Re: [dpdk-dev] [PATCH V2] igb_uio: fix uevent montior issue

["Guo, Jia" <jia.guo@intel.com>]

On 3/27/2018 2:28 AM, Ferruh Yigit wrote:
> On 2/27/2018 7:20 AM, Jeff Guo wrote:
>> udev could not detect remove and add event of device when hotplug in
>> and out devices, that related with the fix about using pointer of
>> rte_uio_pci_dev as dev_id instead of uio_device for irq device handler,
>> that would result igb uio irq failure when kernel version after than 3.17.
>>
>> The root cause is that the older version of Linux kernel don't expose the
>> uio_device structure, only for the kernel version after than 3.17 use
>> uio_device. so this patch correct it by use a macro to check before handle
>> the pci interrupt.
>>
>> Fixes: 6b9ed026a870 ("igb_uio: fix build with kernel <= 3.17")
>> Signed-off-by: Jeff Guo <jia.guo@intel.com>
>> ---
>> v2->v1:
>> use macro in compat.h to replace of version check in .c file, benifit for
>> future backport and make more readable.
>> ---
>>   lib/librte_eal/linuxapp/igb_uio/compat.h  |  4 ++++
>>   lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 16 ++++++++++++++++
>>   2 files changed, 20 insertions(+)
>>
>> diff --git a/lib/librte_eal/linuxapp/igb_uio/compat.h b/lib/librte_eal/linuxapp/igb_uio/compat.h
>> index ce456d4..2c61190 100644
>> --- a/lib/librte_eal/linuxapp/igb_uio/compat.h
>> +++ b/lib/librte_eal/linuxapp/igb_uio/compat.h
>> @@ -132,3 +132,7 @@ static bool pci_check_and_mask_intx(struct pci_dev *pdev)
>>   #if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 5, 0)
>>   #define HAVE_PCI_MSI_MASK_IRQ 1
>>   #endif
>> +
>> +#if LINUX_VERSION_CODE > KERNEL_VERSION(3, 17, 0)
>> +#define HAVE_UIO_DEVICE_STRUCTURE 1
>> +#endif
>> diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>> index 4cae4dd..99018f4 100644
>> --- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>> +++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>> @@ -192,8 +192,14 @@ igbuio_pci_irqcontrol(struct uio_info *info, s32 irq_state)
>>   static irqreturn_t
>>   igbuio_pci_irqhandler(int irq, void *dev_id)
>>   {
>> +#ifndef HAVE_UIO_DEVICE_STRUCTURE
>>   	struct rte_uio_pci_dev *udev = (struct rte_uio_pci_dev *)dev_id;
>>   	struct uio_info *info = &udev->info;
>> +#else
>> +	struct uio_device *idev = (struct uio_device *)dev_id;
>> +	struct uio_info *info = idev->info;
>> +	struct rte_uio_pci_dev *udev = info->priv;
>> +#endif
>>   
>>   	/* Legacy mode need to mask in hardware */
>>   	if (udev->mode == RTE_INTR_MODE_LEGACY &&
>> @@ -279,9 +285,15 @@ igbuio_pci_enable_interrupts(struct rte_uio_pci_dev *udev)
>>   	}
>>   
>>   	if (udev->info.irq != UIO_IRQ_NONE)
>> +#ifndef HAVE_UIO_DEVICE_STRUCTURE
>>   		err = request_irq(udev->info.irq, igbuio_pci_irqhandler,
>>   				  udev->info.irq_flags, udev->info.name,
>>   				  udev);
>> +#else
>> +		err = request_irq(udev->info.irq, igbuio_pci_irqhandler,
>> +				  udev->info.irq_flags, udev->info.name,
>> +				  udev->info.uio_dev);
>> +#endif
> Hi Jeff,
>
> Can you please describe how this is solving the problem. Isn't only requirement
> for dev_id to be unique? Why it differs to pass uio_dev instead of udev pointer?

Hi, ferruh


yes, this is because the uio_device definition is not exposed in kernel 
earlier than 3.17,  you could check the history of commit 
(6b9ed026a8704b9e5ee5da7997617ef7cc82e114), igb_uio: fix build with 
kernel <= 3.17, which fix it by

use using pointer of rte_uio_pci_dev instead.

>>   	dev_info(&udev->pdev->dev, "uio device registered with irq %ld\n",
>>   		 udev->info.irq);
>>   
>> @@ -292,7 +304,11 @@ static void
>>   igbuio_pci_disable_interrupts(struct rte_uio_pci_dev *udev)
>>   {
>>   	if (udev->info.irq) {
>> +#ifndef HAVE_UIO_DEVICE_STRUCTURE
>>   		free_irq(udev->info.irq, udev);
>> +#else
>> +		free_irq(udev->info.irq, udev->info.uio_dev);
>> +#endif
>>   		udev->info.irq = 0;
>>   	}
>>   
>>