Re: [dpdk-dev] [PATCH v2 8/8] ethdev: Decouple interrupt handling from PCI device

[Jan Blunck <jblunck@infradead.org>]

On Tue, Nov 22, 2016 at 1:57 PM, Shreyansh Jain <shreyansh.jain@nxp.com> wrote:
> On Monday 21 November 2016 10:25 PM, Jan Blunck wrote:
>>
>> The struct rte_intr_handle is an abstraction layer for different types of
>> interrupt mechanisms. It is embedded in the low-level device (e.g. PCI).
>> On allocation of a struct rte_eth_dev a reference to the intr_handle
>> should be stored for devices supporting interrupts.
>>
>> Signed-off-by: Jan Blunck <jblunck@infradead.org>
>> ---
>>  lib/librte_ether/rte_ethdev.c | 18 ++++++++++++++++--
>>  lib/librte_ether/rte_ethdev.h |  1 +
>>  2 files changed, 17 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
>> index 4288577..4ecea50 100644
>> --- a/lib/librte_ether/rte_ethdev.c
>> +++ b/lib/librte_ether/rte_ethdev.c
>> @@ -258,6 +258,7 @@ rte_eth_dev_pci_probe(struct rte_pci_driver *pci_drv,
>>                         rte_panic("Cannot allocate memzone for private
>> port data\n");
>>         }
>>         eth_dev->pci_dev = pci_dev;
>> +       eth_dev->intr_handle = &pci_dev->intr_handle;
>>         eth_dev->driver = eth_drv;
>>         eth_dev->data->rx_mbuf_alloc_failed = 0;
>>
>> @@ -2543,7 +2544,13 @@ rte_eth_dev_rx_intr_ctl(uint8_t port_id, int epfd,
>> int op, void *data)
>>         RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>>
>>         dev = &rte_eth_devices[port_id];
>> -       intr_handle = &dev->pci_dev->intr_handle;
>> +
>> +       if (!dev->intr_handle) {
>> +               RTE_PMD_DEBUG_TRACE("RX Intr handle unset\n");
>> +               return -ENOTSUP;
>> +       }
>> +
>> +       intr_handle = dev->intr_handle;
>>         if (!intr_handle->intr_vec) {
>>                 RTE_PMD_DEBUG_TRACE("RX Intr vector unset\n");
>>                 return -EPERM;
>> @@ -2603,7 +2610,12 @@ rte_eth_dev_rx_intr_ctl_q(uint8_t port_id, uint16_t
>> queue_id,
>>                 return -EINVAL;
>>         }
>>
>> -       intr_handle = &dev->pci_dev->intr_handle;
>> +       if (!dev->intr_handle) {
>> +               RTE_PMD_DEBUG_TRACE("RX Intr handle unset\n");
>> +               return -ENOTSUP;
>> +       }
>> +
>> +       intr_handle = dev->intr_handle;
>>         if (!intr_handle->intr_vec) {
>>                 RTE_PMD_DEBUG_TRACE("RX Intr vector unset\n");
>>                 return -EPERM;
>> @@ -3205,6 +3217,8 @@ rte_eth_copy_pci_info(struct rte_eth_dev *eth_dev,
>> struct rte_pci_device *pci_de
>>                 return;
>>         }
>>
>> +       eth_dev->intr_handle = &pci_dev->intr_handle;
>> +
>>         eth_dev->data->dev_flags = 0;
>>         if (pci_dev->driver->drv_flags & RTE_PCI_DRV_INTR_LSC)
>>                 eth_dev->data->dev_flags |= RTE_ETH_DEV_INTR_LSC;
>> diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
>> index 3adbb2b..f1f656a 100644
>> --- a/lib/librte_ether/rte_ethdev.h
>> +++ b/lib/librte_ether/rte_ethdev.h
>> @@ -1629,6 +1629,7 @@ struct rte_eth_dev {
>>         const struct eth_driver *driver;/**< Driver for this device */
>>         const struct eth_dev_ops *dev_ops; /**< Functions exported by PMD
>> */
>>         struct rte_pci_device *pci_dev; /**< PCI info. supplied by probing
>> */
>> +       struct rte_intr_handle *intr_handle; /**< Device interrupt handle
>> */
>>         /** User application callbacks for NIC interrupts */
>>         struct rte_eth_dev_cb_list link_intr_cbs;
>>         /**
>>
>
> Is there another patch which replaces all uses of
> eth_dev->pci_dev->intr_handle with that of eth_dev->intr_handle?
>
> Now that eth_dev has a reference which is initialized as early as probe, we
> should use that rather than pci_dev->intr_handle for PCI PMDs.
>

I've added this indirection because it is required for the ethdev
function. The drivers shouldn't use the indirection through ethdev to
access the intr_handle because they do have direct access to the
device.


> OR maybe, ETH_DEV_INTR_HANDLE() like macro which you have introduced in
> i40e_ethdev.h.
>
> -
> Shreyansh