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

[Ferruh Yigit]

On 3/27/2018 8:46 AM, Guo, Jia wrote:
> 
> 
> 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 at 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

I get this part.

The question is how this is fixing uevent monitor issue.
Isn't the last parameter of the request_irq() is "void *" that has been passed
to handler.
Why and where it differs if that pointer is "struct uio_device" or not?

> 
> 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;
>>>  	}
>>>  
>>>
>