Re: [PATCH v7 3/6] igb_uio: fix MSI-X IRQ assignment with new IRQ function

[Kevin Traynor <ktraynor@redhat.com>]

On 09/12/2017 09:16 AM, Bruce Richardson wrote:
> On Mon, Sep 11, 2017 at 06:56:39PM +0100, Ferruh Yigit wrote:
>> On 9/5/2017 1:04 PM, Markus Theil wrote:
>>> The patch which introduced the usage of pci_alloc_irq_vectors
>>> came after the patch which switched to non-threaded ISR (f0d1896fa1),
>>> but did not use non-threaded ISR, if pci_alloc_irq_vectors
>>> is used.
>>>
>>> Fixes: 99bb58f3adc7 ("igb_uio: switch to new irq function for
>>> MSI-X")
>>> Cc: nicolas.dichtel@6wind.com
>>>
>>> Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>
>>> ---
>>>  lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>>> index 93bb71d..6885e72 100644
>>> --- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>>> +++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>>> @@ -331,6 +331,7 @@ igbuio_pci_enable_interrupts(struct rte_uio_pci_dev *udev)
>>>  #else
>>>  		if (pci_alloc_irq_vectors(udev->pdev, 1, 1, PCI_IRQ_MSIX) == 1) {
>>>  			dev_dbg(&udev->pdev->dev, "using MSI-X");
>>> +			udev->info.irq_flags = IRQF_NO_THREAD;
>>
>> IRQF_NO_THREAD seems has been introduced in 2.6.39, so using this flag
>> causing build error for kernel versions < 2.6.39.
>>
>> btw, the flag is already in use, so issue is not related to this patch.
>>
>> In DPDK documentation supported Linux kernel version is >= 2.6.34 [1].
>>
>> We should either increase supported version to 2.6.39, or update igb_uio
>> code.
>>
>> I am for increasing minimum supported kernel version to 2.6.39, any
>> objection / comment?
>>
>> 2.6.39 released on May 2011
>> 2.6.34 released on May 2010
>>
> 
> Only thing I can think of here is:
> * is the necessary support for this in RHEL 6.x series

It doesn't look to be there

> * anyone still care about RHEL 6 support?
> 

Not an issue with DPDK packages as igb_uio is not included. If someone
was using RHEL6/CentOS6 and igb_uio from DPDK source then seems like it
would be an issue for them. In general, a deprecation notice would be a
good idea if the minimum kernel version is changing.

> /Bruce
>