Re: [PATCH] rdma_rxe: Ensure rdma_rxe module init occurs at correct time

["Stephen Bates" <sbates-pv7U853sEMVWk0Htik3J/w@public.gmane.org>]

On Fri, September 16, 2016 1:06 pm, Doug Ledford wrote:
> On 9/15/2016 5:45 PM, Stephen Bates wrote:
>
>> When the Soft-RoCE module is built into the kernel there is a
>> initialization issue when CONFIG_IPV6 is selected. Use late_initcall to
>> ensure the rxe module is loaded later. This fix is based on one proposed
>> by Logan Gunthorpe on a much older code base [1].
>
> Your commit message doesn't make sense.  You start by saying that
> soft-RoCE is compiled in, then say "the rxe module is loaded later". Well,
> which is it?  I'm not sure exactly the problem you are fixing. However, I
> know that the series Leon posted for the rxe driver included a fix
> specifically for IPv6 tunnel creation issues that result in an oops.  I
> suspect that patch might solve your problem.  So, I'm going to drop this
> patch.  Once you get a chance to test with the other patch applied, if
> your problem still exists, then please repost this patch with a clearer
> commit message and we can add this as well.

Doug

Yes on reflection the commit message associated with this patch was not as
clear as it could have been. Apologies. I will be more explicit on the v1.
To answer your questions:

1. This patch should be applied on top of the three patches that came from
Leon [1]. I will make that clear in v1.

2. My patch applies to the case where rmda_rxe is built-in and not when it
is a module. Currently the module_init is called before IPv6 is setup and
that results in a load failure of rxe.

3. When rdma_rxe is built as a module the problem is not observed because
the rdma_rxe module is not probed until the system is up and running.

4. The change from module_init to late_initcall means that IPv6 has had
enough time to come up befoe the rdma_rxe init is executed.

I hope that clarifies things. I will get a v1 out shortly with an improved
commit log.

[1] http://marc.info/?l=linux-rdma&m=147307739626544&w=2

Cheers

Stephen Bates

>
>> [1] https://github.com/sbates130272/qemu-minimal/blob/rdma/patches/\
>> 0001-Changes-needed-to-use-rxe-compiled-into-the-kernel.patch
>>
>>
>> Signed-off-by: Stephen Bates <sbates-pv7U853sEMVWk0Htik3J/w@public.gmane.org>
>> ---
>> drivers/infiniband/sw/rxe/rxe.c | 2 +- 1 file changed, 1 insertion(+), 1
>> deletion(-)
>>
>> diff --git a/drivers/infiniband/sw/rxe/rxe.c
>> b/drivers/infiniband/sw/rxe/rxe.c index 08e09d9..97bc74a 100644 ---
>> a/drivers/infiniband/sw/rxe/rxe.c +++ b/drivers/infiniband/sw/rxe/rxe.c
>> @@ -392,5 +392,5 @@ static void __exit rxe_module_exit(void)
>> pr_info("rxe: unloaded\n");
>> }
>>
>>
>> -module_init(rxe_module_init);
>> +late_initcall(rxe_module_init);
>> module_exit(rxe_module_exit);
>>
>
>
> --
> Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> GPG Key ID: 0E572FDD
>
>
>

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