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Subject: Re: [HMM 12/15] mm/migrate: new memory migration helper for use with
 device memory v4
To: Jerome Glisse <jglisse@redhat.com>
CC: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
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References: <20170522165206.6284-1-jglisse@redhat.com>
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From: Evgeny Baskakov <ebaskakov@nvidia.com>
Message-ID: <57146eb3-43bc-6e8b-4c8e-0632aa8ed577@nvidia.com>
Date: Mon, 10 Jul 2017 17:17:23 -0700
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On 7/10/17 4:43 PM, Jerome Glisse wrote:

> On Mon, Jul 10, 2017 at 03:59:37PM -0700, Evgeny Baskakov wrote:
> ...
> Horrible stupid bug in the code, most likely from cut and paste. Attached
> patch should fix it. I don't know how long it took for you to trigger it.
>
> Jérôme
Thanks, this indeed fixes the problem! Yes, it took a nightly run before 
it triggered.

One a side note, should this "return NULL" be replaced with "return 
ERR_PTR(-ENOMEM)"?

struct hmm_device *hmm_device_new(void *drvdata)
{
...
     if (hmm_device->minor >= HMM_DEVICE_MAX) {
         spin_unlock(&hmm_device_lock);
         kfree(hmm_device);
->      return NULL;
     }

Thanks!

Evgeny Baskakov
NVIDIA