Re: [PATCH V4 1/5] drivers/bus: restore driver assignment at front of probing

["lihuisong (C)" <lihuisong@huawei.com>]

在 2023/1/11 20:51, Ferruh Yigit 写道:
> On 12/6/2022 9:26 AM, Huisong Li wrote:
>> The driver assignment was moved back at the end of the device probing
>> because there is no something to use rte_driver during the phase of
>> probing. See commit 391797f04208 ("drivers/bus: move driver assignment
>> to end of probing")
>>
>> However, it is necessary for probing callback to reference rte_driver
>> before probing. For example, probing callback may call some APIs which
>> access the rte_pci_driver::driver by the device::driver pointer to get
>> driver information. In this case, a segment fault will occur in probing
>> callback if there is not this assignment.
>>
> Probing callback gets driver as parameter, so callback function can
> access it via 'drv->driver', is there a specific usecase that
> 'dev->device->driver' needs to be accessed explicitly?
>
> I assume this is related to coming patches that setting up device in
> testpmd event callback, but can you please clarify exact need.
For example, rte_eth_dev_info_get is called in this event callback to get
driver name.
>
>> Further, some comments in code need to be updated if we do that. The
>> driver pointer in rte_device is set before probing and needs to be reset
>> if probing failed. And rte_dev_is_probed can not be called inside probing.
>>
>> Fixes: 391797f04208 ("drivers/bus: move driver assignment to end of probing")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Huisong Li <lihuisong@huawei.com>
>> ---
>>   drivers/bus/auxiliary/auxiliary_common.c |  9 +++++++--
>>   drivers/bus/dpaa/dpaa_bus.c              |  9 +++++++--
>>   drivers/bus/fslmc/fslmc_bus.c            |  8 +++++++-
>>   drivers/bus/ifpga/ifpga_bus.c            | 12 +++++++++---
>>   drivers/bus/pci/pci_common.c             |  9 +++++++--
>>   drivers/bus/vdev/vdev.c                  | 10 ++++++++--
>>   drivers/bus/vmbus/vmbus_common.c         |  9 +++++++--
>>   7 files changed, 52 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/bus/auxiliary/auxiliary_common.c b/drivers/bus/auxiliary/auxiliary_common.c
>> index ff1369353a..13cb3fe0f8 100644
>> --- a/drivers/bus/auxiliary/auxiliary_common.c
>> +++ b/drivers/bus/auxiliary/auxiliary_common.c
>> @@ -132,16 +132,21 @@ rte_auxiliary_probe_one_driver(struct rte_auxiliary_driver *drv,
>>   	}
>>   
>>   	dev->driver = drv;
>> +	/*
>> +	 * Reference rte_driver before probing so as to this pointer can
>> +	 * be used to get driver information in case of segment fault in
>> +	 * probing callback.
>> +	 */
>> +	dev->device.driver = &drv->driver;
>>   
>>   	AUXILIARY_LOG(INFO, "Probe auxiliary driver: %s device: %s (NUMA node %i)",
>>   		      drv->driver.name, dev->name, dev->device.numa_node);
>>   	ret = drv->probe(drv, dev);
>>   	if (ret != 0) {
>>   		dev->driver = NULL;
>> +		dev->device.driver = NULL;
>>   		rte_intr_instance_free(dev->intr_handle);
>>   		dev->intr_handle = NULL;
>> -	} else {
>> -		dev->device.driver = &drv->driver;
>>   	}
>>   
>>   	return ret;
>> diff --git a/drivers/bus/dpaa/dpaa_bus.c b/drivers/bus/dpaa/dpaa_bus.c
>> index e57159f5d8..f1b817e58c 100644
>> --- a/drivers/bus/dpaa/dpaa_bus.c
>> +++ b/drivers/bus/dpaa/dpaa_bus.c
>> @@ -693,17 +693,22 @@ rte_dpaa_bus_probe(void)
>>   			    (dev->device.devargs &&
>>   			     dev->device.devargs->policy == RTE_DEV_BLOCKED))
>>   				continue;
>> -
>> +			/*
>> +			 * Reference rte_driver before probing so as to this
>> +			 * pointer can be used to get driver information in case
>> +			 * of segment fault in probing callback.
>> +			 */
>> +			dev->device.driver = &drv->driver;
>>   			if (probe_all ||
>>   			    (dev->device.devargs &&
>>   			     dev->device.devargs->policy == RTE_DEV_ALLOWED)) {
>>   				ret = drv->probe(drv, dev);
>>   				if (ret) {
>> +					dev->device.driver = NULL;
>>   					DPAA_BUS_ERR("unable to probe:%s",
>>   						     dev->name);
>>   				} else {
>>   					dev->driver = drv;
>> -					dev->device.driver = &drv->driver;
>>   				}
>>   			}
>>   			break;
>> diff --git a/drivers/bus/fslmc/fslmc_bus.c b/drivers/bus/fslmc/fslmc_bus.c
>> index 57bfb5111a..4bc0c6d3d4 100644
>> --- a/drivers/bus/fslmc/fslmc_bus.c
>> +++ b/drivers/bus/fslmc/fslmc_bus.c
>> @@ -471,15 +471,21 @@ rte_fslmc_probe(void)
>>   				continue;
>>   			}
>>   
>> +			/*
>> +			 * Reference rte_driver before probing so as to this
>> +			 * pointer can be used to get driver information in case
>> +			 * of segment fault in probing callback.
