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Date:   Fri, 6 Jul 2018 00:46:21 +0200 (CEST)
From:   Thomas Gleixner <tglx@linutronix.de>
To:     Ingo Molnar <mingo@kernel.org>
cc:     KY Srinivasan <kys@microsoft.com>,
        "x86@kernel.org" <x86@kernel.org>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
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        "jasowang@redhat.com" <jasowang@redhat.com>,
        "hpa@zytor.com" <hpa@zytor.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "Michael Kelley (EOSG)" <Michael.H.Kelley@microsoft.com>,
        "vkuznets@redhat.com" <vkuznets@redhat.com>
Subject: Re: [PATCH 1/1] X86/Hyper-V:: Fix the circular dependency in IPI
 enlightenment.
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References: <20180703230155.15160-1-kys@linuxonhyperv.com> <20180704161039.GA23658@gmail.com> <MW2PR2101MB111396005B0F5572C92B4CD7A0400@MW2PR2101MB1113.namprd21.prod.outlook.com> <20180705153820.GA26768@gmail.com> <MW2PR2101MB1113ABC82EC62E2C8DBA2400A0400@MW2PR2101MB1113.namprd21.prod.outlook.com>
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On Fri, 6 Jul 2018, Ingo Molnar wrote:
> * KY Srinivasan <kys@microsoft.com> wrote:
> > I am confused. The label ipi_mask_done was introduced in this patch
> > (the patch under question fixes a circular dependency in this patch):
> > 
> > commit 68bb7bfb7985df2bd15c2dc975cb68b7a901488a
> > Author: K. Y. Srinivasan <kys@microsoft.com>
> > Date:   Wed May 16 14:53:31 2018 -0700
> > 
> >     X86/Hyper-V: Enable IPI enlightenments
> > 
> >     Hyper-V supports hypercalls to implement IPI; use them.
> > 
> >     Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
> >     Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> >     Reviewed-by: Michael Kelley <mikelley@microsoft.com>
> > 
> > This patch was committed by Thomas some weeks ago and is in linux-next.
> > This patch is also in 4.18-rc3.
> 
> And then that name was changed to a different label in:
> 
>   4bd06060762b: x86/hyper-v: Use cheaper HVCALL_SEND_IPI hypercall when possible
> 
> So maybe you were testing on an older kernel. Could you try the latest -tip?

The problem is that the wreckage is in Linus tree and needs to be fixed
there, i.e. via x86/urgent.

Now we have the new bits queued in x86/hyperv already which collide. So we
need to merge x86/urgent into x86/hyperv after applying the fix and mop up
the merge wreckage in x86/hyperv.

I'll have a look tomorrow morning unless you beat me to it.

Thanks,

	tglx