matching PCI device.
>> + *
>>   * - The size of the private data to allocate for each matching device.
>>   */
>>  struct eth_driver {
>>  	struct rte_pci_driver pci_drv;    /**< The PMD is also a PCI driver. */
>>  	eth_dev_init_t eth_dev_init;      /**< Device init function. */
>> +	eth_dev_uninit_t eth_dev_uninit;  /**< Device uninit function. */
>>  	unsigned int dev_private_size;    /**< Size of device private data. */
>>  };
>>  
>>
>