>> +			 */
>> +			dev->device.driver = &drv->driver;
>>   			if (probe_all ||
>>   			   (dev->device.devargs &&
>>   			    dev->device.devargs->policy == RTE_DEV_ALLOWED)) {
>>   				ret = drv->probe(drv, dev);
>>   				if (ret) {
>> +					dev->device.driver = NULL;
>>   					DPAA2_BUS_ERR("Unable to probe");
>>   				} else {
>>   					dev->driver = drv;
>> -					dev->device.driver = &drv->driver;
>>   				}
>>   			}
>>   			break;
>> diff --git a/drivers/bus/ifpga/ifpga_bus.c b/drivers/bus/ifpga/ifpga_bus.c
>> index bb943b58b5..5f23446f41 100644
>> --- a/drivers/bus/ifpga/ifpga_bus.c
>> +++ b/drivers/bus/ifpga/ifpga_bus.c
>> @@ -293,13 +293,19 @@ ifpga_probe_one_driver(struct rte_afu_driver *drv,
>>   
>>   	/* reference driver structure */
>>   	afu_dev->driver = drv;
>> +	/*
>> +	 * Reference rte_driver before probing so as to this pointer can
>> +	 * be used to get driver information in case of segment fault in
>> +	 * probing callback.
>> +	 */
>> +	afu_dev->device.driver = &drv->driver;
>>   
>>   	/* call the driver probe() function */
>>   	ret = drv->probe(afu_dev);
>> -	if (ret)
>> +	if (ret) {
>>   		afu_dev->driver = NULL;
>> -	else
>> -		afu_dev->device.driver = &drv->driver;
>> +		afu_dev->device.driver = NULL;
>> +	}
>>   
>>   	return ret;
>>   }
>> diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
>> index bc3a7f39fe..efaa1792e9 100644
>> --- a/drivers/bus/pci/pci_common.c
>> +++ b/drivers/bus/pci/pci_common.c
>> @@ -302,6 +302,12 @@ rte_pci_probe_one_driver(struct rte_pci_driver *dr,
>>   				return ret;
>>   			}
>>   		}
>> +		/*
>> +		 * Reference rte_driver before probing so as to this pointer can
>> +		 * be used to get driver information in case of segment fault in
>> +		 * probing callback.
>> +		 */
>> +		dev->device.driver = &dr->driver;
>>   	}
>>   
>>   	RTE_LOG(INFO, EAL, "Probe PCI driver: %s (%x:%x) device: "PCI_PRI_FMT" (socket %i)\n",
>> @@ -314,6 +320,7 @@ rte_pci_probe_one_driver(struct rte_pci_driver *dr,
>>   		return ret; /* no rollback if already succeeded earlier */
>>   	if (ret) {
>>   		dev->driver = NULL;
>> +		dev->device.driver = NULL;
>>   		if ((dr->drv_flags & RTE_PCI_DRV_NEED_MAPPING) &&
>>   			/* Don't unmap if device is unsupported and
>>   			 * driver needs mapped resources.
>> @@ -325,8 +332,6 @@ rte_pci_probe_one_driver(struct rte_pci_driver *dr,
>>   		dev->vfio_req_intr_handle = NULL;
>>   		rte_intr_instance_free(dev->intr_handle);
>>   		dev->intr_handle = NULL;
>> -	} else {
>> -		dev->device.driver = &dr->driver;
>>   	}
>>   
>>   	return ret;
>> diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
>> index 41bc07dde7..2e3f0f2e12 100644
>> --- a/drivers/bus/vdev/vdev.c
>> +++ b/drivers/bus/vdev/vdev.c
>> @@ -207,9 +207,15 @@ vdev_probe_all_drivers(struct rte_vdev_device *dev)
>>   		return -1;
>>   	}
>>   
>> +	/*
>> +	 * Reference rte_driver before probing so as to this pointer can
>> +	 * be used to get driver information in case of segment fault in
>> +	 * probing callback.
>> +	 */
>> +	dev->device.driver = &driver->driver;
>>   	ret = driver->probe(dev);
>> -	if (ret == 0)
>> -		dev->device.driver = &driver->driver;
>> +	if (ret != 0)
>> +		dev->device.driver = NULL;
>>   	return ret;
>>   }
>>   
>> diff --git a/drivers/bus/vmbus/vmbus_common.c b/drivers/bus/vmbus/vmbus_common.c
>> index 8d32d66504..feb1651984 100644
>> --- a/drivers/bus/vmbus/vmbus_common.c
>> +++ b/drivers/bus/vmbus/vmbus_common.c
>> @@ -110,6 +110,12 @@ vmbus_probe_one_driver(struct rte_vmbus_driver *dr,
>>   
>>   	/* reference driver structure */
>>   	dev->driver = dr;
>> +	/*
>> +	 * Reference rte_driver before probing so as to this pointer can
>> +	 * be used to get driver information in case of segment fault in
>> +	 * probing callback.
>> +	 */
>> +	dev->device.driver = &dr->driver;
>>   
>>   	if (dev->device.numa_node < 0 && rte_socket_count() > 1)
>>   		VMBUS_LOG(INFO, "Device %s is not NUMA-aware", guid);
>> @@ -119,9 +125,8 @@ vmbus_probe_one_driver(struct rte_vmbus_driver *dr,
>>   	ret = dr->probe(dr, dev);
>>   	if (ret) {
>>   		dev->driver = NULL;
>> +		dev->device.driver = NULL;
>>   		rte_vmbus_unmap_device(dev);
>> -	} else {
>> -		dev->device.driver = &dr->driver;
>>   	}
>>   
>>   	return ret;
> .